Are the head gaskets on the 4.2 the same as the 4.0?

if not, what are the differences?

 

Another related question is the Lincoln 3.9L head gaskets the same as the Jaguar 4.0L? I would suspect so.

 

The reason i am asking is that i currently have the entire intake system apart due to a leaking driver side intercooler. Im %75 of the way there already, and i am thinking about getting a set of multi layered steel head gaskets made. i found them for a 4.2 and a 3.9 but not the 4.0.

from every thing i can find, its the same but i wanted another opinion...

 

A piece of advice..."if it ain't broke, don't fix it."

Other wise, I have no idea. If the bore was increased to increase the displacement then I would imagine not. However if the stroke was increased for the same goal and not the bore, then I don't see why it wouldn't work.

 

squirrel,

I agree with you. I have gone back and forth from do it, to not do it. about a dozen times.

But at least i would like to know if they are the same. from what i can tell the 2000 3.9 Lincoln LS and the 2000 Jaguar 4.0 have the same 86mm bore.

 

I am not sure what material the 4.0 gasket are (some sort of composite), but the 4.2 are multi steel layered.

The other difference is that the 4.2 gaskets are a little bit thinner, and irrc it would increase the compression from 9.0 to about 9.2 something. Depending on any further changes this could be something to consider, as the 4.0 gaskets are not the strongest, many have failed, versus almost none (only exceptional bases) for the 4.2 gaskets.

I think cometic makes also gaskets for our cars; maybe they could make a slighty thicker metal layered one?

 

avos,

I have been looking at the Cometics gaskets. they only have the 4.2 and the 3.9 listed.
they do not have the 4.0. i emailed them and they said they were unsure if it is or not.

This is what they have listed:
T-bird/Lincoln 3.9 engine. "Material: MLS / C.O.T - .030""
Jaguar 4.2 US engine "Material: MLS .030""

With what you are telling me, it sure sounds like it would be a good idea to just go ahead and do it.

 

The 3.9 is the 4.0. The difference is jaguar rounded up.

 

i got my gasket kit today to re-seal every thing, and it came with a new set of stock head gaskets. they do look a bit flimsy. and i measured it out. They are the same size as the 3.9 gaskets. makes me think squirrel is right.

Also, do any of y'all have any other suggestions on what i should look at while i have the engine out to do this? i am going to use some head studs instead of bolts. Any other recommendations??


P.S 3rd gen tensioner's were already installed.

 

Disadvatange of studs is that you can't take your heads of anymore in situ as long as you can't get the studs out first.

 

That had acured to me. Are the stock bolts the type that must be thrown away after each use? Or can they be reused?

 

They say you can use them twice, not more.

 

But the smart money is on replacing them. You don't want to go in and do it again if one of them fails do you?

 

I agree completely with squirrel, as i have no clue if these are the original, i would/will replace them if i go for the gaskets now.

 

Is there some special mounting points or lift plates that need to be used to pull the engine?
or do y'all have any special tricks?