Engine locked up

[Simmo]

Helping a friend with his street car. Has a 383 Gen1 SBC that I built and was running till we pulled it to replace ring gear on flywheel. Sump came off to fix pinhole leak so engine was turned upside down. New spigot bush installed. Fuel pump came off for installation otherwise engine not touched. Upon starting, engine turned half rotation and stopped. With the plugs out Im unable to manually turn either direction.

I didnt assemble the clutch but it appears to be working. Removed starter but no help. I checked the clutch slave cylinder bracket bolt isnt too long and contacting flywheel. Alt and waterpump are ok

I can pull the fuel pump and dizzy easily to see if there is an issue there. After that check remove valve covers to see if anything doesnt look right.

Perhaps someone leaned on the windage tray when the sump was off, but id expect to be able to reverse out.

Any other ideas on where to look. Something to do with the ring gear?

[Keith Morganstein]

I would look at what you changed. Something with the flywheel, bolts, clutch, some interference that has wedged and jammed.

Did you try and rotate the engine 3 revolutions before reinstalling? Always a good practice.

[Newold1]

If the starter motor gear for some reason locks up into the new ring gear on the flywheel it will lock the engine up. Try just a simple thing of removing starter and see if the engine then frees up.

If that is not the issue then was any stop, bolt or other item used to keep the engine from rotating while the flywheel was being unbolted?

Let us know what you find.

[Simmo]

Tried with out starter then put it back, but I think I should remove it again and dust cover to look for anything else.

[Newold1]

Did you pull spark plugs all and try rotating the engine. Could be while upside down a cylinder somehow filled with oil of fuel and is hydro locked?

[pdq67]

Some starters need to be checked using a straightened paper clip as a gage between the bendix teeth and the ring gear teeth.

You use either a GM starter shim, (I think GM makes two of them?), or a couple of thin 3/8" flat washers between the starter and the block mount bolt holes to shim them farter apart if this is the problem.

If you don't check this, you run the risk of breaking the starter snout off. I broke a snout one time so know.

It can't be hydro-locked if you have pulled the plugs and turned it over because any liquid/oil in the cylinders would squirt right out.

Probably using the wrong length flywheel/flex plate bolts, they are different lengths and if not correct will hit the back of the block.

Been there, done that!

Good luck,

pdq67

[steve316]

Sence you have removed plugs and starter like posted earlier; bolts on fly wheel would be next to check.

[Old School]

Did you pull spark plugs all and try rotating the engine. Could be while upside down a cylinder somehow filled with oil of fuel and is hydro locked?

yep, if the oil was left in the engine upside down.

[Newold1]

I did not catch his info that he pulled the plugs during his checks so it's obviously not hydro locked. The lockup must be definite mechanical lockup.
Guess I would like to know why the ring gear had to be changed? Was the engine already frozen up and the starter tore up the ring gear trying to get the engine started? Was the engine running fine before it was pulled to change the ring gear? There appears to be something missing in this dilemma.

[Simmo]

Was told by auto electrician - ring gear chewed up due to not running a front starter brace.

Its an old long, heavy iron starter so I can see the brace is a good idea which we have now fitted.

Was trying to keep this an original numbers matching deal with a bit of extra power.

[FC-Pilot]

I once put a bolt in the flexplate the was for a flywheel. Bolt dug into the rear of the block by the crank seal. Could not budge. After inspection we saw it, pulled it out and put in a flexplate bolt and we were good to go. Look to see if pressure plate bolt or flywheel bolt may have been too long.

Paul

[Simmo]

For those interested I finally found what was wrong with my friends motor. It got hot last year and must have hurt the thin head gasket seal. While no water got into the oil it seeped into the bore and rusted the top of the cylinder while it sat for months. Im hoping I can fix this easily.

[Newold1]

As they say in French, "That'll doer Manure!"

Thanks for reporting back here!