MTFCA Forum

Congratulations Steve and welcome to the club. I have been enjoying the pursuit of incompetence for 57 years with respect to old cars. I must say I prefer my own to that of others. A pinnacle has been reached in my shop.
Rich

With those compression readings it would likely start hard and run poorly at best. Compression can get down around 35 and so long as all cylinders are about even, you can still start & drive, but it will noticeably lack power and run smoky. Much below 35 and you have noticeable oil burning, carbon buildup, frequent spark plug issues. More than 5% to 7% difference in compression between the best and worst cylinder can be an indication of individual cylinder issues. Just to look at your numbers I would think you have valve sealing or valve timing issues. In fact, those numbers are so bad I would even chance the question, “Did you put all the valve keeper pins in?”

You still have a valve issue of some sort,if it was rings, those middle readings would change a bit more with oil.
Another thing, Your gauges could be messed up.Are you useing a screw in gauge or a gauge that is pushed into the plug hole and held in place while cranking?
If I remember correctly,didn't you have Mike Bender there recently working on it? Good gosh,that is kinda like having Thomas edison stop in to chat and offer to help you install a light bulb.If it aint right when he got done with it, you might want to See if you can find a ghost whisperer and ask Henry!

You know, in the 1830's Joseph Whitworth created the three plate method to create a perfectly flat surface plate from nothing, by lapping them to each other...

In the 1910's mechanics invented the "lower the seat hopelessly into the block using a single valve" lapping method. I've always been a fan of new valves, (reground again and handled with care) and mechanically cut seats in the block, using a Neway cutter. If not careful in choosing the correct pilot, a bad job can be done very easily and quickly. Fortunately with care a great job can be done in only a little more time.

No lapping for me, thank you.

Sorry to hear about your troubles...

I would even chance the question, “Did you put all the valve keeper pins in?”

Yes, at least I got that right.

The test with oil shows a problem with rings. Tow start it and let it run a long time not letting it get overly hot.

WARNING!- this is going to sound crazy to most folks...

I know that virtually everyone sings the praises of using copper coat on the head gasket but I wonder if it is really necessary in your case and perhaps it's doing more harm than good? The rule of thumb I was brought up on was that gaskets go on dry. Think about it- your head was machined so the gasket should seal perfectly to it. An excess layer of liquid applied all over the gasket may be preventing a good seal.

Steve,
If you haven't already, Try adding compressed air through the spark plug holes. That may help in determining where the compression pressure is escaping.

Another thing to help identify the problem is to look at what has changed since it was running well. Doing this is not easy and requires lots of thought.

Here's a story on one of my experiences.
A number of years ago, shortly after I learned about the "what-changed" process, a friend had a large truck in which he had installed a big diesel engine and transmission. After driving it for several months, he couldn't get the truck to go into reverse. With my newly acquired knowledge, I asked him what had changed. He said nothing had changed and that he was looking at the linkage to see if it had bent or moved. The next day, he called to tell me what he found. He had gone to the auto parts store to get filters and remembered that he had not installed a filler plug in the transmission and bought one. The transmission had the plastic fill cover on it from since he installed it, and the transmission was shifting fine. The new plug that he installed was too long and protruded into the transmission case far enough to keep the reverse gear from engaging.

So when considering the "what-changed process", even the smallest thing, such as wiping off an oil spill, needs to be considered. Definitely not easy to do.

Art

Your gauges could be messed up. Are you using a screw in gauge or a gauge that is pushed into the plug hole and held in place while cranking?

Screw-in, good and tight. Wondering about the accuracy, I screwed it into the spark plug tester and checked it with the regulator.
Setting the regulator at 40 psi, the tester shows 40 psi.

Setting the regulator at 50 psi sends the tester to 501/2 psi. All those bad numbers were real.

Well that rules out bad tools,scratch that off the flow chart

I’m with Art....TDC on compression stroke, hold engine from turning and blow air into respective cylinders. Air should be escaping somewhere, crankcase, intake or exhaust. If not, I would be double checking valve timing.

It’s a Model T, it can’t be that bad.

If all fails go back to the basics.
1) fire/spark
2) fuel
3) compression

Number one run about getting out of a hole is to quite digging.

