It happens every two years and always on the day of a joyously anticipated car-show. -Fortunately, this was a local event, so the short distance involved allowed us to limp there and back.
Symptoms are as follows: The engine starts just fine and runs smoothly as long as the spark is fully retarded, but advancing the timing causes extremely rough running and an occasional backfire through the carburetor. -I haven't had time yet to grab some tools and dig into the problem, but the first thing I'm planning is to pop off the timer housing for inspection and cleaning. -If that doesn't cure it, I'll go back to lip-flibbing basics like checking for loose connections and cleaning the contacts in the coil box. -Any other ignition-related trouble-shooting suggestions would be most welcome.
Front timing cover to pan bolt in from bottom up? (Like most people put the rest of the bolts most of the time?) That ONE bolt, on SOME cars, will short out the timer contact only SOMETIMES! With a slight difference in the bolt, some cars will short the contact most of the time and be found quickly. Other cars will short the contact never, and never need to be found. A few cars will drive their keepers mad. It does come up on the forum occasionally, and I would expect that you may have checked that in the past. But it may be worth a look?
Drive carefully, and enjoy, W2
I had symptoms like that when one of the timer wires chafed thru the insulation at the clamp that holds the wire harness to the frame. Moving the timer lever would move the harness into contact with ground. That meant one coil was always out of time.
The problem discussed by Wayne and Royce is very common on Model T's. Worse yet it can be very elusive to trouble shoot because as the timer case moves the short may be intermittent. The timer area is not easy to carefully inspect for this kind of trouble. As Royce states the coil with the wire short to ground is now out of time and if left unattended will cause the coil to overheat due to exceeding the its duty cycle.
I see the effect of this problem all the time rebuilding coils, sometimes inside the coil and sometime outside. The over heated tar will literally boil out the top of the coil.
When receiving customers coils exhibiting this I always call them to discuss what to look for and suggest adding the timer wire forming fibers to help prevent this trouble.
Timer wire retainer T-2124A-PDF.pdf (44.1 k)
Well, I cleaned the timer with degreaser and electric contact
cleaner spray, inspected for shorts, and lubed and assembled it.
But the stupid, blankety-blank engine still runs rough, skips and
pops, particularly when the spark is advanced (and there's an
occasional, metallic "ting" in there that has me worried).
Went to Pep Boys and picked up some Liquid Wrench, a magnetic
probe and some Marvel Mystery oil. -The spark plugs were awfully
tight but all came out except the one on which my back got
sprained. -I may have to get a special wrench with a leverage
extension to loosen The Spark Plug from Hell.
Explored the three open combustion chambers with the magnetic
probe, but only came up with some carbon powder, so at least
there aren't any broken valve parts in three of the four cylinders.
Gonna take a break and let the Liquid Wrench soak into that last
plug before wrenching on it again—ain't worth injuring my bionic
Right now, the plan is to spoon some Marvel Mystery Oil into each
cylinder, pour some into the oil sump, start the engine and see if
what they say about MMO is true. If that works—great. If not,
the remaining possibilities are worrisome.
Well, it's a week later and I'm no closer to solving this rough engine problem. The timer was thoroughly cleaned and inspected, and I checked and polished every ignition connection with scotchbrite.
The Ford sparkplug wrench was just rounding off the points on the stuck plug, so I searched around town and found a 6-point, 15/16ths deep-socket. -Man, it's amazing how having the right tool makes short work of everything. The sparkplug came right out.
Okay, so I doped each cylinder with a half-spoon of Marvel Mystery Oil, poured some into the oil sump and gas tank and fired her up. -After about ten minutes of rough running, nothing changed. -So much for the mysterious, perfumed oil.
