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Discussion Starter #1
My 67 sat for a number of years and I decided to do a bit of work on it before getting it back on the road. I replaced the single plane intake and 500 CFM Carter carb with a dual plane Edelbrock RPM Air-Gap intake and Edelbrock 1406 600 CFM carb. Replaced the leaking radiator with an aluminum 2 core ECP radiator with 1" tubes. Since the replacement, I've been dealing with either carb or starter heatsoak. It starts up fine and runs fine until I shut it off. When I go to start it up after say 15-30 minutes, it doesn't crank over at all.

I'm thinking it's starter heatsoak so I'm planning to replaced the starter with a PMGR starter. I do have long tube Hedman headers which I'm thinking are heating up the starter. I thought it might be the starter solenoid so I replaced that but it didn't help. I thought it may be carb heatsoak so I added a half inch spacer (all I could fit due to hood clearance) but that didn't help either. I need to check the timing and I may retard it a bit to see if that helps.

I did some more research online and one of things I came across that I think may help, if its carb heatsoak, is blocking the heat crossover under intake. Question is, how do I do that?? What do I block it with that will still let the intake sit flat against the heads? The car is only driven in the summer so cold weather starts won't be an issue.

Any other steps I should take??


67 coupe with a 289ci, T5, 600 CFM Edelbrock carb, RPM Air-Gap intake, Edelbrock RPM heads, Hedman long tube headers, aluminum radiator and will be installing a clutch fan soon. Also installing a PMGR starter soon.
Driven only in the summer as a cruiser.
 

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your problem could be corrosion on your battery connections and its an easy job to remove cables and replace or clean with bacon soda and sandpaper. Had a 66 gt coupe back 35 years ago i was using for a daily driver and had the same symptoms. Had to wait for 10 to 15 minutes after shutting off to be able to crank the motor normally. After cleaning all battery connections i never had the problem again, last week my daily driver wouldnt start and the corrosion on the cables was again the problem. Wes
 

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If it doesn't crank over at all it's not the carb it's the starter or solenoid, ignition switch or possibly a really ****ty battery I suppose.

You say after 15-30 minutes it won't crank at all does that mean between 1-15 and any longer than 30 minutes it will crank and start fine?
 

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Clean and verify all battery cables, connections and grounds.
 
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Discussion Starter #6
I should have added...before deciding to replace the starter with a PMGR starter which is next on my list, I replaced the starter solenoid with one from Standard Motor Parts or Bluestreak (can't remember), installed a new battery, replaced the battery cables, replaced the cable from starter solenoid to the starter, and also replaced the ground strap and added another ground from the block to the chassis.

When I shut it off, it won't crank over or start at all until it cools. If I shut it down for a few minutes while getting gas, it won't crank over or start after that. (Luckily the gas station is close to my house and I can get help pushing it home). If I drive it to work and it sits until the end of the day, it starts up fine.
 

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So you get a click of the solenoid but no crank or attempt for the starter to even turn? If you put your hand on the starter when you attempt to start it can you feel anything?
 

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Your negative cable from the battery- is it attached to the block behind the alternator? aLSO IS YOUR STARTER SOLENOID attached to the engine compartment sheet metal tight?
 

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1966 Fastback, 289 - C4
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I had a very similar issue. No cranking seemingly when hot. My issue was a poorly adjusted NSS. I adjusted it and now it's fine.. this was on a C4, but something to consider I think?
I also installed the PaPerformance PMGR. Very straightforward install and now I don't have any hot start issues.
 

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do some voltage drop measurements both cold and hot. you'll find the culprit that way.
 

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Discussion Starter #12
"So you get a click of the solenoid but no crank or attempt for the starter to even turn? If you put your hand on the starter when you attempt to start it can you feel anything? "
I get a click from the starter solenoid and no crank at all from the starter. Haven't tried putting my hand on it while trying to start.

"Your negative cable from the battery- is it attached to the block behind the alternator? aLSO IS YOUR STARTER SOLENOID attached to the engine compartment sheet metal tight?"
I believe it is, I replaced this cable also. I'll confirm how tight the starter solenoid is to the sheet metal. How tight should it be?

"when you try to crank the motor with your headlights on do the lights go out or stay on?"
I don't know, I haven't tried. Should they stay on or go out?

"I had a very similar issue. No cranking seemingly when hot. My issue was a poorly adjusted NSS. I adjusted it and now it's fine.. this was on a C4, but something to consider I think?
I also installed the PaPerformance PMGR. Very straightforward install and now I don't have any hot start issues.
"
I have a T5 that was installed by a shop. Not sure if I have a neutral safety switch. Can someone confirm for me please? I know that I can start my car in neutral with the clutch out. I was able to do that before with the T10 4 speed also.

"do some voltage drop measurements both cold and hot. you'll find the culprit that way."
Voltage drop at the battery? What would I be looking for depending on how much it drops?
 

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1966 Fastback, 289 - C4
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I have a T5 that was installed by a shop. Not sure if I have a neutral safety switch. Can someone confirm for me please? I know that I can start my car in neutral with the clutch out. I was able to do that before with the T10 4 speed also.
Can you start in first? Foot on brake of course. ;)
 

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If you get a click at the solenoid it's not the NSS. and yes there should be one but lots of T5 installs just bypass it anyways.

If it was me I'd jump direct to the starter from the battery when it does this to confirm it's the starter.
 

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Pour a bucket of water over the starter the next time you suspect heat soak.
If it starts straight away, you have your answer.
 

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Discussion Starter #16
"Can you start in first? Foot on brake of course. ;) "
...I'll have to try that...:confused:

"Pour a bucket of water over the starter the next time you suspect heat soak."
:unsure: never thought of that but suuuuure, why not?!


Anyways, getting back on track. I'll try jumping directly to the starter from the battery. I assume if it doesn't crank over then it it's the starter.
 

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If you want one more confirmation of the starter you can drive it around then home. Then try to start it and nothing you can beat the starter with a hammer and like magic it might work.
I had a Camaro in college that did that for months until I sold back my text books and bought a starter , I could lay down and hit it without even looking.
 

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I'll confirm how tight the starter solenoid is to the sheet metal. How tight should it be?
As tight as you can get it. The screws are only threaded into the apron sheetmetal. A good idea is to replace them with through bolts and use star washers. The solenoid is grounded to the apron, so a proper ground path is essential.

Sounds like you've covered your bases pretty well, voltage drop testing should be done and only then would I replace the starter.

 
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