I have a 1989 XJS Convertible that needs a new engine.

What are the differences between the 1986 to 1990 Engines?
Where is the engine serial number located and how can I decode it?

I found a good 1986 engine for sale. Will it fit right in to my '89? Is there anything different about the '86 engine that I will have to deal with?

Thanks!
Mark

 

AFAIK they are the same, but some things that bolt onto it may be slightly different, so you'll still need to transfer some stuff.

BTW, how do you know this '86 engine is any good ?

 

I plan to take the heads and pan off the '86 engine so I can do an inspection before I install it into the car. Hopefully everything will check out and all I will need to do it replace the gaskets and install any '89 specific parts.

 

I'm looking for a good book that shows detaliled instructions on how to rebuild the 5.3L V12. Please let me know what books you guys reccommend.
Thanks!

 

This is definitely an engine topic and belongs here, but you might get more feedback by posting in the XJS section. There are at least 3 active engine swap threads going on there now.

 

save the effort. Do a leak down or simple compression test. Since most engines sit for a long time before being used pull the spark plugs and squirt some oil down each cylinder. Crank it over and Re squirt some more.
Now do your compression test with no plugs in and throttle wide open.
If they are all close, chance are excellent you’re ok.
Now drain the oil out of the pan and remove the oil filter. Look for any metal in the oil. Cut the oil filter open. Oops. Slice the oil filter I take a hatchet give it a whack and then use a tin snips to cut it open. Do not saw it open. Then look at the filter. If they look OK don’t risk pulling the heads off. Older timing chain tensioners tend to break. And it’s a $300 part for the newer steel reinforced replacement.
One other consideration The cost a borescopes is down below the cost of one head gasket. Buy one on EBay and inspect not only the 12 cylinders but about a Thousand other things. I promise you you will be glad you did.

 

don’t rebuild. Buy a good used one. Lots of Jaguars rust before the engine is junk. In fact unless you know there is something wrong I really don’t recommend rebuilding one. I’ve taken more than 50 apart and only 2 were damaged. One the oil filter was loose and he drove home without oil. The other there was a lot of trash between the A/C and radiator and ignored the temp gauge

 

An '86 will have Lucas ignition. Your '89 car might have Lucas or Marelli.

I mention this only because a non-Marelli engine might not have the mountings for the crank and flywheel sensors. Just something to research. Or someone here will probably know. And the balancer on Marelli engines was different as well, I think.

Cheers
DD