M90 Home Porting and Rebuild Info

SeanMatteson

Registered User
Hi gang!

I've recently noticed that the chatter is getting to be a little much on my M90. I've got a spare that I wanted to port and rebuild before installing. Would someone kindly point me in the direction of any/all existing technical articles describing how this is to be properly done? Does anyone have a complete parts list indicating all of the pertinent seals and bearings to complete the rebuild?

I'm thinking that I'll document the whole process, and perhaps I can deliver the info to Bill E. for an upcoming CT issue.

Best regards,

Sean
 
From a post by fred4pt3


"THIS ARTICLE WAS ON THE OTHER BOARD FROM FRED
SUPERCHARGER SNOUT REBUILDING INSTRUCTIONS

The snout can be easily rebuilt in a few hours. You will need a better than average mechanical ability. The only special tool needed is a hydraulic press to remove the inboard bearing and drive.
As you look down on the blower you will see 3 main assemblies:
The snout.
A plate (about 1” thick)
The blower housing.

SNOUT NOMENCLATURE:
The snout consists of (from the pulley end working towards the blower housing).
Drive shaft
Pulley nut
Pulley
Pulley key way
Seal retainer
Seal
Front bearing
Rear bearing
Aluminum drive with drive pins
Plastic interface assembly.

PARTS LIST:
The parts can be found at an Industrial Bearing/Seal company.

The seal is manufactured by Chicago Rawhide.
# 7968 (preferred) #7965 or #7966 can also be used.

The bearings are made by NSK. You will need one of each.
# NC6204C3X28
# NC6203C3X28

Loctite sealant
# 51831 Gasket Eliminator 518

Grease:
Husky pt # 00603.

The plastic interface can be reused if it is not damaged. It consists of a plastic disk, a nylon bumper, and a metal spring. I recommend that it be replaced with a one piece plastic interface. I can make you one for $10.00 plus shipping. The new interface will let the blower spin up a little faster and takes the rattle out of the blower.

Remove the blower from the car.
Drain all fluid from the blower.
Remove the pulley nut
Remove the pulley. (use a 3 pronged 2” pulley puller)
Remove the key way.
Remove the seal retainer.
Remove the seal.
Remove the bolts (in a cross pattern) that retain the snout to the blower housing. (The bolts go through the 1” plate and screw into the Blower housing.)
Remove the snout. (Use a plastic hammer to tap the end of the snout to break loose the snout.)
Set the blower housing with the plate aside.
Remove the shaft. (Use a plastic hammer to drive the shaft to the rear of the snout. The front bearing will stay in the snout.)
Remove the front bearing from the snout housing. (Use a wooden dowel to drive the bearing forward.)
Use the hydraulic press to remove the rear bearing and the aluminum drive from the shaft. Be careful not to damage the drive. Note that the end of the shaft and the drive are knurled (splined).

Assembly hints:

Before you start assembling the snout read through the instructions and figure out how you will do the operations. Some tools may have to be made. I would use wood or plastic pipe. This way the assembly will be done quickly an the parts will not heat up or cool down before they can be assembled

All parts to be frozen should be sprayed with WD40 and put into a zip lock bag prior to freezing.

Get the cooled parts set up for assembly first. Then get the heated parts out and assemble.

Heated parts should be placed in a preheated oven for 15 to 20 minutes before assembly.

The heated parts will shrink when they come in contact with the cooled parts but will assemble easily. Remember to assemble quickly.

Get some practice engaging the knurles on the aluminum drive. It is critical that the drive is engaged properly and that the drive goes on square. DO NOT hit the drive’s pins.

When ever you tap something in to place do not use a steel hammer directly on the part. Use a plastic hammer or a block of wood between the part and the hammer.

SNOUT ASSEMBLY:

Clean the snout housing, shaft, and drive.

Spray the shaft and front bearing with WD40 and put them into a Zip Lock bag. Then put them into a freezer. Leave the parts in the freezer for 3 to 4 hours.

When the shaft is frozen, heat the rear bearing to 200 degrees.

When the bearing is heated remove the shaft and assemble the rear bearing insuring that the bearing is fully seated. When the bearing is cool to the touch spray with WD40 and place the shaft with the bearing into the Zip Lock bag and back into the freezer for one hour.

When the shaft is frozen.. Heat the drive to 300 degrees.

Assemble the drive on to the shaft.

Let the drive cool down and then refreeze the shaft assembly.

