SI67

I am once again having the classic "won't crank when engine is hot" issue. Car starts fine when cold, but after running for a while and getting up to operating temperature, then stopping the engine and letting it sit for a few minutes, I can't restart because it just BARELY cranks. Let it cool off for an hour or so, and it starts fine again. This has happened to me before, and replacing the starter fixes the problem. But what has physically happened to the starter? The doesn't get heavily used, so it shouldn't be mechanical wear, and the starter isn't being baked by the running engine for all that many hours per year. so part or parts are detoriorating, and what causes the deterioration?

The starter is not original, so no compelling need to save or rebuild it. I just need a starter that works, and I'd like to know what I can do to keep this problem from occurring yet again.

Particulars of the car: '67 327/300, Powerglide & AC.

DansYellow66

Typically the problem you describe is due to a weak starter solenoid. Did the solenoid get replaced when the starter was replaced? If so, then it could be a starter that's dragging and needs to be shimmed but sort of unlikely you would replace a starter for this problem and a new one would do the same thing. Could be as simple as having received a cheap solenoid or a bad rebuilt starter.

The problem with the solenoid stems from heat soak from the exhaust manifolds. There are shields and blankets that can be installed around the starter to help cure this - but most cars don't need them so why should yours?

Other possibilities - the battery may have a weak cell and be about ready to pack it in. Could be a poor connection at the starter terminals but it's unlikely changing out the starter wouldn't have changed the symptoms. An engine with a lot of compression or a lot of initial timing can be harder to start when warm - shouldn't affect a 327/300 engine. A newly re-built engine could have clearances too tight - but you didn't say anything about being newly rebuilt. An intermittent connection can develop on the big red wire at the firewall block - but that causes a dead connection instead of turning over slow.

You might try hooking an electrical volt meter up at the battery and watch the voltage drop when trying to start it cold and then later when hot. I'm sure the drop will be bigger when hot but I'm not good enough of an electrical person to know if that can point your to anything specific.

R66

I'll try, but here are a few things I have run across:
Headers or exhaust pipe near starter or high underhood temperature. Doesn't take much to melt the insulation on the coils.
High compression engine, 11:1 or more
Carb flooding or heat soak when shut off
Too much initial timing.
Stuck advance weights in distributor.
Stuck advance plate in distributor.
Bad battery cable - resistance increases when hot.
Long cranking times over heat windings and insulation.

How long does the new starter last?? I have gotten bad rebuilds from the parts houses.

Hope this helps.

Frankie the Fink

That starter should whip a stock 300 hp mill around like an egg beater....hot or cold.
DanYellow has covered the turf pretty much. I usually check for loose/corroded connections first, then do a spot check of timing, then - you can have the battery "load tested" at any FLAPS and THEN I delve into the starter itself.

63Corvette

I recommend a Tilton or other small aftermarket starter. You will never have a hot start problem again.

BD104X

I agree. I was going to post this but didn't have the energy for the "if you didn't need it in 1963, you shouldn't need it now" debate! Keep in mind - as a temporary fix if you get stuck, pour some cold water on the starter. That will usually do the trick to get you going again if you don't feel like waiting around until your car feels like starting.

Sky65

I would check for a voltage drop on the positive and negative sides of the starter. Do it cold, then get it hot and repeat the test. For the hot test after warming it up to operating temp leave the hood down for a little bit and let under hood temps rise as it would in a parking situation.

Tom

MikeM

You might not have a problem again, assuming a defective starter was what was really wrong.

What if it was something simple like an internally corroded battery cable that suddenly came to life when the cable was disturbed bolting it to a new starter. Then, in time, it went back to it's corroded state again.

GTOguy

All good advice. Heat increases resistance in an electrical circuit. If it cranks, however slowly, it is NOT the solenoid. Most likely high resistance in the starter windings, battery cables, or possibly an over-advanced condition due to advance weights hanging up. You can see if it cranks normally when hot with the ignition switch off but the starter jumpered to eliminate or verify the advance issue. If it cranks fast with the ign. off, it's in the distributor. If it's still slow, it's in the starter circuit itself.

SI67

Thanks.

