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 ?
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:
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
That can't be good. Pull the oil cap and have a peek. That might give you a clue.
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?
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.