I've been helping a local club member get his 35-year-project '26 RPU sorted and on the road at last.
Yesterday was a milestone day as the mighty T sputtered into life for the first time in decades! However, sputtering was the theme of the day as only the rear cylinders were firing.
I'm at a loss to explain or correct this, and would appreciate any help and all suggestions from the Forum Community...
- Engine has been rebuilt with new babbitt, valves, pistons etc. during the past few years. I know none of the details.
- Compression (the thumb test) is good on all four cylinders.
- No appreciable backfiring through carburetor during starting or running.
- Four new coils purchased from local vendor. These may or may not have been set up correctly, but swapping coils from the back to front cylinders changes nothing — only cylinders 3 & 4 will fire.
- Four new plugs that look to be gapped about right. Swapping back to front changes nothing. Rear plugs are sooty, front ones are whistle-clean.
- All wiring is new and was triple-checked for correct colours to correct terminals. Pulling the plugs and hand-cranking gives a strong spark at the appropriate plugs 1-2-4-3 just after TDC.
- Timer is a new Anderson, all looks good inside and the flapper is not out 180°.
- Coilbox rebuilt, no apparent problems (plus, all plugs fire strong and when they should).
- Timing gear is likely not out 180°, checked by thumbing for compression on #2 and having that plug fire just past TDC.
- Carb is NH, supposedly rebuilt and I suspect has issues, as the engine runs only at a narrow range of throttle position and mixture setting. Carb needs work but we want to get the front cylinders sorted first.
- We pulled the manifolds and the deluxe 3-in-1 gaskets with integral metal rings looked to be making good contact. Mating surface on block is free of protrusions or significant pits. Upon reassembly, we squirted WD-40 around the front intake branch outlet to check for vacuum leaks, found nothing.
- Ran a wire through the front branch of the intake manifold, found no obvious obstruction.
- Both front plugs are leaking a bit of compression (bubbling) past the threads. Number 2 accumulates a puddle of unburnt fuel around the plug base whilst the engine is running.
- Have not had the side cover off yet to check valve clearances etc. That's next on the list, although compression is good and there is no appreciable backfiring.
- One time it seemed #2 fired for a few seconds but it cut out and never came back.
With good compression, fuel getting to the front cylinders (#2 at least), and the timing approximately right the dang thing should at least fire the front two! But no, and that makes us think electrical. But that seems unlikely with a strong spark occurring just after TDC,
Is that firing order correct? Timer wiring ect ? If you have compression and spark and that spark is firing correctly it has to be in the fuel system.
When you replaced the timing cover did you use a centering tool? if your timer is off center It could do that.
Your compression -via your thumb- feels "good" and your plugs "look to be gapped about right".
Get a compression gauge to compare the cylinders and a set of feelers to gap the plugs exact.
You may have a leak between 1-2 through the head gasket
I would try removing the plugs and with them out and the wires connected laid on the head and the switch on batt. turn the engine over with the hand crank and make sure each plug is firing. You can check the rough timing by looking in #1 plug hole and seeing both valves closed and the piston up and #1coil firing.
Make sure your coils are all properly seated in the coil box. Perhaps they are not making tight contact.
Thanks all for your comments.
Charlie - firing order is correct 1-2-4-3, wiring appears correct.
Cheshire - no tool, no check, however, upon hand cranking on battery, each cylinder fires a little past TDC (assumed from crank-handle position).
Bob - Agree totally with checking compression and gaps with proper tools, and would have yesterday had they been available (and will Thursday).
Bob - done, except for the looking in #1 hole.
Denny - checked that too, plus, all plugs fire when out of the head (and spark to ground when the engine is running)
— — — — — — —
So, thinking about Dale's suggestion re a #1-#2 head gasket gap... I would expect lower compression and some backfiring to result (neither is obvious) but I would also think that since #1 would be on compression as #2 is on intake, a gasket gap would permit the #1 piston to push air/fuel into #2, perhaps explaining why raw fuel accumulates around the #2 plug and not the #1. Maybe.
How about a in the dark test to see if fire is going where it is supposed to? Bud.
My Anderson timer fired on two because the spring came loose. Just maybe?
Do you have a vacuum leak at the intake manifold at the 1, 2 cylinders?
You're kind of stabbing in the dark until you put a quantitative number on the compression.
Yeah get a gauge on it because if you're 100% sure about everything you mention it might be a head gasket between cyls. #2 blowing raw fuel thru the plug threads might be an indication of that OR it's not actually firing when it should.
My first reaction is a mud dauber's nest or other obstruction in the intake manifold.
Worth a look!
Oops! Sorry! I see you checked that already.
Here's a wild thought:
If there's fuel getting into the cylinder, and that is shown by the fact there's unburnt fuel bubbling past the plug, and there's compression, which is shown by the fact the unburnt fuel is bubbling, and you're sure the firing order is correct, then maybe the fuel is getting in to the cylinder, but can't get out, so a new charge of fuel can't be sucked in.
That would imply an obstruction either in the exhaust manifold or in the block between the exhaust valve and the manifold, or maybe the exhaust valves are not opening.
Again, worth a look-see!
Easy way to check for a head gasket leak between cylinders. If you have compressed air, a 1/2 to 1/4 pipe bushing and a quick change air nipple. Remove all plugs and apply air pressure into number one cylinder, Hand crank and if no leak it will stop the piston when it comes on compression. If a leak between cylinders it will blow air out number two plug hole.
First thing I would do is get an accurate compression gauge. Compression should be approximately the same on all 4 cylinders. Could vary as much as 5 psi but not more than that. That test would tell you whether you have enough compression to cause the fuel to ignite on all cylinders. A stuck valve would give you zero compression on the cylinder.
My first guess would be a blown gasket between cylinder 1 and cylinder 2. The problem could also be caused by weak spark. Sometimes you will get what looks like a good spark with the plugs outside the engine, but under compression the spark gets weaker, however since you swapped the plugs and coils I don't think that is the problem. Could also be a problem with the timer, but not as likely as a blown gasket.
If that engine hasn't run since the rebuild there is also the possibility that the head bolts in that area are torqued against trash in the bottoms of the holes and pressure on the gasket is inadequate. My inclination however is the timer. Are the shims sometime required behind the Anderson Timer in place to keep it from binding ? Is it centered ?
I , like Richard Eagle, suspect the spring on the Anderson flapper.... is..... MISSING !!!
Again, thanks to all for your input.
Richard and Bob - the Anderson flapper does indeed have a spring — I had the flapper assembly off to examine the camshaft to ensure it didn't have a straight-thru hole which could have allowed the flapper to be out 180°.
