This is weird. I pulled my cam covers yesterday to investigate a VVT engine code issue. I was planning to replace the upper tensioners while I was in there. But, I found that when I align the exhaust cams with the head, the intake cams are rotated about 15 degrees! 130,000 miles total, last 90,000 by me, was running fine other than a ticking sound which the dealer said was my injectors. Not so sure now. Would this engine even run if the cams were off by a whole tooth? Can the ignition system and the VVT compensate this much? Not sure wether to try to retime the engine or button it up like it is. Help!

2000 XJ8 VIN F066xx

 

Bart,

In the thread in which we spoke of replacing the secondary chain tensioners by removing the exhaust cam saddles, it was a XJR thread which doesn't use VVT. With VVT it adds a secondary concern, and that is are the VVT's in the fully retarded position. Always rotate the engine by hand in the direction of normal operation to tension the chains, (clockwise from front) and never in reverse.

When you have the cams locked down and replacing the chains for example, with the special tool (JAGUAR CAM SETTING TOOL - 303-654) or two straight picks you need to turn the VVT to the fully retarted position then lock down the VVT carrier bolt. To get to the fully retarted position you need to turn it (VVT) in the counter clockwise direction.

Having said that, intake cam position can be dependent on it's relationship to VVT. You can follow the same procedure used in the XJR thread to replace the secondary tensioners, just don't move the chain one tooth advanced or retarded.

If the sprocket had moved a tooth, horrible idle would be seen, and 2 teeth, well, then the delicate dance inside the combustion chamber would have the dance partners smacking each other.

If the intake flat is off slightly in relationship to the exhaust flat, it simply may be the intake cam is not in the fully retarded position in the VVT. If idle was smooth and power acceptable before the procedure, and you want to use the exhaust cam saddle removal method, don't play with the sprocket bolts and mark an ident reference on both VVT sprocket/chains to insure after reassembly the chain/sprocket relationship is what it was before removing the saddles.

 

Thanks! I had incorrectly turned the engine CCW. Turned it the other way and they lined up just fine. Glad I don't have to make a living doing this - my kids would go hungry!