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Project Shoehorn - M90 into a 4.0L

Have to ask... Any oiling issues with the compressor on it's side? Other than that and finding a spot for a belt idler, a very interesting solution.

One that, BTW, leaves room above the Jeep intake manifold for an intercooler...

76mm Idler
http://www.jegs.com/i/Gates/465/38041/10002/-1?parentProductId=

Check this page, Gates has pulleys down to 65mm.
http://www.gatespowerpro.com/Comergent/en/US/adirect/gates?cmd=catNavigateFrame&punchInID=600500&CFID=82458306&CFTOKEN=53712714

Hope this helps...
 
I'll have to check what the Gates catalog I have says. IIRC i remember looking at max RPM of the bearings at one time, but I haven't progressed far enough in mine to get in depth yet.
 
I looked at the Jegs link from OGS, and followed it to another product called the "JEGS High Performance Engine Pulley" part #50451, and for the 88mm pulley it specifically lists the 87-01 Cherokee 4.0L as a direct application fit. From that I'd feel safe to assume it can handle the RPM speeds. The space difference between the 88mm (3.464") 50451 pulley and the smallest one they have - a 70 mm (2.755") pulley #50456 - might be the difference between working and not. I also emailed Jegs directly to see if they have a max RPM spec for the 70mm pulley.

EDIT: One note - the 88mm stock idler pulley would spin 9700 RPM at redline while the 70mm would spin 12,200 RPM at redline. It's close, but enough of a difference that I want to get validation from the manufacturer before using it.
 
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Due Diligence. This is what I am seeing here. Getting the Ducks in the corral. Or is it the horses in a row?

At any rate. doing the research and getting it right the first time beats the daylights out of rebuilding due to failure induced by sheer laziness.

Which is why I say that anyone who installs an unknown compressor on his vehicle is asking for it to fail. The concept of "I'll just go to the yard and get another" does not fly.

I am very interested in the end product as I may copy it myself...

After all, the MP90 is good up to 5 litres of displacement whereas what I have (Sprintex S5-210) is actually rated for engines up to 3 litres.

I still maintain that it is better to turn a large compressor slow than a small compressor fast if, for no other reason, than the parasitic loss is less...
 
Found out something interesting today - The throttle body out of an '02-'04 WJ with a 4.7L V8 is 68mm (with a narrowing around the butterfly to 65mm). That is a good bit more flow than even my current bored-out 4.0L throttle body. And apart from one, all of the sensors are cross-compatible.

Mounting plate / bolt pattern doesn't matter since I'm welding a new one on. Wiring and connectors don't matter since I'm splicing the wiring to move it to the other side. One more thing to add to the junkyard shopping list.
 
Mental note - an 15" long piece of scrap 1" diameter wooden dowel fits perfectly in between the rotors to reach from the intake and discharge ports to the rotor plate so I could drive the plate free with a rubber mallet without damaging it. That sucker was TIGHT.

One of the previous owners let gunk get into the intake. The gunk that got in caused some rotational scoring of the walls and rotor edges, so I'll have to hit it with some high grit paper to clean up the ridges. Looks like the oil seals went and I'm not happy with the condition of the needle bearings, so a full rebuild kit is in order. I was hoping I could get away without it so save some cash, but I'd rather do it right this time around.
 
I can't afford to send it out for rebuild, that would run me an easy $600. I'm looking at buying this rebuild kit: https://jonbondperformance.com/index.php?main_page=product_info&products_id=220 But I'm going to try to get the instructions first so that I can get a feel for what is required so I don't cause more issues. If I don't feel confident then I will probably try to find the money and send it to that same place to get the rebuild done.
 
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Which sensor on the TB isn't compatible?
 
kastein said:
Which sensor on the TB isn't compatible?
Click to expand...