I tested the coils with the engine running — nothing; shorted out each sparkplug cable to the head and discovered — nothing. -Now, I'm running out of easy things to check, but there was one thing left: -I ordered a new set of plugs from Lang's. -Figured it couldn't hurt and maybe that'd be the answer. -Don came to the phone and after listening to my tale of woe, mentioned the possibility of a burnt valve, recommending I get a cheapie compression-tester from Harbor Freight if the new plugs don't cure the roughness. -Oh, good grief, I sure do hope I don't have to learn how to replace a blankety-blank valve!
Bob Have you tried turning off all of the lights fire up the motor and look around the timer wiring harness and coil box with someone else manipulating the spark control lever?
It sounds like the timing has slipped, so that with the lever all the way up the timing is correct, but when you pull it down you get too far advanced - backfires, pings, etc.
It's just a guess, but my first take is that the pin that holds the timer roller in place has fallen out or sheared, and the roller (or whatever rotating piece your particular timer uses) has rotated on the shaft.
If you find the roller tight and in correct position, check to see if maybe you hit a piece of trash on the road, and it jumped up and bent your timing rod - the one from the steering shaft to the timer. Less likely, but possible.
It doesn't seem as likely that the timing gear has slipped, because then it wouldn't run well, if at all, at any position of the timer.
Hope this helps!
What shape were the old plugs in? A compression test isn't a bad thing to do as it'll give a reasonable idea as to the condition of the engine. How does it actually run? That is with the lever retarded does it really run well or is it doing the same thing to a lesser extent because of the low revs? It really does sound like an ignition/timing problem but you've checked/repaired most of that stuff. Puzzler. Put a test lamp on the coil box feed terminal and see if the juice is steady there. Intermittent feed power to the coils would cause your problem. I don't see a burned valve myself. "Off the wall": How's the carb needle setting? Farmingdale Wednesday.
PS: Happens both in batt & Mag?
Yeah, I tried the spark-in-the-dark test, but as the problem remains undiagnosed, I think that test bears repeating.
I don't know whether the timing has slipped any. -The car starts normally and runs normally for about 45 seconds after I advance the spark and then it goes rough and stays that way. -That suggests something thermal.
The old plugs look okay, if a little sooty, but I've been told that spark-plugs are kind of hinky in that they can look okay, but still be shot. -For less than $4 per plug, I may as well change 'em out and eliminate that variable.
The engine runs as badly on battery as it does on magneto, so it's not the mag.
I checked what you said about the engine running less rough because of the lower revs of retarded timing rather than because of the timing itself and whereas last week, I was able to limp to and from a local car show, yesterday, the car bucked so badly after I up-shifted, I didn't even try to drive around the block. -Now, even with the timing retarded, the engine roughness increases with RPM. -Looks like something may have worsened.
Would you please elaborate on your suggestion to put a test lamp on the coil box feed terminal? -What kind of test lamp and how do I hook it up?
I played with the carb needle setting and that doesn't seem to be the problem.
I agree with you that this doesn't "feel" like a burnt valve. -My gut says there's something wrong in the ignition, but hey, I could be wrong—happens all the time—just ask my wife.
Try changing out the plugs. You may have a bad one.
I was having some similar problems last few days so bought a coil box rebuild kit from Fun Projects and it seemed to do the trick. In fact, so far, this car ('15 Touring) is now even starting easier. For the first time EVER it started up on a cold engine, only two primes, on the second yank. With my sore shoulders, thought that was pretty good!
Check the terminal washers on the timer. I have had them crush and short the stud to the case. You have to remove them to know for sure. It will be an obvious burn or crack in the washer.
Original tapered washers won't do this but the repos are square edged.
Bob, try this. Advance the spark till the problem is present.....then short each plug, one by one till you can figure out which one is the offender. Sounds to me like it's a timing problem. Run it at night and see if you can see an offending spark somewhere.
The positive feed terminal is the one that's kind of out of line with the 8 that are grouped together. 4 to the plugs and 4 to the timer. The one off to the side is the positive terminal that feeds the coils. Hook a test lamp up to it. ^ volt is best but a 12 volt will work also. It'll just be a bit dimmer. The lamp should give a steady glow when running. If it flickers there's a problem. Possible ign switch. Check the connections on the terminal block too. I'm leaning a bit with the suggested coil box/carbon tracks guys.
