Hot restart issues.

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synchro66

synchro66

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hoping someone on here can offer advice or a solution to to my quandary. - Rubuilt my 360 sb some time ago…..030 over; speed pro hypereutectic pistons ; Clvite bearings; Hastings rings; 11.2 :1 static compression mild cam and re graphed ignition initial 16BTDC. Recently ran the camshaft in using an engine test stand . Ran it for 20 mins varying revs etc as per proper run in procedure. Engine is now in the car and starts up perfectly runs solid, crisp sound response on throttle is brilliant and oil pressure sits on 60PSI. Problem is, if I run it and bring up to temperature and then try and restart it, the battery struggles to turn it over. Battery showing 12.2 volts so I’m sure it’s ok. Engine was very tight whe turning by hand before initial run in of the cam. Any thoughts??! TIA
 
Could be starter going south when hot.
For battery, get a remote starter trigger, and put a test meter on the battery.
When starting hot, the battery voltage shouldn`t drop below 9 V.
 
Too much initial, poor ground/battery cables

Put a jumper cable from the neg battery to block and see if it starts easier.
 
The obvious first. A fully charged battery is 12.6-7 v. So if yours measures 12.2 v, it is discharged. Get a new battery. Also check starter cables for good, clean connections.
Hypo pistons expand more because of the alloy content. If they were installed a bit tight, then they will be tighter at operating temp.
If you haven't already got one, I would get a hi-torque starter. Cheapest is probably Road Star, Hornsby, Sydney.
 
How many grounds do you have? Is this gonna be another hit and run?
 
Not a ground issue if it starts ok cold. It is a heat issue.....
 
Bewy said:
Not a ground issue if it starts ok cold. It is a heat issue.....
Click to expand...
When an engine is hot, it's harder for the starter to turn and can draw more amperage. Try again.
 
New starter and a starter heat sheild/wrap/blanket to keep that Exhaust heat away
 
Sounds like ignition has light springs in it and it is advancing to fast also retard the timing when it is hot. Went through this and broke two starter noses off.
 
First problem is 12.2 volts is bad. Will it charge to 12.5 or higher? Try a fresh battery.

Is battery in trunk or underhood?

Possible problems:
Advanced timing
Bad cables
Bad starter
Not enough ground cable-needs to flow same amps as positive. If batt in trunk you need a large ground cable from engine to frame/body.
 
Put a kill switch on the car. Crank the engine with it off and then turn the switch on while cranking. That will solve the problem if its a timing advance issue.

To see if it is the timing take off the coil wire when its warmed up and see if it turns easy. If not , You have a starter or tight engine issue. Incorrect ring gap good be your problem if the engine is tight,

Had a small block chevy here that was tight and it broke the ring lands on every piston between the top rings from tight ring gap. For your sake I hope its the starter or timing.
 
Oldmanmopar said:
Put a kill switch on the car. Crank the engine with it off and then turn the switch on while cranking. That will solve the problem if its a timing advance issue.

To see if it is the timing take off the coil wire when its warmed up and see if it turns easy. If not , You have a starter or tight engine issue. Incorrect ring gap good be your problem if the engine is tight,

Had a small block chevy here that was tight and it broke the ring lands on every piston between the top rings from tight ring gap. For your sake I hope its the starter or timing.
Click to expand...
Great response!
 
synchro66 said:
Engine was very tight whe turning by hand before initial run in of the cam. Any thoughts??! TI
Click to expand...
Lemmee guess;
Are you running?
KB107s in at near .0015 skirt clearance, and cast rings at the recommended tight gaps?

At the KB specs, I had the same hot-running issue with mine, even with Alloy heads.
I have set up this engine, with oiling mods, and she runs more than enough spring pressure to rev 7500, and I regularly shift at 7200.

