engine and drivetrain Top end noise

[eurotrash]

This sound has been present in my 1975 motor since I took delivery almost 3 years ago. Its rhythmic, fades in and out, happens at low idle, warm or not. -But not during the high idle warm up.. The oil weight seems to alter the severity a bit, but its always there. I decided it to be a tensioner/chain sound.

Someone of authority once said to me, "they all do that". I assume in reference to original motors.

My timing chain and tensioner have been replaced. Dual row. I don't sweat it.

Being a relative newbie, I thought it just an m10 thing.

[Kpeters]

Sounds like a piston slap or a almost a diesel like knock. My Detroit knocks like this. But piston slap would be more of what my guess is. It also could be a worn out rocker

It does sound similar to piston slap I think I got that and It goes away 100% when hot it doesn't go away when revving cold though.

[Robert Kyle]

I got the same noise.

 

Guess I gotta check the rockers.

[Dudeland]

Try the hydraulic chain tensioner.   If it is cold, maybe the oil is cold enough to make it work.  Oil gets hot, and thin, then the hydraulic tensioner is no bueno.   I replaced mine a while ago and made it much quieter. 

 

The other problem that I had was the support bracket for the oil pump came loose and started to knock on the journal bearing.  This happened after the oil pump was replaced.