Another possible heat soak thread
 

I've searched and read through a number of threads talking about the heat soak starter issue and nothing I've read is exactly what I'm experiencing so I'm looking for opinions.

My '67 has a 350 with stock exhaust manifolds. I had the engine rebuilt (stock rebuild) back in 2018 and that is when I installed new battery cables. When I drive for a decent amount of time (20 min) especially on a hot day and turn it off, it won't start. It doesn't crank, it doesn't do a thing. I turn the key and no clicking, no cranking, nothing.

This has happened ever since I bought the pickup in 2018. After a few times of it happening, I bought that heat blanket/shield wrap to go around the starter/solenoid. It seemed like it solved the issue, but then last year it did it again. The last time it did it was a couple weeks ago. This issue is why I dont hardly drive the pickup, since I dont want to be stranded somewhere or have to pay for a tow every time.

I've read on some heat soak threads where people have this issue, but the vehicle starts after maybe 5 min-30min or so. When I have this issue, it won't crank and/or start for over 16 hours.

Hopefully this is something easy. Any help would be appreciated. I just don't know where to start and dont want to just keep throwing money at it hoping.

Re: Another possible heat soak thread
 

I had this same issue with my 72” C10.
I used a 1 inch Phenolic carburetor spacer for my Eldebrock carb.
Hot gas will boil over inside the carb after shutting the hot engine down, creating this “heat soak/hard or no start” situation.
The spacer acts as an insulator.
Many styles and applications to match your carb and intake.
Hope this helps you out.
Good luck.

Re: Another possible heat soak thread
 

Your words in bold tell me it is not a fuel boiling, insulator gasket problem.. Also, I'm guessing it's not a heat soaked starter problem either.. I'd be looking at a loose connection in the purple start wire that's being aggravated by heat.

Re: Another possible heat soak thread
 

[QUOTE=samkost;9217165]

I'm not doubting you or anything, but how would the gas boiling cause the starter to not crank at all?

I know I have one of those spacers in my garage. For some reason I didn't install it after the rebuild and I can't remember why that is.

Re: Another possible heat soak thread
 

[QUOTE=RustyPile;9217174]

I've looked at this wire before as it is spliced, but can't find anything wrong with it. I may have to check it again. The splice is up by the back of the hood where GM ran that plastic wire gutter. Its spliced with just a butt connector. I could cut that out of the equation and do solder and heat shrink. Could be the connection at the solenoid too I spose. Seems odd that it would take over 16 hours for that to go back to normal again.

Re: Another possible heat soak thread
 

My apologies.
I jumped the gun and did not did not read your first post thoroughly. :dohh:

Re: Another possible heat soak thread
 

Have you tried jumping the starter to rule out a wiring issue? If that's not it I'd look at replacing the starter.

Re: Another possible heat soak thread
 

[QUOTE=samkost;9217179]

No worries!

Re: Another possible heat soak thread
 

[QUOTE=body bolt;9217180]

No, I haven't jumped the starter at all. Thats one of the things I was going to try. I'll have to re-create the problem one day and shut the pickup off in my driveway so I can troubleshoot. Just seems odd that if it was a starter/solenoid getting too hot, why is it taking over 16 hours to function again when everyone else i read about isnt even an hour. So I'm just trying to come up with as many things to look at as I can when im troubleshooting.

Re: Another possible heat soak thread
 

First, yes as described 99.9% electrical. .1% mechanical like some odd ball heat related tightening of the engine. Like I said, probably not.
So it's electrical. It sounds like you are sure it's not too small of a battery cable. It could be the solenoid. They are cheap and easy to replace. Could be the starter. Easy, but not not so cheap to replace. My bet is it may be the battery not fully charged.
I very recently went into detail on the wiring system looking for my problem that is sort of similar. From my research, most, even I did it, connect additional power loads to the battery service post. The Junction Block next to the Battery. This Junction Block IS NOT the intended location to connect power loads other than what is already there from the factory. The Junction Block is there solely to service the 14 gauge fusible link easily. Additional devices added to the truck where supposed to be connected at the Horn relay or an additional Block added with a jumper directly to the main harness splice. When the power loads are connected at the battery junction block the Battery Gauge is tricked into thinking the system is getting a charge because the load at the Battery Block is mimicking a battery load. So the Gauge in the truck is telling you that the battery is charging. Switch the load down the 10 gauge wire close or onto the Main splice in the harness by the voltage regulator and the Battery meter will correctly register load and indicate less of a charging state or even discharge. When move my Spal fan power connection it clearly showed I was barely putting out enough power to sort of keep the battery charged if cruising, but in town or idle, I was discharging. Connected at the Battery Block, I showed I was puting out a healthy charge to the battery. That is why I was getting hot start issues. I changed my alternator to a Powermaster DN type (Original type for our trucks by much more Amps) and I now charge as long as I am off idle. The slow RPM spec for my engine puts me a little shy of covering everything when AIR and lights and fan are on.
The problem with loading up the Alternator side of the system is that you can pin the battery meter if the Alternator is not spinning to balance the high load the Factory never envisioned. So careful just wiring up to the main splice.

