72 starter problem???

[Mike G.]

i finaly got my 72 lt1 driver done and took it out for its first road test. this is a recreation of my high school car. looks just like it. the car ran and drove great. when i got home and cut the car off in the drive way i could not get it to restart. the motor would barely turn over. it had juice because the cables were hot. i could not jump it off. i took a battery out of another corvette that was fully charged and it still would not start. after a couple of hours, after i called friends to help me push it back in the garage, the car started fine. with the same dead battery that would not start the car before. so here is the question. is my starter bad? when the car is cold it works great. when the car is hot it does not work, wont spin the motor fast enough to start. here is another thought... i put 69 side pipes on the car because thats what my high school car had ( long story). is the pipe getting the starter too hot? do i need to install a heat shield? what do you think?

[Mike G.]

Re: 72 starter problem???

here is the car

[John P.]

Re: 72 starter problem???

Diagnosing via internet is perilous but the symptoms you are describing are typical of a heat soak condition. Try a solenoid heat shield to start with.

[Jack H.]

Re: 72 starter problem???

In addition to the heat shield John mentioned, you need to make sure you have the correct, 'Corvette' version of the solenoid return spring installed. Starter rebuild kits tend to come with an 'omnibus' return spring and many are guilty of discarding the perfectly good but aged and slightly oxidized solenoid return springs which can cause the 'heat soak' problem...

To diagnose, take the car for a ride, get 'er up to temp and return to the comfort/safety of your driveway/garage. Shut 'er down and wait 5-10 minutes to verify you're re-created the 'no start' condition.

If you do, IMMEDIATELY bath the outside of the starter/solenoid with running water from a garden hose, being careful not to splash too much water onto the exhaust manifolds. If after a few minutes of water bath to cool the starter/solenoid, the car cranks and fires promptly you probably ARE fighting a starter heat soak situation!

You'll want to install BOTH the factory original starter heat shield AND the correct solenoid return spring to address the problem...

[Mike G.]

Re: 72 starter problem???

thanks for the help. that is also the cheapest fix. that does not happen much in my world.

[Mike G.]

Re: 72 starter problem???

oops! forgot to shrink them.

[Joe L.]

Re: 72 starter problem???

thanks for the help. that is also the cheapest fix. that does not happen much in my world.

Mike------


I suffered with this problem almost since the day my 1969 was new. I tried all sorts of fixes, including a complete starter rebuild, a few HIGH QUALITY rebuilt starters, a BRAND NEW starter, several NEW solenoids, various solenoid springs and a host of other things. The only thing that ever solved the problem PERMANENTLY and COMPLETELY was the installation of a slave solenoid. Once I did that, the problem was gone for good.

[Mike G.]

Re: 72 starter problem???

what is a slave solenoid?

[Joe L.]

Re: 72 starter problem???

what is a slave solenoid?

Mike------


It's a secondary, remote-mounted solenoid as was used for a lot of Ford products in days-of-old. Basically, it's a "solenoid that activates a solenoid". In this configuration, the wire from the "S" terminal from the ignition switch activates the slave (remote) solenoid. Then, the slave solenoid energizes the "S" terminal on the starter solenoid through larger gauge wires. 100% fool-proof system. With it, my car will start after a short shut-down in Death Valley in July (no exaggeration; based on actual experience).

Chevrolets actually used this system until the late 40's, then it was dropped in favor of the single solenoid. Bad move.

Secondary benefit: this system removes most of the current draw during starting from the ignition switch. So, this part of the ignition switch lasts a lot longer.

You can find details of wiring the slave solenoid in the archives. Myself and others have discussed it several times previously. Just search on "slave solenoid" or "remote solenoid".

[Timothy B.]

Re: 72 starter problem???

Mike, how about a starter shim just to see if that helps first.. I agree with the others and I would also check the battery cables for resistance.

[John P.]

Re: 72 starter problem???

In general, a problem requiring a shim to fix is constant(It happens when the car is hot or cold)

[Bill C.]

Re: 72 starter problem???

Had a similar issue when I first purchased my car.

Thought it was heat-soak too - turned out to be several bad grounds.
Cleaned them all up and reconnected - never a problem again.

[Patrick H.]

Re: 72 starter problem???

Had a similar issue when I first purchased my car.

Thought it was heat-soak too - turned out to be several bad grounds.
Cleaned them all up and reconnected - never a problem again.

My thought too.
I had the engine-to-frame ground on my 71 come loose and it acted very similarly. Once I tightened it, no troubles.

Check the cheap stuff first, connections being #1.
Oh, and don't forget the sill green cutoff knob. You never know...

Patrick

[Edward J.]

Re: 72 starter problem???

Mike, alot of useful info. I think that with everything said its all guess work here, the correct way is to have a amp meter on the cables to measure the amp draw of the starter after it runs for quick run on the highway.I think that GM made a starter that would work in most conditions,im not saying heat will not effect a starter in a hot soak condition, it will but the type of heat Ive seen that has some affect maybe a set of headers, a few quick runs down the quarter mile, or long run at high rpms such as with 4:10 gears.
There maybe be a underline problem with something like the bushings in the starter are worn in the nose cone and end plate,as the armature heats up it swells and will drag against field windings.as said in the other posts theres alot of possiablitys, check the electrical, system first, all connections and grounds.

[Joe L.]

Re: 72 starter problem???

All-----


By the way, GM never acknowledged this problem and, consequently, never recommended any fix for it for any passenger car or light truck that I am aware of. However, they did acknowledge it for motor home chassis with 454 engine. Their recommended fix? Install a slave solenoid.