3.6 to 4.0 XJR (XJ40) swap

[fergolf]

Hello:

I have the opportunity to buy a 4.0 Jaguar sport engine in good condition, from a 1994 XJ40-XJR. This engine is very rare to find, with 247 bhp, tuned by TWR with new inlet manifolds, uprated cams and a tweaked ECU.

I am thinking of installing this engine in my car, an 1989 XJ-S 3.6 with manual gearbox, so I've some doubts about if this swap is viable. The 4.0 engine comes with his own ECU, but I don't know what other changes must be done. For exemple, about the speedo, fuel or water pump, etc.

Also, I know the XJR was catalysed, and this engine comes from a automatic gearbox car, and my XJ-S is manual and non-catalysed. I know automatic and manual cars have different ECU's, so maybe the ECU that comes with the engine is not suitable with my manual gearbox. But there was another XJR's that they did have manual gearbox too. I don't know the part number of this specific ECU, but sure it will be hard to find.

What do you think about this conversion? Suggestions?

Any help will be welcome. Thank you

[davidr]

Hi Fergolf - an interesting project!
I've no direct experience of what you're thinking of but I'll offer my few thoughts for what they're worth.
I think that a 1989 car will have the speedo sensor on the diff so the engine swap won't affect that.
I'd imagine that the fuel pump will be fine.
The water pump will come with the engine I'd think but otherwise you should be able to transfer your existing one. I'd wonder if the uprated car would have an uprated radiator? It would certainly be a good idea to make sure that at the very least your existing one is in top condition.
I'd also be fairly confident that the engine will physically fit without an issue. I'm not sure about fitting the manual gearbox to an engine from an automatic car but I'd be surprised if it didn't just bolt on.
My suspicion would be that electronics and the engine management systems will be the challenge here.
Keep us posted!

[fergolf]

Thanks, davidr

I agree with you. Water pump is valid the one I've in my 3.6 (EBC8550 part). 4.0 manual cars did have the Getrag 290 gearbox, and my XJ-S has the Getrag 265, but seems there's not problem to cope with the 4.0 power. I think it can be simply plug & play except engine electronic management. I've found the ECU for the manual XJR-XJ40 4.0, but it's very expensive. But is good that at least you can find it.

Another good option (and surely more economic) is remapping the existing ECU. The problem is to find a good specialist that can do this job fine.

I've heard about Andy Stodart (so-called XJRengineer in some forums) or Roger Bywater from AJ6 Engineering, as good options to remapping ECU's. There will probably be more specialists, but I do not know them.

[fergolf]

Hello again:

Well, seems it's not so easy. Besides electronics, I must change flywheel from the automatic car engine to adapt it to my manual gearbox, and I don't know if my current flywheel from the 3.6 manual can be fitted to the 4.0.