Good afternoon to you all! I love this forum, I've been doing a lot of research on replacing the secondary tensioners, however didn't find an answer for this one. First things first, I recently purchased a 2000 xjr with 84000 miles. Everything is running well, but after reading some horror stories on here, I went ahead and bought secondary tensioners. I have printed out the "zip tie" method to follow, however it doesn't tell me how to position camshafts after each side is done. Do I need to position crank to tdc first? Which side do I start with? I gather that the exhaust cam shaft has to be turned to a "free point", so the valves aren't pushing cam back up, risking a cam breakage. After I finish first side, do I need to rotate crank to a different position in order to complete other side? Any help would be awesome, I don't want to screw this up.

 

Welcome to the forum!

Yes, you need to rotate the engine to provide as little valve spring pressure on the cam as possible on the side you are working on. After evenly loosing the cam bolts you may have to rotate the engine, with a socket and breaker bar on the crank shaft bolt, to free up cam. It will be stuck hard due to clearance and oil surface tension. Finish that side up and start all over again on the other side looking for the point of least spring pressure.

TDC or any deviation from it is of no consequence, just don't try to tighten down the cam bolts against spring pressure.

 

Also, be sure to tighten the caps with a bolt sequence of about 1 to 2 turns each at a time. As you get past about half way with the bolts, drop to 1/2 to 1 turn each. Get both bolts on each cap, then go to the next one in the progression..

 

You are going to do two thirds of the work to replace the two top tensioners that you have to do to replace the chains & tensioners, top & bottom. Don't be a mug. Change the lot at the same time. I also suggest going to an engineering supplies/workshop and purchasing better quality chains than the 'genuine orignal' parts. The original I6 Jags (1949 to 1992) used a double link Reynolds chain together with decent tensioners, and they used to last a very, very long time. I have never heard of anyone be able to fit such chains to the newer Jag engines and I doubt that they could be without (a) hellish expense & (b) a truly clever engineering workshop. Having said that, I wonder if Jaguar's brief foray into racing with the Cosworth V10 (which also got 'badged' as a Ford engine) might disclose a way of playing with this problem.

Either way, in my humble opinion. it's madness to only change the tensioners at that (or any) mileage. Do the job once, do it properly. Short cuts usually end up being very expensive in my experience.

Cheers,

Languid

 

Thanks for all the help guys...I am going to start it tomorrow. Languid, I do agree with you about doing the primaries at same time, however I'm not based on two things. 1, I don't have the up front money to do it all at the same time, and 2 if the secondaries go, I could be looking at total engine loss with no warning. Primaries will have some sort of warning, in the form of ticking/noise (so I have read and been told). Plus this is my primary vehicle, so the idea of a 3-4 hour job vs a weekend battle, the quick job wins. If I ever have to replace anything in the front of engine, I will take care of primaries. Of course, this is all dependant on everything else looking great underneath those valve covers...cars and I don't have great relationships lol. I will let you all know how it goes, wish me luck!

 

Luck!

This really isn't a bad job. After you have done it once you will want to help a friend fix theirs.

 

@ Languid, there is an upgrade to the chains, by using 4.2 chains and cogs, simple. The later chain design is a silent, morse style chain, a lot heavier built. It was used on the very last 4 litre engines in XJ/XK around 2002/3.

@mbw - if your going to do the zip method, make sure you mark the cams against something, timing is critical, so double checking before you button it up is always good practice, good luck.

 

seanB ,quick question,, you have 2002 jag, why does it need a 100 restoration??

THX Ron

 

Ron good question, salted roads, a flood, a new bodyshell from Jaguar, an insane justification that it'd be worth doing. The result is better than new in all respects.

 

the word obsession comes to mind.

 

Or its close relative ... obsessive/compulsive

 

there are drugs for that,. heh heh