I go through about 1-2 sets of plugs each year, doesn't matter what plugs I use they all come out dead.
Best yet has been the Champion X they lasted about a year, worst were iridium plugs with an adapter for size, they lasted about 20 miles.
It starts with a misfire that occasionally you can power out of, then it gets to the point of no return. If I take them out and give them a clean I can sometimes get another 20 miles. But after that they are no good at all, out of the engine they look fine, good spark, correct gap, ceramic still intact!?
Up to now I have tried the following.
Carbs: straight through model T, normal T with the dip in the middle, model A, two model Ts, and a marble shelber (I can't spell it sorry.
New crankshaft, it snapped.
New camshaft, also waiting on another new cam.
Timers: 4 standard timers and an E-timer
All wiring replaced time and time again.
Coil boxs: two over engine boxes one with all new wood, one plastic coil box.
Difrent fuel grades.
Coils: hundreds of them!
I'm currently running waukesha Ricardo head, thinking about swapping that?
Any ideas? It's driving me insane!
Jeremy, more info on "dead" would be helpful for remote diagnosis.Are one or both sides of the gap burned away to nothing? Totally fouled? Broken porcelain? Pictures worth a 1000 words.
Hmmm, That's odd. Iv had the same plugs for 7 years. The one thing that is not on your list is plug wires. Maybe they are badly corroded inside and jumping spark inside the insulation? Are the plugs black and sooty when you pull them or are they really clean like maybe a leaking head gasket or cracked water jacket? When you first start the car is there any white or black smoke? Does the car start hard? It sound like you have covered everything else. The only other thing maybe would be low compression.
Your problem is a "puzzler"!!!
My suspicion is low secondary voltage to the plugs.
Are you running on mag or battery?
The E-timer on 6 or 12 volts?
You say "100's" of coils
1. So I will suggest trying ONE set of truly tuned up coils. No garantee, but just a thought
2. Running coils on 6 volt battery can be a bit marginal. The spark voltage is quite low. If you are running on straight 6 volt battery, I will suggest a distributor with a 6 volt coil
And how are you cleaning them? Hopefully, not with a wire brush. That will kill one in a heart beat.
I have two other Ts that are fine and have had the same set for years but they are running distributors.
I will get some photos, but they look good to the naked eye a bits bit black and wet with petrol but I'm not sure if that a problem of a symptom. But they produce a misfire when used.
At the moment I'm using an E-Timer with a 12v battery and no charging system.
I get a constant 75psi compression on all cylinders.
I normally clean them with a rag, but I have also tried a soft brass brush in the past.
Have you tried putting the "dead" plugs into one of your other cars? Don't clean them or anything, just swap them into one of your running cars and see what happens.
If the dead plugs work immediately in another car, then you know it's not the plugs themselves. Rather it will be some other component in the system. For starters, I'm with Les. Most likely low secondary voltage to the plugs.
Since you have another good running car, you can try swapping components (one at a time) from one car to another until you find something that makes your good car go bad. Caution: don't change more than one thing at a time as you won't know which component is at fault when the good car goes bad.
Please note, his other cars have distributors. But I like your idea of swapping the plugs to the outer cars!!!
And trying swapping the whole ignition system certainly has merit
I don't want to change this post but Hal Davis mentioned don't clean spark plugs with a wire brush? Can someone please explain why. I've used a wire brush in the past then blew them out with compressed air and never had a problem.
Many, many years ago as a "middle teenager" working at a full service gas station (remember them ?) - I was cautioned against scratching the porcelain in an attempt to remove carbon deposits.
Seems that a scratch somehow attracts "things" that lead to mis-firing plugs...think carbon-tracks in the wood in a coil box.
Scratching the porcelain, how does that work with the old spark plug cleaner on the bench of every repair shop? It was a sand blaster that you screwed the plug into and blasted away. I'm just wondering....
Metal from the wire brush will embed, at least on the ones with unglazed porcelain and maybe even those with glazed porcelain. One that metal is embedded into the porcelain, it acts as a conductor and the current will want to travel along it rather than jumping the gap.
Please post a clear picture of the electrode end of one of your "dead" plugs, thanks. If your camera has a macro mode, please use it for the picture.
Are you running a water pump?
Without a thermostat, I could see your engine running too cold and fouling the spark plugs prematurely. The symptoms you mentioned may indicate this condition
Les, I, too, was wondering the same thing. Plus, I'd sure get a set of known good coils. Anything less than perfect may misfire with high-compression heads. That may be why the distributor-equipped cars run well and this one doesn't.
some of the worst performing coils are the ones "tuned by ear" by the local expert. Purchase some correctly, professionally rebuilt/adjusted coils. You will be glad that you did.
I've run the same set of plugs for 20+ years in a car with a water pump. In fact, looking at them recently, the ground electrode was nearly burned in half on a couple of them. I'll replace them now. Should be no need to replace as often as you're having to. How rich are you running your carb?
