Hi to all, I had my secondary chain tenseners replaced, when I picked the car up my machanic said it was still tapping when cold. He said the tapits were probably worn causing the slight tapping when cold . Do to a recent illness I wasn't useing the car so my son boughed it. Now it's tapping as bad as before the repair. I've only put 10,000 miles since repair any sugestions or could they be bad that fast.
Thank for any help, Pop

 

Pop,
There is a vast amount of information on this forum regarding the tensioner issues with these cars, as I am sure you know. I doubt that the "tappets" are worn, as that is a term I relate to rocker arm valve trains. Our cars use shimmed cam followers that rarely need adjustment once set. My particluar experience led me to replace the timing chains, as I developed valve noise after replacing only the secondary tensioners. I was doing the job myself and ended up replacing everything... primary, secondary chains, tensioners and guides. I learned about this forum just after completing my DYI project. Sure wish it had been before!

I was pretty sure it was my drivers side secondary chain that was causing the noise, so wanted to simply change it, if I could. At the time, I inquired about secondary chains with a master link but could not find one. The Jag mechanics at my dealer were a bit concerned about using them even if I could find them. I have now read a few posts where people have used that type of chain. (I shudder to think about a link failure , mind you)

Obviously this is only a possible suggestion regarding your issue, but the chain replacement cured the valve ticking for me when new secondary tensioners did not. A set of master link secondary chains would be much easier to install than doing the entire job, but I guess it depends on how far you wish to go with it. I am not sure how highly regarded that type of chain is, but if you have the noise isolated to one bank, it might be an option.

From your post, it did not sound like you went the DIY route, so you might want to find a mechanic that does not suggest worn tappets to investigate a bit further for you. If you don't mind the expense of the complete replacement, that would no doubt be the best fix.

Just my 2¢ worth.

Good luck

 

Replacing the secondary tensioners will not fix the tapping noise if it is the PRIMARY tensioners that have failed. The long curved tensioner guides will bounce around and make alot of noise if the lower tensioners fail.

I know people on this forum will tell you that the plastic primaries cannot fail but I have replaced several under factory warranty when I was at the dealer when these cars were introduced.

The metal retainer and 'O'ring in the tensioner body fails and the oil pressure will not keep the tensioner 'loaded' against the chain guide.

When the cam cover is removed the tensioner guide rail can be pried back and forth with a long bar to determine if the lower tensioner has failed. The hydraulic pressure should be retained for a while after engine shutdown.
The newer metal body tensioners have 'ratchet-teeth' that have a mechanical lock.

If all tensioners and guides have been renewed, then the lash should be measured for each valve.

Piston 'slap' is one of the last things to consider but there was a supercharged XJR 4.0 in the dealer shop years ago for a noise that could not be cured with chains, tensioners, a cylinder head etc.

It was finally determined to be 'piston-slap' and a replacement engine was fitted.

Keep diagnosing!!

bob gauff

 

Bob,
What is your opinion on the secondary chains with a master link?
I was really tempted to try that route before ripping the front of my motor apart!It would have been a quick fix. In the end, I got peace of mind and a quiet engine.

I only suspected my secondary chain, but maybe it was the primary tensioner. Since I did replace everything, I guess I will never know for sure. My primary tensioners looked to be in excellent condition, but your description suggests that they could look brand new and still be faulty. I have seem pictures of them with splits on the side. Mine "looked" good.

 

The primary tensioners don't usually crack but the 'O'ring on the 'piston' in the metal barrel fails and the bottom of the 'O'ring holder breaks off. I found 2 primaries with this fault.

The only master link I have seen is for a Mercedes oil pump and the link must be 'peened' in place. The link has no clip like most master links.

It will work fine if the link is properly installed.

bob gauff

 

Many thanks to all that responded. The tapping is only on the drivers side now when I had the secondaries changed the tapping was on the passenger side. I failed to tell you it's a 1998 XJ8 4.0 engine. This forom has not only saved me money but has given me peace of mond that I'm not getting ripped off by my machanic.
Thanks again,
Pop-

 

i have a 98xj8 replaced all primary and secondary tensioners, guides and seals for vvt. Had a rattle and guides were cracking. I now am having a low oil pressure issue at idle. I already dropped the pan and cleaned it and the oil pick up (found some debris) oil pressre starts at 25psi or so and then after running for 15-20 minutes drops down to 5-8psi. no engine noise. Any thoughts?

 

Lots of thoughts, mainly about crankshaft bearings. How many miles on the engine? What weight oil? You can easily use 10W 40 in the Atlanta area. That oil gauge is not accurate, but if it reads low I would tend to believe it.
RJ__________
97 XK8 86K mi

 

You should probably start a new thread about your oil pressure problem. More members will see it that way.
RJ