Good afternoon everyone,
I just finished replacing the top end on my c3 corvette. Start it up for the first time, break in the cam shaft and turn it off.
Go to start it again after fixing a couple of leaking radiator hoses, the motor turns over twice and I hear a loud thunk. Sounds like the starter disengaged and then reengaged while still spinning. Attempted to start it again and same thing happened. About two seconds of turning over and a loud thunk. Attempt to start it the third time and I just get one click(from the solenoid). No turning over at all.
Removed starter, took it to autozone where they tested it. Said it was bad. Got a new one. Put it on the car and it starts up normally. Turn it off and went to start it again. Same thing happened as before. I just get one click from the solenoid and no turning over.
my thoughts are that the higher compression ratio, went from 8.5 to 10.5 is too much for the stock starter? Or excess heat is frying the starter?
any thoughts are welcome, thanks

 

I really doubt its your new C.R. Any starter should be able to handle that. Keep in mind the intake valve is open when the piston is upward bound for a brief second so its not really 10.5:1 at cranking.
Just for piece of mind, was the piston to valve clearance checked? You need about 0.080-0.0100 on the exhaust valve side. But if there was any contact you should be able to hear it.
How about the two primary wires on the solenoid? You turn the key off and you heard the clunk? Wires reversed? IDK
And if you are running headers I would recommend a starter blanket / heat shield. Summit has em.

 

i have not checked valve clearance to the pistons. But when it does run it sounds fine. Since the starter clicks, that leads me to believe the signal wire to the solenoid is wired correctly. Since the starter won't actually turn I'm thinking that it's not getting power from the battery. Or the starter was just a bad apple. Do you know if the large power wire on the starter has a fusable link?
Thanks for the info on the CR. I'll be getting a heat shield soon as well.

 

Hi R,
Yes, the ignition harness has a fusible link at the starter solenoid.
It should be pretty easy to see if that's been triggered.
Regards,
Alan

 

I believe the LG wire is a fusable link. But, what about a decent ground? For some reason many C3s are missing the extra grd cable from starter to frame.
The odds of getting two bad starters is well, IDK h-m-m-m-m-m-m.

 

Is the battery fully charged?
Are the battery connections clean and tight including the ground under the drivers seat?

 

Thanks for all the thoughts guys. I'll double check the wiring and the grounds. I'll even add a ground from the mounting bolt direct to the frame. If it still won't start I'll pull it and take it to get autozone to check to see if it's bad.

 

Hi R,
There typically a large gauge (2) ground cable that ran from the starter brace mount at the engine block to the frame engine mount horn.
If it's not there, it should be, unless, one has been added someone else to ground the block.
Regards,
Alan

You can see it just forward of the starter/solenoid.

 

I can say from the very few times I have had to install a starter from an auto parts store...that it is a 'hit-or-miss' scenario if the part is actually going to work.

I have had brand new alternators be bad right out of the box and even before the owner of the car took them from the store..and as for starters...I have noticed this same similar issue after a few times of it begin used.

I have run into this and this may help. The lamb nuts on the start solenoid that secure the threaded studs where you attach the cars wiring. Make sure that they are tight. I have seen them loose....and if they are loose.....it does effect what is gong on under the cap of the solenoid.

As mentioned...make sure that your battery terminals at the battery are CLEAN and TIGHT.

Hopefully you are still using the correct bracket that is attached to the end of the armature housing of the starter to give it more support.

Also...you should have a ground cable that is attached to the right engine mount frame support that goes over and is bolted to the engine block right by where the support bracket for your starter is attached also. This cable is IMPORTANT due to this cable being as large at it is.... is like your other battery cables and is providing the engine the ground needed for the electrical system.

Because with the battery being behind the seat...and the negative battery cable from the battery is bolted to the frame under the car. This cable from the right engine mount area to the engine block completes the circuit. Because most cars with the battery in the engine compartment....the negative battery cable is bolted directly to the engine block.

DUB

 

I used Autozone starters and they would last 1-3 years and then fail. All of them failed in different ways. One just cranked slower and slower. Another stripped an internal gear so the motor spun but didn't crank. Last one stripped all the teeth off the bendix gear (luckily didn't damage the ring gear).

Autozone kept giving me warranty replacements but it gets old replacing starters all the time. This year I got a PowerMaster starter instead and so far so good.

 

That confirmation is why I send these electrical parts out to company in my town that rebuilds them when the customer wants it that way. ...and so far...the ones I get rebuilt are not falling apart or failing due to they are checked thoroughly.

DUB

 

thanks a lot for this post. I just took a look and that bracket and grounding strap isn't there. Guess I'll make my own.

 

Or check Zip Corvette, Keen Corvette, maybe Willcox, Corvette Central. This is not a place to skimp with "homemade".

 

Unless you have a bad spot on flexplate/flywheel eating them it sounds like cheap *** starters failing. Heat soaked old wiring might work with stock engine/low compression but higher compression is higher draw. If not starter cables/wires are suspect.

 

why didn't you just rebuild the starter that was working before you rebuilt the engine??? they are easy to do, or take it to a shop that does rebuilds?

 

honestly didn't know that was a thing. Always just bought a remanufactored one for $50 when they go out.

 

I went through 3 autozone statrtes once in 98 degree 2 day span .I will never buy a rebuilt starter from them ,they are crap.


If you have a nice sled go buy a NEW starter and be done .

 

Those $50 minis from eBay work pretty well. I used to do starters for a living, and I have five or ten in the basement. But I still can't mess with them anymore. Just not worth it. But the large main hot wire is not a fusible link.

 

Autozone can't seem to sell rebuild electrical parts that work.

Myself, I'd get a starter from a 95 pickup with a 5.7L engine. Bosch or AC Delco. The smaller permanent magnet one. You don't need the brace with it but still need the ground cable.

 

Make sure that you don't have a piston hydraulic locking. After head work you may have a gasket leaking into a cylinder. The piston comes up against a solid water column. Might pull some plugs and crank it over if the starter stuff turns out to be ok.
Stump