I understand what you are saying about high resistance. What I don't understand is how sticking advance weights or excessive initial timing would cause the starter to to just barely twitch when hot. I'm not saying that it cranks but won't fire (which I could understand if ignition timing, either because of stuck advance mechanism or wrong initial setting, or both) is horribly wrong). I'm saying the starter WON'T SPIN the engine when hot. How could any ignition timing or advance issue cause that?

SI67

I'm pretty sure solenoid and starter have been replaced together. When I say I'm having the problem "again" I mean it works fine for ten years (but not all that much use) after starter and solenoid are replaced, but eventually, exactly the same symptoms show up again.

It's certainly not a high-compression engine. It was rebuilt many years ago with dished pistons to take compression down to 9:25 or so.

If it's a weak cell (or two...) would my car be able to sit for weeks and then crank just fine, which it does?


Thanks for the suggestions.

MelWff

If it spins slowly it could be timing, if it doesn't spin at all the problem is not timing look at the other suggestions. If your starter lasts only 10 years with infrequent use I would look at the quality of the starter you are buying. I assume you have no oil leaks that would effect the starter.

GTOguy

Over advanced timing can cause the engine not to spin...but it will try to crank....you may get about a half of a revolution. This is caused because the spark is igniting the mixture when the pistons are trying to travel upward in the cylinders. The spark is forcing them downwards at the same time, which equals no spinning engine. As I stated, you can verify this in less than 5 minutes by simply jumping the starter with the ign. key off.

SI67

Thanks, Frankie. It should crank even easier than stock, since it was rebuilt to 9ish to one compression many years ago. (I know. Boo, hiss.... Will correct that mistake somewhere down the road). And until this problem shows up after a number of years, it DOES crank easily. Don't see how the timing could be the issue (but I'm always willing to learn something new)---it's a deficiency in CRANKING, not starting. So not, as other folks have mentioned, a flooding or percolation issue.

Will pursue load test etc. Thanks to all for the advice.

buns

I'm betting you are not the first to have this problem. Starting in '64, I believe, every small block car got a heat shield.


.

MikeM

Why do you believe that?

SI67

Ok, thanks. I can visualize that. But why that would happen only when engine sits for a short time after reaching normal temp and problem goes away when things cool off? Also, with the ignition timing so grotesquely wrong, wouldn't the engine run pretty miserably at best?

But yes, there are simple tests I need to do.

PAmotorman

take your solenoid apart and see if the contacts are burnt. if they are clean them up as the burnt area causes more resistance. also make sure all the terminals are tight in the Bakelite cover.

GTOguy

I've had the centrifugal weights stick only when warm....metal expansion? I dunno. Happened on my '65 GTO. And it won't run poorly, it will run fine with the weights out advanced. It just won't want to start easily. This very well may NOT be your problem, but it is SO EASY to rule out, you should do it before you start tearing your car apart. As an automotive tech, that's how I tackle a problem and fix cars. Always eliminate the easy to check stuff BEFORE taking the car apart! Your choice, your car.

R66

Didn't catch your statement "I mean it works fine for ten years (but not all that much use) after starter and solenoid are replaced" when I jumped in to help. Given the duration without knowing how many miles and time the engine was started and not knowing the storage conditions over 10 years, I would expect some kind of corrosion in the starter or ignition system that could be accelerated by moisture and changing temperatures if you live in a variable climate, I.E., Illinois.
I would jump past the battery cables to the starter with jump cables when the problem occurs looking for a corroded battery cable - pos or neg.
Disassemble the starter and look for corrosion on the armature and condition of the brushes. Ground connections will also deteriorate over time. Ground not only to the engine, but at the ignition switch. A bad ground at the ignition would probably result in clicking at the solenoid.
Timing at the distributor is probably not the problem unless you are running a lot of initial advance and flooding is happening. If it cranks hard when hot, it could still be a soak of the cylinders from the float sticking or more likely poor fuel boiling out upon shutting it down even at normal operating temperature.
The big question is, how many times is it started in 10 years? Could be just the contacts in the solenoid or brushes in the starter.
How many starters have you put on it in the last 20 years?
Don't want to be a pain, just trying to help.