Will a Starter Heatshield Help?

Tom Mazz/CT

Tom Mazz/CT

Junior Member
My 59AB engine is slower to crank when hot. I have heavy battery cables, new battery (6 volt), generator is working fine, timing is set properly, water temp is good. It appears that the engine is just harder to turn when hot. I have heard that some have used a heatshield around the starter to prevent heat soaking from the exhaust . Thought I would give it a try. Does anyone know where to get one - or is this something I should make from scratch?

I am open to ideas on the tight motor!

Thanks
 
do you have aftermarket headers? if so that could be the problem-wrap the headers ,if not try making a heat shield
 
I have stock exhaust manifolds that are about 3" from the starter and my exhaust is fabricated from stock pipes that runs parallel to the starter with about about 1 1/4" clearance. All electrical connections are clean.
 
I once made a heat shield for a Lincoln stater motor using a pair of tool clamps and a piece of sheet metal. I used tool clamps that are used to hang tools on the wall of your shop or garage that were for a tool with a 2" handle. The sheet metal was bolted to the clamp and the finished heat shield was clamped to the exhaust where it could be removed for shows and judging.
Heat shield didn't work though, the problem was a bad coil that I sent to Skip Haney and then the problem was solved.
 
Tom, Sounds like you need new brushes and bushings in your starter. Rebuild it and you will be a happy camper once again.
 
How about the coil? Have you tested it? The symptoms you describe point to the coil from my experience. I run Red's Headers on Most of our Flatheads and stock exhaust manifolds on our '39 LZ. I don't think I've ever had a starter crank slower because it was "warm"... I'd check the coil before anything else.
 
I have driven my '36 in the blazing summer heat of southern Nevada (Las Vegas) and southern California.. Never had a problem with a slow cranking engine if the battery and all of the connections were good.
I would suspect that you have a serious problem with you stater.. Bad brushes, bushings, etc., which is causing high voltage drain, etc.
I would suggest that you take the starter to a good re-builder, have them go through it as needed..
Here in Ventura were very lucky, we have an excellent electrical shop that rebuilds starters, generators, alternators, etc.
 
Vic Piano said:
How about the coil? Have you tested it? The symptoms you describe point to the coil from my experience. I run Red's Headers on Most of our Flatheads and stock exhaust manifolds on our '39 LZ. I don't think I've ever had a starter crank slower because it was "warm"... I'd check the coil before anything else.
Click to expand...

VIC ...............
Would a bad coil, cause it to "crank" slower ? It will "crank" with no coil at all.
MIKE :) (mikeburch)
 
Hi Tom Mazz/CT, your experiencing whats call heat soak syndrome. How old is your starter? As 19Fordy indicates it's prevalent when your starter is older and needs rebuilding or a new starter. Also as blucar indicates I haven't seen heat from the engine or headers as a problem causing slow turning except with tired starters. Rebuild it or get a new one. If your not concerned with totally stock I believe I've seen hi-torque starters available which are less prone to heat. ( although I don't think the heat is the problem )
Good luck
 
How many flatheads have you seen with heat shields? I would look for the problem somewhere else as it will probably only get worse.

Charlie Stephens
 
FL&WVMIKE said:
VIC ...............
Would a bad coil, cause it to "crank" slower ? It will "crank" with no coil at all.
MIKE :) (mikeburch)
Click to expand...

Mike, as I understood his post, the slow cranking, when hot, was not enough to fire the engine... That to me, is coil related...:eek: I've had hot or cold slow cranking Flatheads fire up just fine as long as the coil was good.;)
 
Have to agree with the others, Don't think your problem is the headers. I'd look at the starter itself , look at the cables while you have them off..
 
Experienced this problem on a GM muscle car with headers. Put a Ford starter switch on it and modified the starter and the problem went away. A long story short-when the starter and solenoid get hot they take more voltage. This is why I believe it is a starter that needs re-building like others have said.
 
19Fordy said:
Tom, Sounds like you need new brushes and bushings in your starter. Rebuild it and you will be a happy camper once again.
Click to expand...

Vic Piano said:
How about the coil? Have you tested it? The symptoms you describe point to the coil from my experience. I run Red's Headers on Most of our Flatheads and stock exhaust manifolds on our '39 LZ. I don't think I've ever had a starter crank slower because it was "warm"... I'd check the coil before anything else.
Click to expand...

blucar said:
I have driven my '36 in the blazing summer heat of southern Nevada (Las Vegas) and southern California.. Never had a problem with a slow cranking engine if the battery and all of the connections were good.
I would suspect that you have a serious problem with you stater.. Bad brushes, bushings, etc., which is causing high voltage drain, etc.
I would suggest that you take the starter to a good re-builder, have them go through it as needed..
Here in Ventura were very lucky, we have an excellent electrical shop that rebuilds starters, generators, alternators, etc.
Click to expand...

If the bushings are worn on a starter the armature will drag on the field windings when warm. I've experienced this on Ford, GM and one Cat diesel. If all the connections are clean & tight and the solenoid is good. Rebuild or replace the starter. If there is a decent auto electrical shop in your area have them check the starter current at hot and cold. Both readings should be close. If the hot current is higher you have found the problem.
 
On the '30 model Fords that had the stater switch located on the floor between the brake and clutch, it was quite common to have engine cranking problems due to the added wiring and a switch that was in poor condition.
I was a very common practice in the late '40's, early '50's to remove the stock floor mounted switch in favor of a "button" switch on the dash, the only function was to ground the cowl mounted solenoid..
 
Re: Will a Starter Heatshield Help - update

First off - Thanks everyone for the input. This is what I did yesterday.

Pulled the starter to re-inspect. Brushes and springs had been previously replaced and looked good. Bushing in end cap had been replaced and shows no signs of wear. I did not put the other bearing - but no side to side movement noted at all. I cleaned all of the contact hardware and cable end. I did remove some paint at the starter mounting area to make sure the case was properly grounded to the block (block is clean as well). Reinstalled and the cold engine cranks fine. Started the motor and drove it for about 20 minutes to reach running temp of about 175-180.

Shut down engine and restarted it OK (cranked slow but fired quickly). Then shutdown engine.

Measured starter temp at about 110 deg f. (not bad).

Let engine heat soak for about 5 minutes and water temp went up to about 195. Starter was about 105 deg. With ignition on the engine would barely turn over and sometime start up. With ignition off the engine would hardly turnover.

I measured the torque required to turn the crank when engine was at 185 deg. I found it took 48 lb ft to turn the engine. This morning with the engine cool it took 28.5 lb ft. of torque to turn the crank.

The engine has about 100 miles on it since it was re-assembled. Wondering if anyone has an opinion on the "heat soaking" vs "tightness" of the engine?


Tom
 
New info. A fresh engine problem. What are the piston and bearing clearances? What weight oil are you running? If its not making any strange noises when running I'd be tempted to run it in to about 500 miles. If it doesn't free up when hot then look deeper. I'd also change the oil at 500 miles.
 
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