Engine Swap

I have a 90 xj with the 4.0l renix. I just picked up a 4.0 from what I was told to be a 96 but I'm not sure how to find out what year it is for sure. It has no accessories, but the oil filter mounting has the long tube that sticks up from the mounting bracket. any help would be great, i tried searching but couldnt find what was changed overs the years.

The blocks are pretty much interchangeable throughout years. You might have modify a later block to accept the renix knock sensor. You'll have to use the early flywheel, and all the renix sensors. I think you also have to swap in the old distributor, but I.m not sure about that. Depending on how "new" the engine is there may be a mis-fit on the exhaust manifold(96 should be ok)

Alternator, distributor(and its related cam sensor), and every single sensor need to be swapped from the 90. In order to use the HO's intake and TB you will need to adapt the Renix TPS to work with the TB, and you will lose the EGR system. If you want to keep the EGR, you need to put the Renix's head and intake onto the 96 block. The block may or may not have a hole for the knock sensor, either way, it will need to be drilled and tapped if you want to keep this sensor operational. The HO does not have a hole in the block for the Renix ECU water temp sensor, but this sensor should fit in the HO's thermostat housing, assuming this part is the same as a 91-95. I am unsure at which year the gauge temp sensor in the head went away, but that could also be an issue if you are using the HO head and it does not have a hole for this. With either intake manifold, you want to use the Renix fuel injectors, as all of the HOs have a higher flow rate. Since this is a 96, I believe it has the returnless fuel rail, so the Renix fuel rail would need to be adapted to fit on the HO intake if you go that route. If the fuel rail has an intake and a return line, then this is a pre-96 and will work with the Renix fuel system with minimal mods to the fuel lines. The Renix intake manifold does not line up entirely with the ports in any of the later heads without modification to the head.

The easiest way would be swapping the head/intake from the Renix over to the HO, this avoids many issues. Just swap all of the sensors and accessories over and it should work. The only viable alternative is swapping the entire vehicle wiring harness and computer from an XJ of the same year as the engine.

I have a 1993 engine/trans/tc in my Renix. I am using the HO intake manifold/TB as well, but I have never adapted a Renix fuel rail to a manifold made for a returnless system.

You can just swap intake manifold from the Renix over without no trouble. No need to swap heads.

sure, it should run, it would just be wrong. The injectors are firing in the wrong spot with the Renix manifold on the HO head. There is some mod involving grinding of the locating pins to move the intake up to a better spot for this head, the HO's intake ports are 5/8" higher than the Renix's. Whether you swap the head or not, you will not have an engine running at 100% potential.

So the best way to do this with minimal fuss is swap in entire engine including its intake.take out old engine and set aside. pull donor engine including head nad intake. Put in original vehicle. use original harness and sensors, adapt to donor engine.

Wallyman said:

So the best way to do this with minimal fuss is swap in entire engine including its intake.take out old engine and set aside. pull donor engine including head nad intake. Put in original vehicle. use original harness and sensors, adapt to donor engine.

Click to expand...

Indeed.

well I dont have the intake I just got the motor w/o accsories but I think it was a renix system b/c the t-stat cover is the same as mine, plus the oil filter has the long tube sticking up from the threads.

Could be an early HO. I just bought a 92 HO from the JY today to put in my wife's 88 Cherokee. We' ll soon see if there is the need for such a fuss about changing the intakes. I'll keep you all informed.