Is the cam pin in place for the timer roller? My roadster acted kind of like that and the pin was gone. It slowly got further out of time. PK
That ^ should be a 6
Do the compression test as Don Lang suggests.
Well, I got some help from a couple of really nice guys from the forum. -One stopped by my house to do a compression test (all 60 and above) and took the coils home with him to overhaul them. -The other gentleman tuned the coils for me. -This isn’t the first (or second or even third) time I’ve been the recipient of an expert’s time and skill, and for such kindnesses, I’m very appreciative. -Y’all know who you are. -Thanks, guys.
Unfortunately, the new coils didn’t do the trick and after a couple of minutes of normal running, my engine went rough again with one of my coils grounding out with a continuous buzz. -With the remaining suspects consisting of the timer, harness and coil-box, I’ve been advised to do the easy thing first and bypass my existing harness with a new, 5-wire harness which, at that point, would operate side by side with what’ll be left of the old harness whose function would then be limited to supporting non-ignition accessories like headlights, alternator, etc. -Makes perfect sense.
Regardless of whether the timer eventually turns out to be the causative component, I really should have a compatible spare, anyway. -My first instinct would be to go with the new TW unit as nothing but good things have been said of it and I’ve been advised by an expert that this is the way to go, but that would be introducing an new variable to a yet-unsolved problem, so what I’d like to do is find another Ford roller-timer (assuming any Ford timer will work on a ’15-vintage engine). -Problem is, NOS or rebuilt Ford timers are difficult to find, so if any of you folks know a source from which I might purchase one such unit, I’d sure like to know.
Check behind the roller if a chewed up brass plate is your "grounding out with a continuous buzz"..... check for brass slivers on the inside of the insulator/terminal grounding out to the case.
The brass plate was used to retain the felt seal. Chuck both plate & seal & use the modern neoprene cam seal. .....or just chuck the brass & felt, clean the commutator see if the engine runs better. Without some sort of seal, that point would be a oil leak area.
AS discussed: Harness then coil box liner kit. One coil buzzing constantly is a short to ground.
Absolutely. Ordered a new harness yesterday.
In spite of the fresh spark-plugs and newly overhauled and tuned coils, my stupid engine is still running too rough to drive, so I ordered a bunch of inexpensive/easy-to-install ignition parts from Lang's and the box arrived this morning.
Got a new, 5-wire, timer-to-coilbox harness and a neoprene camshaft/timer seal. -Anticipating the possibility of the modern, neoprene seal not fitting, I also ordered an old-fashioned, felt-seal and if it turns out I need to use that, I also bought a new, brass, felt-seal shield. -Maybe my rough engine is being caused by a worn-out brass shield shorting out the timer? -Oh well, if that turns out not to be the case, the new shield was still too inexpensive not to buy.
If any of the above works and fixes the rough engine—great. -If not, it'll be time to get the coil box liner kit Charlie prescribed. -Though a very likely culprit, I saved that for last because installing it would be the least easy repair.
As I'm going to be dismounting the timer's rotor, it would be nice if I could position it with the hidden pin on top before I remove the lock-nut and pin-cap from the camshaft (You see, there's this pesky gremlin who lives in my garage and he'll be laying under my engine with his great, big mouth open, waiting to swallow the pin if I should let it fall). -To what o'clock position should I crank the roller so the pin will be on top when I unscrew the lock-nut and remove the pin-cap?
A few years ago I had a friend with a similar sounding issue. It would start perfectly then as timing was advanced and throttle increased it went rough. Believe it or not I for some reason put my hand in front of the tail pipe and there was almost nothing coming out. Turned out that it had a huge mouse nest blocking it. Cleaned the muffler and pipe and the thing ran like new. Never would have guessed that and he was ready to take the engine apart to see what was wrong. Just a thought if it has been sitting for a while.
