47 ran rough then not at all. Need ideas.

[Mart]

I have experienced a bad cap. It deteriorates and then gets so bad it just won't work. Same with a rotor. You seem to have covered everything else, I'd recommend the crab for ease of access. My personal experience is to use the lowest resistance leads and plug caps, it reduces the ht load on the cap and rotor.

Mart.

[48Flyer]

I know this probably wont help, but a wise old flathead mechanic once told me "90 percent of flathead ignition problems, are fuel related"
Did you by any chance just get a fresh tank of bad fuel somwhere along your route?

[Old Henry]

Originally Posted by Old Henry

If the secondary high tension wire from the bottom of the coil is not attached to anything that will complete a circuit on the other end buried down deep in that crazy two layer distributor cap, no spark would go through it for the timing light pickup to detect. One more indication that it's probably in that distributor cap from heII - a nightmare to deal with - gotta remove the fan, generator, and the entire sparkplug wire harness. Hate it. Don't wanna do it. Just wanna drive it. But, looks like that's the next step.

I just did an experiment to test my theoretical answer above to see if it was correct. Fortunately it was. (Whew. Glad of that. Hate to be wrong. ) I put the timing light pickup on the spare sparkplug wire coming out of the coil then cranked the engine. When the end of the spark plug wire was not close enough to a head stud nut to spark, the timing light did not flash. Whenever the end of the sparkplug wire was close enough to spark, the timing light flashed too. Always nice to have a "calculated guess" verified as accurate. Again, more evidence that there's a break in the circuit somewhere in the high tension line from the coil to the distributor cap or in the cap itself.

[Old Henry]

[QUOTE=JM 35 Sedan;526734]Bypassing the ignition switch, as mentioned above, would be something to try. QUOTE]

Originally Posted by 40cpe

you didn't mention bypassing the ignition switch with a jumper from the battery to the coil.

Thanks for the suggestion. Tried that. Didn't help any.

[Old Henry]

Originally Posted by peewee2you

OldHenry, check coil to distributor wire, the one that runs from the condensor side, if you haven't already maybe a break or shorting out?

Thanks for the suggestion. Bypassed that wire with a jumper wire. Didn't help.

[Old Henry]

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Originally Posted by Shadetree

Henry,
Try replacing the coil. An intermittent coil will drive you nuts while trying to isolate the problem.

Thanks for the suggestion. Bought a new coil that tested good (with Ohm meter) and installed it. Didn't help.

[Old Henry]

Originally Posted by russcc

I would try a another condensor after checking the OHMs to see if it's on the money. Hopefully Bubba will chime in here to point us the right direction.

Thanks for the suggestion. Tried a different condenser that read within specs on the multimeter. Didn't help.

[Old Henry]

Originally Posted by 48Flyer

I know this probably wont help, but a wise old flathead mechanic once told me "90 percent of flathead ignition problems, are fuel related"
Did you by any chance just get a fresh tank of bad fuel somwhere along your route?

I'm not sure how to test for bad fuel. Just filled up at a Texaco which is a Top Tier station so I hope it wasn't bad gas. How would I know?

[Old Henry]

Originally Posted by Ol' Ron

The first thing I'd do is a compression check, you may have stripped the fiber gera??

Just did compression check. Here are the results in psi.

#4-82 #8-65
#3-79 #7-80
#2-91 #6-89
#1-84 #5-84

My engine was rebuilt 25,000 miles ago and this compression test is at 5,000 feet elevation which lowers the sea level specs of 105-125 psi to 70-90 psi.

I'm not seeing any problem here that would keep the engine from starting nor effect its running smoothly. Do you?

[Graeme / New Zealand]

Old Henry have you tried a new set of plugs? Had a similar problem to you. Went through everything. Put in 8 new ones and all was good..

GB

[Old Henry]

Originally Posted by Graeme / New Zealand

Old Henry have you tried a new set of plugs? Had a similar problem to you. Went through everything. Put in 8 new ones and all was good..

GB

Thanks for the suggestion. Although my plugs were new 9,000 miles ago, at your suggestion I just tested each one by removing it, plugging it into the end of the spare wire I have coming out of the bottom of the coil, and cranked the engine with the plug laying on a head bolt. Every one fired consistently and reliable so it does not appear that they are my problem.

But thanks for your suggestion.

[Mart]

All the plugs spark when connected directly to the coil. The coil is working, the plugs are working.

More evidence that the cap is at fault, or at least must be the next area of investigation.

