Can Timing Help!
#1
![Default](/forum/images/icons/icon1.gif)
Recently acquired a 2000 XJ8 with a loud knocking noise from motor. Started it up and it died at idle. Pulled left valve cover off and found the standard broken secondary chain with blown out tensioner. I found a chain with a master link and am going to put that on with a new tensioner to see if the motor is still good before I put any more money into it. Big question is how do I set the timing of the exhaust cam? I’m probably answering my own question right now but do I turn the engine over till the intake cam has the flat spot on top and drop the exhaust cam in with the flat spot up? Seems almost too easy which is why I’m checking with the experts. Thanks! And no I don’t have any cam hold down tools... i don’t see how they’ll help me in this immediate situation.
#2
![Default](/forum/images/icons/icon1.gif)
Recently acquired a 2000 XJ8 with a loud knocking noise from motor. Started it up and it died at idle. Pulled left valve cover off and found the standard broken secondary chain with blown out tensioner. I found a chain with a master link and am going to put that on with a new tensioner to see if the motor is still good before I put any more money into it.
#3
![Default](/forum/images/icons/icon1.gif)
There is no point in doing what you plan to do as the head most probably has a number of bent valves. The head has to come off and, if there is no other damage, replace the bent valves, lap all valves, check the head for any warping and reinstall. Then comes the cam timing but, if you want to have a good engine, you would need to replace the whole of the timing gear (all chains, guides and tensioners) and inspect the other head too. The fact that one chain broke suggests that the whole of the timing gear is way long overdue for replacement.
#4
![Default](/forum/images/icons/icon1.gif)
As I said, not much logic in doing this as the exhaust valves are bent. Also, you need to (after removing the head and all valves) check whether the exhaust cam is turning freely inside the head - perhaps it jammed for some reason in its bearings and caused the chain to brake. Very important: I trust that you are aware that the cam caps are numbered and must be installed with their numbers in correct running order, failing which the cam may seize or even break.
#5
#7
Trending Topics
#8
![Default](/forum/images/icons/icon1.gif)
Not necessarily "toast" engine - the valve stems are so thin (only 5 mm) that they bend easily and there could be practically no damage to the piston crowns or valve guides. If lucky, the exhaust valves could be the only thing to replace (and not all of them may be bent).
#9
![Default](/forum/images/icons/icon1.gif)
The OP isn't about to deep pocket this project, hence my opinion. I've assumed that the 'loud knocking' is one of the many I've seen with wrist pin/con rod bearing damage (snapped valves) = toast, a parts car.
If you throw enough time and money at something you can fix it, it's about economics.
If you throw enough time and money at something you can fix it, it's about economics.
#10
![Default](/forum/images/icons/icon1.gif)
I just fixed one. Valves had not hit the piston. Don't undo the sprocket. Just make sure both flats are in alignment and fit the chain, timing will still be perfect. Fingers crossed on the valves. Of course, you can crank it with the exhaust cam removed and check compression on those four cylinders.
Last edited by kansanbrit; 02-18-2019 at 11:27 AM.
Thread
Thread Starter
Forum
Replies
Last Post
mystype04
S-Type / S type R Supercharged V8 ( X200 )
10
01-15-2024 07:11 PM
viscoussquirrel
General Tech Help
9
01-09-2010 12:55 PM
85_305
X-Type ( X400 )
6
12-02-2009 06:07 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)