Jaguar Mk2 2.4 - Replacement Engine Question

[neil4444]

Hi all,

A friend of a friend has a 2.4 Mk2 auto which requires a new engine. The car is in fairly average shape & owner doesn't want to spend too much money. I know nothing about these cars but was wondering what a suitable replacement engine might be. Would it accept any XK engine and if so up to what date ? Would power be an issue too (e.g. would 4.2 be too much for it to cope) ?

Appreciate any advice !

Cheers,

[288gto]

"The 2.4 was derived from the 3.4-litre XK units, with the drop in capacity achieved by chopping an inch off the top of the block ? rather than narrowing the cylinder bore.

The result was a shorter stroke (down from 106mm to 76.5mm), over-square engine that was lighter and more free-revving than the one it sat below in the range.

The icing on the cake was Jaguar?s decision to fit an E-type style straight-port cylinder head, twin 1?in carburettors and a water-heated inlet manifold."

In theory, a relatively cheap later xk engine should fit, maybe even a n xj6 carburettor one. I know I've seen complete running early xj6 engines complete with auto boxes going for under ?500 when I was looking for the later big valve 4.2 heads.

Simon

[tinworm]

I know someone with a 2.4 unit if you want another.

regards Barrie

[neil4444]

Thanks for info Simon.
Hi Barrie, please PM me with details (location/price/etc).

Regards,

[Dawnpatrol]

Neil doesn't say if the car is a 2.4 or a 240. The straight port head was only introduced when they went to the slim bumpers and the 240 designation, circa 1967 I think.
The inlet manifolds would therefore be different, the early cars had downdraft Solex's IIRC.
Personally I would try and find a complete 3.4 engine, a bit of extra power, even the 240 was struggling with the top of the rice pudding. I learnt to drive in one!
If you went much bigger (heavier) I'd be thinking about having to change the front suspension springs.
A 3.4 upgrade might add a bit of value to the car as well.

[christopher storey]

The fact that it is an automatic car militates strongly in favour of putting a 3.4 engine in, because the 2.4 really struggled with the Borg Warner box whereas the 3.4 gives quite acceptable performance. Almost any XK engine will fit, although it may be necessary to change oil filters, sump and/or engine mountings if the engine has not come from a mark 2 of some kind, and of course if it is the solex carburetted version, then you will need a new manifold and SUs to fit any of the other engines. However, something else to consider is that if you put one of the larger engines in, then it is ( virtually ) necessary to raise the final drive ratio as the 2.4 IIRC had a 4.27 final drive

[paulsco]

Hi Neil,

I?m assuming from your description that it is a Mk2 that your friend has and not a 240?

As has been mentioned the 240 and 340 have a straight port head, like the 3.8 and 4.2 E-Type.

The Mk2 2.4, 3.4 and 3.8 were fitted with the B type head.
The problem occurs with the inlet manifold and radiator , which is different.

If the current engine has the B type head then fitting an engine like a 4.2 will not be a direct replacement.

The radiator on the 240 and 340 is different from the Mk2; the top hose is at a different angle.

What I am trying to say here, is that if you have a B type head it is far easier to stick with a Mk2 2.4, 3.4 or a 3.8 S type engine. If you have a 240, you have more choices in a straight port engine, although the sump and oil filter housing may also need changing.

Going from automatic to manual also has its own set of problems, though I have done this successfully myself on my own 340.

Paul

[paulsco]

Forgot to mention; He may also need to up-rate the front springs if he goes for a bigger engine.

Paul

[JEP41]

If going to a 3.4 or 3.8 litre upgrade the diff will need replacing the 2.4 is a lower ratio another reason to stay with the 2.4 if a budget is in place?