Weak Spark at #2 Cylinder

[TomW]

Hello All,

Last fall I got my father's T running after sitting for about 10 years. After a couple local rides, it started to run kind of rough, so I ended up rebuilding the coil box - the one in the car was very old and loose. This past weekend we got it out for the season and with a little coaxing, got her running. I took her out for a spin and as soon as I shifted into high gear, she struggled and was no faster than low gear - this was on level ground. So, I set about trouble shooting. I have a meter, shaped like a pen, that flashes when you touch it to the plug, cable, etc., I'm sure you guys know the name of this tool - I do not. Anyway, cylinder number two had a very dull flash, but every once in a while it would have a bright flash and I could hear the engine sputter at that moment. The other three plugs/cables had bright flashes every time. Also, when I took the plug out, it was wet. So, the first thing I did was change the plug - this changed nothing. Then, I swapped out the coil with three other coils and that did nothing. So to prove the new coil was good, I swapped it with #1 and it worked fine, but number ones coil did not spark well in the #2 slot - not the coil. Then I thought maybe it's the cable, so I swapped the #1 and #2 cables and still #2 had a weak spark and #1 was fine. I then pried all the contacts in the coil box out for the #2 coil in hopes that it wasn't making a good contact within the box - that changed nothing. I do know that, when testing with the flashing meter, that the flash was weak at the top terminal where the plug connects to the box. Is it possible that it is the bolt, itself? This was a brand new kit with copper bolts.

Any ideas?

Thanks,

Tom

[Moxie26]

Tom , .... It's possible that the wood in your coil box has to be replaced due to old wood and carbon tracking to ground. ... More so than having a bad connection at the coil box contacts or commutator. On the easy side, you can check the gap of your plugs... " 0.25" " gap works great for me.

[Jerry VanOoteghem]

Tom,

Have you had a look at the timer? It would be worthwhile to remove & inspect it. After that, I'd still suspect the coil box. What exactly did you do to rebuild the coil box? What new parts did you use?

[TomW]

Hi Moxie,

The coil box is all new wood and contacts. Also, I did clean the timer with contact cleaner. It was very grimy. But that didn't fix the issue either.

Tom , .... It's possible that the wood in your coil box has to be replaced due to old wood and carbon tracking to ground. ... More so than having a bad connection at the coil box contacts or commutator. On the easy side, you can check the gap of your plugs... " 0.25" " gap works great for me.

[TomW]

I bought a rebuild kit from either Langs or Macs. It's new oak, copper contacts and bolts.

Tom,

Have you had a look at the timer? It would be worthwhile to remove & inspect it. After that, I'd still suspect the coil box. What exactly did you do to rebuild the coil box? What new parts did you use?

[Jerry VanOoteghem]

Is the car a green 1926 Coupe by chance?

[Scott_Conger]

Jerry, does green run rougher than black?

[Jerry VanOoteghem]

Are your sparkplug wire terminals only crimped on, or are they also soldered?

[Jerry VanOoteghem]

Jerry, does green run rougher than black?

Yes! Didn't you know that???

I noticed the OP's last name and recalled a green '26 Coupe that my dad and I worked on for a local guy. He eventually gave the car to his son, who lived "out east" somewhere. You never know...

[Jerry VanOoteghem]

Tom,

As to the timer, dirty is one thing, but wear is another. What style of timer do you have? Roller? Flapper? New Day, (with a brown/red plastic housing)? They each have their own wear characteristics to watch out for.

[Norman Kling]

Before you do any work on the timer, ground the wire from coil 2 which runs from the coil box to the timer. If you get a good spark with that wire grounded, your problem is either in the wire from the coil box to the timer or the timer itself. If that makes no difference, your problem is very likely either the contacts within the coil box, or there is a carbon trace in the wood of the coil box.
Norm

[Moxie26]

Tom.. you could follow Norman's advice. If that checks out okay fine. If not, remove number two spark plug wire from the box and plug and check continuity while flexing the cable if there's any interruption in continuity there would be a break in that wire somewhere........ And since you put new wood in your coil box carbon tracking would not be a problem, or shouldn't be a problem.... And number two spark plug could simply be bad and need replacement. When you remove plug number two use your continuity meter to check the center electrode continuity from the tip to the top connection of the plug should read 100% continuity........ But you stated the spark plug was replaced, no change in running. ...... Plug wire ok ???

[Steve Jelf]

It's been a long time since I rebuilt a coil box, but at that time more experienced T folks told me to use original bolts and contacts because the new ones were too soft to maintain contact. Are the current reproductions still junk, or are they now made correctly?

