some kind of knocking

so i posted a while back with a blown engine with a melted piston. it started and ran fine during the building and only recently gotten it on the road. now i have a knocking noise that im just not sure what its from. when its cold and i first start it i get the typical loud knocking and then goes away and its quiet and fine. but once it warms up it starts to knock.

i cant tell if its piston slap or maybe something else. i reused the original rod bearing as i could still read the text on it and it was not worn. im hoping its a lifter that just going bad. it also gets quieter at around 2500 rpm.

im thinking i may have to swap in the other engine and then have this rebuilt but i would like to hold off until summer.

https://youtu.be/6rL79flxNmo. Clip of the noise. While driving under 1500 rpm it's not noticeable. I ordered a few rod bearings I'm hoping I can just swap it out and make it until summer.

Did you ever figure out what caused the melted piston?

the only thing i could think of was the wrong gasket coupled with loose bolts on the manifold. the head is from an HO and the manifold is Renix.

im going to drop the oil pan this week end and check. but im going to try and find which cylinder is making the noise first.

Ugh. If it's not a bolt loose on the flexplate, hate to say this it sounds like a rod knocking


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turns out it was rod knock. and well... there is a sight hole in the block now.

Sorry. Man that sucks .


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i have another engine lined up to be swapped in. just going to have it rebuilt first and put the 7120 head on it.