The knock gremlin has set up home somewhere in my engine. I've read pretty much every thread related to knocks.
So this is what I have:
I'm using RP 10w40.
Oil 44 psi at idle when cold. Seems a bit high but it drops to 28 psi once it's warmed up. Reving the engine gets the pressure up around 48-50 psi.
Knock is there from cold. Not as loud but it's there. The knock goes away as revs increase.
Don't know if it was ever overheated. Changed the head gaskets about 6 months ago. No sign of liner slip with the heads off. The liners were flush with the block and the gasket looked ok (but I'm not an expert) except for the leaks from the rear water passages out the back.
No coolant loss since then.
Banged on the cats no rattles. Manifold bolts are tight and the y-pipe is tight.
Probing around with a stethoscope I can here the knock on both manifolds. Less on the drivers side.
Listening to the oil pan and the knock is very noticeable without the stethoscope. With the stethoscope I can narrow it down to about the middle of the pan just in front of where it drops down. From RAVE it looks to be around where the oil pickup bolts to the block.
The strange thing is I can also hear it on the exhaust pipes just in front of both cats but nothing from the cats.
So what's the next step. I've heard/read of people tearing the engine down, rebuilding and still knocking.
Doesn't sound like rod/crank bearings because the psi is good.
Slipped liner? No coolant loss or overheating.
Wrist pin or piston slap?
Is it worth droping the pan for a look and what would I be looking for?
Liner hitting the crank, polished cylinder from a slaping piston, loose oil pickup?
Any pointers or suggestions appreciated.
Thanks,
Mark
So this is what I have:
I'm using RP 10w40.
Oil 44 psi at idle when cold. Seems a bit high but it drops to 28 psi once it's warmed up. Reving the engine gets the pressure up around 48-50 psi.
Knock is there from cold. Not as loud but it's there. The knock goes away as revs increase.
Don't know if it was ever overheated. Changed the head gaskets about 6 months ago. No sign of liner slip with the heads off. The liners were flush with the block and the gasket looked ok (but I'm not an expert) except for the leaks from the rear water passages out the back.
No coolant loss since then.
Banged on the cats no rattles. Manifold bolts are tight and the y-pipe is tight.
Probing around with a stethoscope I can here the knock on both manifolds. Less on the drivers side.
Listening to the oil pan and the knock is very noticeable without the stethoscope. With the stethoscope I can narrow it down to about the middle of the pan just in front of where it drops down. From RAVE it looks to be around where the oil pickup bolts to the block.
The strange thing is I can also hear it on the exhaust pipes just in front of both cats but nothing from the cats.
So what's the next step. I've heard/read of people tearing the engine down, rebuilding and still knocking.
Doesn't sound like rod/crank bearings because the psi is good.
Slipped liner? No coolant loss or overheating.
Wrist pin or piston slap?
Is it worth droping the pan for a look and what would I be looking for?
Liner hitting the crank, polished cylinder from a slaping piston, loose oil pickup?
Any pointers or suggestions appreciated.
Thanks,
Mark
