Well I'm underway with my restoration of our '62 mk2 3.8auto. it's been standing in a barn for many years and the engine is seized. Last week we removed the engine and transmission and have now stripped the engine to find one cylinder rusty and the piston will not move. looks like it had a head gasket failure many years ago and so it was left. What I'm now considering is a complete engine / transmission swap (xj6 maybe). Anybody got any advice ?
I think a trip to see Tom at Coventry Classics(Orlando) may be a good idea (thanks Jose for the contact details).
There was also the remnants of a timing chain tensioner pad in the sump, so it looks as though it's had timing chain problems previously, although they are all intact now.
Any thoughts and advice appreciated.
Mike

 

Mike


I had exactly the same problem but with three pistons stuck, I therefore made the attached device on the basis that either the piston will move of the housing will crack. If you are thinking of changing your engine as a solution to your problem this may be a cheaper solution. Basically this is a block of Aluminium machined to about 30 thou smaller than the piston with a recess for the top of the piston for the bulge and then hit with various sizes of hammer till pistons eventually gave up the challenge and came out


Once I removed the old pistons I had the head skimmed and all piston bores machined and ended up only 20 thou oversize so well within limits and fitted new pistons

 

XJ saloon 4.2 litre engines suffer from their own problems not found in the 3.8 engine. Long stud engines in particular crack between the bores, so I wouldn't give up on this engine just yet until you've got it all in bits, and have examined them all. As a linered engine there are only so many rebores you can do, so check piston sizes. The best XK engine was the original 3.4 litre; the 3.8 was a fairly simple development of that.

 

geez I agree the 3.4 liter engine is the "sweetest" of them all. It doesn't run as hot as a 3.8 which is essentially an over-bore of the 3.4.

sure, 3.8 sounds better than 3.4, but let me tell you, having driven Jags with both engines, I can say there was not a giant difference in horsepower, but it sure reflected in the temperature of the engine compartment and the interior of the car.

hey, I'm no expert in engines, I leave that to the EXPERTOS, but for my taste, I would prefer a 3.4 now that I know what I know.

 

If the 3.8 litre is the original engine, I'd be trying to rescue it and rebuild that to use again. I'm not a purist like many out there, but for future resale if you have the option of keeping it the original motor, resale value will be greater or at least easier to sell with the correct motor.


If it isn't a matching number engine, then don't worry about it and change it out.


However a fresh rebuild with some oversized pistons, and new bearings etc would be the way I'd go, peace of mind future motoring knowing its all new, a good motor balance/blueprint and 3angle valve job and head port too would be a nice little way of netting a few extra ponies, you know, "while you're in there".