Project Shoehorn - M90 into a 4.0L

[O-Gauge Steamer]

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.

And it was for this reason and for ignition reasons I added in an oil/air separator into the PCV return. When I had the compressor off for the 68mm TB retrofit, I noticed oil puddling in the low spots of the Sprintex manifold. Increased blow by is a normal issue with any high compression engine. One that is well documented and accepted.

After adding the separator into the PCV system, I discovered that I was able to add 1 degree of timing back into the beasty. Apparently, oil vapours in the intake effectively lower the Octane of the fuel...

Funny how a solution to one issue gives an additional benefit.

SolarBell. I am with you on the need to rebuild. It is my standing recommendation to anyone installing a used compressor.

The condition is unknown and failure will leave you standing at the side of the road... Not very much fun.

IMO, I would attempt to use solvent prior to mechanical methods to remove the gunk. Any rotor reduction does two things. Firstly it reduces the rotor "seal" which reduces the efficiency and secondly, there is a risk of unbalancing the rotor. Keep in mind the speed at which this thing whirls around at...

 

[kastein]

Looking at the wiring diagrams in the FSM I'm not sure why the IAC wouldn't be compatible - unless it's a voltage rating issue, which I really doubt. They're both bipolar step motor type designs, so it's probably just a matter of matching up the right coil drivers (there are 4) with the right coil ends. I'll have to take another look at it and see if I can find out how to splice one into the other later.

 

[O-Gauge Steamer]

If memory serves (it has been almost 10 years now and I am senile after all...) the connector on the IAC is different. The operating voltage, I believe, is the same as all of the sensors.

According to RockAuto, the respective part numbers are:
AC176T for the XJ (1998)
AC543 for the WJ (2002)

Not even in the same family.

I do remember that I found swapping the IAC motor was the fastest solution. Just had to use the pintle from the WJ as the cavity in which the pintle operates is deeper in the 4.7L V-8 TB.

I did mine when I had the stroker in the '97... Made a simple plate out of a chunk of 0.5" T6 aluminium to adapt the four bolt XJ manifold to the three bolt WJ TB. For SolarBell, he has to make a plate for the TB anyway, so why not use the bigger TB. Truth be told, he will need one.

There is a vacuum test that can be performed to find restriction in the intake tract. When I tested my set up, I found that the stock TB was choking the compressor. See my thread on the installation of the 68mm TB.

Made a very large difference. Picked up boost which, quite frankly, proves the point about the stock TB choking the SC.

Made more of a difference than did going with the 54mm drive pulley. What the pulley gave, mostly, was boost at lower engine speeds which has completely altered how it drives.

The compressor is now at it's mechanical limit. If I need (want...) more boost, it will take a larger compressor. Say, an M90... Or a Whipple...

 

[SolarBell]

IMO, I would attempt to use solvent prior to mechanical methods to remove the gunk. Any rotor reduction does two things. Firstly it reduces the rotor "seal" which reduces the efficiency and secondly, there is a risk of unbalancing the rotor. Keep in mind the speed at which this thing whirls around at...

Oh no, I wasn't going to touch the rotors. Not in a million years. It was just thinking about trying to clean up the walls of the body. However I was emailing last night with Jon Bond from Jon Bond Performance, and he said the scoring I see is actually pretty common, even with new blowers, and wasn't a cause for concern.

I'm trying to go through my garage now and have a yard sale of all the stuff I don't need anymore to try and come up with the extra couple hundred to get it done right. Might be a while though. I've been trolling for find deals on the few remaining high-dollar parts to save money, but no luck so far.

 

[SolarBell]

I got my eBay oil separator today. Not impressed, but it will work. Needs a good bit of copper wool pushed into it through the port in the bottom then it should do just fine. But for $17 I can't complain.

 

[Talyn]

Does your ebay AOS have a divider of some sort between the input and output?

The one I got off ebay didn't. I knew this and I knew I had to modify it. I used stainless steel pot scrubbers. Then ran a piece of brake line from the input to about 1" from the bottom of the can. I didn't want the air to bypass the steel wool.

 

[SolarBell]

Nope no divider. And the welded-on closures on top and bottom of the cylinder are surprisingly thick. I suspected it didn't have a divider, so I was considering putting in some sort of rigid metal tube to force the air through the mesh as well. I was only going to run it about halfway down the container as if I picked up a lot of oil I didn't want a collection in the bottom to start bubbling as the tube got below the level of the oil.