Mike, friends of mine had a similar problem. Car would take off in Low just fine, then would hardly run in High gear. Turned out that the spare tire was up against a (reproduction) muffler with a tail pipe. There was enough power to blow the tire away in Low but in High the tire would stop up the tailpipe. Bent the spare carrier and the problem was solved.
Bob's situation sounds similar to one I had a few years ago and since I'd pretty much bullet-proofed everything else, Don Lang handed me a new 5-wire harness and the problem went away. If you have one of those reproduction harnesses with the metal Ford tag that were made in the past decade or so, watch out. Quite a few have failed over the years.
Short in grounding circuit for the coils. Some buzz constantly. Wiring harness or coil box wood lining NG.
Well, I pulled the timer, cleaned the heck out of it and stuck a new felt seal in behind a new brass shield. -Also installed a new timer-to-coilbox harness. -Finished getting everything back together at 3 AM. -Guess we'll see, tomorrow, whether the problem is licked (Oh. it is tomorrow).
Bob, check your fuel supply and delivery. It should flow a good stream at the carb for at least a quart without failure. Just catch it in a jar and pour it back in the tank.
My fuel supply seems to be okay, James. -What I have is one or more coils grounding when they shouldn't, so there's at least one spark plug lighting up out of sequence.
I've replaced all the spark-plugs and installed freshly overhauled & tuned coils; hung a new timer-to-coilbox harness; put in a new, felt camshaft-seal and brass shield; cleaned and polished all my cable-ends, wire-ends, terminals, thumb-nuts and the contacts on the inside of the coil-box; dismounted and cleaned the living daylights out of the timer and roller. -At this point, I've addressed, in one way or another, every piece of the ignition system from the dashboard, forward. -Today, we'll see whether the rough engine has been cured.
You do have that one pan bolt under the timer turned over, right? If not it sometimes can short a connection.
Hope you find the answer.
Larry, I don't have engine pans (if it's that to which you're referring).
No crankcase pan.
Check this thread and see the diagram.
Ah! -I see. -Will check that. -Thanks, Larry.
Started the engine and in spite of all the new parts, it ran
as rough as ever. -Man, this is getting old. -Was able to
locate and purchase a rebuilt, aluminum-housing timer; the
last one on the shelf. -Maybe I'll get lucky this time.
Just a thought. I had a problem with my 14 starting and found that the ground path to the engine was the problem. Just for giggles run a 12 gauge wire from the negative side of the battery directly to the engine and see if that helps. Another thing is to see if the contacts in the coil box are clean and bright. The bolts that connect the contacts were originally plated and I have found that the bolt to contact sometimes is a problem. When I rebuild a coil box I always solder the bolt to contact connection.
I had a case of a "whispering" coil in the '20 Coupe I had.
It was only a faint buzz.......actually more like a light hiss when the switch was on........and the engine was acting stupid.
I cleaned and cleaned the timer to no avail.
I finally took it off and checked for continuity and grounds and, sure as hell, I found an internal ground at one terminal.
Enough metallic dust had "imbedded" in one of the bottom terminals creating a weak ground and would not wash out.
I removed all of the terminals, cleaned, reassembled and bored it to true it up again after having disturbed the tightness of the terminals.......and it WAS out of round.
That cured the problem.
Well, it seems the answer to my problem was indeed the timer. -Had I the experience of
changing out a roller, I might have done that first, but figuring it would be too difficult a job for
the know-nothing newbie, I looked elsewhere for the answer (which sort of reminds me of the
old joke about the guy who searches for his lost contact lens where he knows it can't be, but
"...the light's better, here"). -That manner of thinking cost me six weeks of the driving season—
and as it turns out, replacing a roller is not all that difficult.
I was fortunate to buy the last rebuilt, aluminum-body roller-timer on the supplier's shelf. -The
roller seemed to be home-made and was a bit rough around the edges. -In fact, it needed to be
de-burred and some filing was necessary to get it to fit on the camshaft, but once installed, the
timer worked beautifully.