In 25 years, my car has had 3 cams.
1) The first was a 292/292/108 Mopar, in at 11.3Scr, it ran hot. I suspected the cam.
I didn't like that cam anyway so I pulled it out and sold it to racer, who loved it.
2) The Second was a 270/276/110 cam (223/230), still at 11.3, it still ran hot.
I had to take the engine down.
I loosened up those skirts and reinstalled those pistons, with Plasma-Moly rings, with much looser ring gaps; and I reduced the Scr to 10.7;
With the heads off, the crank had very little resistance to rotating.
The skirts were assembled at around .0035, and
the top ring-gaps were over IIRC, .032
Second gap is only a little over the recommended gap,
No more issues!
Obviously; In my case, the KB specs did not work.
Set up like this, this 223 cam got as high as 32 mpgs. I really loved that cam, but one day, it lost lobes
3) so next up was; a 276/286/110 cam, (230/237), with the Scr now 11.0.
This cam has gone 93 in the Eighth at 3450 pounds, me in it. I luv it, but
Even with overdrive, it sux gas. With this cam, I have tried final drive ratios as low as
2.52 (65=2040, but finally settled on
2.77 (65=2240). Engine now has over 100,000 miles on it; and hot-running is decades behind me.

Don't let the loose specs scare you.

EDIT
FYI, my timings are;
Idle-Timing of 12>14 @700
Power curve is Two-stage ; 28*@2800 going to 34@3400
Vacuum advance is 22* coming in fast and hard.
Cruise Timing at 65=2240 varies from 56> 60 degrees, by Dial-back
Parade-Timing is 5*@550rpm. also adjusted by Dial-back.
Dial back is an old Jacob's dash-mounted, electronic timing module, with an adjustability range of 15 degrees, that I set for up to 6*Advance/9*Retard..
 
Last edited:
Bewy said:
Not a ground issue if it starts ok cold. It is a heat issue.....
Click to expand...

What happens to the load carrying capabilities of a cable when it is at 60* or 150*?

It is reduced, end of story

Don't attempt any diagnosis, just take wild *** guesses, nope not that. Cables many times are the issue.
 
Last edited:
Crackedback,
You forgot that the starter could be the issue.....or a batt down to 12.2 v. Starters have copper windings, the resistance of which increases with HEAT......which reduces the current in the windings, reducing the HP that the starter can generate to crank the engine. That is why a GOOD battery is reqd so that the voltage drop internally IN the battery is minimised & as much voltage as possible is supplied to the starter. With low bat voltage, you start diagnosis with a good battery, not battery cables.

Unlikely to be a ground issue be cause it starts ok cold with low temp, thick oil & cold weather starts really test the starting system. Ask someone who flattened the batt trying to start the engine on a cold winters day....
 
12.2 is a problem. Start there. Pun intended.

Does the charging system work, 14.5volts?
 
413 said:
First problem is 12.2 volts is bad. Will it charge to 12.5 or higher? Try a fresh battery.

Is battery in trunk or underhood?

Possible problems:
Advanced timing
Bad cables
Bad starter
Not enough ground cable-needs to flow same amps as positive. If batt in trunk you need a large ground cable from engine to frame/body.
Click to expand...
Yes batt is in trunk but initial start up is easy … engine cranks over no problem. I’m will try what you suggest, but I’m wondering whether timing is implicated as well
 
Bewy said:
Crackedback,
You forgot that the starter could be the issue.....or a batt down to 12.2 v. Starters have copper windings, the resistance of which increases with HEAT......which reduces the current in the windings, reducing the HP that the starter can generate to crank the engine. That is why a GOOD battery is reqd so that the voltage drop internally IN the battery is minimised & as much voltage as possible is supplied to the starter. With low bat voltage, you start diagnosis with a good battery, not battery cables.

Unlikely to be a ground issue be cause it starts ok cold with low temp, thick oil & cold weather starts really test the starting system. Ask someone who flattened the batt trying to start the engine on a cold winters day....
Click to expand...
Thin oil but I think you may be right.. I’ll try another battery and see what happens. Was also wondering whether the timiming may be an issue also, although the guy that. Did the regraph is a guru and this is what he suggested.
 