I've been cogitating on all this today and my strongest inclination is a #1-#2 head gasket leak.
Next work day for this car is Thursday. I'll take my compression tester w/pipe thread adaptor, feeler gauges, spare head gasket, and the bottoming tap for head bolts. I believe there is no compressed air on site.
Any further comments always welcome and I'll report our findings later on Thursday.
"Denny - checked that too, plus, all plugs fire when out of the head (and spark to ground when the engine is running)"
Wonder how you can have the engine running and the plugs out of the cylinder head while the engine is running??
Still suspect the coils in the box for 1 and 2 are jumping enough to lose contact. Note the photo posted the lid is off and fan is turning so motor is running enough to shake that coil box. That spring loaded lid is needed to keep coils in contact.
Yes Dan, that would be quite a trick!
Better phrasing on my part would have made it clear that:
1. All plugs fire when out of the head, and
2. When engine is running each plug shows sparking when the terminals are shorted to ground.
The coils are so tight in this box that they pretty much need to be pried out of their spots, and the lid made no apparent difference.
We had the lid off from time to time to make it easier to isolate individual cylinders (gently pushing down the brass disc atop each coil). Agree it should always be on as a matter of principle.
This is really a mystery. Please let us all know what you have found when you solve it.
What Dan was suggesting, checking the plugs when running, is not a bad idea. But don't take the plugs out, just ground a screw driver on the top of the head and move it close to the top of the plug to see if you get a spark.
The other things that people have suggested that are good to check is the centering of the timer. You said that you did not have a tool for that. And checking for any blockage. And using a gauge to check the compression.
Other than that I cannot think of anything. You said that you checked for a vacuum leak.
I re-read your response and see that you did the screw driver test.
How about a timing light? The old strobe ones just hooked to the plug wire. The pin on the fan pulley on the crankshaft is horizontal at TDC. You could check each plug for timing and function.
Did you get a compression gauge?
Regarding sealing the pipe thread on the plugs: use regular Teflon tape available at any hardware store. Works as an anti-seize too.
Only 3 basic things are needed to get the engine to run - spark at the right time, compression, and fuel.
If you have spark at one and two we can assume it is at the right time since it runs on 3 and 4.
A compression gauge will tell if compression is there. For this the thumb test is probably good enough.
If you have both of those you can assume there is a fuel problem.
I would pull all the spark plugs, shine a light down the spark plug holes and watch the valves go up and down as the engine is slowly cranked.
If you are sure the spark is at the right time (the wires for 1 & 2 not crossed), and you have good compression, and the valves go up and down I would pull the head and/or intake manifold and see what is happening
If you are running it without the coil box lid, as is shown in your photo, it might be that the coils in question are not making contact. The lid is equipped with springs that force the coils down into the box so as to make sure they are making contact with the bottom and side contacts. If you are running it without the lid, "to see what is going on", put the coil box lid on and clamp it down and see if that doesn't correct the problem. Jim Patrick
I would sooner suspect the plugs are firing, but there is no gas getting into the cylinders for some reason, most likely a blockage in the intake manifold.
Please guys: read the post! At least the first few.
Chris, don't take this the wrong way. Go back over the things you have already checked. Slowly and carefully. I have been repairing machinery for a long time, and almost every time I have had difficulty, has been because I assumed something, or didn't verify it completely. The bigger the problem, the simpler the solution. I have embarrassed myself many times, by finding something simple, after spending too much time on an issue. I get the feeling you're heading for one of these "Doh!" moments.
Good advice. Every time I cannot get something to work it is because I have not spent enough money yet.
there has to be a reason and the list of possibilities is not very long. philip
pour some gas in 1 and 2 replace the plugs if you have fire timing correct and compression it will run
on all four for a second or two.
Have you considered a carbon track in the coil box wood? The spark takes the path of least resistance. That can be to the plugs when you are testing it static. Then when you spin the crank and create compression the resistance across the plug gap goes up. Then the carbon track in the wood which had been too high resistance to short the spark becomes the path of least resistance and the plug stops firing being shorted by the carbon. Replace the wood or try another coil box to test this out.
That is one possibility, but I like the bad head gasket or junk in the head bolt hole hypothesis. Head bolts can be too long also, just put some washers on them to check that.
Another way to test my idea would be to swap the wires around so #1 coil fires #4, #2 fires #3, #3 fires #2, and #4 fires #1. This will require a timer wire swap as well as plug wire swap. I know it sounds crazy but you can do it. The result is that if the problem swapped to #3 and #4 you know the coil box is the problem!
Nothing to add that hasnt been said except humor! Maybe it the 1st Ford eco-boost? Drops two cylinders until more power is needed.
Please let us know what you find.
Now you know why there are more than a few of those 2 cylinder engines made out of a "T' block-
if those two cylinders dont come online, just chop them off!
Has anybody suggested trying some MMO?
While I agree with Terry Horlick that carbon tracking in the coil box on the front 2 cylinders would cause the issue I kinda doubt that since usually carbon tracking shows up firstly on one cylinder and does so rather strongly killing that one cylinder.
One piece of info that I can't find is whether you were using Battery or Magneto for all of the testing. The reason I ask is the one clue that was quickly overlooked was the one where you said that it seemed to run OK for a very short time then never again. I bet that one time might have been when you were running on magneto. Why? Because unlike other timers the Anderson can hit the floor or have its terminals accidentally loosened during wiring up the timer harness and this mislocation of contact is sometimes somewhat forgiven by running on magneto. I had a friend who had a new one on tour and the car ran like crap on battery but only a bit better on mag. I told him to fully retard the spark lever and to do this to rule out the timer namely to pull the engine slowly with ignition on BAT and STOP immediately when he heard any coil buzz then notice the position of the front crank pin. On a 26/27 use a mirror. It should be just past horizontal by a small amount. He quickly learned that 2 of the timer contacts were firing more than 20 degree off from the other 2 and that means more than 40 degrees off at the crankshaft. He swapped timers and it ran like a top. I like Anderson timers but you do have to make sure that you don't disturb the contact adjustment since the ONE THING that they can do that the roller type, NEW DAY type, and TW type cannot do is to get way way off in inter-cylinder timing adjustment. This is a quick test before you tear things apart. I agree that blown head gasket between 1 and 2 would do this but the head gasket issue may be a head bolt or head bolt thread issue or warped head...
