My 1997 EVO lost oil pressure. Shut it down fast so hopefully no major damage to engine.

Pulled the oil pump and found a piece of metal had jammed the gears on the back side of the pump and sheared the key on the drive gear.

Pulled the gear cover and can not see any damage to gears, cam or lifters.

The piece of metal is about the size of a small paper clip and a 1/4 of an inch long.

The motor was running fine and not making any more noise then a normal EVO.

Any suggestion on how to track down where it came from?

 

I think I would pull the timing chest open and look in there. Look particularly at the inner cam bearing. If that is all OK, then take the rocker boxes off and inspect.

What's inside the oil filter? Cut it open and see.

 

Post a pic of that thing. Put it next to a dime so we can see how big it is.

 

I would inspect the cam bearing, may be a roller found it's way out. It was suggested by a member here to put a strong magnet on the cam before pulling...this may keep the rollers in the camchest area, you do not want them falling to the crank side, ask me how I know.

 

Remove your lifters and inspect the tappet rollers for any missing/broken needle bearings.

 

Yeah, what he said.

 

Yep ... I'd look there too.

 

Thanks for the suggestions. Will let you know what I find.

 

Had time today to check things out more.

Found adjustable push rods had been installed by the previous owner so made it easy to take apart.

Inner cam bearing looks good. Have not measured it but does not seem to be much, if any play in the crankshaft bearing. The cam is in good shape as are all the gear teeth.

Found the rollers on two of the lifter had about .010 of play. But even with that much play I don't see how the piece I found could have passed between the roller and the side of the lifter body (sorry no way to post a picture of the piece).

I had just changed the oil and filter. Upon draining the oil did not see a metal particles in it. Will be taking off the oil filter and mount and flush all the lines. Will cut open the filter and see if there is anything inside.

I am wondering if the metal is a piece of trash left over from when the previous owner had the solid push rods removed and put in the adjustable ones.

 

Lifters shouldn't have any play, if you can move a roller up & down or twist it even a hair it's bad.