I'd like to swap a 94 head on to a 90, anybody done this?
Side by side they look identical, but the parts interchange software says no.
That could be for the smallest of reasons though. I actually only need the cams, but i can get the head for a song, so why not just exchange heads.

 

Hey Buddy - long time no see!
The only small reason I could see for them not being compatible is that the 94 cam cover is held down with 13 bolts whereas the earlier head has what? Seven?
So more than likely you'd have to check out te cam cover plumbing and of course the oil filler cap is on the cam cover on a 94 also ...
so good luck with that!!

btw, the parts catalog won't tell you the 94 has 13 bolts and in fact I had the guy at JHT in the UK refuse to sell me thirteen because the parts catalog only specified 7!!


all the best

Larry

 

Hi mrtalkradio,

I don't know if you can use the '94 head on your '90 block either, but a few things to look into would be:

1. The head gaskets are different for the '90 and '94 - why? I know that at some point Jaguar improved the seal around the oil port (the one that leaked above the distributor before the gasket was revised), but I don't what other changes were made and whether any ports, water jackets, etc. were resized or relocated.

2. The fuel injectors on the '93-'94 cars were changed to a dual-orifice plate type. I can't recall if the new injectors were "Peak & Hold" or simple 12V pulse like the earlier injectors, but it is possible that your '90 engine managment system might not work optimally with the '94 injectors. I don't know if it would be possible to use the '94 ECM in the '90 - the O2 sensor and possibly other components might also have to be changed. Here's a link to a little info on injectors:

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3. If your '90 has the ZF 4HP24 electronically-controlled transmission, then it is possible the Throttle Position Sensor (TPS) on the '94's Throttle Body (TB) will work with your gearbox, but if your '90 has the non-electronic hydro-mechanical 4HP22 gearbox, you will probably need to use the '90 TPS, and possibly the TB as well. If you have the 4HP24, then it would be worth trying the '94 TB & TPS, and you could try the '94 TCM as well.

4. I can't remember if the crankcase breather system has different port locations between the '90 and '94 models but you would want to check in case you need to revise some hoses.

5. I think the EGR setup will be the same on both cars, but you'll want to check.


Having said all of that, since it's easier to remove and install just the cams than the entire head, if your head gasket is not too old, it might be worth just swapping the cams...

Please keep us informed!

Cheers,

Don