QuestionHi, I am doing some engine work on my just purchased jaguar, I was replacing the valve springs on the dual cam engine an it occurred to me how i was going to put the cam shafts back on (since I took apart the cylinder head). Is there a possibility that putting both camshafts back at random in will cause timing problems? I am hoping that you can give me information on how to put them back in whithout having anything go wrong.
AnswerHi Fernando,
It is very critical that you follow the correct proceedure on reasembling. You are replacing the valve springs? My first question is why are you replacing the valve springs?
To answer your question however, You must assemble the cams in the following manor. If the head is mounted on the block you must first set the crank so it has #1 & #6 EXACTLY at TDC
Install one (either cam)with the notch in the flange at EXACTLY 90 degrees to the cam cover gasket surface. (If the head is off the car, you must support the head off the bench so you don't bend a valve.) With one cam in place and the notch exactly 90 degrees to that cam cover gasket surface, (use the mark on the front pulley or a rod through the #6 spark plug hole for TDC. Niether the cam nor the crank can be rotated around when not in time and the sprockets and chain inplace. At this time you should have the one cam notch at 90 degrees to it's gasket surface and the crank at TDC. Now you can install the other cam but you MUST install it with the notch at 90 degrees to it's respective cam cover gasket surface. You can not just install it and rotate it to the correct position. At this time the bolt holes should line up to allow you to reinstall two of the bolts with their lock tab (if you have the later 4 bolt pattern) or one bolt of the older two bolt design that was safty wired.
(note!) If the hub of the sprockets are made of two pieces of heavy sheet metal in a cross you need to discard them and get the full circle hubs. If you removed the large spring clips in the sprockets and removed the sprockets from the splined hubs you must get one of the Jagusr cam alignment tools to time the cams.
With both cams in time and the crank at TDC and just two bolts in each hub, rotate the crank until you can access the other two bolts with their lock tabs. If the last two bolts don't want to start, loosen the first two just a little and wiggle the cam back and forth a little to get the last two bolts in. Then tighten all four bolts on each cam and lock the tabs. The same procedure is used on the wired two bolt type. Don't forget to retighten the chain tensioner. (note!) A wise move is to stuff a shop rag down into the cam chain area when installing or removing the cam sprocket bolts. It is easy to drop a bolt or lock tab down in the front cover and that is a very large job to get it out. And a very large disaster to leave it down there. Also, the cam bolts must never be replaced with a standard bolt. Be sure to note the number on each cam bearing cap as they can not be mixed up. A number is stamped on the head and on each cap. (NOTE!) If you remove the spring collar and the keepers be SURE to keep the keepers in pairs. They must never be mixed together. If they have been mixed together, discard them and buy new ones.
I hope you know all of the valve adjustment pads are sized to get the valve clearance correct and can not be mixed either. The lifters also must not be mixed up.
If you have any problems you can e-mail me at longez8@bellsouth.net good luck
HMF