Steve

at TDC compression, do a leak down test and listen to intake, exhaust, crankcase, for sounds of air escaping. One test each for all 4 cylinders. You will find the source of non-sealing pretty quickly with no guessing. Have the car in gear, wheels chocked, throttle open, and don't use too much pressure. This is a simple, gross test which will lead you to the correct source(s).

If all fails go back to the basics.
1) fire/spark
2) fuel
3) compression

The tester says it's compression.

don't use too much pressure.

I haven't done this before.10 psi enough, or more?

Steve Jelf wrote: ↑

Tue Mar 17, 2020 4:52 pm

don't use too much pressure.

I haven't done this before.10 psi enough, or more?

No I would use 60-80psi. Just make sure the valves are closed and the engine can’t turn over.
A little air from the crankcase is normal, but virtually none should go past the valves.

Steve - Whew! There's sure a lot to read here, and I probably have not read as completely and carefully as I should, so probably shouldn't comment at all,....but you know me well enough to know that I probably should just keep quiet and let those (and there are many) that know T's a whole lot better than I do. However, having said that, I'll do it anyway,....stick my nose in where it really doesn't belong. But just take this as a sort of BS session that you and I might have had we both met again at Chickasha and were chatting over a cuppa' coffee.

I almost commented awhile back when you wrote about and showed photos of your recent valve work. Far be it for me to ( criticize...SP?) when you're a far better mechanic than me, however, while the old fashioned valve lapping procedures worked okay back in the day, and probably still will work "okay", I'm honestly a big believer in the more modern "3-angle" valve job with carbide valve seat cutters. Having said that, I'm sure your valve work is certainly sufficient to preclude the possibility that the valves are leaking so badly as to cause the hard starting and poor running.

I think you're doing the right thing by stepping back for a time, and after "cooling off" going back to it later. In just thinking about how I would proceed at that time if it were me,....here are my thoughts, which are probably not worth much, however, "FWIW".....

While the air pressure method described above is probably best, I think a thoroughly done, in the right order, wet & dry compression test is very adequate to determine either worn rings/cylinders or leaking valves to be the low compression problem. Results of the wet/dry compression test should be conclusive, however, if not, it just might be that you are dealing with a worn out camshaft. Forgive me if I might have missed the possibility that you might have installed a new or reground camshaft, however, not to say that even a new or reground camshaft might be the problem. I'm sure Mike Bender would not have missed something like a defective (for whatever reason) camshaft.

Having said all that, I can only think that if the cylinders are perfectly round and not tapered, and the rings are sealing, and the valves are sealing after your valve work, and if the valves are opening (far enough) and at the right time, I can't think what else I would check that could account for the low compression. Hmmm.......valves opening far enough and AT THE RIGHT TIME,......timing gear improperly drilled, or timing marks stamped on the wrong place during manufacturing? Far-fetched I guess, but SOMETHING'S wrong, right?

Taking a break is the right move right now Steve, and try not to get too frustrated, but hang in there, because you'll find it,.......o.k......useless "rambling's" over with now,......harold

Has anyone mentioned loose valve guides?

sounds like cam timing to me.

I can remember a line in one of Floyd Clymers book that said” when things get blue in the garage let it go and come back another day.” Good advice that’s been around a LONG time.

Dave Hanlon

somehow I missed your post the first time...if I had seen it I would not have repeated your advice. Once is enough, and it is good advice.

Steve

looking back on another thread it looks like I spy you using a Neway cutter prior to Clover compound. Lapping is not necessary and may even be injurious to a freshly-cut seat. FYI.

Gotta tell you when those #'s went up with oil added I got a bad feeling in my stomach.You know what I mean too. The horse is long out of the barn but this is what comes from ripping the head off before doing any testing. Even comp testing the 2 good cyls you originally had left when the gasket went would have given you an indication of the engines condition. And all this after perpetual hard starting before the head gasket blew and after you knocked yourself out checking and eliminatng everything else. Except compression. As to the air testing: air is going to leak past the rings especially on a cold engine. Absolutely no doubt about it. You might get some past the valves but since you just did them they might not be properly seated yet anyway.You'll learn very little from that.

