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Heat Soak, 70 Mach1 Help
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Posted by: audit123

Here is the problem: after I drive the Mach1 for a while up to temp, then shut it down to say fill up with gas, the motor cranks really slow, but it does start.
I purchased the Mach1 in 2003 and since then have had the motor rebuilt, blue printed and balanced; trans. rebuilt; floor pans and quarters; repaint to original Red color code T; new seat covers; detailed engine bay, etc. the car looks killer. All this was finished 2/17/06. The slow crank existed before the rebuild. The only thing not done during partial restoration was repair of a bad resistor wire, but it now has in it and did before the rebuild (it slow cranked before and after) an electonic ignition, Petronics and coil.

The slow crank is driving me crazy, have replaced the positive battery cable, run an extra ground to the frame, the starter was new last summer (slow crank before and after); the distributor was replaced last year as well and the timing is not advanced.

So what is it?

Posted by: Aussie XAXB

Sounds like typical heat soaking of the starter. If you have headers on this engine it is not uncommon for them to cradle the starter and just soak it with heat. Then when you go to start it again the starter turns very slowly, sometimes not at all. To fix this you need to get or fabricate a heat shield to protect the starter from the heat of the headers.

Also, have you had the charging system checked? You should have about 12 volts at the battery at idle and 13-14.5 volts at RPM. Also have the battery load tested just incase.

Steve

Posted by: LarryW

I had similar problems with a 351C. Tough cranking after a short shutdown. I went to a later model stock Ford PMGR (Permanent Magnet Gear Reduction) starter. I got it through my local starter and alternator guy. $109. and I've never had a problem since.