[Scott_Conger]

...and solder the bolt/contact interface...

this is where the new copper-plated bolts are so nice...you can get a very nice sweated joint with them (not so much with cleaned/rusted original bolts). This is one of the few places where I will swap almost-perfectly-good parts with new parts if soldering is the least bit problematic with the old bolts (though with effort and pre-tinning, old bolts can be just fine)

[speedytinc]

I heard tell of others here about running in a dark garage looking for wayward sparking. Couldnt hurt.

[TomW]

It's a black 23 roadster pickup.

Is the car a green 1926 Coupe by chance?

[TomW]

It's a roller.

Tom,

As to the timer, dirty is one thing, but wear is another. What style of timer do you have? Roller? Flapper? New Day, (with a brown/red plastic housing)? They each have their own wear characteristics to watch out for.

[TomW]

I will try what you and Norman have suggested. Thank you.

Tom.. you could follow Norman's advice. If that checks out okay fine. If not, remove number two spark plug wire from the box and plug and check continuity while flexing the cable if there's any interruption in continuity there would be a break in that wire somewhere........ And since you put new wood in your coil box carbon tracking would not be a problem, or shouldn't be a problem.... And number two spark plug could simply be bad and need replacement. When you remove plug number two use your continuity meter to check the center electrode continuity from the tip to the top connection of the plug should read 100% continuity.

[Moxie26]

Tom.. you could follow Norman's advice. If that checks out okay fine. If not, remove number two spark plug wire from the box and plug and check continuity while flexing the cable if there's any interruption in continuity there would be a break in that wire somewhere........ And since you put new wood in your coil box carbon tracking would not be a problem, or shouldn't be a problem.... And number two spark plug could simply be bad and need replacement. When you remove plug number two use your continuity meter to check the center electrode continuity from the tip to the top connection of the plug should read 100% continuity........ But you stated the spark plug was replaced, no change in running. ...... Plug wire ok ???

[TomW]

After I changed the plug, I swapped the wire with the #1 plug and #1 continued to run fine, #2 did not. I will check the continuity while flexing it, however; that's a good idea.

Tom.. you could follow Norman's advice. If that checks out okay fine. If not, remove number two spark plug wire from the box and plug and check continuity while flexing the cable if there's any interruption in continuity there would be a break in that wire somewhere........ And since you put new wood in your coil box carbon tracking would not be a problem, or shouldn't be a problem.... And number two spark plug could simply be bad and need replacement. When you remove plug number two use your continuity meter to check the center electrode continuity from the tip to the top connection of the plug should read 100% continuity........ But you stated the spark plug was replaced, no change in running. ...... Plug wire ok ???

[Moxie26]

Perplexing

[Mark Nunn]

Perplexing

Yes, but we are all learning from Tom's misfortune. We are all pulling for you, Tom.

[TomW]

Thanks Mark. A little more troubleshooting and I'll get her fixed.

Perplexing

Yes, but we are all learning from Tom's misfortune. We are all pulling for you, Tom.

[George Mills]

If you feel better having someone looking over your shoulder, give me a shout out...I live in Cherry Hill and could run over most any time. Most of my T 'stuff' is now at the Florida house or scattered between my sons, so I can't help with swap out trial and errors...but the mind still works...and been doing this for over 40 years now .

[Moxie26]

Tom.. you may want to consider replacing the complete timer harness. .. while driving the movement of the spark lever changes position of the commutator and after a while through slight bending those wires, even though they are stranded copper, will thin out and eventually break due to age and use...... Norman came up with a great idea on checking the commutator wires.

[BobShirleyAtlantaTx]

Move the coil from #2 to say-#4 and see if the weak spark followes, then you will know if it’s the coil.

[Moxie26]

Tom.. please post a picture of your coil box mounted on the firewall showing all wire connections. Thanks

[John kuehn]

Have you checked the coil box wire connection going to the no.2 plug? Remove the wire from the post and scrape it with a knife or use sand paper. Use a wire brush to clean up the threaded post. Yes it sounds simple but try that before you do anything else.

You mentioned it was a new coil box rebuild but how long ago? How about the timer? Maybe it’s time to replace it. Is it a roller timer or ? I’ve had less trouble with the New Day timer than a roller timer. But that’s a question of which to use that has lots of different viewpoints.

To me your timer sounds suspect but that’s my opinion.

