I have a 98 xjr with 98k miles . drove it to the store , running OK would not start, rattled a little. checked the compression and found cylinders 1st and 4th on left bank had 0 compression. the rest about 140 lbs.any body have a clue what happened? Dealer had replaced the chain tenshioners 20k ago.
Thanks mike
Dear Mike,
Zero compression is not good, even engines with scored cylinders will create some compression.
I would remove the valve cover from the bank in question and check to see if the cams are out of sync with the crankshaft at TDC. Next turn the engine until the cam lobes on the cylinder in qustion are pointed upwards and measure the valve clearances. If the chain became loose you may have bent some valves, if so you will have excessive valve clearance on the bent valves.
If you dont want to do the above....see if you can rent or borrow a boroscope and look inside to inspect the cylinder walls and valves. If the valves contacted the pistons you would see fresh marks on the piston crowns and the valves.
Regards, Blake Dodson
Have something to add? Share your thoughts — no account required.
Ask the community — no account required