For those following this thread. Haven't gotten it completely apart but found 3 spun bearing out of 4 taken out. Weirdest thing is sometimes it knocked other times it didnt. Found this that fell out of the engine. Looks like a top of a lifter but all lifters were fine....Any clue what this might be? Definitely lost oil pressure and with that many bearings spun I believe it was do to oil pressure. What I cant figure out is why i spun bearings. Seems like the Oil pump was clogged from bearing material. if that is the case why.
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To be current I decided to update this thread. I found a deal on two 502 mag mpi gen vi motors. Both had water intrusion. #1 was said to be running and probably head gasket or intake gasket leaking and no other problems. I opened the engine had the heads pressure tested and put it back together. The engine looked great on the inside like new. No metal shavings and just immaculate, # 2 was locked up with water intrusion and was said to be something on the exhaust. After looking into number 2 I found a broken valve spring and valve guide leaking water in the exhaust. Number 1 I never could fine a leak. They had decided to replace both motors since this had happen. I got a good deal so I bought them with the intention of upgrading my 454 mag to a 502 mag. I put #1 in the boat and was going to rebuild number 2 with performance upgrades. Once the #1 engine is in the boat it sounds amazing outside but has a tick that i thought was a valve clattering but now believe it to be a spun rod bearing. Ill post the link below to listen and get your opinion. Im still not confident its a rod bearing but the tick requires the engine to be pulled back out and looked at.

Now the plan is to make one good motor out of the two. I got #2 apart and the crank looks good. If everything works out Ill use the crank from #2 in the engine of #1 that is in the boat since I know everything else about #1 seems fine. Long way around this but I was truly hoping #1 was as it was stated....good. Lesson learned never take someone word for it. I should have just spent the money to rebuilt the engine while I had it out.

H
and to tell on videos but sounds like top end noise. Lifter, push rod, rocker.

I dont have speakers on my home computer BUT are you sure its NOT a exhaust leak? I had a header gasket blow out on a boat I did motors for (customer put exhaust on with cheap gaskets that came with his new exhaust) instead of buying ultraseals Iike I recommend. He was positive motor was hurt, started ripping all kinds of stuff apart, pulled a header off and gasket was blown out, fwiw, Smitty

Just watched it on.my phone, sounds like a lifter or valve spring, the key is the noise will be at half the crankshaft speed if its in top end

I know you work on these a lot, but those intake manifolds are nothing but acoustic amplifiers for all the valve train noise coming up the runner. I believe what you are hearing is not the lifter but the sound of the intake valve closing (hammering down on the seat) and that sound gets amplified by the manifold. My motor makes the same sound. Normal from my perspective.

Can’t you also hear the injectors clicking as they cycle some on these engines?

Without being there in person its hard to really tell. Id probably cut the filter and look for debris, if I didnt find anything id go run it on the water and see how it acts warmed up (unless it REALLY sounds bad)

Both of my 502 MPIs sound exactly the same. There is nothing wrong with that engine.

Mine sounds like that, it is the internal exhiast flappers clacking on mine.