Will an XK140 engine fit into a 3.4 Litre Mark 2 saloon?

Hello all, I have a friend that is thinking about putting an XK140 engine into a 3.4 Litre Mark 2 saloon. If he got a Mark 2 sump instead of the XK140 sump is that basically all he needs to do? I wonder if there are issues with the coolant hose positions. Thanks in advance, Gary

Is he just replacing the short block or does he not have the original engine?

Sorry, I should have said more detail. At present he has an inline Chevrolet six cylinder in the saloon and wants to have a complete Jaguar engine. There is available locally a freshly rebuilt XK140 engine. I know the XK140 engine to a degree but that is not the case at all with Mark 2’s. Thank you

Possibly the engine mounts might be in as different position but seeing as there is a foreigner in there it might be a moot point.

Robin, Thank you for that insight about the possibility of a different engine mount position.

I’m guessing that would apply to many questions, such as cooling hose locations, overall engine length for engine/radiator location, etc, as many things may have been tweaked (changed) to make the foreigner comfy while it was visiting.

It’s a 3.4l XK engine and so it should fit.

Ancillaries such as sump, oil filter housing, carburettors and inlet manifold, water pump, etc etc would need to be sourced, which may not be either easy or cheap…

As it’s an older design it has a scroll rear main seal design, which isn’t ideal.

I’m sure there are other things I’ve missed.

Overall, there’s a lot to think about, and potentially a lot of additional cost.

What about the transmission ? Would your friend also not need to source a Jaguar compatible transmission ? ditto for rest of drive train. Your friend needs to get the Big Picture as to what he now has in the car and what would need to be replaced.

Thanks all for your help here: Schmitty, I must ask about the gearbox and many other things need to exorcise the Chevrolet engine and, I am just guessing, Chevrolet transmission from the Mark 2. Andrew, you are correct in that the XK140 engine mentioned for sale does not have any ancillaries included. I know next to nothing about the value of Mark 2’s but I think that the cost to restore it back to something more original would have to be observed versus the value of the car. Thank you

Hi Gary,

Length will be identical, but there are many other things to take into account.

I just note: mounts, hoses, type of gearbox, water pump, oil filter, possibly tacho, flywheel, starter to name some.

It will work with efdort but a genuine xk140 engine is worth money for any xk enthusiast that wants a period matching engine, even more in case it is a S spec.

My advice would ve to try and find a suitable engine plus box (plus od) combo that is a direct fit.



Hello Mr. Gimeno, The more items that are pointed out the more complicated this swap may become. I thank you for pointing this out.

Gary, it really depends: there is too little information to say something definitive. Chances are (but not compulsory) that the 140 was mated to a Moss gearbox (+OD perhaps). Does your MKII have a gearbox? which one? An automatic will need more work to match to a “manual” engine (flywheel). But it all depends. MKII experts will know better, but possibly a 140 engine from a 140 with a Moss can directly mate a MKII Moss (although I am really quite sure that it’s a different bell housing).

Since you go for a non-matching (in the sense as not totally original engine-car combination), perhaps a period MK2 with the same gearbox is the easiest option. In case you cannot find it, perhaps a latter XK (even 4.2), with an all-synchro 4 is (since you will be facing adaptations anyway) a better option.

I also think (but this is not your problem) that the person selling a genuine 140 engine is better off selling it to someone needing a period 140 engine

The Mark 2 owner wishes to put back an automatic transmission as it had originally. This Mark 2 is a 1962 by the way and is therefore a 3.8 Litre. Perhaps best to find a 3.8 Litre Mark 2 engine and BW transmission as you have said. Therefore, going forward, I have joined a Mark 2 Facebook group that may yield, as you have suggested, a 3.8 Litre Mark 2 engine and BW transmission as an assembly. Thank you all for the advice and I see now there are many variables between the two models. Besides the fact that ithis Mark 2 really should have a 3.8 Litre as fitted from the factory.