Steve,

It is frustrating but surly not incompetence. It is just bad luck.
Just sit down take a beer or two or three and change your mind on something else for a while and start all over again.

Two weeks ago I started to swap the oil pan of the 1915 touring with the bent nose from the accident about a year ago.
What I found is to hard to tell but what should be an easy oil pan swap became a total overhaul with about $1,000.- parts only.
It was frustrating and bad luck. I set it away for a few days ( the time to get the parts here) and started all over by cleaning every part piece by piece and found other parts to be changed.

Just a suggestion: set it back for a few days clear your mind and start all over again by taking the engine out and take it all apart, clean it and look for everything that could be wrong.

Good Luck.

Andre
Belgium

Have your taken your timer off recently and replace or cleaned the bruch or roller. Easy to get timing 180 degrees off.

Your compression test saga/story is similar to this one written in 2012 by Bill Stephan. (There's much more info in the link.) How wide is the 'circle' of contact between the valve and the seat? With all the soot you've likely got in there, a wide contact surface is prone to fouling with resulting leakage. If you've already looked into all this stuff, I apologize for repeating. Good luck, jb

http://www.mtfca.com/discus/messages/25 ... 1325953529

By Bill Stephan on Friday, January 06, 2012 - 01:24 pm:
So the other day, I finished putting my top end together, New valves (1/64 os) adjustable lifters (1/64) new springs keepers and pins. Lapped the valves and everything looked 100%!! Set the lifter clearance at .022"
Did a compression test and the numbers were 5-35-15-10 not too good. I pulled it all back today to see whats what... Ive blue checked several and so far all Ive noticed is about a 25% contact by pushing down with my finger. If I give it a tap with a piece of brass, I can feel the valve settle down into the seat another .010" and make 100% contact. The valve then needs to be popped back off the seat with my knife under the stem. The cylinder that showed 35 psi doesnt do this. I tap on it to seat the bluing and the stem twists right back up and out.
I think I am gonna try swapping valves around... any other ideas??? ws

Steve, I looked back through your posts and I do not see any mention of what your valve lash is? When you lapped them, did you blue them up and look at the valve and seat to see what the contact area looked like to confirm full around contact?

Weak valve springs? Just a thought.

I still say" it is a problem with your rings". Nothing else suggested would change between a dry compression test and a wet test with oil. Think about it. Stuck rings, broken rings or worn out rings.

Well we know you likely have:

broken rings or
worn rings or
bad valves or
worn guides or
timer roller out 180 degrees or
weak valve springs or
wrong valve lash or
sealant on the head gasket is keeping it from sealing

And we also know:

that it would be a good idea to do a leak down test and
that it would be a waste of time to do a leak down test, as it would be worthless

Evidence presented indicates that this can't be fixed and should be sold

I’ll give you $6 for it !!

You’re a treasure Scott !

let’s start this !! Opening bid ?? Anyone ? Anyone ?? Bueller ?

Steve is a friend. I will give you $20.

Steve,

The chalenge you face-up will help other folks like us to resolve a similar issue in future. I'm really impatient to know what is the cause and the solution. Scott is a master making a good résumé of all different options you may have... I'm in for $20 .

Steve,

With all due respect, take a break and breath slowly.

I'll share a personal saga as there is a point in there somewhere. I just can't tell an anecdote without writing an epistle!

I've been a roadside master Model T mechanic for going on 50 years now, I reckin'. Only once in my life did I need vulture wagon and later analysis put that problem 100% on me. (I had turned in the clutch fingers an additional turn for good measure for some unfathomable reason and on the first hill that clutch locked up in high tighter than a drum!) I might have gotten it roadside, but that was one of the first Elgin road race re-creations and it was coming on banquet time and I wanted to get home and back. In fact, I was heading home to change and one fellow member arranged for a roustabout crew of roughnecks to get me home. In my troubleshooting later, I backed off the clutch fingers that turn, installed those cotters, and that engine is still that way today with both low n high! Over the years I took delight on learning and paying forward by helping others get theirs home without need for a vulture truck.

