Got my car back! but then it went boom :(

I never ran a gear drive but I bought one before I had my Cleveland built. I took it to the engine builder, who handed it back to me, and told me to take it back home. They put a nice racing chain and gears in instead

 

I'm thinking that was the result...not the cause.

 

The way all of the crank teeth are gone, but only some of the cam gear teeth are missing, would tell me the cam (for whatever reason) stopped and the crank kept on going??

 

That was my thought as well.

 

that could be the oil pump locking up and the shaft stopping the cam...

 

So i tore the engine out of the car today and took a closer look at a bunch of things..the little tab that goes on the crank & holds crank gear was a bit chewed up and the gear had spun a little bit.. so that was some damage..looks like cylinder walls and crank bearings all good, cam spins free.. everything was right there under the gears, everything really looks pretty good what i seen sofar, so ill take it apart..clean it out, re-assemble and go again..next spring..maybe turbo'd.

continuing on with the problem of the crank gear being spun a little bit...when i first fireed the car up and got it back on the road this summer after all the body was done and painted, was probably 2 weeks later after i'd drive the car for a while it was a hard start when hot, seemed to me the timing was out, we changed it literally 10 different times because i swore that was the issue, sounded like it to me..then a guy said maybe boiling fuel and some other thing. but is it possible that it could have spun a while ago and that was why it was a hard start when hot? then finally the gears smashed into each other and decided to meet in my oil pain? just a thought..

 

You would think that if the cam seized the distributor gear would look just like the gear drive gears..................if the oil pump seized there would also be damage to the distributor/cam gears.
Looking at the crank gear suggests it took a tremendous amount of force before it sheared by the hairline cracks that run perpendicular and the way the gears were sheared off.............if I had to hesitate a guess I'd say he lost a tooth on the idler and it got jammed causing the crank gear to shear. Stock block SBF's are not known for great oil delivery to the distributor gear area as well as the chain area. One reason a lot of people drill and tap a hole in the that area for more oil delivery (years ago before Ford and the aftermarket started making blocks with priority oiling) or enlarged the hole in the front of the block.......IMHO
Pictured is my old 351w block that is sitting under my work bench.

 

That is a woodruff key and fits into the keyway on the crank connecting the crank and balancer together.
If that is chewed up take it out and see if a new one will fit in without any slop..................if it is sloppy then something will have to be done to make sure if fits tight. If not the same thing will happen again even if you use a chain.
A lot of aftermarket cranks come with more than one keyway..........my billet crank has three........

 

Is this very possible? Pistons have large valve reliefs.. Was really hoping to not have to tear the heads apart.

Thinking now.. Ill see the pistons if they hit.

 

When the "big bang" came and your gear drive blew apart, your cam stopped moving leaving some valves open and some valves closed. Your crank continued moving because you were in gear with the car still in motion causing your pistons to keep moving up and down with the crank until it also stopped. Those valve reliefs are only cut for clearance when everything is moving together in time. It could be possible that a piston might have come in contact with a fully open valve.

 

Jut pulled the heads, there was slight contact, the carbon build up was hit, but not the piston itself.. I'm really suprises at the amount of carbon build-up so quickly, what causes that?

Thank god for these extremely massive valve reliefs

 

How about some more pictures?????
How many miles do you have on the motor?
Carbon buildup can be, an over rich fuel mixture, oil going past the rings, oil going past the valve seals.................among other things.
My neighbor across the street has a show car 39 Chevy with very healthy 383 stroker motor and dual fours, today he was recharging the air conditioner and the car was idling for maybe 10 minutes................I was standing by the car talking and after I left and went in the house I smelled like gas........................I had to take a shower and change my clothes..................the car is running wayyyyyyyyyyyyyyyy too rich and this is part of the reason he is getting 8mpg.

 

I miss that cologne

 

If you want Gene, I'll go across the street and have my neighbor let his car idle for a while and I'll bottle some and send it to you