OK, I have a quandry....

I've recently bought my first Jaguar or more accurately a Daimler Super V8. It has a full Jaguar history and 93k miles but despite my best efforts calling almost every dealer it was ever serviced by I was unable to check whether it was affected by Nikasil + tensioners + water pump etc so given it started fine and run silently I decided to take a chance.

The good news is:

The car starts first time every time
There is no rattle from the tensioners or any other noise
It drives beautifully

However:

Compression is 100-115 PSI on all cylinders (post flush). Was just under 90 beforehand. In both instances the measures are pretty consistent.
The tensioners are amazingly the original plastic ones and have no cracks

So my quandry is:

With this mileage and the fact the car runs/drives/starts well and I intend to keep it is the compression something to worry about?

My very trustworthy mechanic suggests it is not worth doing the tensioners as there are no cracks/noises/rattles etc.

What do you think? If the compression was OK for the age of the car and mileage I'd be inclined to get it done.

Thanks

Chris

 

Do them, my xjr had only 50k miles on it and a full service history from the dealer. I decided to change the tensioners even though there were no signs of sounds. I am glad I did, I had small cracks forming on the secondary ones and some substantial ones present on the slipper guides. if you want to keep the car change them all.

 

+1 get them done!

 

It puzzles me. You know the tensioners are original plastic ones,.....that means that the cam cover(s) was open. When it was open (and assuming you paid for someone to do it), why not get the upper tensioners (they are CHEAP!) and pay few more bucks to swap them right away? It's a piece of mind for cheap.

Nicasil is a non issue. If the engine was affected by the sulphur, it would've been gone by this mileage.

 

Does it burn oil?

 

Welcome to the forum Chris!

You might want to stop by here New Member Area - Intro a MUST & say a few words as well.

So you have two issues, question is which one to tackle first....

If my understanding is correct, cylinder compression in a supercharged engine also depends on the amount of boost the supercharger delivers. i.e. a S/C engine running 15PSI boost will show higher cylinder compression than one running at 7PSI.

I would get a boost gauge on it & see how the supercharger is performing, might help narrow things down a little.

A full leakdown test to show the sealing of the piston rings & valves, is also a must.
I get the feeling the compression test alone doesn't tell the whole story.

What exactly was the "flush" you did? Terracleaning or something else?

Now regarding the tensioners. Have a look at this X308 Sovereign for sale in Germany
Google Translated Autoscout Advertisement

Beautiful car, wonderful condition, someone obviously took care of it.
But the chain tensioners went, & now it's selling for peanuts...

Up to you...

 

Thanks all. You have convinced me to do the tensioners (I guess worth doing them all?).

I suppose my reticence is only whether the engine was any good but if it is running fine and Nikasil really isn't an issue any more then I am worrying unnecessarily?

If the compression had come back as 125PSI on all cylinders I'd not hestiate for a moment. It doesn't use any oil but then the mileage has been pretty low in the last four years.

Any other views?

Thanks

 

I would just do the secondaries. The primaries will not cause a catastrophic engine failure and add a lot to the labor.
You could have some damage to the nikasil liners, a leakdown test will answer that question.

 

Yes, secondaries only. Couple hundred for parts, and ZIP tie method (one lazy afternoon of your own wrenching - EASY to do!). Nicasil? One can of Engine Restore, and the engine will last untill you get tired of the car.

Nicasil WAS a problem in the past. Not any more. But public has a long memory, and people are scared of these cars (just the way I like it, so I can buy them cheap!).

 

The secondary tensioners crack on the side you can not see with the installed. Mine looked fine at 89K miles but when I removed them they were cracked on the back side. Using the zip-tie method they are very easy to change

 

If you all had seen what my chain guides looked like after only 50,000 miles, you would be telling him to do the entire job. I had this same though to only doing the secondary ones but am glad that I decided to take the extra step. My car had a pampered life and never missed an oil change, if you want to keep the car my vote is the entire job.

 

Oh, I agree whole hartedly! If one is planning to keep the car for a VERY LONG time, one should do it all. Some people want to be "on the budget", and changing the secondaries only, will at least eliminate the disaster. But if one wants to have a problem free car, one SHOULD change it all (and by all, I mean ALL known issues with X308, to include thermostat housing, water pump, and even the A drum in the tranny!). Of course one can go in stages, and spend money when needed (if needed). Secondaries are a PRIORITY, the rest can wait until the problem presents itself (if the money is a concern).

 

He has a Super v8, so it has the same set-up as the XJR, this car does not suffer from all the same issues as an XJ8 for example no A drum issues in the tranny. If you are already pulling the valve covers off (needs a new gasket), I would simply take it one step further and finish the job in one shot then have to do it twice.