Then I shattered my kneecap in 50 places and at the same time had already arranged to move one of my T's to Florida so I'd have T's at both places. Between immobilization for months, then learning to walk again from scratch, and the Florida hot days in the garage...the car sat forever and stupid me got it fired up and learned how to drive it getting in and out with only one good and reliable leg. All set for a weekend muster up I dumped in a couple of additional gallons of Florida fuel atop what was stabl'd New Jersey fuel and....didn't make it a mile! Because of the muster...no one was willing to help so I was on my own and couldn't get under the car! Vulture wagon from AAA and it was back in the garage. It sat...really sat...disgusted with it and then I did some work and the fuel system had black goo! So I figured just slosh all that crap into the next universe, rebuild the carb, rifle rod the fuel line and hey...good to go, right? NOT. Couldn't start that thing to save my butt!

I became disillusioned for a bit but still took modern iron to car meets to roam and chat. One guy who Scott C knows well and who lives in N. Reddington beach took pity on me and called one day and offered to stop by.

Took him 15 minutes and he said it was a stuck valve! I said, Nahhhhhhhhh.... He went on to prove it to me relatively quickly (he had apparently had a similar issue on his 27 a while back). Cylinder #1 came through fine. Cylinder #2 would not pass the thumb test on the spark plug hole at max compression...no poof! He told me to get top dead center on #2 at the top of the ignition stroke and he looked and prodded and declared, yup...a valve was actually floating open and not closing. Let's hope it isn't the keeper he said!

He then used a drift and/or screwdriver, and tapped that valve hoping to seat. Dumped in some Kroil or the like and tried again. Itthen popped down. Turn it thru again, still hung...he'd tap it down again. We did this maybe 10 times and I was willing to give up but he said, 'Yo, we're gaining on it!' and maybe 2 times later it following the cam rotation perfectly! Hooked up the plugs, gave it a whirl, it roared to life! We took it for a ride and he commented how nice and smooth it drove. Nick Miller of Sun Coast T's is now my hero

I share the story because it could be that simple and as to the low compression, my own experience is that as long as there is some compression/any compression and you pass the fuel and ignition part strong...it'll eventually start and run. Maybe not have any guts behind it, but it will idle!

Good luck...you'll get it.

George

that was a nice shout out to Nick...a very nice guy

I'm surprised this hasn't been one of the recommendations...

I'll bid $30.00 for Steve....his pictures are worth more than that, and the effort he puts into describing hois travails...and the responses that his words elicit are PRICELESS!

Dave

Check your rotor! If your cam is drilled all the way through you can easily put it on backwards.

Steve, is this the fresh engine you just had the crank changed in? To me, it sounds like the cam gear is a tooth off or two.
If I can, I will offer three rolls of charmin ultra strong, half a bottle of hand sanitizer, and $25 cash!

A valve seat should be cut at two different angles, 44 degrees and 45 degrees and the face of the valve should contact about a thin dime. Valves repeatedly lapped have too wide a surface contact. The valve guide also tends to get out of round. Are you experiencing backfiring? I would swear by Sioux Valve grinding equipment. Did you replace pistons when the new crank was installed? I’m working on an A now with a friend and measurement is the key.

If I remember correctly you lost a freeze plug and dropped most if not all of your coolant on your way home from the OCF. I would suggest removing one of the pistons and checking the rings and bore of the cylinder. Maybe checking for cracks while you are in there. Keep us posted on your progress.

Hi Steve...

I see that you are now online...any update on your situation? Dave

For a few days I've been taking a vacation from working on the car. Soon I'll turn on the air and do the leak-down test.

The coolant loss may have done some damage, or not, as I have no idea if it happened just before I discovered it in the parking lot or sometime the day before. If it had any effect it was to make matters worse, because the hard starting and lack of guts began before that.

Just a quick thought:

Maybe 40 years ago, I had a 6000 Ford farm tractor. My son got it hot, but no hot enough to hurt anything - we/I thought. It turns out that it got hot enough to draw the temper out of the rings, but not enough to crack anything or score the cylinder walls. I had the same thing coming up Black Mountain on I 40 in North Carolina with a 318 Detroit Diesel. Collapsed rings, but didn't hurt anything else.

Could the same happen to a Model T? Beats me.

