Internal engine noise

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pjfellhauer

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Michigan
First Name
Pj
Truck Year
1978
Truck Model
Chevy C10 Scottsdale BigTen
Engine Size
350
Video of engine

from what we have diagnosed its not anything ran off a belt or the mechanical fuel pump, my uncle thinks it could be a loose timing chain, front harmonic balancer flywheel thing, or the oil pump but curious as to what other ears have to offer.

All fluids are normal and it seems to be running just fine besides making an awful noise, gonna do a compression check before I tear down into it, have a feeling it could be a bad bearing as well but

Any help appreciated!!

1978 Chevy Bigten
 

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75gmck25

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Bruce
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1975
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K25 Camper Special TH350 NP203
Engine Size
5.7
Pull both valve covers and check for loose pushrods and rockers. Adjuster nut may have loosened up and the pushrod is bouncing against something.
 

pjfellhauer

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Chevy C10 Scottsdale BigTen
Engine Size
350
Will be one of the first things I was gonna check, working on it tomorrow, will update. I trust your ears! Lol

Thanks!
 

Smtty58

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Lyle
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R3500 Crewcab
Engine Size
350
Pull the distributor cap. Rotate the motor by hand until the rotor just starts to move. Then rotate the engine in the opposite direction, and note how much you need to rotate it until the rotor starts moving. This will give an indication of how much wear is in the timing chain, in case that noise is the chain rubbing on the cover.
 
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