Hard Starting - 68 Corvette

[Kurt B.]

Gentlemen:
Another little stumbling block in the restoration process:
My newly restored engine with 0 miles starts easily when cold. After running in the garage for 30-45 minutes (car is not drivable or registered) when I turn off the engine and then try to restart I get one or two cranks and then the battery dies.
I am not convinced it is heat soak of the starter as I never had a heat soak problem with this car before.
Engine new, starter and alternator new, all ignition components new, battery new, all wires routed exactly according to Assembly Manual.
I tried to find the heat soak thread in the archives but was unsuccessful.
I have absolutley no knowledge of electrical things.
I would be very interested in any input or suggestions regarding what my problem could be. I have checked all connections for tightness and there is no corrosion as everything is new and clean.
Once car cools down, starter cranks normal and engine starts and purrs like a kitten. Engine is 327 cid 350 horsepower. Carburetor rebuilt and tested 3 weeks ago. Battery is Delco Tar Top from Restoration Battery. All gauges in car check out normal for temp and oil pressure and battery gauge indicates slight charging after startup.
Any input appreciated.
Thank you,
Kurt Bunting # 26406

[Donald M.]

Re: Hard Starting - 68 Corvette

Kurt, It sounds like a tight engine. You mentioned that the engine is new, the pistons expand with heat and tend to drag when re-starting.Waiting for a few minutes "cures" the problem when the pistons cool down. You're talking thousanths of an inch or maybe even ten thousanths of clearance change Only time and usage will cure this. Did you check the timing, over-advanced timing will cause a hard start?

[John R.]

Re: Hard Starting - 68 Corvette

I encountered the same problem when we rebuilt my L36 big block a couple of years ago. I tried everything to eliminate the problem, with plenty of good advice on this board. After two years and a couple of thousand miles I no longer have a problem. I believe that it was the result of the engine being "too tight" after the rebuild.

[Joe L.]

Re: Hard Starting - 68 Corvette

Kurt-----

I concur with the others; I think that a tight engine could be the cause of your problems. I wouldn't rule out heat soak in the solenoid/starter as being a contributory problem, though. These sorts of problems are "additive".

Another "additive" factor could be the battery. Personally, I'd install a high capacity current-issue Delco, Die Hard, or Interstate battery. Group 24 or 78 DT. Save the reproduction battery for "judging".

[Les Jacobs]

Re: Hard Starting - 68 Corvette

Kurt I haven't tried this on a starter (but it worked on a hot-flooding carb), but you might try to cool off the starter with an ice bag, to see if a "cool" starter can crank a hot engine.

[Roy B.]

Re: Hard Starting - 68 Corvette

I have had this problem before after a rebuilt and after I restored a 67. We all like things painted and pretty. Each time it was a grounding problem and had to sand and clean all ground areas like the starter housing , bolts,wire harness wire grounds and so on. To see if this is your problem use a jumper cable , connect one end to the battery ground post , other to the starter bolt with NO paint on it and try it again when hot. If it starts your not grounded some where.

[Roger Legge]

Re: Hard Starting - 68 Corvette

I agree with the idea of the engine being tight because it's new. Kurt, you mention running the engine for 30 or 45 minutes, but not driving it due to tags, etc. Assuming an L79 hydraulic cam, you or someone else should have broken the cam in by running it at a fast idle for 15 or 20 minutes. Beyond that, my personal opinion would be not to run it a lot until you can drive it and put the typical load on it for ring seating, etc. Just a guess, but I don't know as if extended running at idle is a good thing for a new engine. Now, if it was already broken in on a dyno, etc, that's a different story.

Roger
#36316

[ronnie robertson # 36786]

Re: Long shot.....

But you might check the clearance of the starter teeth and the flywheel. If it is too tight, a hot starter will bind and show symptoms you describe.
Good Luck,
Ronnie

[Les Jacobs]

Re: Long shot. , Part 2

It also might tell you something to put a wrench on the crankshaft pulley, and turn the engine hot and cold to check the "stiction".

[Tracy C.]

Re: Hard Starting - 68 Corvette

Kurt,

If the starter has some miles on it, I think its a probable candidate for your problem.

I recently replaced the starter on my Sons 81 Chevy pickup that was doing this exact same thing! It had about 80K miles of use. He would drive into town and would be stuck where ever he shut it off for about 30 minutes to an hour until things cooled off.

The new started fixed the problem...hands down!

New engines are tight, but I think that's more a product of Bearings than Piston growth. The rings contact the cylinder wall and the pistons have more than adequate clearance for thermal expansion.

You might try Joe's suggestion on the battery first, but a replacement starter can be had for around $30 at most automotive supply houses. If your starter is the original "Keeper" and the replacement cures the problem, you can get it rebuilt an make a spare out of the replacement.

Chin up dude...this is no biggie.
tc

[Larry Clain]

Re: Hard Starting - 68 Corvette

First take the battery to a dealer and have them test it for LOAD capacity. You may not have a heavy enough amp rating to start a hot motor. 850 or 900 Amp. should do the job.

Running a new motor that long can heat soak the starter. It needs to be drove to help cool it off so it will start again. Like all the other guys have said you have a new motor and it will start that way for a few weeks till it breaks in. If you are going to keep starting it like this then turn on a big fan pointing back at the radiator.