Good Luck Steve - thanks for the update1

I hope that it is not too serious...(may be selfish of me, but I do not wish to have you take so much time repairing things that you don't have time for your pictorial explanations.

Dave

Read the wet/dry comp test results; Rings. It's rings. It's the only thing he didn't check through the hard starting situation. It's very simple guys. Very very simple. Compression that low in and engine with compression that should average say 55 Lbs = hard starting. It's why I always check T compression on a cold engine. That's what the conditions will be when first starting up.

A rotor on 180 degrees off won’t make the compression low, and it will never run that wat way.
I’d make sure all the valves have at least .010” clearance, although .008 would be ok.
Stale gas can make an engine hard to star and run crappy.
Take the plugs out and watch the spark jump while spinning the engine with the starter or hand crank.
But you have a compression problem.

With number one prison at top center wen you hand turn the enginback and forth slightly or rock it back and forth in high pedal , the valves on either number one or number four must start to open and close, depending on which cylinder is on the fire stroke. That will tell you if the cam is in time with the crank.

With number one piston, not prison.
With that much variation in compression it probably is not cam timing.

doing a compression test dry, then squirting oil into each cylinder will indicate whether or not the rings are perfect. It will not indicate relative wear, discern between worn or broken rings, nor account for the cumulative effect of several or many faults that an engine may have.

a vacuum gauge and proper diagnosis on an engine once coaxed to life will detect:

a problem with rings
a sticking valve
burnt or leaking valve(s)
loose valve guides
late valve timing
late ignition timing
leaking intake manifold
blown headgasket between cylinders
choked muffler

It is a very versatile test, but is not widely used or understood these days. One of the few guesses posited that it will not detect is a timer mistimed by 180 degrees

Steve you must have alot more patience than me.That engine would be in it's smallest parts until I found the issue if it was doing that to me.I know,it is better to walk away a day or so,but this long,Nope,I would have torn that thing down today!

Scott might have something there with the choked muffler. I don't remember if you tried it with the muffler off. Worth a try I've had plugged exhaust cause all kinds of weird problems. Good luck and keep us posted. George

Hey Steve,

Any update of thesituation. I'm impatient to know the happy ending.

Steve, we're all sitting here on the edge of our seats waiting for this mystery to unfold...... It's like a thriller at the movie house!

Could you please give us an update? We can hardly wait.

Thanks,

Keith

No news is no news. Saturday was windy, as sometimes happens in Kansas, and a strong gust caught the south door of my shop and wrecked it, and I do mean wrecked. For now it's bolted back in the frame and I'm using the north (back) door. Before I replace the door I'm building a porch roof that will keep the rain off it. I've poured the footings for the poles, and lumber will be delivered tomorrow. I hope to get the project done this week and then get back to Model T work.

The roof will cover the big garage door so rain doesn't blow into the shop, and will keep rain from weakening the small door as well.

Hi Steve, Thanks for the update, even though there's been no recent progress. It's good to know that thinks are ok for the time being and that you'll get to it when your more immediate projects are done. In the meantime, we're still interested in this mystery of yours and will be patiently waiting for the news.
Thanks,
Keith

So I have been watching this thread grow in popularity since your original post, and I finally read thru the whole thing. There are a number of good suggestions, a few good stories, and a little bit of thread drift. So I’m going to do my best to keep on topic...

You already identified your hard starting issue... low compression. But what’s causing the low compression...?

Is the head gasket sealing? Yes! A couple times you report the same compression readings after swapping the gasket and surfacing. This is an easy one to get right too

Are the rings sealing? Arguably they are leaking as shown by the wet compression test... but are they leaking too much? I don’t think so. You had the head off to change the gasket, my guess is that you would have noticed an 1/8” of ring gap...?