Have you tried using old spark plugs, from the T era? Either "good used" or NOS? That's usually all I'll use.
Do the "dead" plugs still have continuity between the center electrode and the threaded top? Just checking.
Anyone close to you?? It sounds as if your wandering in the dark! Bud.
He refers to "petrol", so off shore some where!!!
Good eye Les!!
Have you replaced the wood in your coil box? The spark will take the path of least resistance and it might be jumping somewhere inside the box instead of through the plug. The new plug will conduct, but then as it gets burned, the spark finds another path. Another thing to do is to change to gap to a closer gap and see how it works. I don't know much about a Ricardo head, but higher compression causes difficulty with the spark jumping, so if that is a high compression head it would be another factor in causing the spark to jump somewhere other than at the spark plug.
Do your other cars have high comp. heads too? That seems to be the only thing different from a "normal" T. Hard to understand what's happening as you say they look fine when their removed. Do or did you check for spark to the cyls when the plugs go bad? Or I should say when your miss develops because I just don't see that many plugs going bad. Continuity check them or install in another car to be sure. Don't think the fact that other other car's have distributor's is a factor. I think you have an Ign system/electrical problem.
Jeremy, What kind of spark plug wires are you using? Resistance wires will work on a distributor ignition but not on a Model T ignition.
Same thing with resister type plugs. On one car we tried two sets of modern 14 MM plugs with the same results. The resistors do not like the uneven voltage put out by the coil and burn out.
Here's another poster guy that didn't list is location and we have no way of knowing if he is somebody next door...
Many here are not thinking about the fact he is running an Etimer so the coil ideas are not realistic.
Hard for me to believe its a plug issue... more likely fuel problem or something else. I know I always think electrical problem cause I can't see that..
Good luck and swap One thing at a Time
Please come back and tell us~~~
Sorry for the slow reply. I live in the uk in cheshire.
I will reply properly in a moment, I want to go and have a play first and test some theories.
Again thank you so much for helping, you have given me some ideas i wouldn't have thought of.
Some photos to be going on with.
The last one is after a clean up with a rag.
And I have updated my location after Gene Carrothers telling off.
A quick slow mo video of the cleaned pug.
To my eye, the plugs in the first three pictures look black and shiny, which indicates that they are oil fouled. Is the engine fairly fresh, or worn out?
The insulator in the fourth picture doesn't look as wet, but it is still black, indicating a very rich mixture. If the shell that the insulator came out of is wet, then that plug is also oil fouled.
The insulator in the fifth picture looks pretty good to me, is that the way it came out of the engine, or is that after cleaning?
Excessive oil will deposit onto the plugs and form a conductive coating that will provide an alternate path for electricity, eventually preventing that plug from firing.
Bad capacitor in the coils?
To add to what Mark stated, all the new plugs that I know of, uses a more porous, bisque finish on the plug porcelain. This absorbs oil & carbon that will short the plug out. The reason I use "antique" plugs, as I mentioned above, is because their porcelain has a glass-like glaze on it that does not allow the contaminants to be absorbed. This may also be why Hal frowns on wire wheeling plugs. The course, bisque finish of new plugs will be slightly abrasive and cause metal from the wire wheel to deposit on its surface, leaving a faint but somewhat conductive track for the spark to follow and ground it out.
BTW, the area of porcelain that I'm concerned with, is the portion that's inside the combustion chamber, not on the outside of the plug.
Adding to what I've said above, I think you still may be running too rich. Check your intake manifold gaskets/gland rings for leaks. A vacuum leak at the manifold gaskets will cause certain cylinders to run too lean. To compensate, you enrich the mixture and it seems to run fine. However, this automatically makes two other cylinders, not affected by the leak, run too rich. On the whole, you may not notice it, as all 4 cylinders may be operating within a "normal" stoichiometric range, but at extreme ends of this range. The spark plugs however are the "canary in the mine" that shows there's troubles in the air... or in this case air/fuel.
Just something more to check out.
I think Mark might have nailed it. Oil consumption needs to be considered. Mixture is of course a possible, but after all the carb changes mentioned??
With a E timer the capacitors wouldn't likely be a factor
If he's got a vacuum leak he'll keep adjusting 2 cylinders rich, no matter what carb.
Would be interesting if there's one or two cylinders that result in the worst plug usage. Has it been mentioned?
I certainly agree, but was thinking with the variety of carbs that he probably had changed intake manifolds. Perhaps not. It is a puzzler
With an Etimer, do you still use the coil box? If so, I'd do as Norm says and check the voltage available. Don't know about U.K. but at NAPA U.S.A. you can get a simple tester, or just do it the old fashioned way. Dave in Bellingham,WA
With an E-Timer, the coil primary and secondary windings must be good. The coil points are jumpered (shorted) using a small fuse jumper which bypasses the point contacts and capacitor. The point contacts will still vibrate/buzz but strictly cosmetic provided the fuse jumpers have not been accidently blown (open) by touching a timer wire to engine ground while powered. You can check the fuse jumpers are good using an Ohm meter set on its lowest resistance scale. Measuring across both point contacts should measure low resistance with the point contacts open or closed. The meter reading should be the same value as shorting the two meter leads together for this test (Less than 0.5 Ohms), otherwise, the fuse jumper is blown and should be replaced.