I know I am not the sharpest pencil in the desk drawer but if fuel is getting in there,and there is spark, there should be no raw fuel left unless the spark is happening at the wrong time or the fuel is not compressed.. 3 and 4 are running. 1 and 2 are not. I know the timer wiring has been checked.But if I were scratching my head and backside on this particular problem I would start with the timer,it's roller or brush and the wires coming from it and make dang sure for the 5th time, it was correct. Spark and gas will make something go boom if there is enough compression.
IF the wires and so forth are correct,there has to be a issue compression related. A sticky intake valve or something. Use a compression gauge and get numbers.Use the oil trick to see if the numbers go higher or stay the same. I bet they stay the same rather they are low or normal because this is more than likely valves or gasket.
1 thing for sure,when you find it,you will be thinking, "SHEESH,I have been working on T's x number of years ,how did I miss THAT"?
I vote for a firing order problem. I've messed up enough firing orders myself. Another dimension to this type of issue on a gasoline engine, is that when an engine runs long enough with a dead cylinder, the compression on that cylinder may drop due to the un-burned fuel rinsing the oil from the rings. Engine oil performs 5 things. It lubricates, cools, cushions, cleans, and seals.
That's one of the things I love about the Anderson style timers. You can mess with the contacts... and get them right. By carefully setting them up you can get them hitting all in the same spot or 180° off. This is great because you can even compensate for a timing cover not set properly concentric with the cam.
It was my understanding that Frank used to set his contacts on a jig to get them hitting correctly before shipping. I don't know because I get most of mine in swap meets and they have moderate wear on the contacts. I often swap contacts around between timers to get the best matched set. No matter what I have done I finish by checking the position of initial contact on my Anderson style timer... and they run great!
I still smile when I think of the time I picked up a $1 ADVERTISER timer (That was stamped on them by the manufacturer about 100 years ago) and asked the vendor "how much?" He says " wall, it says $1 on it..."!!! Best swap meet deal yet!
The very same thing happened to me but you’ve already checked for the reason for my mishap Chris. 3 and 4 fired but 1 and 2 didn’t. I assembled the engine from restored parts hanging on the wall for several months. I aggravated with the problem for several days. Then it came to me !! Friggin’ mud daubbers!! But you said you already found no intake obstruction. Keep at it !!
I'm sure this comment is way off base here, unless perhaps something I've noticed somehow adds to, or compounds some other problem that effects the way the engine runs. However, off the subject or not, it is evident that the photo was taken while the engine was running. And I don't know how long it had been running, but it looks to me like that carburetor, and the intake manifold is very, very cold,....in fact, showing evidence of frost all the way up one side of the vertical portion of the manifold. I don't think this could possibly cause the problem talked about here, but on the other hand, it sure wouldn't help either,....FWIW,.....harold
Several people have mentioned obstruction in the intake, head gasket leaks, valves not closing, etc. A quick and easy way to see if the induction system is working properly is by the same "thumb test" that you used in testing for compression. Just hold your thumb over the spark plug hole and turn the engine with the crank. You should feel suction on the down stroke just prior to the compression of the up stroke.
Regarding my post above: I forgot to mention that you need to cover the carburetor inlet while checking for suction. The only reason for having your thumb over the spark plug hole is to know for sure that you are testing the cylinder that you intend to test.
I find it interesting that your photo shows frost from the carburetor up to the forward intake manifold branch and not the posterior arm. This graphically shows the manifold is open and clear to #1&2. If it were blocked there wouldn't be a lowered pressure there causing frosting. #3&4 are firing so their heat prevents that manifold arm from forming frost. So the photo seems to rule out manifold problems.
Harold, thanks for a brilliant observation!
You're testing for spark with the timing retarded. But with it running, you'll have advanced it. Check the timer terminals aren't shorting on something in that position. I had to put a rubber sleeve on my timer rod to stop it shorting my Anderson.
Wow! Our forum is such a wonderful community, with so many knowledgeable and helpful members. Thank you everyone for your continued thought and comments on this situation (several PMs as well).
I'm all packed up for later today, armed with compression and feeler gauges, spare head gasket, bottoming tap (head bolts) and plumbers' tape.
Further diagnostics today include, as needed, compression test, watch the valves thru the plug holes, re-re-check firing order and wiring, timer short when advanced (thanks Jem), compressed air into cylinder when valves are closed, coil box observation in the the dark.
I'll post our findings later this evening.
Time does not permit me to reply to every post above individually, but the following does address selected questions/comments that were not covered earlier...
- All testing/running the other day was done on battery, never magneto.
- Timing was rough-checked fully retarded, by observing crank-handle position (not pin position), and found to occur slightly ATDC.
- The coil box has been rebuilt with the kit, although not by me.
Ed & Mack — a Duh or Sheesh moment would be very very nice!
I have run into this same issue on a local T only 1 and 2 are firing and 3 and 4 are not. Don't mean to hi-jack this post as it is eerily similar to our issue!
New rings, valves, commutator etc. Stumped. Going to rebuild the coil box but it appears that probably won't fix it either.
Compression equal across all 4 cylinders. Spark at all 4 spark plugs and wired correctly.
Here is a another possibility: I enlarged your photo at the beginning of the thread and it looks like the intake manifold is frosty towards the front of the engine. You may want to try to install the "stove pipe", the part that takes warm air from the exhaust manifold and leads it to the carburetor to help vaporize the fuel. I know on my car, if the conditions are just right, it will not run without the stove pipe. Modern fuels have a percentage of alcohol which makes the cooling effect more pronounced. The fuel has to be vaporized before it will burn. Don't try this, but you can put a lit match out in gasoline.
If you can put a match out in gasoline, you have some pretty lousy gas.
Well it was an interesting afternoon...
1. First order of business was to pull plugs, retard spark, and hand crank through several revolutions while peering in through the plug holes to ensure valve action corresponded to spark timing and firing order 1-2-4-3. All checked out OK.
2. Compression test next, dry then wet:
Looks like a valve leak in #1 but no problem with #2-#3-#4. I would expect the numbers to be a bit higher when the rings seat in.
3. Leakage test done next. We hand-cranked each cylinder until the spark started just ATDC, fully retarded. Transmission in high, wheels chocked. 80 PSI applied to the plug hole. We gauged leakage by placing tissue paper over each of the other plug holes and the oil filler up front, then observing how much each tissue moved (if at all):
All cylinders had some leakage past the rings to the crankcase, as one might expect. I listened at the muffler for any leaks, heard nothing.
But strangely, air pressure in cylinder #1 leaked out (puffed the tissue paper at) all other plug holes! Volume was approximately the same at all three holes.
