Peter Zimmermann

I'm sorry, for some reason I thought that you had settled for a rebuilt unit off the shelf. I also had a new, high torque starter fail (the same way) in my '81 SC. It wasn't even too hot on the day that one died!

Amber Gramps

A new relay is going to fix this? I will be at performance products in the morning to pick up my new distributor cap and rotor and will ask about this. Last time I was in there they had a Martini car behind velvet ropes to drool on.

Tmack

That was it. Voltage drop. Why we don't know. My mechanic installed the starter relay. Problem solved.

3.2SLANTNOSE

This may be late, but it really does sound like the starter solenoid is over heating and seizing up. If it starts properly after a cool down, that is where I would start.

Peter Zimmermann

Tmack: Good result. We discovered at the shop that the relay only fixed about 1/3 of the cars that we put one on (my '82 SC has one, but the car still has the hot no-crank issue in severe conditions).

jgrosjean

I had a 1969 911E once and had the same problem. It took a long time to figure it out. As these cars get older, the spot welded joints corrode. The battery in the front is grounded to the chassis and the body is used to carry the negative current from the engine to the battery. In old cars, the resistance gets high and the voltage drop is high. In my case, the starter would run, but the CD ignition would not fire because the voltage was too low. I ran a big ground wire from the negative terminal of the battery (actually where the battery is grounded to the body) back to one of the bolts on the starter.
The starter ran much faster and it always started. Had the same problem with my Vanagon, and it fixed that also.

jakeflyer

As you know, the starter is 2 devices, the starter motor(large round unit) and the solenoid(small round unit). With the key turned to start, current runs thru one of the two small wires and there is a click in the solenoid when the brass strap contacts the power from battery post to the starter motor post inside the solenoid. If the starter is frozen, you should still be able to hear the click. If no click, you can power from the large terminal from the battery to the small wire post with a little wire with clips and see if you get the click. This will tell you if you have power to the solenoid when you turn the key on. A MUCH less likely problem would be, do you have 12V at the starter post when it is hot? Your muti meter will give you some basic information. Zimmerman's comment was accurate about several bad units in a row. I did 4 starters in my chevy truck in 2 days The last one has been good for 5 years. Quite a tiff at the parts house.

Tmack

Thanks Guys. When my mechanic tested the voltage there was a woltage drop on the negative side.
Installing the relay a 20.00 dollar part (but requires getting up under the car) fixed the problem.
The car would always start when it was cold. It was when it was hot that it would not start. I think the combination of the new starter and the relay did the trick. Hvan't had a problem since.
If any body needs a relay I have an extra that I got from Performance parts never been used. I ordered thinking I could do the job but I cant get my car up high enough in my garage to work safely under it.
I also have the original starter and solenoid if anybody is interest in rebuilding and needs a core.