• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

68 charger 440 hot start problem

O

Outbackbobcat

Member
Local time
5:08 PM
Joined
Jul 27, 2025
Messages
6
Reaction score
0
Location
Wisconsin
I think I know the problem but am interested if anyone else ran into this. Fresh rebuild runs great starts cold great, hot won't turn over, huge battery cable new 1000 cold crank battery, new high torque mini starter, still a problem, 14 degree advance, 35 overall, 10.5 compression. Here's what I fear is the problem, I installed both top and second rings at .022 - .025, I'm now reading the top should be more like .028. If I leave it cool down about 20 mins fires up, I'm thinking the rings are binding in the cylinder
 
Welcome... I guess. "Won't turn over" ok.... turn the key and... WHAT HAPPENS ? Engine locked ? Cranks but no fire ? My question is: Do you have heat saturation in the starter cable ?
 
Maybe it’s simpler? Like fuel evaporation or whatever it’s called when your gas boils in your fuel pump or carb. You could try a carb spacer and heat shield fuel lines.
 
Headers? Heat soak starter.
Battery in trunk? Or underhood?

Both battery cables need to flow the same amount of current.
 
You only need large ring gaps with hypereutectic pistons. Is that what you used?
 
Please describe symptoms better. In my case starter gets heat soaked and wont turn over fast enough.
 
This reads like the problem I just resolved - warm start: it felt like a dead battery, wouldn't crank. Let it cool and cranks/starts right now.

Ended up being the silly stupid disconnect I had on the battery. . . I don't know why that would be temp sensitive, but took it out and starts right up warm.

The 1000+ amp battery is in the trunk w 2/0 cables. I wrapped the headers and exhaust, I checked clearance of RobbMc starter. Nothing helped until a took out that disconnect.

Before you spend too much money - check the voltages at battery and starter, during start. If the starter voltage falls below 10 you might have a connector/wire problem that is adding resistance and stealing your amps.

Hope that helps.
 
Ok, I have both pos, neg 0# size cables, it is in the trunk, I have speedpro forged pistons cast rings, I run a mopar tunnel ram with 2 edelbrock 600's. I have wrapped the headers near the starter, does anyone run a heat shield over their starter? I have 12volts under starter load, I don't have any disconnects in the line, the fuel pressure is adjusted to 5 1/2 pounds, and is routed away from any heat source, I have 915 heads with oversized valves, ported, I don't think some of this matters but I'm checking the boxes
 
In addition I installed the high torque mini starter 3+hp, I already had one in but tried their largest one, it sure sounds like a heat soak, I could possibly fabricate a heat sheild and try that
 
I would suggest comparing the effort to rotate cold and hot with a bar on the crank.
That will tell you something.
 
Do you have a #0 size cable from the engine to the frame? This needs to be done with battery in the trunk.

Underhood battery has the negative cable to the block. So battery in Trunk the car needs a large ground to starter flow 250+ amps to the starter.
 
R413 said:
Do you have a #0 size cable from the engine to the frame? This needs to be done with battery in the trunk.

Underhood battery has the negative cable to the block. So battery in Trunk the car needs a large ground to starter flow 250+ amps to the starter.
Click to expand...

Agree, but I would run the Negative all the way from the battery to the block if possible.
 
I have two big grounding straps from the block to the frame. Yes, 0/1# cables both negative to frame and positive to starter
 
Ok,here's an update, I had the battery checked just for laughs and it's good, turned the motor over cold and hot only a + 5ft lb difference hot, I did fabric a heat shield and that did make a good difference, I will run a negative cable from the battery to the block and maybe that will be the final touch, now it's hard to turn when it's hot and sits for a bit, but I have electric fans and turn them on manually for a couple minutes and she'll fire up
 
You must log in or register to reply here.

Similar threads

M
Not starting/not able to keep running 432
Replies
7
Views
461
68-500
68-500
Krooser
I may have hot tanked the wrong oil pan...
Replies
17
Views
2K
Krooser
Krooser
1970charger440
dodge charger falls and stalls slightly when cold. Won't rund when hot.
2
Replies
34
Views
5K
Greg - Mopar2U
Greg - Mopar2U
W
68 GTX 440 puking AF
Replies
11
Views
2K
oldkimmer
O
79B100
318 Woes
2
Replies
35
Views
5K
dvw
dvw
Auto Transport Service
Back
Top