Is the cam out of time? Easy to check with the timing cover off... not so easy without! You could look down thru the spark plug hole and pull the engine over with the hand crank. The valves should have near equal “overlap” at the top of the exhaust stroke. If you are a tooth off, the overlap will be offset whatever 1 tooth equals in crank degrees (15?). You should be able to see this without a degree wheel. But in reality, this is a hard one to screw up during assembly, and all 4 cylinders would show the same issue

Are your valves sealing? This is the one I feel you should consider the most. Model T valve springs are reaaaaaly weak, and it takes spring pressure to seal the valves. Valve seat pressure is the simple formula of spring force divided by the surface area of valve contact face. If you double the contact width, you half your spring pressure! The 3 angle valve grind is not a performance grind, it is the bare minimum to achieve proper seat contact area, maintain seat pressure, and therefore ensure a good seal. Of course you can have concentricity, roundness, and guide clearance issues that will all negatively affect the quality of your valve job. As stated above, it’s common practice to grind your valves and seats 1 degree different. This technique ensures the maximum spring pressure due to minimum contact area, and so wears away almost instantly. Also, when you do your leakdown, try using the 10 pounds you questioned originally. The 80 psi suggested above could actually force the valves closed and cause them to seal better and provide you with a false sense of security. The same effect that causes an old motor to start hard and “run fine”. Run the test again with the lower pressure, and the leak may be obvious!

Why do your compression readings vary? You are hand cranking! We all get tired... your readings show a relatively consistent pattern and so I can believe they are relatively accurate, but I believe some of your wild wet/dry readings could be explained by the additional top end lube and/or operator fatigue

My .02 cents... pull the head, throw away the lapping sticks, and grind em right! She’ll probably purr like a kitten

Sounds like you are gaining on the door. I wish it were easier to come over to give you a hand. Be safe. jw

Steve, we're all still sitting here on the edge of our seats waiting the happy ending and knowing if the hero will survive... I finished all my popcorns!

Steve has been busy on another project:

http://dauntlessgeezer.com/blog420.html

Yep, I need to get that door replaced and finish getting a roof over it, then I can get back to Model T adventures.

Steve, for what it's worth...I would have to be 10 times the mechanic I currently am in order to be as "incompetent" as you.
See you at OCF (hopefully)
John

What is the verdict, is the shop fixed, how about the 15 Runabout?

I learned a long time ago that, "when something goes wrong, look at what you did last". This is a long series of posts to go through and I may have missed some early points so excuse my ignorance. One of the things you did was mill the head. Did you use the original head bolts and check to see if the bolts were bottoming out? I recently made this mistake and resulted in the same conditions you have. I ended up with new head bolts. The combination of milling and perhaps stretched bolts could be your problem. It seems so simple but I would check. Dick C.

I agree with Dick, however, 'what you didn't do last' is important too, I'm still concerned valve function/dysfunction may not have been adequately addressed earlier. Good luck, Steve, you are a good sport in sharing all this and maintaining a sense of humor when people offer you $5 for you car. Please let us know 'the final answer(s)' when you know them. jb

New porch is done, but I still need to replace the broken door that's bolted shut. Then I'll replace the bad air regulator in the shop and get back to Model T work.

Hey Steve, when will we get to hear the "rest" of the story?

He is too busy on his map program trying to figure out where Scott is going to drive next.

Mark, thank you for the link! Been too busy.
Steve, thank you. Too much to say and my brain is pushing me to other things right now. Jalapeños? Oof. HOT. Good for us tho.
Awaiting the answer here too.

Steve, you could make a nice T table with the differential housings as legs. So if anyone stays at your house guest room do T parts fall out of the closet?

Steve Jelf wrote: ↑

Wed Apr 22, 2020 12:57 pm

New porch is done, but I still need to replace the broken door that's bolted shut. Then I'll replace the bad air regulator in the shop and get back to Model T work.


IMG_5050 copy.JPG

Steve, First I have not read all of these replies, but one thing comes to mine when doing compression test is that the throttle needs to be wide open, that fact will not cause a variance from cylinder to cylinder but is part of the compression test procedure. Good luck .

After taking April off to attend to other things, I got back to this today. A month of sitting didn't cure the compression: 33,15, 25, 20.

I tried the leak-down test and it didn't make me any smarter than I was before. I set the regulator at 60 psi, set each cylinder at TDC, and shot in the air. I could hear air moving somewhere, very, very faintly. I think it may have been in the exhaust manifold, but the sound was so faint I'm not sure. With a stethoscope I couldn't hear anything at all. I think this engine needs to go to somebody who knows what he's doing.