I got some more information on this today. From what I understand, the IAC motor on the WJ TB is not wiring compatible, so the pintle from the WJ TB has to be attached to the XJ IAC motor and installed. The XJ TPS also has to be retained. The hard part that I didn't realize earlier is that the linkage isn't compatible, so there is some creative fabrication that has to be done to mate an XJ cable linkage onto the WJ TB. None of them seem to be show-stoppers, just a little more work for a decent gain.
 
kastein said:
Which sensor on the TB isn't compatible?
Click to expand...

I got some more information on this today. From what I understand, the IAC motor on the WJ TB is not wiring compatible, so the pintle from the WJ TB has to be attached to the XJ IAC motor and installed. The XJ TPS also has to be retained. The hard part that I didn't realize earlier is that the linkage isn't compatible, so there is some creative fabrication that has to be done to mate an XJ cable linkage onto the WJ TB. None of them seem to be show-stoppers, just a little more work for a decent gain.

Talyn said:
The problem with the rebuild is that the gears aren't indexed. Its difficult to time the rotors and gears while pressing them on.
Click to expand...

I was just doing some reading on this and it makes me very nervous. Looks like I'm going to have to pony up the dough. Maybe I can find someone in the market for a kidney.
 
SolarBell said:
I got some more information on this today. From what I understand, the IAC motor on the WJ TB is not wiring compatible, so the pintle from the WJ TB has to be attached to the XJ IAC motor and installed. The XJ TPS also has to be retained. The hard part that I didn't realize earlier is that the linkage isn't compatible, so there is some creative fabrication that has to be done to mate an XJ cable linkage onto the WJ TB. None of them seem to be show-stoppers, just a little more work for a decent gain.
Click to expand...
I couldn't remember which part of the sensors wasn't compatible, but the IAC rings a bell. And yes, the XJ linkage needs to be welded to the WJ shaft. If you can do the work it beats the $400 for a new drop in 68+mm.
I was just doing some reading on this and it makes me very nervous. Looks like I'm going to have to pony up the dough. Maybe I can find someone in the market for a kidney.
Click to expand...
This is why I am hesitant to rebuilt the Eaton SCs. The snout bearings and rear bearing are easy. The ones behind the gears are the problem.
 
Talyn said:
This is why I am hesitant to rebuilt the Eaton SCs. The snout bearings and rear bearing are easy. The ones behind the gears are the problem.
Click to expand...

The bearings don't concern me, it's the oil seals that I'm pretty sure are leaking. But it takes the same level to disassembly and reassembly to do the seals as it does to replace the bearings, so I might as well get them all done at once.
 
So I ran the numbers a few times last night. In addition to the $700 rebuild, I also have to factor in another $200 for a replacement pulley and the pulley removal tool that I forgot about. In all, if I do the rebuild I'm going to end up over $600 short of the money I have for the project. I had originally budgeted more, but the expenses that come along with being a husband, father, and home owner took their chunk.

So here's the plan right now. I'm going to stand the rotors on end and fill the snout area with oil and spin them some, then see if any oil comes through the oil seals. If not, then I'm going to replace the rear needle bearings and snout bearings and call it good for the time being until I can save up for a full rebuild. If the oil seals are leaking then this whole project is going to sit for a while until I can save up more money to afford the rebuild. To have that happen would be frustrating as for personal reasons I really want to get this done before the end of the year. I could work on the rest of the mock-up and build of the mounting, but wouldn't be able to actually finish the install.
 
One bit of good news. I heard back from Jegs on their pulleys.

The engineers involved with our pulleys said that they have tested them to 22,000 rpm at our test facility. This was not a burst test but a constant cycle test.
Click to expand...

According to the Jegs interchange list, the replacement stock idler pulley for the 4.0L (50451) is 1.062" wide and 3.464" (88mm) in diameter. The smallest pulley in that width is 50456, which is 2.755" (70mm) in diameter. They make one smaller at 2.559" (65mm) in diameter, but it is only 0.905" wide, which would likely cause belt issues.

All that to say, the Jegs Performance Pulley #50456 is the smallest diameter correct width idler pulley I can find, and it is definitely rated for the RPM load it will see.
 
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