ehrhartc

Fresh build on the 454 with 9.5 compression.
I have replaced all 3 battery cables - positive to starter, negative to frame, block to frame.
I have also added a 3rd ground from the starter bolt to the frame.
I have replaced the starter (reman Delco) and the battery (650 CCA)
Put a charger on the battery to make sure I had it fully charged.
I have added a remote solenoid mounted on the firewall.
I scraped the frame clean at the battery and the engine mount.
I have checked to ensure all connections are tight.
The starter has the stock heat shield between the solenoid and the stock exhaust manifold.

When cold it starts up quickly.
When hot - the starter will barely turn over and I can hear a noise coming from the remote solenoid.
After a few hours of cool down - it starts just fine.

I know there are a hundred posts on this subject and that is where I picked up the idea of the remote solenoid.
I am stumped.
Is there electrical testing I can conduct to check voltage, resistance, etc ??

Tampa Jerry

Did you get the Delco heavy duty starter made for the big block? Jerry

pspicci

Sounds like you have replaced almost everything. There are other checks you can do that members will chime in on for you to try. In case you can't find the problem I will tell you my experience I had up until last year. for the last 30 years I had a problem similar to yours. when cold usually no problems but when hot 50-75% of the time my starter would grind the ring gear. the only way I could reliably start the car when hot was by flipping my ignition kill switch off then turn the key to crank the engine then flip the ignition back on - like starting a race car.well after 30 years of replacing batteries, starters battery cables and just about everything else and figuring I was going to have to live with the problem until i died I unknowingly fixed it while fixing something else. I replace the engine wiring harness last year and have not had a starter issue since. my guess is that the original 12v wire that goes to the switch on the solenoid was so deteriated being 62yrs old that when everything was hot is was not getting 12v to the solenoid.

Pat

ctmccloskey

I am running 12.25-1 Compression in my 1968 C3 BB Convertible and I spent a lot of time finally getting a reliable starting car that I can trust. Between the high compression and Long tube headers they would both cook my starter. The car had to cool down for a while before it would crank even with a GM Performance Starter.

For me the solution was simple, I bought a Gear Drive Starter capable of much higher compression than I use. This alone would start the engine even when hot. Then to really make things work great I put a MSD Ignition that would retard the ignition by up to 20* ONLY while cranking and then returning to normal timing after you reach 400 r.p.m. This unloads the starter in a Big way and with the Gear Drive Starter and the timing retard box together my 12.25-1 makes my 427 crank like a Slant Six, it starts up very quickly.

There are several ways to do it, even the Holley Sniper Series EFI systems have the ability to pull timing while cranking There are several devices that can pull the timing. Between the gear drive starter and retarding timing the starting issues on my Corvette are GONE.

Richard454

EXACTLY- my V12 actually delays turning on the ignition till the engine is spinning-


You can hear the starter turning - then the ignition is turned on-

ehrhartc

I assume so - the Delco starter for 454 has a different part number from the one offered for the 350 engine.

ehrhartc

pspicci. - There are 2 wires at the large connection on the solenoid - the positive cable (replaced) and a wire that runs to the junction box - passenger side near the alternator.
there is the purple wire on the "S" terminal on the solenoid that runs back to the seat belt interlock relay (spliced to the seat belt interlock override)
the yellow runs to the coil
are you saying I should replace the wire running to the junction block ? or the purple wire going to the relay?

Jebbysan

Put a CVR mini starter on it and be done forever.
This has been a common big block issue for as long as I have been alive. If it is still doing it with the heat shield then the only thing you can do is get another one and see if the first one was defective or go mini starter.....what is your timing set at? Excessively retarded timing elevates EGT's and will make the starter very hot.......electricity requires more amps at higher temps.....this is why it peters out when hot.
Once you remove the 25lb. Delco and install the 8lb. CVR.....you will never look back. Lighter, smaller stronger and draws almost half the amps......everything I own and build gets one.


Jebby

Eric P

those big old starters are like a Heat Sink for the exhaust system , even the modern factory gear reduction starters (96 Suburban) which will bolt up to the old stuff are way better than those big heavy old starter or go CVR ... make sure the ignition advance weights aren't sticking hot too

ehrhartc

running Petronix for distributor with dedicated 12v direct from battery

ehrhartc

I think I will try replacing red wire to the junction block first - then purple wire to interlock relay
and then go to mini starter if wiring does not fix the problem

ehrhartc

timing set at 14 degrees BTDC

Jud Chapin

Did you "LOAD TEST" the battery? I wouldn't doubt the battery is your problem.

qwazipsycho

I may be late to this party but did you put a load tester on it to see what the starter is drawing when cold or hot? It may shed some light on the issue.

acroy

I would try another battery -
Different car platform (C5) but similar situation. High compression 427ci. New battery. Hard hot starts. Drove me nuts.
'New' battery was weak when hot. I popped in an Odyssey battery ($$, but 1 and done) and zero issues since.

ehrhartc

no - I haven't done a load test on the battery.
It is new - less than 60 days since purchase

Jud Chapin

There are bad "new" batteries. I worked at an auto parts store and every once in a while a new one would be returned that prove faulty.

pspicci

Purple wire going to the solenoid but i would not replace anything with out first checking to make sure it is the problem. after you try some of the other suggestions if they don't work you could try rigging a jumper wire to the switch terminal of the solenoid (with a switch to it so you can kill the power if the engine starts.) hopefully your problem is something else easier to fix. I replaced batteries & battery cables and numerous mini starters reduced initial timing etc. and nothing worked until I replaced the wiring harness.

Pat

ctmccloskey

The original Poster is describing a classic "Heat Soak" situation that happens on many Big Block Corvettes. My 427 is running high compression and I used two batteries( in Parallel) and the starter still would not spin fast enough to start the engine without risking a back fire.

One of the easiest solutions is going with a Gear Drive Starter which start at $130 at Summit Racing. Watch the maximum recommended Compression Ratio of each product to be sure it will work for you. Many of the small ones would not work on my 427. After switching to a Gear Drive the engine always spins when you need it to.

Check the design to be sure that you can rotate the electric motor if needed to get more room under the headers. I have a small starter with a very high Torque electric motor and it was a breeze to install back thirty years ago. I have not had to do anything.

Retarding the timing temporarily made a huge difference as well. I have a MSD 6AL with a MSD Digital Retard Box which allows me to pull up to 20* of timing only while cranking. The retard box has several inputs and allows you to choose how much timing you want to pull in 5* increments. Today my 427 cranks up very quickly and it doesn't sound like it did before. I am very glad they have accommodated this feature in the Holley EFI systems as it makes any high compression car start easier. The newer MSD 6AL ignition boxes have the timing retard built into them now.

ZIOGEO

I had this problem on a 67 BB Mustang after a rebuild. The problem turned out to be a poor ground between the engine block and the chassis. Once that got sorted out, it started just fine hot or cold.