Slow Cranking when hot

[RJS]

OK 72 B-Body 512 stroker, been having this issue for appro. 3-4 years and in turn this doesn't allow me to put enough timing (initial or locking dist.) in to help get a nicer idle. The cam is 245 @ .050 compression is 10.5 with aluminum heads. TTI 1 7/8" coated headers and exhaust, car never runs hot. Normal temps for this car are 175-185 area at most.

Slow crank when hot what to check first and how/why??? This has been like 3+ year thing. Different batteries ,solenoid, starters, checked grounds with meter, measured 12.9 at battery post on starter also, so is the next thing while cranking HOT I have to measure battery post and or starter post??? My cables are restoration style purchased 10 years ago when car was put together. Does someone make a restoration style cable that is actually much better now a days? Would a less chance of getting burned a good idea to make up a 10g wire with eyes to also go from battery cable post to starter post???
Thank Ron

 

[pnora]

What starter?

 

[RJS]

Oops forgot to say, I have had 2 different new dakota starters and just installed a Power Master XS last week which cranks faster so I tryed locking the distributor and it went to slow crank when hot. I now have distributor back to unlocked with 20 initial and it will tolerate that.

Ron

 

[RJS]

I'm going to make up the additional wire from battery post to starter stud to help positive wire because I can do this cold and see what happens when hot . Working alone sucks when doing stuff like this.

Ron

 

[Rick@Laysons]

Just my 2 cents worth......cuz I'm old and been right where you are.....

First thing I'd be lookin at is that "restoration" style battery cable.

Big cubes, advanced timing, modern hi-amp batteries, and heat soaked starters.....when trying to hot start, that "restoration" cable is pulling way more amps thru it than it was designed for.

You need a heavier gauge cable with high quality ends.

 

[PurpleBeeper]

OK 72 B-Body 512 stroker, been having this issue for appro. 3-4 years and in turn this doesn't allow me to put enough timing (initial or locking dist.) in to help get a nicer idle. The cam is 245 @ .050 compression is 10.5 with aluminum heads. TTI 1 7/8" coated headers and exhaust, car never runs hot. Normal temps for this car are 175-185 area at most.

Slow crank when hot what to check first and how/why??? This has been like 3+ year thing. Different batteries ,solenoid, starters, checked grounds with meter, measured 12.9 at battery post on starter also, so is the next thing while cranking HOT I have to measure battery post and or starter post??? My cables are restoration style purchased 10 years ago when car was put together. Does someone make a restoration style cable that is actually much better now a days? Would a less chance of getting burned a good idea to make up a 10g wire with eyes to also go from battery cable post to starter post???
Thank Ron

Your stater(s) are getting hot. Electrical resistance goes up with heat. Try header wrap & wrapping the stater in heat shield also. Additionally, you could add a timing retard while cranking. A MSD multiple retard box does this

 

[Bird 426]

Do you have a shield or heat blanket at the starter? Have you tried spinning the engine over when hot with the ignition disconnected? If so, does it still turn over with difficulty? It may be cable related as has been suggested.

 

[R413]

The best starter is only as good as the cables. Go buy some bigger aftermarket battery cables to try as a test to see if that's the problem. Do Both cables the pos and neg need to flow the same amperage.

You have changed everything but the cables.

 

[RemCharger]

See if the cables are hot.

 

[BSB67]

What is your cranking cylinder pressure?
What is your initial timing?
What starter(s) are you using?

 

[RJS]

OK just to answer some questions and tell what I did today.
I made an 10g wire to sort of help the battery cable, the end on the battery cable actually cracked today when I attached the wire. It is since 2015 when car was built so ordered another restoration cable (I'm a gluten for punishment). I did ask in my original thread is anyone making a better cable (heavier gauge) that has a stockish look??

I didn't get to test the car today but will tomorrow.
I have to still check at the starter stud while doing a hot slow start.
I also have to check what one of you suggested to eliminate ignition when doing a hot start too.

I've been around the block a few times at age 66 so I'm sure it could very well be the resto cables.

Give me some more time I wore myself out today working on the car, I'm in the middle of putting on a Schumacher engine limiter so tomorrow I'll continue.

I have a Rev n nator ignition box not MSD so don't believe I could put a retard in for starting.

I really appreciate everyone's help.

Ron

 

[gtx6970]

Who did you get yours from ?

The best cables are from MH wiring

 

[Geoff 2]

[1] Resto cables are probably thin cables. Get some thicker cables or connect two sets of cables in parallel. That will reduce voltage drop & might just get you over the 'hump'.
[2] Locked timing. Use a switch to cut the ign. Get the engine cranking with ign off, & switch ign on while cranking.
[3] The MSD Dyna starter is the most powerful starter that I am aware of. 3.2 or 3.4 hp. If your PM starter is less than this, then the MSD will help.
[4] Locked timing for better idle. You can use man vac adv to get the same thing, easier on the starter. Examples below. You need a minimum of 8-10" of vac, in gear, if auto.

 

[68 Sport Satellite]

been exactly where you're at 5 yrs ago. Heat soaked starter + too small battery cables with subpar cable eye connections. Upgrade to 2/0 size positive and negative cables made by a reputable company and your problems will go away due to a drastic decrease in electrical resistance (= less heat). To make things even better, upgrade to a higher cranking amp battery. I too run a dakota mini starter and there is little to no room to wrap it or squeeze a heat shield in there...

 

[Bird 426]

I have a DEI heat wrap on my SB stroker, tti headers. I did have to modify the wrap some, it has a Dakota starter. New M&H cables. Same set up on my Hemi Road Runner. So if the same starters and cables are inadequate, why don't alot of us have the same problem? This is why I suggested taking out the ign possibly. Hope that you can find out the next time that you work on it.
Good luck!

 

[RJS]

OK haven,t got outside yet but want to address today's comments.
Not sure where the present cables were from but just ordered one from Frank Badalson. As far as M+H cables those are YO sold only and I looked at them but gave Frank the nod. I'll assume his are from there.
The last starter was covered with a starter insulator cover and didn't help. I've also read it may be a bad thing to do but in my case it was of no significance.
The Power Master starter is 4 hp and recommended by a trusted friend mechanic in the hobby most of you know.

Two cables may be the way to go or for me to make a good larger cable but I want to find larger cable than with a red outter insulation for the "fake" resto look.

Lastly if I have to put in a switch to kill ignition while cranking I will.

Thank you everyone

Ron

 

[Fran Blacker]

You can buy 5/8" red heat shrink tubing here. Other sizes also.
https://www.cabletiesandmore.com/he...ping&msclkid=caa6b65237001c875f2cdeaed0276fd1

 

[toolmanmike]

Any video's of what it is doing? Cranking slow and bucking against the starter (like from too much timing) are 2 different things.

 

[Black_Sheep]

OK haven,t got outside yet but want to address today's comments.
Not sure where the present cables were from but just ordered one from Frank Badalson. As far as M+H cables those are YO sold only and I looked at them but gave Frank the nod. I'll assume his are from there.
The last starter was covered with a starter insulator cover and didn't help. I've also read it may be a bad thing to do but in my case it was of no significance.
The Power Master starter is 4 hp and recommended by a trusted friend mechanic in the hobby most of you know.

Two cables may be the way to go or for me to make a good larger cable but I want to find larger cable than with a red outter insulation for the "fake" resto look.

Lastly if I have to put in a switch to kill ignition while cranking I will.

Thank you everyone

Ron

NAPA has bulk battery cable in both red and black, they will have the lugs too. When I built a positive cable for the GTX I went up a size, I also upsized the ground cable.