My 72 Chevelle BB-402 doesn't like to turn over when the engine is warm on hot days, especially when I use air conditioning. If you let it sit for 15-20 minutes it starts fine. When the car is cold it always starts great. The battery is new (850 cold cranking), the starter is new, the thermostat is 160 degrees and I also have the correct clutch fan. Is this a common problem with BB's? Any ideas?

This is one of the most famous BB characteristics - especially if you have headers. There are many fixes including installing a remote solenoid, starter heat shield and the one I've used; high quality 2-guage battery cables. I'm sure others have found other solutions as well.

wtw
kevin most likely nailed it.the only other thing i was thinking , mabey heavy carbon deposits on your pistons n valves.kevin should be right, i had a GOAT a long time ago that the exaust made the starter hot and it turned hard,heat shield fixed it.hope ya weed it out. 67rat member #199

WTW you may want to check your distributors' total timing as well. Too much advance will put a real strain on the starter after the engine is warmed up. Hope you find the solution soon. http://www.chevelles.com/forum/smile.gif

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70' Malibu - 383 Stroker that loves Dental Gas! Chevellz Alwayz!

All above are very correct. But one, if not the most, important factor that you need to be sure about is that you have the hi-torque and not the standard starter. They look just alike and are interchangeable with the different starter noses and solenoids. The way to tell them apart by external appearance is by looking at the location of the brass strap which comes out of the starter case and is attached by a screw to the lower terminal of the solenoid. The standard starter has the brass strap coming up and connecting right up against the solenoid terminal. The hi-torque has about a 3/4in long bushing or spacer BETWEEN the lower solenoid terminal and the brass strap coming out of the starter case. The holes in the starter cases for the different position of this brass strap are in 2 completely different locations, with the strap hole for the hi-torque being closer to the front end plate of the starter case. Once you see the difference in these 2 starters, you will never mistake the difference. Now, one last thing about a hi-torque starter. Just because you may have a hi-torque starter doesn't necessarily mean it is a good one. The internals must be good quality parts (new or used). The armature, fields, coils, brushes and holders and end bushings must be in A-1 condition. And the starter needs a GOOD quality NEW, not rebuilt solenoid. If you are fortunate enough to live where there is a good starter/alternator shop, go by, get acquainted and explain that you need a top quality, hi-torque starter. Not just a rebuilt exchange from Auto Zone or Pep Boys. And, last, but not least, you CAN build your own. Once you have an A-1 starter, all of the above will be like icing on the cake.

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i'd guess that timing is the culprit if you have a heavy duty starter. when i bought my BB it was set up to run on manifold vacuum i switched to ported and it starts fine, i even kicked the total advance up a bit, 36 deg. and she turns over just fine when hot.

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