70 BB starter

[andrew strauss]

I have a 70BB that I have been fighting a hot start problem with for some time.When cold the starter will spin and start the car with no problem.When hot or even slightly warm it grinds badly and wont crank the car.This condition can occur with as little as 5 minutes idling time in the driveway.I have hooked a battery charger to the battery and put it on the highest setting when this occurs and this does nothing,so I dont think it is a battery amperage problem at least at the battery end.I have installed new cables,harness new starter and a new battery.All connections are clean and tight.The one confession I can make is that I have a cheap starter on the car at this time.If a quality starter will fix the problem I will get one ,I just want to cover all the bases first.I understand that a hot start problem for thses cars may not be uncommon,but with as little as this car warms up before it happens cant be right.I find it hard to believe that in 1970 you couldnt go to the store and then 5 minutes latter start your car to go home.

Thanks in advance

Andrew Strauss

[Mark #28455]

several possibilities

The starter solenoid can also contribute to this problem. If the contacts are corroded, it will not deliver the full voltage - I believe the test involves checking the voltage at the power lead that enters the starter body.

A bad ground can also cause this problem.

Finally, the original BB starters were different internally to cope with the higher torque demands. The chassis service or overhaul manual lists the specs including the no-load RPM for each starter.

Mark

[Mark S. Lovejoy]

Re: 70 BB starter

Andrew,

You may need a shim (or two) between the starter and the block. The 'grinding' noise is a symtom of this problem. Some starters are a little too close to the centerline of the flywheel. Try it, it's a cheap fix.

Hope this helps.

Mark

[andrew strauss]

Re: 70 BB starter

I have tried shims.Would shims cause this problem in hot start only,but not affect cold start?

[Joe L.]

Re: 70 BB starter

andrew-----

The problem with hot re-start is a common one. For it to be also associated with a "grinding" condition is not so common. The "grinding" condition, if it's a TRUE grinding condition is usually associated with the need to shim the starter. In your case, however, it may just be due to insufficient engagement of the starter drive due to the same factors which cause the hot re-start problems. A need for shimming the starter should not be any different from cold start as from hot start. I suppose that it's possible that metal expansion under hot conditions might "push you over the edge into" into a starter drive mis-alignment condition, but I've never seen that.

If you are currently using a "cheap" starter, that could, indeed, be the root cause of your problem. In addition to being inferior, it may be an incorrect, standard torque starter. A high torque starter can be identified by a 1" copper spacer between the starter field coil terminal and the solenoid. If there is no spacer, then you have a standard torque starter and that's not the correct one.

You can no longer purchase a NEW starter for your application from GM (unless you go to a high torque, gear reduction, mini-starter). However, yoiu can still get a FAIRLY high quality rebuilt unit from Delco. I suggest the following:

Obtain a Delco remanufactured starter:

if 4 speed equipped-----GM #1876552, aka Delco #323-254

if THM-equipped--------GM #1876555, aka Delco #323-255

Inspect the starter you receive:

If it has an obviously NEW solenoid (which they usually do), leave it as-is. If it looks reconditioned, replace it with a NEW solenoid of GM #1114493, aka Delco #D992.

Inspect the starter drive. If it looks "reconditioned" AND ESPECIALLY IF THE TEETH HAVE ANY CHIPS OR WORN AREAS, then remove the starter nose and replace the drive with a NEW Delco #D2051. Yes, I know that it seems ridiculous to have to do this with a rebuilt starter, but you will find that most rebuilds, even Delco, will reuse thee starter drive. 99.9% of the time, the used drive will be fine. However, I DO NOT USE a starter with a used starter drive. PERIOD.

Install the starter on the car. If it does not solve the problem, then the ONLY way you're going to solve it PERMANENTLY and RELIABLY is to install a remote (i.e. "slave") solenoid.

[David D.]

Re: 70 BB starter

Andrew, If the starter has a cast iron nose, the bushing area has an open end. If you have the starter out, check that the end bushing is not worn or loose. I have seen many of those bushings work loose and come almost completely out, on big block engine's. If this is the case, the engine usually starts cold, but after it warms up a little, the starter may grind on start up or may not turn the engine over at all. Usually the problem starts out with just a slight grinding of the starter when the engine is cold, but when the engine starts to get warm, it gets steadily worse. I only mention it, because seem's very much like a heat soaked starter, except for the grinding and happens it in a fairly short period of time. A lot of the low cost rebuilder's don't even bother to replace the bushing, and if they do, don't bother to at least stake the end of the housing, to keep the bushing in place. Dave