Out of ideas - need help

[adileo]

If you read my last post - 39 coupe - you know my car is not well and will not start. The last time is ran in garage (thus am) at idle it ran for 5-10 minutes and stalled. Prior to that car was bucking bad on a short ride.

So far:
Took both edlebrok 94s (Charlie rebuild few years ago) off cleaned all ports with carb cleaner and blew out with air. There was some dirt particles in carb prior but cleaning did not solve issue of no start.

I tried 3 different coils and 3 different condensers. I currently have on a Skip built coil.

I replaced the ignition switch.

When testing coil I’m getting 3.5-4 volts while cranking

I pulled the distributor and replaced the points (.015 gap- no machine) and condenser with NOS parts.

Tried to start and car cranks well it is backfiring thru exhaust but will not start.

Note after installing points and no start. I had spark on number one plug on an initial crank but then no spark.

I’m taking a break from it, as it’s wearing me down.

[Brian]

Rotor shorted

[adileo]

Sorry forgot that...when changing points put in new rotor.

6v pos grd
Helmet distro (bubba 11a)

[Ken/Alabama]

Condenser

[Phil Gillespie]

It was suggested to:
check the coils: Primary & Secondary sides.
Get hold of a spark plug tester and you will be able to check each cylinder for a good spark
Just remove air cleaner and operate carb to check fuel flow.

You have swapped out a few different elements and it kinda makes fault finding a little tricky.
My policy in these cases is check again what you last played with as quite often a fault is introduced.
hope you work through it.
Phil NZ

[adileo]

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Ok thanks Phil. I’ll test test cylinder. I tested number 1 got a spark then on additional cranks no spark

Please help me better understand how to test the primary and secondary on a helmet coil.

[Andy]

No power to the coil?

[Tinker]

Originally Posted by adileo

Ok thanks Phil. I’ll test test cylinder. I tested number 1 got a spark then on additional cranks no spark

Please help me better understand how to test the primary and secondary on a helmet coil.

Even if you bench test it, it may not preform the same under a hot condition.

Thought you had this running well under idle, but was bucking under load?


Intermittent spark on the 1 seems like something with the rotor. Add a additional engine ground. Never enough grounds.




.

[tubman]

How old is the engine? IF it's not a recent rebuild, I would suspect a few stripped teeth on the fibre timing gear.

[Tinker]

Not sure why you created another thread other then a fresh look or less info.

from the other thread... "It's pretty easy to see if the resistor is working with a volt meter. Cold and hot."







What's your vacuum look like. Just throwing out some ideas that might help.




.

[Charlie ny]

AD,
Try a jumper across the posts of the column mounted ign switch or a wire directly
from the battery to the coil. I've experienced night mares with the repop condensers
and adapt IH 200 condensers with excellent results. That backfire thing sounds like
timing. Send me the distributor while you are on break ,if you wish.
Charlie ny

[deuce_roadster]

Bad condenser can make backfires.

[Tinker]

and misfires.

[JSeery]

Originally Posted by Charlie ny

AD,
Try a jumper across the posts of the column mounted ign switch or a wire directly
from the battery to the coil. I've experienced night mares with the repop condensers
and adapt IH 200 condensers with excellent results. That backfire thing sounds like
timing. Send me the distributor while you are on break ,if you wish.
Charlie ny

Charlie, I think he has already tried that. It seems he has something intermittent going on. It will run ok sometimes and then quit and not start or run poorly. It sounds like some type of wiring issues or a fuel supply issue. You would guess coil or condenser which was going bad when hot, but he has tried several different coils and condenser combinations.

Adileo, have you really checked all of the ground connections to be sure they are clean and tight? Might even try an additional ground from the engine to the battery. Try clipping the voltmeter on the coil and see if it is still reading 3.5/4.0 volts when it starts to act up. And try Charlie's idea with the jumper again, you have to be missing something somewhere along the line. Put a temporary fuel pressure gauge on it. Think it might be time to start trouble shooting the problem in place of changing parts.

[Tinker]

do one thing at a time. If you haven't put vacuum on it, that will help.

[adileo]

Ok thanks for all the good advise. I haven’t done all this at once and have tried each after doing the work on each.

Today:
Check again for fuel going into carbs.
All the grds are clean but I’ll add more. Also when it was running, I turned off the battery (I have a switch on grd strap) and car continued to run
Test voltage at coil again. I’m still in the dark on one suggestion on testing primary and secondary.
Test each spark plug for spark. Last tested number one had spark then no spark.

[adileo]

3.5-4 to coil
Spark on all plugs - have to touch wire to plug to see spark
Backfire thru exhaust no start

[37 Cab]

Compression test to verify cam timing.

[adileo]

Retest now no spark to plugs.

[adileo]

Retest now no spark to plugs what’s that tell me?