I thought that I had blown a head gasket but on removing the head discovered that the exhaust camshaft was in two pieces and some of the valves were bent, much crying into my tea. Now do I buy a later model used engine, say a 2006 . While unknown, would have the bigger engine ( would it fit the same as a 98, and what about the ECU, ECM) Do I get a rebuilt head and replace all the chains and tensioners etc. as I was planning, this way I would have a known product but a smaller engine with one camshaft already breaking on me. Cost wise it's pretty much a wash time you count gaskets, chains and labor. Part of me say's one way and the other side say's the other. I would love the thoughts of the forum with members that know these cars inside out.

 

Going to a 4.2 over a 4.0 is not for the faint of heart. The systems connection will be a very, very difficult. The engine is not a plug and play unit.

 

Sorry! Do you have any idea what led to breaking the cam?

Jaguar used an AJ26 engine for the '97 - '98 model years and made significant changes for the '99 - '02 years as an AJ27 and more changes from '03 to '06. While it is possible to bridge the model year changes it comes at significant cost, very significant cost if you are paying someone's labor.

If a rebuilt head would solve the issue that is going to be the most cost effective solution.

 

Thank you both for your imput

 

Are you saying that even a 99 to 2002 requires to many changes, just nervous of the other camshaft. I have no idea why it let loose. I have the top tensioners changed about a month ago but can't see how that would have affected the camshaft. It seems getting the head would be the best way.

 

Provided the combustion chambers are intact, a rebuild is going to be the cost effective choice.

An upgrade will probably cost more than the value of the vehicle.

Graham

 

Yeah, the AJ26 to AJ27 involved significant changes from cams to flex plates and sensors and ECM and harness.

Do you know if the tensioners were changed using the zip tie method? It is possible to break the cam by tightening the cam caps down unevenly.

 

Test Point, I assume you mean that by either removing and/ or replacing the caps with the cam in the wrong orientation, or by tightening incorrectly, it may have cracked and finally failed. This would certainly be a reason for a lawsuit against the shop that changed the tensioners, although it would be hard to prove.

 

I supposed that's possible but I have driven it couple ofl hundred miles since then and no way to prove it anyway, repair rebuild it is. Thanks again guys.

 

Yes it was done with the zip tie method, but again tough to prove, and a lawyer would cost more than the repair, maybe more than the car.

 

Agree on the rebuild- you get to sleep better knowing that you KNOW what is going on inside versus hoping.

 

I would pull the engine and tear it down. If you have bent valves you almost certainly need a few new pistons and I would want to check the rods and cylinder walls as well.

If your cylinders are scored I think you will need a new engine if it is the original nikasil engine. If it is iron lined you may be able to rehone it.