Equally strange, pressure in #3 leaked out the #2 plug hole at quite a high rate.
4. Put the plugs back in and fired it up — still running on #3 and #4 only, just like the other day. Lots of spark at the #1 and #2 plugs when shorting the terminals to ground.
5. Closed the garage door, turned out the lights, and looked for unauthorized sparks, shorts, lightning tracks, etc. in and around the coil box. Nothing found.
6. By now the engine had been running for almost 10 minutes. This is how much raw gas had accumulated around the #2 plug, which was actually quite tight in the head:
The leakage can be corrected (and there may be a fault with the thread) but jeeze — with gas and spark and compression why will this cylinder not fire??
7. We pulled the cylinder head next, and here is the top of the block (gasket stuck to the head):
So, lots of soot in #3 and #4, expected because it needed rich to run at all. Zero soot in the front two except a little bit on the #1 intake and exhaust valves, and the #2 exhaust valve only. #2 intake was clean.
We examined the bottom of the gasket (next photo) and deck and found no obvious sign of a head gasket breach or leakage.
8. Cylinder head told much the same story. #1 and #2 whistle clean, #3 and #4 black and sooty. This side of the head gasket (block side) looked good:
9. Photo below shows the mating surfaces of head and head gasket. No apparent signs of trouble:
10. It was here that I learned the story of this engine. Owner shipped the short block and head to Langs about three-four years ago for a complete rebuild, babbitt, pistons, valves etc. Cost $2,200. Accessories and assembly to pan and transmission etc. were done locally by the owner.
11. Pulled the side cover for a look and to observe valve action. We did not check clearances, but each valve, when closed, had some clearance and the lifter turned freely:
12: Puddle of raw gas found in the valve chamber recess between #2 intake and exhaust valves:
13: Checked the intake valves for leakage next. Smeared engine oil around each pair of intakes then pressured up the intake port with 80 PSI. Modest bubbling noted around all four intakes, but not any greater at #1 and #2. Photo shows oil around the rear two intakes:
14. Checked the head bolts and holes for length and clearance. All the bolts are equal length.
Hole depth checked by putting head on with no gasket and tightening one bolt into each hole. Each time the head clamped to the block and would not jiggle. I'm confident this indicates we are not bottoming out.
At this point we are out of time for today. I had to get home where we had company over for dinner and, as one might expect, I was a little preoccupied with Model T thoughts and not sparkling dinner conversation.
_ _ _ _ _ _ _ _ _ _ _
I've brought home the entire ignition system to install on my known-good '26 Touring for testing: Coils, box, Anderson timer, flapper, all wires attached.
I also have his intake manifold with carb attached, also for testing on my '26.
One thing I forgot to do was ensure the exhaust manifold (still attached to the pipe) is clear of any obstructions. I'll ask the owner to do that tomorrow.
Beyond these three things, its a matter of reflecting on what we found, and trying to sort out the weird leakage test results and preponderance of raw gasoline around Cylinder #2.
All comments and suggestions welcome!
Hmmm,.....no black carbon in #1 & #2 makes me think of something like an internal crack in the block between water jacket and single intake passage that allows coolant into the intake port for #1 & #2. Those two cylinders not firing due to coolant being drawn into both of those cylinders past #1 & #2 intake valves, and frost on forward part of intake manifold due to no heat radiated into that end of the intake manifold as forward end of engine much cooler than rear part of the engine. Might be that unburned gasoline & oil mixture is collecting in #2 spark plug well because water evaporates but oil does not. Apparently, #1 spark plug seals tight but slight compression leak past spark plug in #2 where unburned gasoline/oil mixture collects.
All conjecture on my part of course, and I sure hope I'm wrong and end up feeling like a fool for this hypothetical "theory", because nobody wants to even consider a cracked block, but,......???
Further thought,.....as long as you have the intake manifold off, check as carefully as you can for possible crack inside the intake port that feeds #1 & #2,.....maybe a little inspection mirror and strong light,.....again,.....hope I'm wrong,......harold
Ar those Champion 25's .... throw them in the garbage where they belong. When I bought my racer from Manny #1 cylinder was dead. Had good compression and spark to the plug, but the cylinder would not fire. I dug out my old Champion sparkplug tester and it confirmed the plug was dead - zero spark. Tested a set of new X's under 60 lbs air pressure and they all fired good. Put them in and went for a very nice drive on the highway at full throttle. Wish I had a picture of my ugly face on that ride - I was smiling all the way. I smacked the insulation off the bad Champion 25 for a visual inspection, and checked it with an ohmmeter but couldn't get a reading thru the electrode and the top cap. There was a lot of corrosion between the two pieces. When high voltage can't get thru, there's a problem.
To test what Harold said you need first to mount the head on the motor block than block the water inlet (left side), fill the block with water and set some pressure on the water at the outlet (front side).
An old inner tube can help here. One flap go over the inlet and hold with a strap. The stem part go over the outlet, hold the same way. Pressure can be set on it with your compressor.
From your leak down test, it looks like # 1 and # 3 intake valves are not sealing well. The reason you were getting air transfer to the other cylinders was because your throttle was closed. I like the leak down test because you can isolate each cylinder. You do that by listing to the intake, exhaust and crank case. So where do we go from here? I would start with the valves,(because you can), fix the valves and check clearance, then make sure that they are opening (I think about .240 on a stock cam). Use a dial indicator ( cheep at Harbor Freight) and check opening height. Note when they open and close ( just measure where the piston is and compare them. The easiest way to check valve timing is during overlap. When you turn the engine over watch the valves from tdc (top dead center, crank pin horizontal) on compression, both valves will be closed, when the piston gets to the bottom of the cylinder, the exhaust valve will open and remain open until the piston gets close to the top, it will close and the intake valve will open. The closing of the exhaust and opening of the intake valve will happen very close to tdc,(just before tdc on stock timing). Most engines have both valves not seated at this time witch is called overlap. On our model T's the overlap is slight, but this a great way to see if an engine is in time. Then the intake will remain open until bdc (bottom dead center,again crank pin horizontal). I would do these tests because you can ( head off, valve cover off). I Prefer the tube and crush copper manifold gaskets, because they seal better. I suspect you may have a few problems. Sort out the valves first. I don't think that the puddling is fuel, I suspect is oil. Like mentioned earlier, Intake (fuel air mixture) Compression, Ignition (at tdc), and exhaust. If these are present each cylinder will run. You can reuse your head gasket, I paint them with some sort of metallic paint (silver,copper,gold). I hope you well on your adventure.