Keep going it will become clear soon enough.

Remove the cap and leads and examine it very closely, there may be a crack allowing the spark to leak to ground or just get lost in the ether.

Mart.

[donald1950]

a plug can break down under compression. replace them and see if thats a contributer. less expensive start before tearing the distributer apart first
... don

[Walt Dupont--Me.]

Are you useing the dist cap with the rabbitt ears or the crab cap. I've had 2 of the black crab caps that have a carbon trace from the terminal close to the 2 snap clips and the spark would go right through the cap to the snap clip. Walt

[George/Maine]

Take the dist out and lay on fender run a ground wire to dist case.
Add longer wire from points to coil,longer power wire to coil.
The coil wire out put to near ground should spark 1/2"
Turn key on and turn dist by hand and watch it spark.
If good and sharp turn check for loose shaft if ok
Must be caps and rotor.

[Chris Nelson]

It would seem that you have checked everything short of the plug wires. If you get a steady spark out of the coil, but not when you run through the caps and the wire looms, that woudl be a good place to check. If you are using the orignal wire loom tubes, it is possible that you are cross firing through bad wires inside the tube. Try running a seperate set of wires that are new and outside the tubes.

[Old Henry]

Originally Posted by Don

. . . dist cap might need a good cleaning

Originally Posted by Henry/Kokomo

From what you've said, I suspect a bad high tension lead between the coil and distributor. also, carefully check distributor cap and rotor as suggested by KenCt. Good luck.

Originally Posted by Mart

I have experienced a bad cap. It deteriorates and then gets so bad it just won't work. Same with a rotor. You seem to have covered everything else . . . Mart.

Originally Posted by Mart

. . . the cap is at fault, or at least must be the next area of investigation.
Mart.

Originally Posted by George/Maine

Must be caps and rotor.

Originally Posted by Chris Nelson

It would seem that you have checked everything short of the plug wires. If you get a steady spark out of the coil, but not when you run through the caps and the wire looms, that woudl be a good place to check. If you are using the orignal wire loom tubes, it is possible that you are cross firing through bad wires inside the tube. Try running a seperate set of wires that are new and outside the tubes.

Originally Posted by Walt Dupont--Me.

Are you useing the dist cap with the rabbitt ears or the crab cap. I've had 2 of the black crab caps that have a carbon trace from the terminal close to the 2 snap clips and the spark would go right through the cap to the snap clip. Walt

I'm using the stock double distributor cap. That's all there is left to check. I've left it 'til last since that's the hardest thing to check. I've got to remove the fan, generator, and entire spark plug wire loom to check it but I'm at that point now. I will order a new cap and wires and when they come I'll replace them and hopefully have the problem solved.

THANKS TO ALL FOR YOUR KIND CONSIDERATION OF MY PROBLEM AND ALL OF YOUR HELPFUL SUGGESTIONS. I APPRECIATE IT VERY MUCH.

[Old Henry]

OK. I peeled the ruddy octopus off of the top of my engine. Here's the inside of my distributor cap.







Even with my untrained eye I think those big gouges in many of the posts can't be good. For sure the cap has got to be replaced. (It only has 30,000 miles on it. Why not?)

Question is: The only way I can think those gouges got in there is for the rotor to hit them. Why did it hit them? Is there something wrong with my distributor that it would allow the rotor to hit those posts and wear those big gouges in them? If so, how do I diagnose the problem and how do I fix it?

ADDENDUM: I think I found the answer. I took the distributor out and found play in the shaft that the rotor is mounted on. Worn shaft or bushing I'm thinking.

What's next? New distributor? Keep in mind I'm not a machinist that can remove and reinstall that bushing if that's what it takes.

AND LATER: I see where I can buy both of the bushings for both ends of the distributor shaft (they're both worn). Is that all that I need to replace? Is that something I can do without machinist's equipment? If so, how do I get the old bushings out? I expect that if I can get the old ones out that I can press the new ones in.

[Mike in AZ]

i think you can get most of the parts you need from the catalog guys....C&G looks to have the bushings...maybe more parts if needed....Mike

[JM 35 Sedan]

Henry, it sounds/looks like you have found the main source of the problem.

A couple thoughts....

1. If the bushings are worn, make sure the shaft journals that ride in those bushings are not damaged.

2. You should be able to press or pull those old bushings out and press new bushings in place. However, after those new bushings are in place, they may need their ID's reamed to give proper clearance for shaft journals. I know this is what I had to do when I put new bushings in a '35 helmet distributor.