The original roller is on the left, the replacement on the right. -You can see the replacement is
beefier than my original and has a larger drum. -Somebody somewhere was a good machinist.
Well, the engine sounds great now and it'll be a pleasure to get the car back on the road. -My
next endeavor will be to find someone who can overhaul the original timer so I'll have a spare.
Bob, unless they are now making them correctly, the brass shields are not the right size and can move forward and cause all kinds of trouble. The shield is supposed to fit behind the timer case and be held in place by the timer. The ones being sold can slip right into the timer case. Unless the outside diameter of the shield is the same as the outside diameter of the timer I would not use it. You can put a bit of gasket cement on the back of the felt to keep it in place while you look for an original shield that is the right size or you can go for a modern seal and forget the shield completely. I have found enough shields at flea markets in the dollar piles for my cars but when I have access to the timing cover I switch to the new seals.
I'm Glad you solved your problem, Bob. I was going to comment that if changing the timing affected the problem, it would seem that the problem would have to do with the timing. Read as timer. Last Sunday my T arrived back at the house on a ramp truck for just the symptoms that you described. I immediately pulled the timer cover apart and found that one of the roller contacts had loosened, shifted, and beat the hell out of the roller as well as shorting. A new timer kit from Lang's solved the problem in about 30 minutes.
Bob, that roller timer is not the only type of timers available. 20 plus years ago I kept having problems with those roller timers shorting and jumping when the timer case got worn. (jump caused mis-fire).
I switched to an Anderson timer (ANCO) with a flapper. Almost all those timer problems were gone.
A purist might not like them, but I have my cars for fun, not for some silly judging contest.
--The outer edge of the old brass shield had been worn between the timer housing and engine to razor sharpness, which, I suppose, means it was of sufficient diameter. -I wish I could say the same about the new replacement, but I neglected to check on that before installing.
--My original intent was to replace the felt seal with a modern neoprene seal, but there was already a neoprene seal in there. -Unfortunately, it was leaking. -I couldn't get enough of a grip to remove it and install the new replacement, so I just stuck an old-style seal on top of it and held that in place with the new brass shield.
--Yeah, now I wish I'd have checked the replacement shield's diameter against that of the new timer. -I goofed that up, but hey, the engine is percolating happily and for now, I'll let that particular dog lie. -Next season, I'll probably stick a TW timer in there, anyway.
--Out of curiosity, I converted our approximate engine redline of 1600 RPM to revolutions per second, came up with 26 and cut that in half for the camshaft. -It's hard to imagine an unbalanced, low-tech roller whirling around at 13 revolutions per second over a bumpy track and holding together. -It's also hard for me to understand why the sparks generated in the small confines of the metallic timer housing don't overlap and short each other out. -No doubt about it; our timers suffer a heck of a lot of stress.
--I've been given to understand that Anderson-type timers can be sneaky in that, after you retard the timing for hand-cranking, the darned thing can spontaneously advance the timing and cause a bone-splintering kick-back. -I was going to replace my timer with the new, very reputable TW timer, but didn't want to introduce another variable to my puzzle (but at this point, I wish I had).
-I'm a semi-purist. -There are some things about the Model T that are so unique as to be part of the heart and soul of what defines the car, therefore I want an operating magneto and some kind—any kind—of rotary timer.
Well you've got 5 rebuilt coils with new caps & points and they've been HCCT'd. Your old timer wiring harness had electrical tape on it and the plugs are new. I'd say you made out OK. Nothing changed that didn't need to be. Lessons learned. Good Luck.
For the first time, I can hear the individual points ticking in sequence. -It's a much more precise sound than that to which I'd become accustomed and the engine will idle much lower than before, to the point where I can count the coil clicks. -With the newly overhauled & tuned coils, plus the new spark-plugs, harness and timer, my engine is running very sweetly, indeed.
Now's the time to go for ice cream ..... enjoy your ride !~