Thank you Harold, Garnet, Andre and John. Not discounting anything at this point!
But just to clarify John, we are pretty sure it IS gas accumulating around #2 and not oil — it was very thin, and when we sopped it up with a paper towel and lit it off the burn was very vigorous with much black smoke.
The look of those spark plugs sends up a red flag.
the compression test tells me it should have enough compression to run. the clean cylinders tell me it is getting gas. i would say for whatever reason
you have spark when turning slow by hand but not at
running speed. timer issue? hope you get it soon i
know it is not fun. philip
I could have sworn I commented on this earlier today, but are you sure it’s not as simple as you running it way, way too rich?
Checking for blockage in the exhaust manifold is the obvious next step.
You stated earlier that moving spark plugs around did not change things so we can rule out the spark plugs.
An interesting experiment would be to take the exhaust manifold off, put the intake manifold back on, and try running it. You could hold your hand over the exhaust ports to see if air was flowing through.
It may be that the problem is with 3 and 4. You state that you have to run it really rich to run at all. Maybe too rich for 1 and 2. But you stated earlier that you tried different mixture settings for the carburetor.
Could it be that 1 and 2 are pumping air/fuel to 3 and 4 or visa versa and screwing up the air/fuel ratio. It is interesting that 1 and 2 draw air/fuel one after the other then 3 and 4.
You are right to try the ignition system on the other car. It may come down to the ignition system.
From what I see in the pictures and your description, you are getting fuel to cylinders 1 and 2. I would suspect an ignition problem. Are you sure the wires at the timer are on the correct post? If they are reversed, you could be getting the spark at the wrong time and your fuel would be going right out the exhaust instead of burning. The other thing I would suspect would be the wood in the coil box. If you have carbon tracks in the box, you might have enough spark to fire the plugs when they are laying on top of the engine but not under compression. The spark will take the path of least resistance.
The firing order is 1,2,4,3. So if 4 and 3 are on the correct terminals at the timer, 1 should be next to 3 and 2 next to 1 then 4 and last 3.
Is the carb adjusting needle the correct one? There are different lengths. I accidentally put the wrong one in one time (too short) and had similar outcome.
Also the Anderson timer flapper has instructions about shimming it ahead on certain cams. My instructions are long gone but I recall I had to do this on mine.
I don't have an answer beyond ( still believe), an ignition problem but you've gone beyond where you should have. The comp test showed good numbers on all 4. End of story there. Pulling the head proved nothing. Minor leakage at valves proves nothing. (see comp #'s). You have completely missed something which is why it hasn't been brought up here and it's going to be simple. Show the timer & wiring.
Maybe in SPAM folder if not obvious
Try using the correct intake and exhaust gaskets.
Good catch Jerry....
Are you sure the timing gear marks are meshed properly?
Spark, Compression, Fuel, Timing.
If they're all present, combustion has to occur.
Seems like you're down to timing from what I can tell.
I don't know where it came from historically but laying the spark plugs on the head with wires attached is a TOTALLY BOGUS test of anything. With this test a bad coil can look good, a bad spark plug can look good, a carbon tracked coil box can look good, a bad timer (usually an Anderson) with miss-timed contact locations can look good, even a bad spark plug wire with a small internal "break" gap in it can look good. The reason this test is invalid is that it takes about 1/4 of the high voltage to spark a properly gapped plug when it is not under compression in the T motor. This "spark test" has led many people to begin pursuit of that elusive wild goose. Given the problem at hand I suspect putting the whole ignition only on another car can cause you to get led astray if the timer cover on that test car is more properly aligned - just a warning. Nothing is worse at finding things than a committee with illogical tests being attempted by others and results assumed as valid. I for one will bow out since there are many capable people here but we all have our own way and this appears to be another committee hunting in all directions and the evidence trail is getting cluttered and corrupted. I have a lot of respect for all of us but any one of us would probably be better if we could personally see what is happening.
If valve opening and timing checks out,also check the firing order by watching your valves, just in case someone has installed a strange cam. I know you said that you have checked and re-checked your wiring, but it sure seems like 1 and 2 are crossed.
As usual John Regan's assessment is right on. I was going to write a similar post regarding the incomplete and nondecisive tests completed. Watching this stream and waiting to learn the outcome.
I concur with JFR & JC. this has gone way beyond where it needed to go. They've created tons of extra work and expense and it all has to be repaired with the original problem still present. I'll repeat: It's something damn simple that was missed or misdiagnosed earlier.
I am too lazy to read all of these posts, but I would swap #1 and #2 coils with #3 and #$ and see what happens. If #1 and #2 fire, then you have bad coils - send them to Ron Patterson in Kentucky. I agree that this has gone waayy too far. If it is getting fuel, air and spark, and has compression, it will run. It seems to have fuel air and compression, so that leaves spark. Either the timer or the coils are FU.
I don't know how to edit, but #$ should read #4.
Well, it isnt a head gasket, that woulda been too simple!
So maybe its something a bit exotic- I'd go with John W's suggestion- roll it over and watch the valve action- every cylinders valves should cycle exactly the same.
Maybe the camshaft is the culprit. I've seen plenty of conversions where the engine is split, one half an engine running as Otto, Daimler and Maybach intended, the other half turned into an air compressor.
Maybe you have a odd-ball air compressor conversion cam. Or maybe the cam grinder messed up and simply ground out a bad cam profile.
The kicker is all your ancillary components work on the back 2 cylinders, but not on the front 2. I cant find if you have rewired the coil box inputs so the 1 & 2 coil positions would then actually fire the rear ones and vice-versa. That would find or eliminate any possible coil box internal grounds or open circuits being the cause- if your back two now refuse to function and the front two now fire. (yes, they all fire out in the open- but under compression things can be much different)
Yes, these suggestions are a REAL STRETCH, but all the easy stuff seems to have been tried at this point!
Again thanks to all for comments and suggestions, also several PMs.
Lessee now... could be valve leak, carbon tracks, cheap plugs, cheap gaskets, carb needle, confused wiring, bad flapper, off-centre timer, timing gear out of time, manifold leak, manifold blockage, cracked block, firing order, coilbox lid, stretched head bolts, crap in the bolt holes, stuck valves, warped head, timing rod short or a missing stove pipe. Not to mention confusion from illogical, ill-conceived, incomplete and non-decisive tests!
Not sure how to do Smilies on this forum but there should be a big one right HERE.
Also, no offense taken at any commentary on our test procedures. None. We do what we can with the resources and the knowledge we have, but we can do better. Always so much more to learn. Thanks for your input.
