timing question
Thread Starter
Junior Member
Joined: Nov 2016
Posts: 91
Likes: 0
From: Henderson NV
Year: 2001
Model: Grand Cherokee
Engine: 4.0
so i timed my crank and cam sprockets and i just realized piston number 1 was at BDC not TDC. its mounted in the jeep but havent gotten the radiator and stuff put back in so retiming the sprockets wouldnt be difficult but i just wanted to clarify that piston #1 needs to be timed at TDC correct? got the timing marks lined up and everything but its 180 off, do i need to retime to TDC on 1 or can i just time the cam sensor from where im at?
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 741
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
#1 must be at TDC with the timing marks lined up. If you turn the crank one full turn, then the cam sprocket mark will be 180* around on the other side of the camshaft and the valves will be open at the top of the exhaust stroke.
How did you get the crank sprocket to line up at BDC?
How did you get the crank sprocket to line up at BDC?
Thread Starter
Junior Member
Joined: Nov 2016
Posts: 91
Likes: 0
From: Henderson NV
Year: 2001
Model: Grand Cherokee
Engine: 4.0
lined up the timing marks and #1 piston was all the way down, i wasnt thinking about it being at TDC, i was just curious if it had to be at TDC because it all lined up when it wasnt at TDC. didnt know if i could just rotate it around to TDC when i get the cam synchro installed and have it be correctly timed
Thread Starter
Junior Member
Joined: Nov 2016
Posts: 91
Likes: 0
From: Henderson NV
Year: 2001
Model: Grand Cherokee
Engine: 4.0
nevermind, answered my own question, cam gear would still be 180 out, looks like im loosening the rockers and messing with the timing this weekend.


