my 99 XJR arrived with a stack of repair receipts & thankfully one was for dealer installed "upgraded tensioners". That gave me the peace of mind to leave the valve covers on and dive into work I knew had to be taken care of. Now it's time to take the valve covers off for new gaskets and my pan is to check the work on the chains to see how it's holding up and what was actually done. My plan is to change the plugs & install new gaskets if things look ok. If the primaries weren't touched or if the secondaries don't look right I'll order the kit to replace the works and start taking the covers off.
I've found some kits for the valve cover gaskets but when I check fit am told they won't fit my XJR. I though the engines (covers & sealing surfaces) were the same, XJ8 vs XJR. Can someone confirm (or deny) that for me?

 

DW, I believe that the early motors (both XJ8 & XJR) were A26 motors, the later ones were A27s, and differ in several ways, one being the valve cover gaskets.

I think the simplest way to see if you have a A26 or an A27 engine is to look at the solenoids for the Variable Valve Timing units (VVTs). On the A26 engines the vvt solenoids are horizontal to the timing cover, where as on the A27 engines, they are "vertical". (The A26s are single stage operation, the A27s are continual variable operation).

The A26 gaskets are thicker, and colored orange, and gray, the A27s are thinner and are black (L&R)

Don't forget the spark plug o-rings, the valve cover bolt seals, (and vvt solenoid seals if A27).







.

 

Thanks Kid, I think I have the AJ26 just based on my year but will check under the hood this afternoon when I get home. My confusion is really related to the XJ8 compared to the XJR. Both pictures you posted are XJ8's and the AJ26 valve covers look the same as I remember mine looking but I wanted to check and see if anyone knew definitively. I could see compression ratios being slightly different between the supercharged and NA motors but can't see why Jaguar would make the valve covers different.
If my tensioners need attention the kit I found comes with the gaskets I need I just don't want to order that and find out the tensioners look good. My wife tells me (several times a week) that I already have too many spare auto parts collecting in the basement!

 

Important: XJ8 3.2l and XJR share the same valve covers. The 4.0l NA has different covers full stop. The gaskets though are the same between AJ26 NA and AJ26S models. Same as AJ27 NA and AJ27S.

​​​​​

 

I opened the hood and sure enough the old girl has the expected AJ26 lump under those valve covers. The driver's side definitely looks orange and the passenger's side looks grey. Not sure why that would be important but another post I found mentioned that difference side to side. The engine number will remain a mystery until the supercharger comes off as there seems to be no clear view of the back of the engine with everything assembled. Someone in another post mentioned the Ford Thunderbird V8 kit fitting the AJ26 which open up suppliers like Fel-Pro but that wasn't a big seller so it might not make finding parts any easier.

 

The AJ26 engine number is on the top of the block at the front left of center. The orange and grey gaskets are thicker than than the AJ27 and I don't think there is a aftermarket source.

 

There is. SNG sells them.

 

I meant aftermarket manufacturer such as Fel Pro. There are several parts suppliers listing the gasket sets that are not Jag dealers.

 

Well after a bunch of searching I found the correct color gaskets at XKs unlimited. Still not sure why they would be different across the V but I guess I'll find out when I swap them for the tired ones. Now I just need to wait for spring to arrive...

 

And as stated previously, don't forget the spark plugs o-rings and valve cover bolt seals.

 

Yeah, I ordered those as well. One confusing (surprised no one has thought of this confusion) thing is the trouble I had finding anyone selling a comprehensive kit for this application. I found plenty of kits for other engines. XKs Unlimited included the plug seals with the valve covers but the cam bolt seals had to be ordered separately. Fine if you know what you need to order but I'm trying to collect parts and do the job after they arrive without having to start off another order in the middle of the job.

 

Christopher's Foreign Car Parts does a complete timing chain gasket set, pretty sure they do a "complete" valve cover set too. They are extremely knowledgeable and helpful.

https://christophersforeigncarparts....ections/jaguar

(Not sure if this is "permissible" as I doin't think Christopher's is forum vendor......let me know and i will delete/refrain)

 

Hi Carnival Kid, have you used Christohper's Foreign Car Parts Valve Cover Set? If so, what's your experience with them? Are they as good as the Jaguar OEM?
Thanks for the feedback
Dirtboy Nay

 

for North American owners, we have less concerns since we only have 4.0 engine either with or without SC.

 

Hi, Buddy, I just realized you are not far from me. I live at White plains.

I have the valve coverer gasket changed serval times during the ownership of past 15 years. as long as the you the right model year, it should be a good fit. just get the best brand.

 

THERE ARE TWO DIFFERENT CAM COVERS GASKETS FOR AJ26 (plus early AJ27) AND LATER AJ27.

The 'orange and grey' gaskets are for the AJV8 engines TO ENGINE NUMBER 9810290000.
This includes early 1999MY AJ27 sedans and coupe/conv.

The thinner black colored gaskets are for the AJV8 engines later than that.

The XJ8 sedan gives the VIN break for the orange/grey gaskets TO VIN 853935.
The sedans use thinner black gaskets FROM VIN 853936.

ALL bets are off if people start swapping cam covers from different engines so you are on your own if that has happened.

ALL 4.0 SC engines lack VVT so any cam cover can be used on the engine.
The early engine cam covers have a wider groove to use the orange/grey gaskets.
The later cam covers have a thinner groove to use the thin black gaskets.

The spark plug seals are also very different between the cam covers. (joined vs separate)