My motor doesn't crank when warmed up easy.

[aggressive male]

I'm using an olds 307 now and have a real hard time getting my car to start when the motors warm. The starter has a real hard time turning it over when warm. I thought maybe I was getting too much ignition advance so I unplugged the power from the distributor and tried to crank to see if it would turn easy. Still hard to crank. I think a couple of the strands for the starter cable are broken so maybe that would help a little but still doesn't explain why the starter cranks it fine when cold but barely cranks at all when warm? What else could it be?

[Scott Parkhurst]

Swap in new positive and negative cables. I bet it cures the problem. Good connections through good cables is a big part of easy vs. hard cranking, and adding heat only makes everything tougher...

[hotrdblder]

worn out starter bushings causing armatuer to expand when warm and rub on outer case, thus dragging and sticking when hot.
i would check/replace cables first, but starters can be rebuilt for 40 bucks around here

[astroracer]

Are there headers on the motor? Heat soak at the starter/solenoid can cause hard starting after warm-up. I had this problem with my Firebird. The best way to eliminate this condition is to put a remote solenoid on the fenderwell or firewall to get it away from exhaust heat. Summit, Jegs or MAD have kits to convert your starter mounted solenoid to a remote mount.
Mark

[6'9"Witha69]

Or switch to a mini starter and clock the solenoid away from the headers. This alone has fixed many SBC and BBC issues I have seen.

[bochnak]

I've had this same problem. It is not a solenoid issue, since the motor is cranking. The cause is a weak starter motor or corroded cables. I replaced my cables to 1/0 ga wire and relocated the ground from the alternator bracket to the block. I also switched to a mini high torque from dbelectrical.com. Starts like a champ now.

BTW, if the symptom was a "click" or nothing at all, the problem would be a solenoid issue.

Make sure to with at least 2ga wire.

[bochnak]

the starter cranks it fine when cold but barely cranks at all when warm?

Resistance goes up with temperature, so current drops.

[aggressive male]

Are there headers on the motor? Heat soak at the starter/solenoid can cause hard starting after warm-up. I had this problem with my Firebird. The best way to eliminate this condition is to put a remote solenoid on the fenderwell or firewall to get it away from exhaust heat. Summit, Jegs or MAD have kits to convert your starter mounted solenoid to a remote mount.
MarkNo headers, stock exhaust on this one, at least up to where the cat goes. It's stock compression also. and being that I took off the smog pump and the ac pump I would think it would be easier to crank now.

[aggressive male]

I've had this same problem. It is not a solenoid issue, since the motor is cranking. The cause is a weak starter motor or corroded cables. I replaced my cables to 1/0 ga wire and relocated the ground from the alternator bracket to the block. I also switched to a mini high torque from dbelectrical.com. Starts like a champ now.

BTW, if the symptom was a "click" or nothing at all, the problem would be a solenoid issue.

Make sure to with at least 2ga wire. Just curious, did you try the cables before you got a new starter and found the cables alone were not enough?

[aggressive male]

I was looking at the battery connectors again today. The one for the starter is 1/2" thick and has one of those bolt on terminals for the battery. There is some slight corrosion on the terminal. The ground connector is actually about 1/16" thinner but I know for a fact it came off a much bigger 425 and it worked fine while on that motor. Could it be this 307 needs more amperage than a 425? Either way what shall I try next? A thicker ground cable? Maybe before I buy anything I should run jumper cables in addition to what the car already has to see if that helps?

[megaladon6]

the side terminals SUCK!!! pull them off and clean the crap out of it. make sure you fully tighten them down. also inspect the cable for any bad spots or cracks. it's probably going to be the starter but may (also)be the cables as previously stated.

[Vegas69]

Easy....if you don't have a large voltage drop from your battery positive to the starter or from body to your negative battery terminal then your starter is junk.

[bochnak]

Just curious, did you try the cables before you got a new starter and found the cables alone were not enough?

No, I replaced the starter and the cables at the same time.

[Adam's 55 Chevy]

Could be as simple as crap on the battery posts. You remove it, you don't do it!!

[aggressive male]

I just tried running jumper cables from the dual post battery ground to the engine. That didn't seem to help. I was going to run the jumpers from the other terminal to the starter terminal but it looked like it might arc out on the exhaust if I did that. Do you guys think it's possible to get a bigger starter for an olds 307?