Hey guys just ran into a small problem. There is a light knocking noise coming from my motor and it is really starting to get annoying. You can only hear it at idle and the rythem does increase with rpm's but is not audible past 1300 rpm. The only time you can hear it is when the car is parked next to a curb or wall where it echos and it doesn't matter if the motor is cold or hot. I pulled apart the bottom end to make sure it was not the bearings and they all look perfect and clearences are well within spec. I used a stethascope to try and trace it down and it is loudest where the oil pump mates to the block. Can the oil pump make a knocing noise like that? It was replaced when I built the motor (only about 6000 miles with no oil starvation) but I know anything can happen. I used the stethascope everywhere on the motor and that is where it is the loudest. Also oil pressure is right where it should be. What are some takes on what this could be. Your help would be greatly appreciated!!!. Thanks.

 

how is the oil pump gear?

 

haven't pulled it out to check yet but the whole pump was used in the rebuild about 6 months ago (not that it means anything). You think that could be what it is? Also if it is that would I see a fluctuation in Oil pressure?

 

bump

 

what crank pulley are you running
what clutch are you running
did you try to check the thrust play when you had the motor apart?

 

The Crank pulley is stock w/ the ac removed. The crank key that locks the pulley was missing for a while. Got another one about 2 months ago. The clutch is an excedy type one w/ fidenza flywheel, and the free play is correct. You think it could be the crank pulley? Thanks.

 

so you ran your motor without a woodruff key?

If you did I wouldn't be suprised if you fucked up the crank or the pulley.

 

valve adj??

 

no key in the crank pulley could possibly let your crank pulley wobble. Not very likely, but it's possible. After a bit of that it could have put it out of round. The oil pump is in the same area as the crank pulley, so it's possible you're hearing that wobble.
Take off the crank pulley bolt and see if you can feel any play/wobble when you try to move the crank pulley by hand. If you do, time to get a new crank and pulley.
Sucks that a $0.35 part may possibly cost you hundres of $$$$ now.

 

also check your timing belt tension, sometimes it sounds like a rod knock when it is slapping against something inside the cover, it has happened to me before.

 

I pulled the bottom end apart again just to make sure and everything is fine. Bearings look perfect and the clearences are still well within spec. I did do some searching and want some opinions if this could be it. I am running an eagle crank with eagle H beam rods and wiesco 11.8:1 82mm bore pistons. Since the rods and pistons are full floating now could that be it? I don't think that the noise is piston slap because the knock is still present after the car warms up. But is it possible that full floating assemblies would make a sound like that? Thanks again for all your help so far!!!!

 

well this usually happens with full floating pistons, but if the noise still exists after the warm up it usually means that they are too loose in the bore, at least that's what people say.