Hard starting when hot

B

bbook

Member
A couple of summers ago, I had trouble starting my 36 Truck after the engine was hot. All was good after I installed a phenolic spacer between the carb and manifold. Now I am having the problem again, and I think it is the coil. I have a 6 volt with a conversion to a tube coil with an internal resistor (couldn't find one without), also wired through the resistor under the dash. Would I be better off going back to the coil on top of the distributor?
 
If my understanding is correct, you have two active resistors when only one is needed. Suggest you bypass the resistor under the dash by attaching the wires to one terminal.
 
Send an original to Skip and have rebuilt. It is all I will use! Drove my 32 from Ms. to Oregon years ago and even driving up to the copped mine in St Louis and ruined a S.W. Gage that only went to 260 if I remember I shut down car and just for a test turned key on and touched the starter and it started right up and idled fine! I was sold. I opened the hood and did tour etc. and then added water to replace what I lost on way up running in 2nd gear with 354 rear gears. jm2cw Kerk
 
I agree with Kerk. I wouldn't leave the end of my driveway without a rewound Skip Haney original style coil on my '35 fordor sedan. However, in your case, running with both internal and external resistors in your ignition circuit is most likely causing the hard starting.
 
Have you checked the resistance of the coil? If it is ok on its own, the fix might be as simple as moving a wire from one end of the underdash resistor to the other and bypassing it.
 
I will try bypassing the external resistor. I went to the conversion coil because I exploded (literally) the one on the distributor when I left the ignition switch on, so I can't go back to that one. However, I found another distributor mount coil in a box of parts from the previous owner. I don't know the condition, other than it appears to be intact. As long as it is intact, can Skip Haney rebuild it?
 
I had them same issue with my 36. I had the distributor rebuilt and new coil. The issue went away and has not come back
 
I moved one wire from one post to the other on the under dash resistor to bypass it and went for a test drive and got to full temperature. Upon return, I had no starting problems.

As an aside, during the drive, I noticed deteriorating performance of the engine, but managed to get home. When I opened the hood, I noticed three plug wires were off on the left bank. I had loosened them earlier to check spark and forgot to push them all the way back on. It was actually idling pretty well on 5 cylinders. At least it got me home.

Thanks to each who replied with help. It is much appreciated.
 
I forgot to add that I did send the spare distributor mount coil to Skip Haney for rebuilding, so I can go back to the original style if I want to.
 
I have found that 99% of hard start issues with a flathead V8 are ignition related. If your ignition system is set up properly you should have no problem starting.
 
Often overlooked is the condition of the starter. A starter with worn bushings and/or commutator and brushes can cause a high voltage drop in the system, particularly when it is hot and high resistance in the winding comes into play. The usual amperage drain with a good starter is around 200 amps. We have see it rise to nearly 500 on worn units. This leaves insufficient power to the ignition system to allow easy starting. Find a shop with an Amprobe tester to determine whether that is the cause. Old starters are common as they are out of sight and mind. Auto electric shops are often hard to find these days. C&G
offers new or rebuilt starters for under $200. 800/266-0470
 
What should the resistance read on the coil, mine reads 13050 on an analog tester and 7050 on my digital VOM. I'm reading from where the wire on top connects to the carbon brush, with wire disconnected. It's a helmet dist on a 41 ford. Al
 
supereal said:
Often overlooked is the condition of the starter. A starter with worn bushings and/or commutator and brushes can cause a high voltage drop in the system, particularly when it is hot and high resistance in the winding comes into play. The usual amperage drain with a good starter is around 200 amps. We have see it rise to nearly 500 on worn units. This leaves insufficient power to the ignition system to allow easy starting. Find a shop with an Amprobe tester to determine whether that is the cause. Old starters are common as they are out of sight and mind. Auto electric shops are often hard to find these days. C&G
offers new or rebuilt starters for under $200. 800/266-0470
Click to expand...

Thanks for this post! I was thinking that this is what's going on with my car. Old starter cranks fine when cold but once warmed up, it stalls momentarily each compression stroke and after some effort it'll start. We had an old time auto electric rebuilder 2 blocks from the house...went away a year ago and is now a Karate studio. I'll run this starter till winter and either have it rebuilt or get a rebuilt one.
 
supereal said:
Often overlooked is the condition of the starter. A starter with worn bushings and/or commutator and brushes can cause a high voltage drop in the system, particularly when it is hot and high resistance in the winding comes into play. The usual amperage drain with a good starter is around 200 amps. We have see it rise to nearly 500 on worn units. This leaves insufficient power to the ignition system to allow easy starting. Find a shop with an Amprobe tester to determine whether that is the cause. Old starters are common as they are out of sight and mind. Auto electric shops are often hard to find these days. C&G
offers new or rebuilt starters for under $200. 800/266-0470
Click to expand...
.

I had my starter completely rebuilt by a motor rewinder outfit and they fitted a new bendix set-up that I got from Mac Van Pelt..good USA quality one. That coupled to a rebuilt Skip coil has made the starting system as reliable as a 12v setup.

GB
 
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