2000 xj8.

so I just did chains and tensioners. No problems with the job. I've done this twice before.

While the car is sitting still it sounds great. Rev to 4k or let it idle, doesn't matter. I let it run long enough to burp the coolant, no issues.

Then I take of down the road and when I gas it I get a banging noise, not rattles like chains loose. When I let off the gas or rev in nuetral it is quiet again.

Car ran perfect before so I am certain this is something I did while I had the front of the motor apart. Could this be VVT? Any ideas?

 

update, unplug the vvt and the motor runs quiet, even going down the road. I had crank locking and two cam locking tools on the motor. What could mess up the vvt?

 

Did you use the tool to adjust them out?

 

I did, but lets assume that I somehow got it wrong. How would I re-set once everything is back together? Can it be done just pulling valve covers? BTW I get no codes.

 

so I remembered that the right side intake cam was a touch off of level with the exhaust cam so I just unplugged that vvt side. Motor runs great so that sides valve timing is off. I thought I had it set back to the few degrees out that it was when I started, but obviously not. Can I just locate the crank, lock it with the tool, loosen vvt sprocket, set both cams to dead level with the cam tool and a wrench, re-torque the vvt?

 

The cam timing flats will be slightly off from aligned when the clamping tool is removed. That is because of the pressure of valve springs on the cam lobes. If I remember correctly, they will make a very shallow 'V', only about 2-3 degrees off parallel.

If you did not loosen the intake bolt there is no reason that it needs to adjusted unless obviously out of align per the comments above. Normally, only the exhaust timing needs to be addressed.

Locked down by the flex plate pin, the intake cam flat should be nearly flat with the head machined surfaces.

Did you change the oil during this process? VVT issues usually are associated with oil pressure.

 

This is a possible problem. Not sure I understand what/why or if you loosened the VVT from the intake cam at any point in the process, or if you changed the position of the VVT. VVTs have to be in the fully retarded position when the cams are locked in place. If not, you'll be changing the relationship of the intake cam to the exhaust cam on that bank, meaning that the intake cam will retard farther than the farthest point it should during deceleration, and it will not advance as many degrees as it should about 3200rpm and above, and out of balance with the other bank.

After you started and ran, have you taken off the covers, rotated clockwise to the flats and observed if all four camshafts are in the proper orientation?

 

I pulled the vvt sprocket because I was doing all 4 chains, tensioners and sprockets. I am going to pull the valve cover tonight and see how "flat" those cam surfaces are. From what you are telling me it would seem that I did not have the intake at full retard when I tightend the sprocket down.