Stew2000

iTrader: (2)

pdxmotorhead

Hard to tell for sure but,,,

1. Broken valve spring
2. Bent/cracked push rod
3. Collapsed lifter
4. Spun bearing (Cam maybe)

I'd pull the rocker covers first and check the valve train for non moving rockers. Loose rocker arms broken valve springs, start easy and work your way in..

A.R. Shale Targa

iTrader: (2)

Oil pump O-ring

pdxmotorhead

Oops missed the hard to swap but easy to fix one...

alfablue

Motorhead is correct. Pull valve covers and see if the valvetrain is intact. If it is then my guess is rod knock. Especially with that wonky oil pressure.

JustGreg

While researching a oil pressure gauge reading I'm having I came across this post. I realize it's an old thread with newer comments but wanted to relate a recent experience I had with similar(ish) symptoms. There's a good lesson here for most everyone so please bear with me.

My 96 Formulat WS.6 (bone stock) began knocking last August while parked and idling in my banks parking lot. Oil pressure was within hot specs which baffled the hell out of me given the obvious monkeys from Hell trying to beat their way out of the block. As pressure is generally determined by mains, with connecting rods next, I was confused. I drove it the short distance home and began troubleshooting after it cooled. A temporarily attached mechanical gauge confirmed oil pressure was good. I moved on to belt driven accessories...everything looked as it should.

As the car needed a clutch soon anyway I decided to pull the trans and oil pan to take a look-see. By the way...pulling the oil pan with engine installed?...sucks rhino turds! In hindsight I should have dropped the K member and engine. Lesson learned.

After the tranny was out (but before I got the oil pan all the way out) I rolled myself to the front of the vehicle to remove the serpentine belt. As soon as I removed the belt I immediately realized where the horrendous knock was coming from. The rubber between the outer and inner rings of the harmonic damper had degraded over time and was missing probably 50%! That left the outer ring to slam against the inner each revolution!

It wasn't a great feeling for a 58 year old journeyman mechanic and lover of all machines to lay under there holding the outer ring in my hands thinking of how one missed step in diagnosis turned a one hour repair into shelving the car for the entire season. (I moved right after so had no time to dig into it again until this spring). I replaced the oil pump and driven shaft with its crappy plastic coupler, replaced all bearings with fresh standard size (the crank journal measurements indicated I could get away with that), new Fidanza flywheel and Stage 2 clutch..etc etc.

The moral?..there's more to a crank than the middle and output ends!

HappySalesman

iTrader: (3)

lol. I work as an installer for a car audio chain. I can't count the number of times I've smacked my forehead because I missed something extremely obvious because I thought it was something much worse