Anyone know what the Jaguar rebuild policy or spec on genuine exchange engines (Nikasil issues) was - I have documents to show that my original 1997 engine was replaced in 2003 after failing the blow by test. The replacement engine is a 1998 unit, from the engine number. I am interested to know whether Jaguar exchange engines had other components changed under the refurbishment such as the cam chain tensioners. I am thinking that third generation metal tensioners where available in 2003 I think, although I guess it depends when the 1998 engine was refurbished.....Anyone know? Thanks, Allan

 

You really ought to just simply pull a valve cover and have a look to be 100% sure. My 2002 XJR, was supposed to have the updated tensioners, per Jag per the vin#, but did NOT. I had also called a local independent Jaguar "expert" who had told me I would have had the updated tensioners.

They were both wrong. I'm glad I checked for myself. Mine were orange plastic and both were cracked.

The only way to be sure is to check for yourself. Too important to trust the dealer.

 

I replaced my XJ8's plastic secondary chain tensioners this weekend. both were badly cracked. See my post Secondary Tensioners - I was on borrowed time!
So check yours ASAP!

 

The zip tie method is surprisingly easy.

1. Remove airbox and intake tube
2. Remove valve covers and spark plugs
3. Remove fans (2 bolts and 2 elect connectors) not necessary, but very easy and makes access to turn crank pulley very easy
4. use socket on crank pulley to turn cams to all flats up so there is no pressure on the cams

5. use a zip tie or 2 to tie timing chain to sproket
6. slowly and evenly un torque bolts holding down cam (leave the rear ones loose but still attached so the cam doesn't roll away
7. unbolt and simply lift cam, slide out tensioner, slide in new one and bolt down.
8. assemble in reverse order as above.


Use a electric drill to drive sockets on the valve cover, etc, this will save you a hour of labor.

Here is a video of the hardest and scariest part: Easy as pie:
https://www.jaguarforums.com/forum/j...sioners-96803/

 

I used the zip tie method to replace the tensioners this past weekend. I did not need to remove the fans. Took me about 4 hours due to various non related stops I had to make. I replaced the plugs at the same time.

 

I've read that Jaguar outsourced the refurbishment of returned Nikasil engines and then held them in stock against future warranty exchanges.

This seems logical to prevent disruption to the Bridgend production line but does raise concerns about exactly what was replaced during the rebuild.

It also means your replacement engine, supplied in 2003, could have been in stock for some considerable time. Therefore very unlikely that it had third generation tensioners fitted as part of the refurbishment.

As other have recommended - pull the covers and check exactly what tensioners you do have fitted.

Graham

 

Thanks all, good advice, I'll pop a cam cover and look. Many thanks, Allan

 

OK, I took the right hand cam/valve cover off the engine tonight to see what upper tensioners I have. It appears that I have second generation platstic ones, different design, Yellow, couldn't see the cut-out/notch that causes all the problems starting the crack and break up in the first generation ones. Mine are yellow and look to be in very good condition and very clean too, as was everything else under the cam box cover. I am thinking that I'll upgrade to the latest ones at some point, I noted that you can pick up a pair for £75, free delivery on ebay from one of two jaguar specialists. I am no longer in a rush to do it looking at the second generation and the condition of them.....what are your views - leave or change and why? Thanks Allan

 

I think you have first gen tensioners - second were reddish. Change them out. Better safe than . . ..

 

I have a HL for sale and was wondering if there is a sale section?

 

Oh, I thought the first generation tensioners were reddish and the later ones yellow then Aluminium.......Allan

Jaguar V8 Secondary Tensioners - Preventive Replacement

 

You may be right, either are bad.

 

Good point Jim, I have ordered a pair of the latest generation tensioners, should have them for the weekend...

Are their many cases of primary chain tensioner failures? Thanks again, Allan

 

There have been no reports of engine destruction with primaries as in the case of secondary tensioner failure, not to my knowledge in here, and considering the amount of units in the USA/WW....if it's plastic, change it.

Jaguar exchange units came as bottom ends, heads, pumps etc off the dead engine were used, along with new seals.

 

Thanks Sean, changing the tensioners is this weekend's job for me....Tell you what though, just working on the engine, taking the rocker box (cam/valve cover) off was a real pleassure, bit long winded and involved first time round, however, having done it once etc.....I really enjoy working on the car. I haven't enjoyed working on a car like I have on this one in a long time - I've done the Triumph Spitfire/herald vitesse thing and built a home grown bike engined locost - but I feel connected to the Jaguar XJ8 like never before.....anyway.... Allan

 

Must've taken off the cam cover on the right-hand side. The left hand side will be a little tougher. The hard part is getting the oil dipstick retainer out of the way. I took a hacksaw cut a groove. Be very careful for the plastic radio fifes a break real easy (good lord Siri!), Plastic radiator hoses Break real easy.

 

Yes Jim you are correct; I took the right bank cover off. Thanks for the tips re the L/H side. I received the new metal tensioners today so am ready for the weekend.....

I have noticed that the left and right tensioners are not direct mirror images of each other as I expected - it looks like that, once installed, the right bank one will have the smaller of the two plastic chain runners at the top whilst the left bank will have the larger of the plastic chain runners at the top....anyone know why - ie why they both don't end up with the smaller or larger plastic chain runners at the top - so they are the same I mean? Thanks Allan

 

Aren't the second generation (yellow) tensioners fine and not prone to failure. I have a set on my xj8 and they look to have aluminum where the cracks formed in the plastic first gens.

Please confirm. It is my understanding that they are fine as they are.

 

Hi WaterDragon, My understanding is that 1st generation (red plastic ones) are bad as they are prone to cracking as you mentioned. That the yellow plastic 2nd generation ones are 'better' (I have these in my engine at 102k miles) however, they were upgraded to the 3rd generation aluminium for a reason (I am not clear exactly what the reason/issue is) and the general advice I have understood is that the plastic tensioners should be changed out as a precaution to 3rd/4th generation Aluminium bodied ones (the ones I have received and the ones I have seen pictures of have aluminium bodies and bolt mounting flanges and cream not bright yellow coloured chain runner shoes/guides. From you post I am not sure whether you have the gen 2 bright yellow ones or the gen 3 aluminim boddied ones where only the cream coloured chain runners/guides, top and bottom, are plastic material..... Allan

 

What is your engine serial number?