Slow Cranking When Warm

[gbhrps]

Gentlemen,

This issue has creeped into my 55 ( entirely stock ) over the last few years. When cold the engine cranks over just fine and fires right up.

When warm the darn thing struggles to crank fast enough to fire. Sometimes it will fire after two or three slow revolutions, and sometimes the 6 volt battery just doesn't have enough umph to last long enough to have it fire.

I've taken to carrying a 12 volt jumper pack around for those times when it is being stubborn, hook it up to the 6 volt battery and she spins quickly and fires right up. The timing is perfect as there is no indications, cold or hot engine, that the starter is fighting compression or firing strokes.

No, I do not want to convert to a 12 volt system, and yes, I've checked all connections for corrosion at the battery, solenoid, and starter. The system worked fine for the first 8 years or so since its restoration.

I'm thinking that the battery cables are corroded internally, or that the starter has an internal breakdown when it gets warm.

Any thoughts of other issues?

Gene

 

[paul2748]

Have you checked the connections on all the grounds. Grounds are as important as the rest of the electrical system.

 

[Jimz Bird]

"I'm thinking that the battery cables are corroded internally..."
Sounds like a good place to start. Even if you want to keep it original looking a new set of cables from CASCO or another vender is not that much.
A starter overhaul kit(brushes and bushings) from the vendors is not that much either so that may be a thought also.
As Paul said, grounds are important as well as matched battery cable sizes. Has one cable been replace with a smaller size?
You probably have had he battery load tested as those other concomitant issues can load it fairly heavily.

 

[gbhrps]

Gentlemen,

As stated, the car is as it rolled from the factory floor. I'll check all of the engine grounds, and maybe add another in some out of site place. Then get some heavier battery cables made up. If that doesn't solve the issue, the starter will get a checkout and overhaul.

This is going to take some time, as other matters concerning the arrival of spring here will take the forefront. I'll post again to bring this up to date.

Gene

 

[HeadacheGuy]

Voltage drop test is always better than blindly replacing parts and quick too. The warm thing usually indicates starter. Word to the wise. This could be (and usually is) the windings are breaking down internally. If you get your unit back with new brushes and bushings you may end up with the same problem. New is always preferable if you can find one