Model T coils can also suffer from an internal fault if they have been operated without a proper spark gap. Coils that have been power with a spark gap with a wide spark gap (greater than 1/4") or no spark gap can experience insulation breakdown and spark internally. That is why coils are tested (without the fuse jumper installed!) using a 1/4" spark gap to ensure the internal insulation is sufficient to prevent internal arcing. Coils that are observed to have missing sparks when tested (without fuse jumpers installed) using a 1/4" spark gap may suffer from this non-repairable defect and likely result in poor engine performance; even with the E-Timer.
Are you running the spark too advanced? I once had a 38 Plymouth and advanced the spark too far. It used to ping a lot and one day it started to misfire. The center electrode of one spark plug was gone! I set the spark back to the normal setting and never had any more trouble. Pre-ignition was the cause.
What type of motor oil are you using? Or, more specifically, is it possible that your motor oil contains graphite, or some other compound that may be shorting out the spark plugs? Or, and this is pretty far-fetched, but is it possible that despite what type of motor oil you are using presently, is it possible that sometime in the past, the engine has contained some type of motor oil, or possibly an additive, that has left some sort of "residue" in the engine that is shorting out the spark plugs? This truly is a very weird problem, and I can imagine your frustration.
By the way, several posts in this thread have mentioned something that I learned "the hard" way with my first car, a Model A Ford, when I was a kid. I had cleaned the spark plugs with a wire wheel in my Dad's shop, and after doing such, the engine would not run at all! Would not even fire! I determined that my Dad had used some sort of polishing compound, or something else that had contaminated the wire wheel to the point where it was leaving something on the spark plug electrodes, and/or porcelain, that was causing the plugs to short out,....FWIW,......harold
Not to change the subject, but I was surprised that several forum members that responded to this post were wondering where Jeremy Gibson lived. I thought everybody knew that just by clicking on a posters name, the profile will appear and thereby reflect personal information, including residence information. Or, I'm wondering if perhaps with the many electronic devises now available, like cell-phones, perhaps on some such certain devices, perhaps it's not possible to bring up a forum members profile as easy as can be done on a computer. Just wondering,.......harold
Yep he is across the pond. I would invite the author to send me a PM and I can perhaps give him some tests to run to determine what it is. I think he has so many helpers now that I don't want to add more because I fear that more problems will be added rather than some being fixed. He has tried all the obvious stuff so no point in doing that again. I would rather work offline so as not to have multiple tests being done at the same time.
If you have a car running rough especially under load, on a good dark night start it up and watch for spark jump. then you will know if your problem is in the wiring.
Man that sure looks like carbon to me. You're not complaining about oil smoke so I'm going with a rich fuel mix. On my first T, before I learned to use the carb adjustment needle, I did that to my plugs too. Got so bad it wouldn't run. Went nuts checking everything until I finally pulled them to take a comp test. (couldn't find anything else wrong). Was amazed at the perfect totally insulating coating on each plug. I wised up fast. If all 4 are the same I'm assuming you're having the same problem. You've changed enough parts for a couple of cars so I'll guess you can check the condition of your carb needle to look for any damage. If that's OK learn to use it properly. Again: I'm figuring you're not burning oil.
Jeremy,With Henry being cheap do you think between model T's and A's approx 21 million Fords had DRIVER carb adjustment if it was not ment to be used????? Bud.
OK guys fingers crossed (everything crossed) I think "WE" and I say we as its been a forum effort, I had run out of ideas, have solved it.
When I first had the car I opened the hogs head and found a little ball of sealant blocking the oil pipe to the front. So I fitted an extra oil line to the front. (first mistake)
About 5 years ago I swapped to a racing 10-60 oil, the racing bit means it has lots of zinc in it. (second mistake)
Since I have blocked the extra oil line i have don't about 300 miles and its not started to miss, fingers crossed for this weekend as I'm doing a demonstration sprint at the Flywheel Festival.
I'm sorry i haven't got back to people who have contacted me, I'm also in the process of moving house, plus trying to put miles on the car testing.
I really couldn't have solved this without everyone on this forum, I need to say a massive thank you to you all! I had run out of ideas and it was driving me insane!
Also a special thank you to Harold Schwendeman who very nearly hit the nail on the head!
Sorry when I said
"When I first had the car I opened the hogs head and found a little ball of sealant blocking the oil pipe to the front. So I fitted an extra oil line to the front."
I ment to say that I fitted the extra oil line to stop that problem happening again.
I can only think that the oil and extra oil line didnt show this problem instantly because my rings were sealing better, now they are getting old they are letting more oil past.