Grandfather's 68 SS Camaro.

[JRC99]

Annnnd my knock is back!

Using a stethoscope, it seems to be coming from near the timing cover.

And, it wouldn't be this car if something else didn't also go wrong- the fuel pump is leaking. Great.

That header leak sound, though? Gone. Was either from the wrong firing order, or, something cam related if that rocker arm nut came loose. I'll probably yank the cover again and double check.

EDIT: Cranking it by hand while watching the rotor proves the chain is trashed. I'll start there.

[WILMASBOYL78]

The factory nylon gear and crappy chain were an accident waiting to happen. If you can see the wear from watching the rotor, don't wait too long take care of it. Be sure you get a quality double roller steel chain and a new set of gears.

Other items to check are the valve train parts...the big block motors of that vintage were known for 'dropping valves'. The BB springs and hardware were part of the problem...you might want to look at changing out the top end pieces, if time and budget allow. I did it on our 70 TH400 car many years ago...the timing chain fell off into my hand when I took the cover off

I changed all the valve springs, keepers, retainers...installed new valve seals. Reused pushrods and rocker arms, balls and nuts....they looked pretty good. Those 291 heads are the hi-perf units...big valves, rectangular ports...typically meant for high compression like 11 to 1.

Good luck with the car...

-wilma

[JRC99]

Originally Posted by WILMASBOYL78

The factory nylon gear and crappy chain were an accident waiting to happen. If you can see the wear from watching the rotor, don't wait too long take care of it. Be sure you get a quality double roller steel chain and a new set of gears.

Other items to check are the valve train parts...the big block motors of that vintage were known for 'dropping valves'. The BB springs and hardware were part of the problem...you might want to look at changing out the top end pieces, if time and budget allow. I did it on our 70 TH400 car many years ago...the timing chain fell off into my hand when I took the cover off

I changed all the valve springs, keepers, retainers...installed new valve seals. Reused pushrods and rocker arms, balls and nuts....they looked pretty good. Those 291 heads are the hi-perf units...big valves, rectangular ports...typically meant for high compression like 11 to 1.

Good luck with the car...

-wilma

Most, if not all of the valve train, is probably Comp Cams at this point. It had a 305H installed at some point in the 80s and I'd imagine the pushrods and springs were done too.

As for the chain, it's definitely getting done sooner rather than later.