Renix engine into a 2000

Sorry if i missed something on my search, but i need a quick answer. Trying to help a friend get his 2000 cherokee running again. Lost the oil pump in it and froze the bottom end. Its a 2000 sport/4.0/auto. Another friend of mine has an 89 MJ eliminator, with a 4.0 auto. The engine in this truck has only 42k on it. From what I have gathered, To make the engine from the MJ work well in the 2000 he would need to swap the 2000 head, intake, and exhaust onto the 89 short block, is this correct? I read that there are differences in the cam profiles to cover the emissions when the eliminated the EGR, so should he also use a 2000 cam? Can he get by with the renix head? I read that they raised the ports by 5/8 of an inch, can the renix ports be made to work with the 2000 manifolds?

seems like getting a junk yard motor of the correct year would be way less hassle and time consuming

I don't think the ports can be made to work with the manifolds. Easily.

Best bet would be to swap out the short block (since that's what's wrecked anyhow,) and swap the cam if you're subject to the Air Police (being in Iowa, I somehow doubt you are.) Easiest way to handle the project, methinks.

That will also save you having to adapt the later accessory mounts to the earlier intake manifold - AFAIK, the mounting for the block bracketry did not change.

Just too bad you're so damned far away - I could really use an MJ...

This particular MJ is up for the chopping block because the unirail coming out of the cab on the drivers side snapped in half from rust..............

You DO know about the great propensity for the 0331 heads on 2000/1 to crack. And apparantly some of the heads were replaced under warranty with welded ones. Check for milky condensation under the oil fill cap.

winterbeater said:

You DO know about the great propensity for the 0331 heads on 2000/1 to crack. .......

Click to expand...

This is talked about much more than it actually happens. The main contributors to head cracking are lack of routine maintenance and vehicle abuse. I have 100,000 + miles on my 2000 with no problems.

Tim_MN said:

This is talked about much more than it actually happens. The main contributors to head cracking are lack of routine maintenance and vehicle abuse. I have 100,000 + miles on my 2000 with no problems.

Click to expand...

Many, many reports of cracked heads, and also porosity/cracks in cylinder bores in 2000's. What king of "routine maintenance" prevents heads cracking? Don't drive when overheating, sure, but oil changes and tune-ups don't stop heads from cracking. If you research it more, you will see that it was so prevalent that dealers were using welded heads to get vehicles through the warranty periods. I'm not saying that every one will crack, but if I ever shopped for an XJ again, it would be pre 2000.

As for the short block swap, will there be a slight misalignment of the coolant passages Renix block to HO head? I've read of some plugging to get them properly sealed.

If at all possible, I'd use the later model head/manifolds. More power. As for the cam, IIRC, the Renix cam actually makes more hp. The later cam has more overlap to allow exhaust gas to remain in the cylinder and act as an inherent EGR. The Renix cam is reputed to be stronger. What made the HO better was all in the head and manifold - those raised ports covered up the loss from the cam.

Again, if the Air Police require certification, you may actually get failed for using the wrong block in the worst case. It's a non CARB combination, I doubt most would notice, but some seem to be real sticklers.

winterbeater said:

Many, many reports of cracked heads, and also porosity/cracks in cylinder bores in 2000's. What king of "routine maintenance" prevents heads cracking?

Click to expand...

Maybe I should have wrote preventative maintenance, as in, replace it before it's broke.

My Cherokee gets:
Fresh coolant and thermostat every 3 years/36,000 miles
New radiator cap and fan belt at 50,000 and 100,000 miles
New mechanical fan clutch and new radiator hoses at 100,000 miles

I think there is much more talk of cracked heads than actual cracking. I also think that abuse in the form of lack of routine (low coolant levels) and preventative maintenance is the greatest contributing factor to 0331 cracking.

If it was lack of (preventative) maintenance, all years would have the same rate of failure. The head is inherently flawed. Maybe the casting molds had thin spots or maybe knocking them out of the sand too soon before enough normalizing occurred. But hey, that is not a reason to not use your good preventative measures and hope for the best.

Won't there be some difference in a Renix engine and a 2000 for mounting points of the accessories?

joe_peters said:

Won't there be some difference in a Renix engine and a 2000 for mounting points of the accessories?

Click to expand...

Yes and no, you'll probably have to modify the timing cover mounts, but everything else should work. If you're mechanically inclined enough to replace a whole engine, you will be enough to figure out the small bracketry problems.

and yeah, a RENIX cam will be an upgrade from the HO cam, as others have said the later cams have more overlap to eliminate the EGR valve.

5-90 said:

I don't think the ports can be made to work with the manifolds. Easily.

Best bet would be to swap out the short block (since that's what's wrecked anyhow,) and swap the cam if you're subject to the Air Police (being in Iowa, I somehow doubt you are.) Easiest way to handle the project, methinks.

That will also save you having to adapt the later accessory mounts to the earlier intake manifold - AFAIK, the mounting for the block bracketry did not change.

Just too bad you're so damned far away - I could really use an MJ...

Click to expand...

wait.... do what with the cam because what about Air police?

Djmack said:

wait.... do what with the cam because what about Air police?

Click to expand...

In 1987, when the thing came out, it was saddled with a (wholly unnecessary) EGR system.

For 1991, when ChryCo took over design work, the EGR system was (properly) eliminated. It isn't necessary on low-compression engines, and I've got reports that say it runs cleaner without the thing than with (not my test - CA Air Police tests. The only point of mechanical failure was the EGR valve, and emissions were damned near zero.)

Quite a few people think it was due to changes in the camshaft profile (done to promote exhaust gas reversion, thereby accomplishing what the EGR did,) but there wasn't any change in the cam until 1995/1996 - when OBD-II hit. There were slight changes to duration (and, I believe, overlap) at that point.

If you're subject to the Air Police, swap out the short block, put the 2000 cam in the RENIX SB, and install new lifters. That will give the same cam profile (which is ground to get along with OBD-II controls.) I do not believe that the OBD-II cam was much different from the RENIX grind, so you may not even get a CEL/MIL from having the "wrong cam" in there - OBD-II can sometimes tell when the cam is wrong for the design, and that's what gives OBD-II aftermarket cam designers fits (and why so many cams say "Not for use on Computer-controlled vehicles" or "Not for use on Emissions-Controlled vehicles.")

That's what I was trying to say. Putting the RENIX short block under the OBD-II top end should allow you to do the swap with minimal work - since all of your trouble seems to be in the short block anyhow, and it would save you the trouble of adapting the OBD-II stuff to the RENIX head and/or manifolds. Problem solved!

Thanks for the info!!! That is exactly what i was trying to tell him to do, swap only the SB, but he was concerned with expense of gaskets. SOOO i guess ill just buy the gasket set and trade him for his renix head and injection for spares for my 87

lol, i guess i just asked the right question