knocking engine

k-man said:

i just got a 95 gt, had a bad vibration at idle and found that the harmonic balancer had come apart, so changed it out with one off parts engine and now runs smooth.. and yes it is 50oz had same part number as old one..
but now that all is fixed the car has a rod knock, guess the guy ran it long time messed up.
so anyone know if i yank the engine and just replace the rod bearings if that would be all i need or replace the mains also?

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I think it's more than likely the main bearings will be shot. Just cross your fingers and hope that the crank journals won't need to be reground.

Hopefully if, as soon as you noticed the knocking, you parked the car, the damage won't be too bad... A friend of mine with an N/A 300zx chipped his car and it brought the rev limit to 7,800, even though his cams ran out of juice by like 5-6 grand... He constantly revved it that high, and ended up getting a knock about a month ago. Instantly shut the car off, towed it to his shop, we tore into it and just found a single spun rod bearing. The rest of the rotating assembly looked just fine, so I hope you have the same luck!

On the bright side, if the internals are unfortunately shot, 351 swap?