My favorite times messing around with old cars are those where I've revived a long dormant engine and figured out why it won't run.
Wish I was there to help you get it going.
"It's something damn simple that was missed or misdiagnosed earlier."
"Simplicity is the most deceitful mistress that ever betrayed man"
OK, you apparently used a wire to check the intake manifold. I haven't reread the entire post, but I would take off the intake manifold, look for a blockage in the block AND put on a different intake manifold and see if that changes things.
Although gas is getting to #2. . .
Watch the valve movement while turning the engine over. this is a weird problem. Some say it has gone to far,I don't think so.A common coil issue or a fuel issue would have been apparent by now.
Add to your list a bad cam shaft ;)
This is when I pray and miracles happen.
I was thinking broke camshaft and if it was the back 2 cylinders that could be logical but the front 2 not working nulls that idea.
so I kept that tidbit to myself until I read your comment Matt.
He had compression. On all 4 cyls.
Yep,but think about it,what if the valves aint opening? It would have compression wouldn't it?
After reading all the ideas, including my own, $5 says its an ignition problem.
Then how does #2 pump raw fuel out between the plug threads?
Colin's suggestion of a too short carb adjusting needle sounds like the most logical to me. That would men lots of extra gas and some of the unburned fuel is pushed through the bad spark plug threads and accumulates. Try starting with a known good carburetor and seal the spark plug with aluminum foil. Good luck
How does a carburetor decide to run cylinders 3 & 4, but not 1 & 2?
Could the camshaft gear be 180 out?
I cant believe no one thought to check the air in the right rear tire! Too many cooks in the kitchen.
What Jerry said. Smells like electrical issue to me. Need an old fashion spark plug tester to see if those plugs are firing under pressure.
They have 2 Model T's at their disposal. One runs, the other doesn't. Heck, start swapping parts. One part at a time. Simple stuff first. The bad part will eventually show up. That shouldn't take long either.
Good luck fellows, whatever you do!
Jerry - maybe there's a leak at the rear intake port for #3 and 4, giving them a mix that can fire while it's far to rich at #1 and 2. Only the front intake connection was tested for leaks as far as I can read Chris description and the carb only runs at a narrow range of throttle positions, so something is obviously wrong with the mix the rear cylinders are getting also..
Roger - you may be onto something. I still find it interesting that the intake manifold is frosted to 1 & 2, but not 3 & 4. That and it is running to rich on 3 & 4 and still barely running.
Not that I have ever done this after grinding a port, but is it possible that there is an obstruction in the exhaust manifold between cylinders numbers 2 and 3? Something like a wad of paper towel or rag that was forgotten? Best of luck, Bill
Chris go back to the basics.The leakage test results have to be sorted out FIRST.I think John Warrens post Friday June 15 @ 9.55 is spot on.cheers pete
That leakage test would be very inconclusive! no way you can shove 80psi up the inlet port like Chris has stated and not have the valve lift of it's seat, especially with the weak tension a T valve spring has.
A leakage test is always thru the sparkplug hole.You will never left the valve.
That's right Peter, but that's not what Chris did.
Well the post @ Friday June 15@ 1.58 has a table sparkplug hole 1 to 4 etc with results Chris what did you do?
Frank looking at those results of the leakage numbers ,what do you think is happening?
Peter, I think that showed un-seated rings.
As to why the engine is running on 2, I put my money on electrical.
Peter, just so we are both on the same track, my reference to the leakage test was No 13 of
charlie,my thinking is the exhaust valves are not opening. It would pull in fuel,and blow it out everywhere it could,including a worn valve guide to get it in the oil chamber or out the plug.
improper break in will score a camshaft in a modern engine with a fully pressurized oiling system- I've done it myself rather quickly by not bringing the rotating assembly in a fresh engine up to the proper RPMs to allow sufficient slippery coating via pressure and slinging of the oil.
Imagine what could happen when the lubrication system is dependent on splash, gravity and prayer!
A few wiped out cam lobes and lifter bases are a possibility............
Seems like my suggestion of putting air pressure into each spark plug hole was not understood as what is tested by doing this. Under pressure, on the compression stroke no air should escape from intake or exhaust when hand cranked. It will lock up the engine if no valves leak. On the intake stroke, air will be forced out the carb and no where else. On exhaust, air will come out muffler. This tells if the valves are working properly. If rings are leaking, air will come out the oil fill hole. So simple to get many results.
This thread has been going for 5 days. I check it each day hoping to see the mystery solved. I will continue to check in each day and hope to see the solution. It will probably turn out to be a simple problem that was overlooked in an earlier diagnostic test. We can all learn from this as just about every possible problem has been suggested. Good luck and don't stop this thread before letting us know what the problem was. Jim Patrick
I'm with Jim P. , waiting in Bellingham, WA..ds
Have you checked to be sure the Anderson flapper is able to move? I installed a new one on our '27 touring and the car had NO power at all. The flapper was binding on the cam nut and not making good contact with the tabs on the timer. It was NOT obvious when I just looked at the flapper, I had to try to make the flapper move in and out on the spring.
Is the head flat? A warped head will allow leaks as will as a block that is not flat
Is it parked facing up a hill?
Maybe there's just enough gas in the tank to reach the back two cylinders....
This better have a good ending. Feels like one of those reality shows of finding pirate or confederate gold that never delivers after a dozen episodes. I’m guessing that most guys who work on their own Ts and tweak them on a regular basis would probably find the problem in an afternoon of trouble shooting.
I've learned something already, I'll keep my problems to myself ;)
That helps!! MOCKERY will solve this T's problem!! for sure.
Like most here, I'm fascinated by this thread and can't wait to hear what exactly caused this unusual circumstance of only having half the engine run. On the other hand i think its unfair to criticize Chris because he has not quenched the desire of some here for a definite cause in the time-frame they desire. People have lives beyond helping others work on T's, and i think he has updated us more than most usually do here. Let him figure it out without the stupid pictures and analogies, and maybe we all might learn something here in the end.
Hey guys, lighten up-
This thread has taken on a life of its own!
I'm sorry if a couple of funny pictures upset you but come on, this post has become great fun (well, maybe not for Chris...), like a Saturday night bench-racing B.S. session with a bunch of your best buddies trying to figure out a stubborn problem by just throwing everything out there and seeing what does the trick. Of course there'll be some insightful, reasoned and well thought out responses, but theres going to be some crazy stuff and goofing around thrown into the mix! Life's too short friends- have SOME FUN!