 

[O-Gauge Steamer]

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

Had a thought...

As Talyn points out, the rotors are not indexed. Could one put witness marks on the gears and shafts? I am thinking perhaps a sharp punch could be used to make the "timing" indexes as is done with crank/cam gearing.

Just asking as I have not yet rebuilt an Eaton.

 

[Talyn]

That is a possibility. Maybe score some close matching lines from the gear to the rotor shaft and on the gears themselves

 

[SolarBell]

I don't have a ton of experience with precision press-fitting parts. I also saw some pictures where someone did a rebuild and the rotors were off by about a degree and completely trashed the entire blower. It was enough to convince me not to touch the timing myself at this time. I think witness marks might work, but I just don't trust myself that much at that level of precision yet.

EDIT: Don't forget, the rotors have to be exactly the same distance from the gear plate as well.

 

[SolarBell]

Picked up a new air intake setup (6" round x 10" Spectre P5 filter, flex tubing, 3"-2.5" adapter) from my local auto parts and "performance" shop since my current K&N FIPK setup is in the way of moving the battery. The filter is more than twice the size of the filter I have now. But it should be plenty for the airflow with the supercharger. I'm thinking about making my own cowl intake to get nice cold air. Colder intake air = lower discharge temps = lower load on supercharger and better performance! I was thinking of doing a similar mod to Talyn to ensure I get as cold of air as possible, but there won't be a ton of room up front with the supercharger, A/C fittings, and coolant overflow. I still wheel this thing so water is a concern as well.

Picking up battery cables tonight. Should be able to relocate the battery next week as soon as I get some fittings.

 

[O-Gauge Steamer]

I had considered a cowl intake until...

Redsnake installed the Spectre unit and found the noise to be rather incredible.

What we need to figure out is how to get the fresh air without filling the cabin with noise. Perhaps drawing from the upper fender like YellaHeep did? I believe he installed bilge vents to get fresh air into the bay.

 

[Talyn]

Mine takes air from around the headlight area. The hole in the header panel was enlarged to allow more air through.

 

[SolarBell]

I had considered a cowl intake until...

Redsnake installed the Spectre unit and found the noise to be rather incredible.

What we need to figure out is how to get the fresh air without filling the cabin with noise. Perhaps drawing from the upper fender like YellaHeep did? I believe he installed bilge vents to get fresh air into the bay.

Yellaheep actually put those in to replace the snorkel he originally had there. Not a bad idea though.


I was doing some reading last night after my un-researched air filter purchase. Turns out Spectre has a neat setup. A lot of their filters have an opening in the front, and they make an adapter for that front opening to allow another hose to be run to an outside port. Then you get a mix of under-hood air and outside cold air, without the tremendous sound of it all coming from the cowl or fender.

 

[Talyn]

I'm glad you aren't going blow through on the throttle body.

This is the style catch can I used: http://www.ebay.com/itm/BLACK-UNIVE...Parts_Accessories&hash=item232e15d620&vxp=mtr

The top and bottom unbolt making modification easy.

 

[SolarBell]

This is the one I got:
http://www.ebay.com/itm/260813530336?item=260813530336&viewitem=&vxp=mtr

Top and bottom are not removable. Wish I had found the one you referenced.

Yes, blow-through seemed like a really silly idea since I'll be intercepting all of the other control signals anyway with the FIC. Besides, then all the money I paid for my bored throttle body becomes an expensive choke point. I'm going to work with a machinist to get an adapter build to allow me to run the largest bore from the discharge tube into the intake manifold as possible. I'm hoping I can get it up to 65mm or 68mm or bigger if I swap the bolts from hex head to socket cap screw to allow for a larger center tube.

 

[SolarBell]

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.

Well, balls. I didn't check fully before, glad I did now.. The 50456 is a ribbed idler pulley, not a flat idler pulley like I need. Instead I need a 50458, which is 0.080" wider but is the same 70mm diameter.

 

[yossarian19]

I'm on the edge of my figurative seat.

 

[SolarBell]

Modifications are inauspiciously under way. Removed my K&N intake and put in a temporary setup to make room for the battery relocation. Also played around with some options for where to put the AOS canister.

 

[Talyn]

In reference to the pulley speed. The best you can do is purchase one with an NTK bearing. They list their max RPMS.