Does you guys know of a common issue with the 330 not starting good when warm? Because I've got one in a 1965ish ton and a half truck that won't start very well after being driven around awhile. It will start good first start when cold but not after it warms up.

 

Just throwing a few ideas out there...one, have you checked your coil? I know a hot coil can cause resistance, and an engine not wanting to start. Also, im assuming the carb is good? My 390 was having just what you have, great when it was cold, but a terrible time after I drove it around at all, rebuilt it and its never been easier to start.

 

I assume what you rebuilt was your motor, or was it your carb? How would you check your coil, measure the resistance with a meter?

 

Possible vapor lock.

 

or boiling over, or poor compression. If the engine runs while hot, I wouldn't worry about weak spark just yet.

 

Actually, I put in a rebuilt 390, with the old carb that came with the truck when I bought it (it had a bad 390) and it didn't really cross my mind that it'd be a big deal. But after rebuilding the carb, this engine seems brand new, its the smoothest sounding I've ever heard, aside from exhaust noise its almost silent underhood. Anyhow, back to the point, theres a decent chance it could be your carb, have you had it rebuilt? Know if the seals and floats are any good? I first thought possibily points and condensor on mine, didn't do it, then coil, tried the old ice truck (which I'll explain in a bit), then finally the carb...now it starts almost as if its fuel injected, its great.

Yes, you could check the could with a meter power side to plug distrubuter side, your going to want to test it NOT HOT, key off, negative disconnected just to be safe, either that or make sure you unplug the distributer wire, and the power wire on it. Can't remember the exact numbers on this, but you should be able to use an Ohm test, and Volt test to get her figured. Something like 6,000 k ohms? 12.3 +/- Volts?? If someone could chime in that would be helpful.

As for the "ice trick" I spoke of. Get the truck to the point you know, or at leats assume its going to start bad when warm, you could even crank it to see, if it doesn't fire...go for this. Get a baggy of ice, or an ice pack, just something really cold and set it on the coil, wait for it to cool a bit and try starting, if it starts up fine, and you can tell a big improvement, its probably coil related. I know these old truck's starting problems are often related to a hot coil from running them.

I hope all this is of some help to you, its what I've learned working on and getting both of my trucks going good, hopefully it helps you out too!

 

When was the last time you changed your plugs?

 

Weak starter that still works OK when cold, doesn't draw the battery voltage down to much, stays above 10.5 volts but when warm pulls battery voltage below 10 volts not leaving enough voltage to run the ignition properly.

 

That's a good point ...

When you say it doesn't start good, is it that it doesn't crank fast enough, or that it just won't start but cranks good?

 

Actually...very good point. I was just assuming the problem I had, won't start but you sure as hell can crank it all day, hahah.

 

Sorry for taking a long time to reply. Anyway an answer to your question about starting it won't crank very fast when warm. Could the starter possibly be getting warm and then not working properly?

 

Is it OEM stuff or a reman "Hecho en la Pueblo" ?

 

The starter gets hot from radiated engine and exhaust heat. When hot they are less efficient and when old and weak along with hot, are very hard on the battery in amp draw which lowers the voltage, not leaving enough power for the ignition to operate properly.

 

Vapor lock = very common once = the fuel vaporizes in the fuel lines, usually caused by heat radiating from the exhaust manifolds. On older vehicles, the fuel lines ran adjacent to the exhaust manifolds. Old timey fixes to prevent vapor lock: Fuel lines wrapped in aluminum foil / Wooden clothes pins clipped on the fuel lines (yes, it sounds crazy, but it works). Try using your ice pack on the fuel lines and fuel pump, that's what ppl used to do way back then.

1949/51 Cadillac & Oldsmobile OHV V8 engines: The batteries used then didn't have enough amps to crank the engines over when hot. GM solved the problem by switching to 12 volt batteries in 1952.

Why did I mention the above? Your 12V battery might be too small, with insufficent cranking amps.

A common problem occured with 352/360 and 390 engines in 1965/76 F100/350's. Ppl installed a smaller amp battery (usually 45 amp-Group R22F) to save a buck....then whined and moaned because the trucks didn't want to start when warm.

With your engine, you should have...at least, a 70 amp battery = Group: R27-F or R27-FA, an 80 amp battery

 

Very true. In the marine industy most boaters replace a bad battery with a smaller one and Gee, have starting problems when warm.