Besides, I'm pretty sure that SOMEBODY has already given the right answer somewhere in this longest post yet this year (??) free-for-all.
If not, we should all swear off mechanical things and take up crocheting.
Bill Hoffer may have something there--an obstruction in the exhaust manifold. That would explain the gasoline build up in the non-firing cylinder--I think.
While I appreciate the humor, I know we'd all like to find out just what the cure is!
Good post. Can't wait for answer. Also wish more on the 26 that had no high gear. Hope that solution will also be posted. My T mechanic friend( born in 1915 and starting sweeping floors before he was 10 in his dad's garage) from Mobile described me and my friend working on our T,s as" Two monkeys trying to open a coconut" Probably a good observation. I really miss him. Keep things light,
David - There are two (2) non-firing cylinders,.....#1 & #2. I just had the exact same thing which was caused by a head gasket blown out between #1 & #2 however, that does not seem to be that case with the problem Chris has,.....harold
Thumbs up on the Porsche mechanics pix IMHO. A good laugh! Cheers, Bill
One question I don't see here unless I missed it. Do we know if this car has EVER run on all four?. May help with the differential diagnosis. Could eliminate some of proposed causes like cam ground wrong. My question/answer would revolve around why the gasoline is being forced past the plug and not going out one of the manifolds. Takes a lot of pressure to force a liquid through a tight opening. This would lead me down the "something mechanical" path. Is this gas building up in the cylinder to the extent the cylinder become a hydraulic pump powered by 3/4? My conclusion from this would be obstruction on exhaust side (non-opening valve, at least not at the right time maybe)and gas with no where to go but through a crevice once fills cylinder head space. My two cents -- I'm fairly new to model T's but love a good 'figure it out' on anything mechanical. My dad never threw anything out without trying to fix it first. Guess I inherited that.
Good point Garland!
I- and maybe others as well- ASSUMED it had never been run before by the condition of the combustion chambers and piston crowns in the pictures, and the general cleanliness of the engine and the painted exhaust manifold.
But you know what happens when you assume.....
Yesterday I was told a story about a 1921 touring that was running on two cylinders and this was after the driver had washed the car. It seems that water had somehow got into the coil box and caused two of the coils to short out, switching the coils did nothing but because the wood lining of the coil box was wet this was the cause which started the whole problem. This would not be a problem with the plastic liners that can now replace the wood. Just a thought.
Richard E"s thoughts could be solved by jury rigging a 1926/7 coil boy on the engine....Neil.
I look at this thread almost every day expecting to find why the engine misses on cylinder 1 & 2.
Chris, when are you going to solve this, so we can move on.....
We may have to appoint a Project Manager and establish a budget and all that other stuff that the bean counters used to impose on us.
By the way I think it’s carbon leakage in the coil box :-)
Hello all. I have news and the news is good.
Dale, great pix! They might just end up in our local newsletter. That looks like me on the far right in the second photo.
Good question Garland — Answer is yes, it probably ran on all four decades ago when my friend bought the car but although it was running he never actually drove it before dismantling.
Sorry for the delay in posting, but although there was progress over the weekend, it wasn't until this afternoon we had the car running smooth — on all four! — and my friend Jerry had his first ride EVER in the Model T he has owned for 35 years and that has faithfully followed him from house to house and town to town throughout most of his working life.
So, it wasn't a bad camshaft, blown head gasket, missing stove pipe, confused wiring or low air in the right rear tire (thanks Mike!)
Instead, it turns out that the
Oh — someone's at the door. Hang on...
Chris that was downright cruel! I'll listen for the drum roll and come back in a hurry to find out the answer. Glad you were able to solve the mystery.
Oh! I know what it was;)
How many Model T owners does it take to change a light bulb?
. . .
. . .
. . .
. . .
. . .
Oh LOOK! There goes a squirrel!!
Come on! For cryin' out loud.
Well, that is a surprise. I would have never though about checking such an obvious detail.
Chris...you are a sick man. :-)
Your KILLING ME SMALLS!!!
I'm only bumping this for the suspense.
Those darned water pump salesman. Sheesh. Finally got rid of him!
Lots of interesting comments and suggestions and comments over the past nine days, and lots of head-scratching at our end. Reviewing the whole thread this morning, recognition should go to Neil, Jerry, Roger and Garnet for looking in the right directionS (plural — there were TWO problem areas) and also Jim, Charlie, Ed, Mack and the other folks expecting it to end up something minor.
I had taken my friend's ignition system (complete from Anderson flapper to spark plugs) and his carb and intake assembly home to swap onto my '26 touring.
Sunday morning and the ignition system went on first. All was well, fired on all four, ran as it should.
Carb and intake manifold went on next, and huh?? the engine only ran on the back two!
I noticed the gasket between the NH carb and intake manifold was missing (although the bolts were tight) so put a gasket in and bolted it securely. The outlet flanges looked pretty good, but I faced them smooth on the belt sander just in case.
My touring has the three-in-one green manifold gaskets with six steel rings. Put the intake assembly back on the car, fired it up and Voila — all four running! Adjusted the mixture to lean it out considerably and then took his intake and ignition out for a half hour drive. All was well.
Monday morning I started it up and yikes, we are down to three cylinders... #2 sparked merrily during the short-with-screwdriver quick test but was obviously not contributing. I replaced that Champion #25 with an original Champion X from my car and we are back to four strong cylinders. Intermittently junk plug!
My friend's car had an unusual manifold gasket that I've never seen before... three-in-one with built-in rings that only go ONE direction.
The gaskets had originally been installed dry — the blue silicone was something we added to both sides on the first day in an effort to eliminate vacuum leakage as a possibility. The gaskets might have worked OK; we certainly never heard any exhaust leakage.
The weird gaskets have been trashed and we put the car together with these wonderful copper crush rings.
I had spent some time earlier on the cylinder head plug threads, and our compression leakage from Cyl #2 seems to be a thing of the past.
All is well and we enjoyed a lovely no-drama drive around the subdivision yesterday afternoon.
So apparently it all boiled down to vacuum leakage and a naughty spark plug. Could a missing carb gasket cause airflows to somehow over-fuel the front two cylinders and prevent combustion? Sure sounds unlikely to me. Would blue silicone have effectively sealed any manifold leakage and let the car run on four? I would think so.
So, mysteries remain but bottom line the car is back together and running well.
Thanks again to everyone who followed along and offered encouragement and insights. Very much appreciated by both of us!
Glad to hear that the car is now running well.
