axle83651

My 1973 Corvette Big Block will not roll-over when the engine is warm. I've replaced the starter and still have the same problem. When cold, the engine rolls and starts just fine. When placing a jumper wire from the starter to battery (key on)the vehicle will start right up. But when trying to start the vehicle using the key, the starter will not engage or roll. Again this problem only occures when the engine is warm. By allowing the engine to cool for a couple of hours the vehicle will start right up using the key. Any ideas on what might be the cause?

midyearvette

too much initial timing or starter is overheated..good luck

calwldlife

are you running headers? heat soak
are the bat cables good or running close to heat source? heat soak
did the new starter come with a new engage solenoid?
What is the CCAmps of the battery? wrong bat

Duke94

Starter heat soak. There are heat shields you can buy to stop this. There should be a small one one the starter already. Is it there? Here's a link to Summit that shows a sample of shields.
http://www.summitracing.com/search/?...20shield&dds=1

Gary

capevettes

Check all of your battery connections thoroughly.

joewill

is your battery old? it takes alot of amps to crank a hot big block .. go out and get you the biggest, most cold cranking amp battery you can find... even a 3 year old battery usually has lost half its cranking rating when new...
I had the same problem several times with big blocks or big pontiacs.. a 1000 amp battery cured it every time...

Derrick Reynolds

Let me make sure I understand your post properly: Starting the engine cold works fine. Starting the engine warm with the key doesn't work, but if you leave the key in the "on" position and jump from the battery to the starter motor, it starts right up. Correct?

If so, you can eliminate your battery and your starter motor as the problem, which means you have a poor connection somewhere in the system.

I had a similar problem when I brought my car home last year, started great when cold, but when hot, the starter would barely turn the engine over. Mine turned out to be some boogered up connections on my solenoid. I replaced the solenoid and (knock wood) I haven't had any trouble starting the car since.

Heat soak can play a role, and there is nothing wrong with putting a heat shield on your starter motor (I have one), but in this case, I doubt it will solve your problem since jumping the amperage to the starter works when the starter is hot.

GruntyPants

What terminals are you jumpering to make it start right up while hot? Are you just jumping the battery terminal on the starter over to the solenoid?

My point is that if you're having high resistance in the starting circuit using the key, you should have the same amount of resistance using a jumper/screwdriver/remote starter button.

The solenoid circuit just energizes the path between the battery and the starter, so there's no huge amount of power in the soleniod/starting circuit.

Usually fixing a 'hot start' problem, is as simple as replacing 30+ year old cables and terminals and ensuring you have a good battery. This fixed it on my '69 427.


By the way I'm not a big believer in 'heat soak'.

Shawn

ANY VETTE

Headers will eventually burn out your solenoid, when this occurs buy an external ford solenoid that mounts to your firwall away from your headers.

GruntyPants

Now that I re-read the OP, it says that the starter won't engage, meaning the solenoid is faulty. You can replace it with a stock one, and might have this issue again in a few years, or run a remote solenoid on the firewall.

HamadUP

I'm using the stock solenoid heat shield but I applied a layer of zero-clearance insultion on its surface, never got any problem since then even in 100F+ weather.

BHRIG

could possibly be battery ground to frame located under battery box .

Access is from under car.....A lot of dirt, rust,etc, builds up at ground connection.

Remove 1 bolt holding cable to frame,, clean both frame and cable end where bolt attaches and see if your problem is solved......

Good Luck

c31980

kaiserbud

stingraydriver74

I'm having the same problem but with a '74 and 350 engine, but mine only does it if I've had the headlights burning and the motor is hot. If I cut the car off before I kill the lights it will not start (I don't just leave the lights on either.) Everything Else in the car works great and seems like the battery has plenty of juice but not enough to even make the starter engage. Also, jumping the vette with another car fixes it instantaneously. The only things I can think of are "heat sink" in the starter, or that the starter isn't grounding well when the engine is hot. Any other suggestions would be highly appreciated, I think I will try the starter insulator wrap.

Thanks,

Brad

Duke94

I'd check the ground wires first. The one from the battery to the frame and the engine to the frame. Remove the bolt, clean the contact surface then use a new star washer between the terminal and frame.

Gary

tommyleea

Shoot some wires. See if you are getting power to the starter when you hit the ignition switch. If you have power, then it must be starter/solenoid problem. If you don't have power, then you have to trace the wire. Maybe fusible link? I am not sure if they reset or not.

TommyJ

FB007

It's the solenoid. Chevy had a service bulletin on this about 1984 or so.

stingraydriver74

I can fully see how the solenoid can be getting "heat soak" as I've replaced the starter several times and temporarily solved the issue. But doesn't anyone make a higher quality starter that will stand up to the heat? I've just been using reman. Advance Auto jobs, but I don't know where else to go...

TheBuz96

GM did have a service bulletin way back when... I solved this problem on my '77 and friends 'Vettes by purchasing a special solenoid return spring and special nut from GM. Surprisingly it only took those two parts. Sorry, I don't recall the part numbers as this was done in the early '80s. Perhaps an oldtimer from GM can help. There were articles in Corvette magazines circa 1980.

I solved the same problem in the mid '90s on a truck by simply using a high-speed heater fan relay. One post goes to the battery, one to the start wire (instead of it going to the starter) and the 3rd pin to the relay (in place of the start wire). It never missed a beat.

Also, I never replace a starter. I take mine to a place that rebuilds starters (usually an oldtimers place) and ask them to rebuild it to high performance specs which a good shop can do. I first did this back in the late '60s on my '60 and it would spin anything. When my friends face car wouldn't start with a regular starter we put mine on his car and it cranked like low compression engine!

I don't know if these suggestions will help C4 and later owners but it worked on C3 and earlier vehilcles.

Buz