A stethoscope won't do it. a piece of vacuum or fuel line will help. Put one end in your ear and hold the other near the carb, muffler outlet, oil filler, radiator filler, and other spark plug holes. With a piston on TDC compression, air out the carb is intake valve, out the exhaust is exhaust valve, a little in the oil filler is normal ring gap, while a lot is broken ring, ring land, or head gasket. Other spark plug holes or radiator filler is also head gasket.

Jeff, I'm not trying to be an old fuddy duddy on this but like I said before, "have you cleaned the head bolt taps in the block and measured the head and tapped hole to ensure that the head bolts are not reaching bottom and failing to tighten the head? I know this sounds simple but my recent experience was that way. Cleaned holes and new bolts did the trick and was simple to test. Dick C.

Steve -
Take off the manifolds and do the air test again, setting each piston at TDC. If the exhaust valve in a cylinder is leaking, you will feel air pushing out of the port for that cylinder. The same with the intake. Repeat for each cylinder. You can get a better feel for the leakage this way than by leaving the manifolds in place and guessing whether it's the exhaust or intake valve that's defective. Hold a piece of paper over the open port. If it flutters, there's your culprit! Using this method, I found that valve #6 in cylinder #3 was leaking in the '24 Coupe's engine that I'm redoing, even though we cut new seats with Neway cutters. No matter where we set the piston in the bore, air leaked past the intake.
You may be sacrificing manifold gaskets to do this, but they probably needed replacing anyway. Be sure to use the high dollar copper gland style gaskets. They seal very well and will eliminate possible intake leakage that could contribute to your engine's problems.
Marshall

Steve have been following this thread as well and on my new to me T finding a stuck exhaust valve on #1 with zero and the rest in the 50's. After going through new lifters, valves/springs ect. got the head back on and torqued this week. Will get back to my T later this week and hope better results from #1 when I do a compression test.

Hope all goes well for you and as others have mentioned it turns out to be an easy fix, and after all this you may have something to add to your "model T articles" on your Dauntless Geezer site. Your Model T articles on that site have been very helpful to me getting my 26 back together. The "how to set model T timing" was perfect and only had to make slight adjustments to my timer rod.

Incompetence, absolutely not. That's why it's called "troubleshooting" a problem

Has this engine overheated at some point? As in take the temper out of the rings?
Also,I know this is a LONG shot,but does anyone know if a cam gear on the crank shaft can shear the key and cause timeing to be off just enough that valves are open at the wrong time?
This is a odd issue and I feel like the problem is not going to be a by the book problem.Something odd

Well, I did the test today following Marshall's suggestion of removing the manifolds.

With strips of tissue hanging over the ports it wasn't hard to see air movement. #3 was the worst, and you can see the tissue on #3 exhaust blowing in the wind. Most of the valves leaked at least a little. I'll do this again and take notes on which valves are especially problematic.

I also stuck a hose in the oil filler and listened to the crank case. I could hear air on every cylinder. I think Fred and Mack are on the mark with their suspicion of fried rings. It probably happened when I ran out of coolant in Illinois last September. I hope that incident didn't damage any more than the rings. I shot some oil into #3 and listened again as I applied the air. I could still hear air leaking past the rings, with a little gurgle of oil blowing through. Looks like those pistons will be coming up.

Great job Steve !! Sounds like you’ve made some positive conclusions and can move forward now.
I also hope there’s no major hidden damage to the block. Probably a scuff with a hone and new rings will cure the bottom end.
I would double check valve clearance before removing them, just to see, but the valve seats should be obvious once the valves are out.
Carry on....

Great idea about the tissue paper, I hope you can salvage some for the bathroom.

I hope you can salvage some for the bathroom.

I always buy the biggest package for the lowest price, so I had a stock to last several months when the Great TP Panic of 2020 arrived.

Sounds like a valve lapping ,a cylinder honing,and some new rings might get you going again.

If it did get that hot, the rings may be compromised. A little honing and a new set of rings will fix that, as long as the pistons and cylinder walls are not damaged? I think that you also need to get the valves and seats properly ground and the lash properly adjusted.