Some times, a cylinder that is not firing due to a vacuum leak will start firing when the engine is revved up - since the piston is moving more quickly, the intake suction and compression doesn't have as much time to leak away. The results are an engine that idles roughly, but runs OK at higher speeds.
LOL I am SO glad I wasn't following this thread as it happened. Chris man, that cliff hanger from Tuesday evening to Wednesday morning was absolutely beautiful. You are the best kind of awful and a man after my own heart! HAHAHA
I'm excited y'all finally got it running right. Ultimately, I think the adage I heard on some medical TV show applies well here: when you hear hoof beats, think horses, not zebras.
I love threads like this because I always learn so much...not just from the ultimate solution, but also from all the input.
Thanks for keeping us posted and thanks to all who submitted entries.
Gotta love it, and the fact that his T is now a runner.
Congrats on finding the problem...........it's a relief, mostly because I was running out of breath just reading this thread!!
Hey, I cited "Need an old fashion spark plug tester to see if those plugs are firing under pressure" way back on 6/16. That would have identified the junk plug. Not totally convinced intermittent junk plug(s) were (are) the root cause all along. Time will tell.
Thank heavens that every troubleshooting event doesn't take this long but we're all Sure glad to hear your running and back on the road! Great back story about the car as well. Whew,, I'm soooo relieved and will now get some better sleep.
Thanks for posting!
PS.. I knew what it was all along but I just wanted you guys to find it on your own so you'd remember it for next time! LOL
Chris - sure glad you got 'er firing on all four,.....FINALLY, right? Interesting that Neil Kaminar "nailed it" on June 11th when he mentioned "vacuum leak". You also mentioned originally that you had checked for the possibility of a vacuum leak prior to Neils' comment. You also mentioned when checking for possible manifold leak that you didn't "HEAR" and exhaust leaks. The interesting thing to note here is that an intake manifold leak is an entirely different thing than an exhaust leak, because a vacuum leak is all but impossible to hear. As you mentioned Chris,....this is all still somewhat of a "mystery" even though the problem is apparently solved and the engine is FINALLY running on all four.
I think there might still be some things we can all learn from all of this:
One thing I have learned from long Model T and Model A experience is that assembly of the intake and exhaust manifold assembly is a very "touchy" situation. Here are two things that can cause problems:
1) - The metal rings (glands) in each of the six ports (four exhaust and 2 intakes) can sometimes protrude out from the machined counterbore in the port to cause the one or even both, manifolds to fail to seat firmly enough to fully crush & compress the gasket sufficiently to seal. It is necessary to (INITIALLY) fit the manifolds to the engine block WITHOUT any gasket to ensure that the manifolds will fit flush against the surface of the engine. That way, you will KNOW that the gasket(s) when fitted, will be fully crushed and compressed and will seal.
2) - This is a detail that I feel is equally important, but easy to miss. I think that it is a huge mistake to try to fit both intake and exhaust manifolds to the engine, bolted together as a unit, at the same time. Do NOT attach the intake manifold to the exhaust manifold together tightly (to each other), with the two cap screws, until both manifolds are individually attached to the engine and until it has been determined that the engine runs properly with no noisy exhaust leaks or any intake manifold vacuum leaks. When you are all finished, then (AND ONLY THEN) bolt the intake manifold to the exhaust manifold with the two cap screws. This procedure will ensure that the intake manifold is exerting maximum pressure and is crushing & compressing the gasket(s) properly.
Sorry for the long-winded post here, but I have learned (the hard way) that this is the best way (I think anyway) to avoid the possibility of a vacuum leak,......FWIW,......harold
Just had a sort of "mental block" and the more I think about it, the less sure I am. I can't remember if there are six (6) steel gland rings, or only four (4) just for the exhaust ports. But whatever the case, I still feel the same about the comment I made above about NOT bolting the two manifolds TOGETHER until you're all done and have engine/manifolds all assembled and running,.....sorry for my "confusion" but that's what happens when you're approaching old age senility and writing something from "memory",....FWIW,....harold
This would have diagnosed the problem it in seconds.
The entire kit (not shown) presently backordered at vendors, but available in the future once my shop is back fully operational.
Harold, there should be one ring in each of the four exhaust ports on the manifd and one in each of the intake, making it 6 total.
Thanks John,....I think I actually, probably, might have known that, a long time ago,......hmmm,.....maybe,......yeah,......thanks,.....harold ( ;^)
Harold, I don't quite understand your comment about bolting the intake and exhaust manifolds together. Do you mean fitting one first and getting that set right, held in place with two half clamps, and then fitting the other, holding that in place with a whole clamp on the other two studs?
I like to fit the exhaust manifold first, holding it in place with just two half clamps. That leaves both hands free to fit the intake manifold next. Once the second manifold is fitted, all the clamps can be fitted and drawn up to tension.
Allan from down under.
Allan - Oh boy! I am embarrassed! I was thinking Model A instead of Model T. The Model A intake manifold has a flat surface that mates up to a corresponding flat surface on the exhaust manifold. You place the intake manifold flat surface on it's inward side against the corresponding flat surface on the outward side of the exhaust manifold and then attach the two manifolds together with two cap screws. The cap screws go thru' clearance holes on the flat surface of the intake manifold and screw into tapped and threaded corresponding holes in the flat surface of the exhaust manifold. The two manifolds then are one solid assembly that have all six ports (4 exhaust and 2 intake) that line up in a straight line and fit on the side of the engine. But that's only on the Model A, not the Model T which has the two manifolds completely separate. Sorry for the confusion I caused,.....another case where I got "A" & "T" mixed up,.....like I said,.....old and senile,.....sorry,....harold
I thought there might have been 2 factors at work. (had situations almost exactly like this before)
Those copper rings are a really good gasket when your block & manifolds are nice and smooth. One of my fav's but not so easy to get.
Kep, the copper rings are a product made by Fuel Tank and Radiator Services in Australia. They are available directly from them, or through the vendors in USA. Just Google them to order your needs.
Hope this helps.
Allan from over the dutch.
Yaaay!!! CONGRATULATIONS. You deserve an "Atta-boy" for your perseverance. Jim Patrick
A very interesting thread. It’s usually something very simple. In our business we have a saying when trying to identify a type of 19th century photograph. “when you hear the sound of hoof steps behind you ... think horse ... not zebra.” In other words, it’s usually the simple answer.
Occam's razor strikes again!
Still, why did a vacuum leak (or "uncontrolled pressure differential variable") cause the intake manifold to frost up?
Well thank goodness the reason has been found !! I applied for a Passport last week to fly up there and have a look. Do you believe the lack of a carb-to-intake gasket played a role?