A little more detail for those interested in the Battery Meter workings. I found it very interesting, but it is not on the subject of this threads topic. So I offer as a fact tid bit but lets not get off topic with further replies on this point...The Battery Gauge is NOT a Amp Meter. It is a device that compares voltage. That is why it is important not to change the 10 gauge wire in the harness from the main splice (close to the voltage regulator) to the Battery service Junction Block. That wire needs to be 10ft of 10 gauge copper. At the Splice is a 4 amp fused wire that goes to the Battery Meter. It is Positive voltage. At the other end of this ~10ft 10 gauge wire the Battery Block. There is another Positive lead also 4 amp fused that goes to the second positive lead at the Battery Meter. At the cluster there is a third lead from the Battery Meter to ground. The Battery Meter is affected by the voltage difference between the Main Harness Splice and the Battery Service Junction Block that is connected by that 10ft 10 gauge wire. This is counter intuitive so stay with me. Even though there is only 10 ft of wire between the two points, splice and block, there is a voltage difference. If the voltage at the Battery Block is higher than at the Splice, the battery is discharging. If the Splice has higher voltage, then the battery is charging. It was an ingenious way the GM engineers mimicked a amp meter that was always burning out in other makes and GM avoided the issue with this really cool wiring trick.

Re: Another possible heat soak thread
 

Just a thought, I had a big block nova that would do the same thing. I had a pos&neg battery cable made up custom using 1 gauge Cable(I think that is the correct gauge) anyway my point is they were at least twice as thick as the original gm cables and never had the problem again. My positive went to starter and ground directly to engine block. Problem solved.

Re: Another possible heat soak thread
 

From what I read the factory Shunt wire (junction block to splice joint) is about 5 ft long. A longer wire can be used and it will give more deflection in the battery gauge. Member dmjlambert mentioned that an extra 6 ft should double the deflection.

LockDoc

Re: Another possible heat soak thread
 

[quote=ryans69chevy;9217178]I would fix or replace that wire. butt connectors do not belong in any wiring system. If the wire is fatigued (brittle) from heat exposure, replace it.

The wires that run behind motor to starter take a beating from engine/exhaust manifold heat. They need to be held away from engine with loop fastener to firewall. Using heat wrap tube is helpful in this area of wire harness.

IMHO I would use #2 at a minimum for battery cables and for the + one that runs along the engine, that section should have heat wrap sleeve on it. I use this AC Delco one (Amazon) for my 78 series (side post) battery

Starter, swapping to a true gear reduction type is better. Smaller and considerably more & faster cranking. Got my Remy (new) from Rockauto for around $70.

Re: Another possible heat soak thread
 

Its gonna be your starter and/or power cable. I am leaning more towards the starter.. you said the issues went away after you put a heat shield around it...well that starter has probably been weak for awhile and is getting weaker hence why the issues started back up again. I would swap out to a starter from a 97 Tahoe, its smaller and will give you more room between the exhaust and the starter, while swapping that out I would replace the main power wire and go thru all the wire connections.

Re: Another possible heat soak thread
 

[quote=ryans69chevy;9217178]Again, referencing the statement in bold... Not "odd" at all. Actually very typical of a loose/bad connection.. Sometimes, they "correct themselves" almost immediately.. And then on the other end of the spectrum -- The open is permanent, never to function properly again.. 16 hours gives you plenty of time to find the problem..

Guessing and arbitrarily tossing parts at it , especially expensive ones, is not the way to solve the problem.. Skill and systematic troubleshooting is the most logical method. Locate the problem and repair that.

A crimped butt splice is just about the worse method to repair/join two wires.. The joint can be soldered but the best method is to get rid of it. Everything, including purple insulated wire, is available to replace the wire all the way from the ignition switch to the starter.

Re: Another possible heat soak thread
 

[quote=RustyPile;9217338]FAA approves and prefers butt splices for joining wires. A soldered connection can melt. Crimp properly and there will be no issues.

Re: Another possible heat soak thread
 

Nothing at all means it's a solenoid issue. The + battery cable and starter aren't involved at this point. Look at the solenoid wire to the S-terminal and the voltage there when trying to crank.

Re: Another possible heat soak thread
 

-
What transmission does it have?

LockDoc

Re: Another possible heat soak thread
 

Neutral safety switch? Bad/faulty switch would cause this issue. I have this prob every once in a while in my 72. If i put a little upward pressure on the shift lever (like moving it into park), it starts right up.

Re: Another possible heat soak thread
 

[QUOTE=PbFut;9217195]

My battery was bought brand new in 2018 and this problem has been occurring since 2018. I dont believe it would be my battery, but I could do a load test on it and see. That junction block on the passenger side fender that you are talking about doesn't have anymore than what came on there from the factory. This pickup doesn't have any crazy accessories or anything. No AC, my heater doesn't work, no radio, no electric fans. The only thing is the engine and headlights and taillights basically. So there (shouldn't) be too much of a load on the battery, alternator.

Re: Another possible heat soak thread
 

[QUOTE=ghackett1;9217231]

I can look at what gauge I'm using, like stated before, these were brand new in 2018. Would be kinda weird if that was the issue. I'll check it out.

Re: Another possible heat soak thread
 

[QUOTE=72SB;9217246]

The heat wrap is a good idea. I'll check out my battery cables.

Re: Another possible heat soak thread
 

[QUOTE=PowerdbyChevy79;9217252]

I'll replace that wire and go through the wiring. I'll have to try and jump start my starter when I re-create the issue one of these days and see if it cranks.

Re: Another possible heat soak thread
 

[QUOTE=RustyPile;9217338]

I will replace that wire. Yea, I don't want to just start replacing everything to see if that fixes the issue like you said. If it is a bad solenoid/starter gonna have to figure out a way to keep the heat off it.

Re: Another possible heat soak thread
 

[QUOTE=franken;9217415]

I will do that. Gotta get enough time after work one of these days to work on it.