I had a blown head gasket so I am using this opportunity to go through the entire top end of my 2000 XKR, including tensioners, water pump, etc... . I've read throughout the forum the advice to use the 4.2L head gasket instead of the 4.0 gasket. I also received advise to use the OEM Jaguar 4.2L gaskets (part no. AJ88987 and part no. AJ88988)(not too many places seem to carry the OEM, at least not from my Internet search).

I previously purchased the entire head gasket set for the 4.0L, before reading this advice. The reason everyone advises use of the 4.2L head gasket, as I understand it, is because the 4.2L head gasket has metal or other reinforcement at the critical point (around the piston area), whereas the 4.0L head gasket does not.

I dug out the 4.0L head gasket set I purchased. They are Eurospares 4.0L, part no. JLM20751 (entire head gasket set)(first two images). The Eurospares head gasket I previously purchased for this job has a metal reinforcement band around the circumference of the cylinder (see image attached). It looks more reinforced than the OEM 4.2L gasket.

The gasket image for the OEM Jaguar 4.2L head gasket (part no. AJ8-8988) (from XKs Unlimited) (image also attached) does not seem to have the metal bands around the top of the cylinder perimeter. I am not sure if or why I should opt for the OEM 4.2L head gasket.

As yet another option, although I haven't seen the Cometic 4.2L gasket first hand, the images of the Cometic gasket seem to show, and the name implies, that they use a multi-layer-system (MLS). They also sell them in multiple thicknesses (.030, .040, .070). (Ebay ad states: "Jaguar 3.8L / 4.2L V8 AJ33 and AJ35 UK Engine (C4376 Left Side; C4377 Right Side)".

Bottom line, I am concerned about which gasket to use. I'd hate to put all this work into the engine and use an inferior gasket. As a side note I did buy new headbolts. I will also check the head for warpage or cracks. Anyone have any experience with any of these gaskets, or other input? Sorry if I am making way too big of a deal over this. Thanks in advance.

 

The OEM 4.2 are also MLS ones, and are about 0.030 thick. You can't go wrong with these, they are even holding up on my engine ;-). Its very uncommon for the 4.2 engines to get head gasket failures, contrary to 4.0 engines with the composite head gasket.

 

question: I must do a new head gasket for my new 4.8L engine (with holes for 92mm pistons) that will be built by a specialized company. I looked in the block and in the heads that the water passages in the original gaskets are closed. Could it cool off better to make new head gaskets with these open holes?

 

Best to ask your specialized company, I wouldn't do it because you will affect the flow in such a way that the rear of the engines/heads will have much less coolant flow with all the consequences...

RSR did bore little holes there though, which iirc was to be able to release potential micro steam bubbles. As they have sold you the engine, they should be able to give you an advice there as well. I never went that route and choose evans coolant to reduce that particular chance

 

thank you. Tony Gentilozzi was more interested in selling me the engine than to follow this project until the end. The heads gaskets that he sent me are wrong (some holes in the water passage are uncovered). on the advice of Ferlito, I will have them redone with sporting material with the 92mm pistons holes but like oem
I'm using the Motul MoCool product

 

I take it Tony send you Cometic gaskets for a Lincoln ls engine, although very close to ours these indeed do not close of the some coolant holes from the jaguar/Landrover blocks. The partnos above are correct, they have for these stock and 93mm bores available, even different thicknesses.

 

Question for you.
Are you using older 4.0 heads, or AM heads, or did you have your head chambers reworked? See image below.
I still wonder what is the best chamber shape. (Asked this question in the past on the forum.)
Shape effects swirl and tumble and compression..
It doesn't look like your chamber is 92mm, otherwise I would see more room around the valves.
Thanks.

 

they are not my heads. I am a simple image of the web. it was only used to make the issue of water passages understand

 

I See. Thanks.

 

Littledan, I know you pulled the whole engine, but if you only had to replace camshaft cover gaskets, does it look to you like they can be done without pulling the engine?
No matter how long I look at it, it just looks too tight to get to them in situ. Especially with having to pull injectors.
Valve cover gaskets typically aren't a big deal, but this just looks too tight to get to them.