Hard start when hot
 

I would appreciate all thoughts and comments on my question. Here is my issue. When the engine is cold, engines cranks, starts right up no issues. After driving and getting the engine up to temperature and then stopping, I have a hard time starting. The starter motor sounds like it is laboring and cranking slow as if I have a low battery. The motor does start, but after a period of continuous slow cranking. Do I have some sort of heat issue in the starter motor where it is getting too hot and not able to draw sufficient current? Thanks in advance for all who take the time to read and answer. Jerry

I would start with looking at heat soak issues on the starter and the size of the battery cables to make sure they are sufficient for the distance.

Do a load test on the battery first. I had the same problem and replaced the starter only to discover it was the battery.

"Hot" motors ie: cams, heads, compression etc can be harder to start hot for many reasons.

Starter motor current draw can be higher due to heat soak, resistance increases as temp increases, coupled with high compression and more static timing than stock only adds to the "drag" on the starter.

Try retarding your timing back to 7 - 10 degrees to see if starts easier, or even disable the ignition system and crank the engine without spark.

If it's still slow, then start looking at voltage drop loss up to the starter.

Could be a faulty starter motor.

Do you have a standard or mini-starter? Heat soak is more of an issue with standard starters. It is also one of the reasons with a mini-starter and a firewall mounted solenoid, the high current positive battery lead is not switched, the start signal is. This then points to proper grounding of the starter/engine. What kind of ground are you using? Did you run the negative battery post directly to the engine and then a ground strap to the chassis or the other way around?

Starter should spin engine about 200 rpms

Thanks, I will start to look at the wire and ground. I have a standard starter. Can someone elaborate on "heat soak" and some remedies?

Heat soak occurs when the starter is heated up by the ambient temperature in the area of the starter. I had the problem with a Cleveland once...it would start fine when cold, but as soon as the engine was heated up it would act exactly like yours, struggling to turn the motor over.

A couple of suggestions:

You might be able to get the engine to turn more quickly if you trim off a couple of degrees of initial timing. If your car has a high compression ratio, the starter will be "challenged" without the heat factor, much less when it gets up to operating temperature (and particularly at the high end of the operating temperature range).

Here's what I did (don't know if you will be able to do this or not): I went to the auto supply store and bought a thick asbestos pad large enough to wrap the starter. I cut it to clear the cable attachment, wrapped it around the starter, and then cut a metal coffee can up so that I could wrap it around the starter on top of the asbestos pad. I used a large clamp (one for securing the exhaust hose from a clothes dryer) to hold the items together. Never had any trouble again, started VERY well regardless of temperature. I don't know if asbestos pads are still available or not....you might want to check a welding supply store, they sell various forms of heat shield materials that might make the job possible without the asbestos product.

One more thing....rebuilt starters are real problems where heat soak is concerned....get a NEW starter if yours wasn't. That might fix the problem real quickly.

Cheers from Dugly :cool:

You might have a bad starter, old style cost about $25.00?

Jerry:
I feel your pain man. I had similar problem: Here is what I did, purchased a Hi-Torque starter from Summit Racing, installed the heat shiled on it changed the 2nd solenoid, installed a 1/2" phenolic spacer between the carb and manifold, changed the gas filter element and now it is fine. The issue is really for the most part vapor lock, the engine gets hot (but not overheated) and the gas boils in the line as well as the carb when you try to start the car-----zippo nothing. There is another trick slapp the accelerator 2-3 times (no choke) and try to start it wil go. Naturally you also need to ensure that your timing, battery cables are ok . Hope it helps.
Lou

Thanks to all who replied, this gives me several options to try. Best regards...Jerry

For anyone interested I bought a thermal wrap from jegs specifically for protecting Starter motors from heat, happy to report my problem of starting when hot is solved......