Slow crank when hot ? '71 GTX

[WP29440SE]

same symptoms here, I thought I had to change my stock starter because of heat from the headers. it would crank over really slow when hot after a 5-10 minute shutdown (convenience store) like the battery was dead. pedal to floor, starts every time. 10 years later, still using the same starter.

just for shits and grins , I'm going to try that the next time I'm in that situation.
I guess I should have mentioned I'm running a weiand tunnel ram and 2 600's lol

 

[SlinktRR]

1. first year i had my car, shut the car off for awhile. Tried to restart, nothing, hard crank, starter turning at 2rpm. Ran the battery down all in vain. Had spark & fuel, must be the damn starter. started visualization of the pain and suffering I was about to endure pulling the starter out of a header sandwich when i got the car home. Called for a Hagerty tow. I was out in the boons so i had some time, about an hour. Tow arrives, i say what the hell let's see if it starts. Fires right up.

i didn't have a tunnel ram though!

 

[Dennis H]

Heat soak in 30 seconds?! I'm here to learn.

 

[SlinktRR]

never underestimate an edelbrock carb...

to your point though, sitting on top of a tunnel ram out the hood maybe not.

 

[gary h]

I have an update, the slow crank when hot problem appears to be gone after installing a New group 27 Battery a few days ago. The old Battery (group 24) tested good but was from 2012. Finally putting some miles on after Chronic ignition issues.

 

[bad88ttop]

Hi guys, I'm also having a similar issue with my freshly restored 1970 Charger R/T. She fires right up when cold. If you drive it in stop/go traffic for 15 minutes and shut it off, she barely cranks. If you let it sit for 10 minutes she'll fire right up. I noticed the negative battery cable that's grounded to the intake bolt and radiator support gets pretty limp when trying to start it when hot. Battery is a brand new reproduction that measures 12.7V when it's unhooked. 1970 B bodies only had these 2 ground points and none of my other 70's have this problem. I'm open to ideas and thanks in advance. Bill

 

[gary h]

My 1966 Imperials and '71 GTX have a Ground strap on the back of the Engine on the Pass.side.The strap goes from Eng.block to the firewall.I had a hot start problem and a New group 27 Battery solved the slow crank issue.

 

[Super-Bee-69]

What is a group 27 battery??

 

[furious70]

Wasn't the OP's problem but will second the check your cables. Original starter cable in my fury looked fine from outside, but had the same barely start when hot even with a mini. Turned out that cable was almost powered corrosion inside, the copper had disintegrated.

 

[mopar 3 B]

What is a group 27 battery??

A larger more capable one than a 24.

 

[SlinktRR]

Yes my group 27 battery is 800cca and I've had it for about 8 years using the battery tender.

 

[mopar 3 B]

One way around hard starts is to kill the ignition untill the engine is turning. Then fire it up.