I know these cars share the same engine as a Lincoln LS and other models, I have a 2003 STR in need of a short block, the motors runs but has a HARD KNOCK. Will a short block work from a N/A S-type 4.0 or a Lincoln LS?

 

The AJ-V8, which is a Jaguar design, is different from the variant 3.9 litre built in Ohio and used by Ford in the Lincoln LS.

You mention your vehicle is a 2003, so you have the 4.2 litre AJ33 that is again different in design and displacement from the 4.0 litre AJ28 used in the S-Type through 2002.

While the engine may fit in the vehicle, it may not work with the other components such as the inlet and exhaust manifolds, wiring looms, etc. It may be far simpler to find a used 4.2 litre unit.

 

http://www.getallparts.com/Jaguar




this website has engine assemblies. check it out.

 

You should be able to use a 2005 and newer 4.2L Supercharged engine as a baseline. The block and head castings are around 95% the same. But there are differences that will have to be adapted. (How they mount accessories on the engine changed over the years.) You will have to sit the original engine next to the replacement engine and drill and tap numerous holes. You will also have to swap to the original engine harness and use the original sensors and accessories (like throttle body, power steering, AC, perhaps the EGR valve... The newer STR engines have VVT, so if you use the newer heads, you will have to adapt the new engine to utilize this feature. (There is a forum posting how to do this.) If you swap and use the older heads, be sure the oil ports and water ports match up. They changed the head casting/chambers slightly on the newer engines. You should be able to swap cams, but then you have to adjust all the cam to bucket shim clearances.

From my perspective, if your donor motor has more than 75K miles on it then I would plan on replacing the oil pump, timing chains, water pump, spark plugs, hoses, especially the infamous valley hose, clean out the intercoolers, throttle body, EGR, change oil in the supercharger. I'd spend an extra $1k on parts to be sure the donor motor will last a long time.

I have an 03 donor STR motor that I recently purchased that I will be working on in the next few months, for my 03 STR with a blown engine.

Whatever direction you choose, don't screw around with a 4.0 or 3.9LS engine. Too many differences.

 

You do have to use an engine from a supercharged R model. The compression ratio for the NA engine is 11.0 to 1 and it is 9.1 to 1 for the supercharged engine. The NA motor probably wouldn't last too long, the internals are probably tougher in the supercharged engine too. Most supercharged and turbo motors are lower compression motors than their NA counterparts. For used parts, Car-Part.com--Used Auto Parts Market has listings from junk yards from all over and would be a good source for parts, or at least pricing.

 

The SC is lower when off boost, but.........

The SC does indeed have internal changes.

 

On the 2003 and 2004 STRs, Jaguar added piston oil squirters and an oil pump that has a pair of crankshaft timing gear squirters. The second generation oil pump with squirters is almost impossible to find, but in 2005 they went with a 3rd generation oil pump for all the 4.2L engines. I am not sure if they kept the oil squirters on the late model SC engines. (I have an 07 XKR parts engine and haven't pulled the bottom of it yet to see.) As stated above, the compression on a SC engine is lower. Pistons only? I have seen several versions of heads where the head's chamber has different shapes. (Another detail I am slowly researching.