Mystery engine knock

[iflypropjobs]

Would a jumped time on an AMC 360 (1982 vintage) cause the engine to knock? I have a mystery knock & I've tried everything I know before pulling the engine for an indepth investigation. I thought it was a collapsed lifter at first - starting like it was fighting compression, knock would come & go - so I replaced all the lifters & push rods. No change

The motor will run, it will knock for about the first 5 seconds & then stop - run fine till you gas it - knock starts again. The engine never looses oil pressure, it never even fluctuates and it never gets hot.

If it was a bottom end problem, I would think the problem would steadily get worse & oil pressure would start going away, especially when warm. It can sound really nasty, but has got me confused.

Any suggestions?

Thanks

[Chevelleguy]

Sounds like a rod knock.

[Ristow]

Sounds like a rod knock.

yup. pull the pan,and the rod/main caps. if you catch it early sometimes new bearings will buy you a lot of time. once the journal is tore up you're done though.

[iflypropjobs]

If its a rod knock, then why am I fighting compression when trying to start? I haven't messed with the timing & it was running fine before. Like I said - it's a big mystery that makes me think I really need to pull the motor & find out for sure.