1968 Riviera 430

Will the motor continue to rotate if the timing gear gives way or will it lock up due to making contact with a valve? Assuming on the older high compression motors that it will stop spinning but not sure. I believe my stock gear may have finally given out but was looking for some high level info before I start troubleshooting. Thanks in advance.

 

It'll keep spinning long enough to do some damage. Don't expect an OHV engine to be a non-interference design.

 

You will bend your valves before it stops spinning. Easy 30 second diag: Pull your distributor cap and see if the rotor is spinning while cranking. If not, your timing chain is most likely broken (couple other things like distributor gear being sheared off can also cause this, but a quick one to get you going in the right direction.)

 

Ahh, I forgot about the nylon teeth on these engines (never built one ). Have seen broken chains though.

 

I have a picture of about 15 of my nylon teeth wedged into the crevasse above the cam tunnel and that many easily in the oil pan. When they go, they go

 

Oh, yeah buddy, I've been around nylon gears in engines and the effects of the teeth coming off before. Just forgot the BBB had them, too.

 

Eh the checking the distributor like that isn't very sound. Everyone I've seen the chain jumps but still spins the cam. You can put a timing light on it and check it while it's cranking..

 

That's why I said it'd show a broken chain or a sheared distributor gear.......

 

I don't think there has ever been such a case with a BBB..

 

As I said, I've never built one. But I've been around thousands and thousands of other engines (There's 5 torn apart in the shop right now), and I have seen it happen a few times. Sorry I was trying to help the OP out with a nice, easy suggestion for him to check. I'll try better next time.

 

Geez you've got a delicate ego.. I never said you were wrong or dumb for suggesting anything chuck.....

 

430 is a non interference engine. Unless a keeper lets go and drops a valve they will not contact the piston on a stock engine. Use a bore scope down the dist hole or into the fuel pump opening and check the chain. If its never been changed 99% chance thats the issue.

 

Thanks for that. Not what I expected.

 

Thanks for the replies. This is a project that will not see any progress at least until next spring. In the event there is major damage, and to keep things simple, has anyone had experience with the crate engines that CME or Precision Engine offer? Or are there others that offer a 430 or 455 that are recommended?

 

Just rebuild your own. Even if you have a shop do the work you'll be in under 5K as long as ya dont go crazy with up grades