Steve, all the suggestions being made are good a valid. It would appear that you have multiple leakage issues. This was the situation I had recently and why I suggested the simple approach to first ensure that your head bolts are not bottoming. Before you take everything apart, just check to make sure this is not your problem. In my case, I tried to torque one bolt and it snapped. That meant a lot more work than necessary if I had checked the bolt measurement first. I'm out of your hair now, best wishes. Dick C.

Steve, all the suggestions are good but before you do a tear down please check the head bolts. With all the leakage that you seem to have with the air leak down test, it may just be the proper torque is not possible. Checking the head bolts is easy and not too invasive. I'm out of this now, Best wishes, Dick C.

Sorry for the double message but I didn't think the first went through. I guess it is late--or maybe too early!!!!

So the majority of you have finally settled on rings? Good O. It's the correct answer.

Today I finally pulled a piston to look at the rings.

After previous discussions I was expecting the rings to be fried and breaking apart, but I can't see a thing wrong with these.

What I did find wrong was what look like rust spots inside two of the cylinders. This is in #3. They aren't terribly deep, but I can feel them with a fingernail. I suppose they must contribute to the leakage, but they can't be the main problem. There are none of these in #1 and #2, and #2 had the worst compression of all.

These are in #4. I suppose they must have come from a leaking head gasket, but I didn't find any coolant in the oil.


I think the main problem is valves.

The gasket leaks that I have experienced leave drip trails from the leak point, and also leave a rust ring where the water sits on the top ring. These rust spots look more like condensation to me...?

The valve contact area on our valves looks really inconsistent, and we already know they were leaking... but you neglect to show pictures of the valve seats or discuss how the valve seats were cut/ground/lapped

Steve, I don't think that pitting in the cylinders is causing any detectable issues. I do see some slight scoring o the piston skirt, but nothing worth worrying about. Are those cast iron, or chrome rings? Chrome rings can withstand higher heat ranges than cast iron rings.
Can you show us pictures of the valve seats? Did you ever check and see what the valve lash is? Also, check the clearance between the valve stems and valve guides.

Hello Steve,

I will cut to the chase. With the vertical scoring completely around all three rings, the rings are trash. The vertical scoring on the piston and cylinder walls also leads me to believe the piston and possibly the rings started to seize in the cylinder. If you can feel the vertical scoring in the cylinders with your finger nail, the cylinder scoring is excessive. This appears to be your main problem to me.If I remember correctly you did state the engine was overheated at some time during your travels.

Now for the rust pits you can feel with your finger nail. Those types of rust pits can damage rings, although I do not feel it is the primary cause of the ring failure at this time. If it was my engine and I wanted it reliable I would be re boring it.

On the valves. It looks to me like they are basically seating about one third of the way down from the top of the valve face (the shiny area) which is correct. What I see wrong is the seat width is not wide enough and is inconsistent around the diameter. I believe this is a secondary problem that should be corrected as well.

Respectfully,
Terry.

The compression would not have gone up with the addition of oil to the cylinders if the rings were good. It's not rocket science. It's n.g. rings. The valve seating is nothing to scream about either BUT re-read line one of this post.

OK, I don't know if the pictures are good enough to show anything, but here are the valve seats. There are two shots at each cylinder, one from straight above and one from the side.

#1:
#2:

#3:

#4:

A couple of questions before I go check some other things:
1 This engine is already bored .080" over. That's the safe limit isn't it?
2 Would a cylinder hone be an adequate alternative to reboring?

Steve

you absolutely MUST change the rings. It isn't terribly expensive or difficult, but if you do not, Charlie will haunt you forever. It will of course not fix any of the air blowing past the valves, but at least he will be able to sleep at night.

I think you have a pretty good grasp on what needs to be done, including figuring out why so much moisture got into #4. That thing looks nasty and I wonder at this point if you don't have a crack in the head somwhere that bead blasting and dye penetrant testing might uncover. That's a lot of rust in the top of that cylinder to not have a blown head gasket obviously showing up

Steve, did you clean the top of that piston? Or, was already that clean? Show us the tops of all four pistons. Also show us the chambers of the head, if you have not cleaned it up yet.