How do you get these big boys started after they're warmed up?

[driverjohnlh]

I have a '68 SDV with the 472. When the engine is cool, it cranks over easily and starts right up. When it reaches operating temp. , however, if you turn it off, you are going to be there a while because it won't crank over fast enough to start. I also have a '66 CDV 429 that I'm rebuilding but It didn't do it quite as bad. My dad had a "75 CDV back when it was fairly new and I remember it being hard to crank as well. I've also had Pontiac's with the same problem. I have hot batteries, good starters and good cables mounted at the correct locations. Any idea's? Thanks in advance for your input.

[MagicRat]

Love those old caddys.

A few years ago I considered swapping a 15 year old BMW with big issues for both a '65 CDV and a '68 CDV, package deal. Nice cars but had some rust issues. Supposedly, the '65 had such low miles, it still had the original bias ply tires. It also had a rusty frame
These days, though I think maybe I should have made the swap.

3 things come to mind for your starting issues.

1. My first guess is the starter motors may be getting too hot due to their close proximity to the exhaust manifold and pipe. One can get starter motor heat shields for this.... many Chevys had such shields as standard equipment. Such shields are available aftermakret, or one can wrap the pipe and manifold in "header wrap".

Lots of high compression, big engines have this problem, especially, GM products, in my experience.


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2. The starter motor may simply be worn-out. Sometimes, worn armature bushings will allow the armature to drag along the inside of the starter motor housing. A rebuild kit is usually pretty easy to install for these starters.

3. The mechanical advance weights in the distributor may be rusty and/or sticky, or the weight springs are weak or broken. When this happens, the weights do not retract when the engine stops, and allow the ignition to be over-advanced, which causes slow cranking. One can inspect the weights and springs. New springs are easy to install and the underside of the weights can be sanded smooth with #220 sandpaper. Don't oil the weights.... that will attract dirt and then they will stick like crazy.

[maxwedge]

Common problem with lots of GM cars from that era, when I worked for Cadillac, we did the things that Magic pointed out, all are possibilites, when all else failed we had rebuilt/new hi-torque starters installed and there was a heat shield used to protect the solenoid also.