Oldmanmopar said:
Put a kill switch on the car. Crank the engine with it off and then turn the switch on while cranking. That will solve the problem if its a timing advance issue.

To see if it is the timing take off the coil wire when its warmed up and see if it turns easy. If not , You have a starter or tight engine issue. Incorrect ring gap good be your problem if the engine is tight,

Had a small block chevy here that was tight and it broke the ring lands on every piston between the top rings from tight ring gap. For your sake I hope its the starter or timing.
Click to expand...
Yeah thanks .. I’m concerned that tight rings is the problem, or maybe the timing. It’s just that he engine is so crisp and responsive that has me thinking is maybe a starter/grounding / batt issue. I will follow your suggestions and see where it leads. Will keep you posted. thanks for the input bud!
 
synchro66 said:
I think you’re right, but wondering if the timing is causing it. Also maybe needs a few thousand miles to bed the rings in???
Click to expand...

Ok, I missed the battery in the trunk.

The minimum size wire is 1/0 and that’s pushing it. Bigger won’t hurt.

You need to ground the battery to the engine. I know almost no one does it, but in full bodied cars like these, the battery ground cable needs to be the same size as the positive cable and it needs to ground to the engine.

If you ground the battery to the chassis you make the entire car part of the electrical system.

I can’t explain it exactly because I’m not that fluent in electrical stuff but that is the correct way to do it with the battery in the trunk.

If you have some form of ignition that has a box, that box SHOULD be grounded to the battery, regardless of where the battery is mounted.
 
Newbomb Turk said:
Ok, I missed the battery in the trunk.

The minimum size wire is 1/0 and that’s pushing it. Bigger won’t hurt.

You need to ground the battery to the engine. I know almost no one does it, but in full bodied cars like these, the battery ground cable needs to be the same size as the positive cable and it needs to ground to the engine.

If you ground the battery to the chassis you make the entire car part of the electrical system.

I can’t explain it exactly because I’m not that fluent in electrical stuff but that is the correct way to do it with the battery in the trunk.

If you have some form of ignition that has a box, that box SHOULD be grounded to the battery, regardless of where the battery is mounted.
Click to expand...
the entire car 'is' part of the electrical system, every circuit grounds somewhere to the body. the body is a better conductor than even the biggest battery cable and with no heat sink front to back. as long as the power and earth cables are properly sized and more importantly the earth's are properly grounded at every connection they are fine. yes some ignition/fuel injection boxes are required to ground back to the battery but that has no bearing on slow cranking when hot. :thumbsup:
neil.
 
mygasser said:
the entire car 'is' part of the electrical system, every circuit grounds somewhere to the body. the body is a better conductor than even the biggest battery cable and with no heat sink front to back. as long as the power and earth cables are properly sized and more importantly the earth's are properly grounded at every connection they are fine. yes some ignition/fuel injection boxes are required to ground back to the battery but that has no bearing on slow cranking when hot. :thumbsup:
neil.
Click to expand...
 
Bewy said:
Crackedback,
You forgot that the starter could be the issue.....or a batt down to 12.2 v. Starters have copper windings, the resistance of which increases with HEAT......which reduces the current in the windings, reducing the HP that the starter can generate to crank the engine. That is why a GOOD battery is reqd so that the voltage drop internally IN the battery is minimised & as much voltage as possible is supplied to the starter. With low bat voltage, you start diagnosis with a good battery, not battery cables.

Unlikely to be a ground issue be cause it starts ok cold with low temp, thick oil & cold weather starts really test the starting system. Ask someone who flattened the batt trying to start the engine on a cold winters day....
Click to expand...

A conclusion with zero diagnosis. Hook up a jumper, simple 1-2 minute test. Allows them to rule it out as a potential issue.

Carry on...
 
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