: What gives ?



1993coupdeville
01-19-09, 11:30 AM
I recently overhauled the top end of a 4.6l and reinstalled said engine .
Started fine , ran quietly all of a sudden oil pressure dropped and will not come back up . Timing chains are loud and noisy as well as the valve train I checked the crank damper to ensure that the sleeve that drives oil pump was still turning Bottom end is quiet however top end is noisier than hell . What gives ?

chubbyranger
01-19-09, 11:34 AM
Oil pump not primed? I believe the procedure is to overfill the crankcase by 8 quarts and rev it to 3-4K RPM. Drain to normal level before driving. Another option (a few threads down right now) is that the crank damper is not torqued enough:

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/159403-motor-will-coming-back-out-after.html

1993coupdeville
01-19-09, 12:25 PM
CRANK DAMPER HAS BEEN TORQUED DOWN i HAD OIL PRESSURE FOR 4 DAYS EVERY THING WAS SUPER QUIET AND JUST SUDDENLY NOTHING SOUNDS AS THOUGH THE CHAINS ARE SLOPPING AROUND INSIDE THE TIMING CASE

Ranger
01-19-09, 05:45 PM
That can't be good. Pull the oil cap and have a peek. That might give you a clue.

stoveguyy
01-20-09, 10:00 PM
how are you measuring your oil pressure? tensioners are oil feed so lack of pressure would cause chain slop/noise. are you checking pressure at idle and higher rpms?

97EldoCoupe
01-20-09, 11:38 PM
1993coupedeville- Did you ensure that the curved chain tensioner shoes/guides (the ones that are held in place with one bolt) are moving freely? I had this same issue on one of my HG jobs and wound up shimming the one bolt.

Sometimes (one out of 4 or 5 engines) I will have to file down the tensioner shoe in order for it to move freely- if you do this, file down the block-side of the tensioner around the bolt and make sure the surface is smooth. Wash it down to get rid of any metal shavings/dust.

Best way is to remove the cam covers and check your chain tension. Good luck.