[TomW]

Hi everybody. So, since the last time I posted, I identified at least part of the electrical problem. The wires connecting to the timer had worn bare against the motor, but I couldn't see it because it was the underside of the wires. Needless to say, I replaced the entire wire harness and the timer cover, as it was worn unevenly. When I started the car, the manifold gasket immediately blew - this was in June. July we did a lot of traveling, so I didn't have time to work on it. Anyway, we got the manifold gasket replaced today and when I was starting it - I had the spark fully retarded - it turned over but then sounded almost like it backfired. I turned it over a second time, and it did the same thing. After that it would no longer turn over. I checked the voltage to the starter and that was fine. I then tried to turn the engine over with the crank and found that it would not budge, as if it was seized.

Is it possible the Bendix spring broke and a piece of it is binding the gear so that the engine will not turn?

Thanks for the help.

Tom

[Moxie26]

Could be that the Bendix itself is jammed and stays on the flywheel because the starter motor is a loose mounting on the hogshead. Disconnect your battery remove the starter, Bendix first and have your starter checked for a bent armature

[TomW]

Thank you for the suggestion Moxie26.

[Scott_Conger]

Tom

#1, I'd give the new harness a good look over to ensure you have not misrouted/miswired the commutator
#2 be sure to time the new commutator correctly. There is no guarantee that the new one is mechanically EXACTLY like the last one
#3 if the bendix is jammed, and it sounds like it is, you are not going to "just remove" the bendix...not for love nor money. Usually leaving the car in gear and giving the car a good "heave-ho" will unlock it (backwards is the one that seems to do it). If that fails, simply loosen but do not remove the 4 round head screws that holds the starter in place so that it just wiggles. This will relieve pressure on the gear(s) and now your heave-ho will work. Don't forget to retighten the screws.
#4 if it comes to it, and you simply must remove the starter (say, shaft is really bent) then be SURE to follow the FORD manual for starter removal and in doing so you MUST remove the bendix first or you'll kill the MAG ring and still fail to get the starter out. There is a right way and every other way is wrong (in truth, some guy is going to tell you there are two ways, meaning the FORD method of lifting the hog's head, and that's true, but there are few 20 y/o he-men in the hobby who can or want to screw with the hog's head just to get a starter out and anyone suggesting it probably hasn't actually done it)

[TomW]

Scott, thank you for the detailed response. We did throw it in high gear and rocked it, but it obviously didn't fix the issue. I, also, didn't consider that swapping out the timer cover might throw it slightly out of time. I'll let you know how I make out.

[Scott_Conger]

Tom
you're welcome

my '19 has a horribly chewed up ring gear and on a cold day if I accidentally let up on the starter button and immediately reapply juice, I am 50/50 chance of slamming it together like a weld...no rocking will do it UNTIL I loosen the 4 screws and allow the bendix to just move away from the ring gear and then rocking the car will pop it loose. So long as I hit the starter solidly and until it fires, or I turn the engine 1/4 turn before starter engagement I can go years without binding up since I know the formula to it! I have zero interest in pulling things apart to change the ring gear as I don't feel like it and it's an original engine in all respects that would be silly to pull without heavy freshening up and I just don't want to do that...so...I hand crank now and will until I no longer can

I think you'll figure out what works for you

all the best and drive safe once you can drive!

[Norman Kling]

To check the teeth on the ring gear you must remove the bendix. First take off the cover toward the rear of the car and check out the bendix. To remove the bendix, you remove the cover and then the bolts which hold the spring on the bendix. Remove the cap on the rear of the shaft and remove the key from the shaft. after you have the bendix removed you can check out the spring and the gear. also rotate the starter shaft to be sure it is not bent. Now use a good flashlight and have the car in neutral while someone rotates the crank. Carefully inspect all the teeth on the ring gear for wear or broken teeth. It they are worn at the tapered side where the bendix connects to the gear, the ring gear needs to be replaced. This is a hard job which requires pulling the engine and transmission and you might as well go over everything while it is out. I would recommend the booklets. Transmission and Electrical System, and Engine which are sold by the club. Those booklets give step by step instructions for the hobbiest to repair these things.
To get back to the reasons for the backfire and sticking. I would suspect that the timing is off and the spark is still advanced when you have the lever all the way up. Check all the linkeage from the steering column to the timer for loose or worn parts which would give you play while moving the lever up and down. It should respond immediately when you move it by rotating the timer. Also each brand of timer is a little different to find the correct setting for full retard. I suggest that you turn the crankshaft so the pin through the front pulley is at the 10:20 position when looking from the front. toward the pulley. then rotate the timer so that when you move it counter clockwise when looking from the front it will just start to buzz the coils. Bend the timer rod to reach that position with the lever all the way up.
Norm