Heat the snout housing to 250 degrees.

Install the frozen front bearing. Make sure the bearing is fully seated.

Heat the snout with the bearing to 250 degrees.

Install the shaft into the snout housing, Make sure the front bearing does not move and that the shaft is fully seated.
Put some Blower oil on the bearings. Turn the shaft through both ways make sure it is smooth and there is no grinding.

Put some tape on the sharp edge of the shaft to protect the seal.

Put some Blower oil on the rubber part of the seal and tap the seal in. Make sure it is fully seated.

Install the seal retainer.

Install the Key way.

Install the Pulley.

Install the nut.

Now take a minute to inspect the completed assembly and get ready to finish the assembly process.

BLOWER ROTORS/HOUSING:

You can do this while you are waiting for the parts to freeze.

Set the blower on it’s end and remove the 1” plate and rotors. Be careful do not damage the rotors. I like to put a couple fluffy towels down and lay the rotors on them. Look for damage. There are 2 bearings with seals in the inlet side of the case. These bearings are packed with grease. Check the seals they should be supple and flexible. Re pack with the listed grease prior to reassembly.

Use red Scotch Bright to clean all mating surfaces.

Wipe the rotors, mating surfaces, and blower housing down with a clean rag dampened with Carb cleaner prior to reassembly.

Put a thin coating of the sealant ¼ “ wide (starting at the outer edge) and only on one side of the part to be assembled.

For assembly set the blower housing on its inlet side (with the big hole side up) and drop all parts down.

Be careful sliding the rotors in. Do it very gently. Once fully seated tap the parts together and look for sealant squeeze out .

Put the plastic interface on the blower side of the drive.

Put the snout on the blower housing. Tap it look for sealant squeeze out. Replace the bolts tighten (in a cross pattern) hand tight first then to 65 INCH pounds (use the cross pattern).

Wipe off the excess sealant.

Turn the blower through a few times look for binding grinding ETC.

When you are satisfied that all is well put the Blower in, fire it up, and happy motoring.

fred "too much timing for sealevel" holzhauer - Mail me !
A friend walks in when the rest of the world walks out . . .
"

also for the seals, you can use a metric seal, 20x47x7SC if you cant find the Chicago Rawhide brand ones. Should be only around $3-5 for the seal.

As for porting, heres what was done to mine. Removed the bolt bosses from the "v", and cut down the snout bolts so that they would not protrude from where the bosses used to be.
on the intake inlet, opened up both the SC side and the intake side by hogging out the oval port. gained approximately 1 sqaure inch of area total. could have gone more but felt it was a safe first try. also i removed the fins from the sc top. dont know if this was helpful or hurtful. but have had no adverse effects of anything i have done so far. the car pulls much harder above 2500rpm than it did before the 'porting'.
 
Grifter,

That's great! Now that you've refreshed my memory, I believe I've seen Fred's article before.

Thanks,

Sean
 
Has anyone replaced the bearings in the rear of the case (behind the rotors)? How is this done, and what are the appropriate part numbers for the bearings, the special compound that they're seated in, and the dust covers (on the back of the case)? If I do this, I want to do it all, and I want it all done properly so that I don't need to worry about this blower for a long time to come.

Thanks,

Sean
 
Sean you can take a look at Sabby blower that he ported if you like, When I take it apart to look I will need to re-rebuild it I guess, maybe we can do it at the same time so I can learn as well. I would love to get the blower case polished while its all apart too but I think I am just dreaming a little too much :)
 
Ah now thats just plain MEAN, now I am jealous and want it polished even more, how did you do that, or who did it? I tried to polish my old SC blower but it was very hard to get in between the fines on the sides, I know have a better polishing kit and may try again. The hard part was getting the old powder coating off, but I think my current blower already has it off, its painted now. Also if I remove allthe guts from the blower I could sand blast the case then polishing should be easy with the kit I have now.
 
AsScLoWn,

Very nice work!

To be honest, guys, I was looking at using the spare blower that I have but it has been spray painted flat black (don't ask, I didn't do it?!). I was thinking that I could have the empty case bead blasted in the hopes of stripping the original powder coat. I then have a contact who can redo the powder coat. I was thinking I might change colours and have the blower, top, IC tubes and the top IC tank, and the intake plenum/inlet elbow all done in the same colour.

...But, first and foremost I want to port and rebuild the blower.

Cheers,

Sean
 
yeah I may just have moine powder coated instead, Anyone wanna go halvies on a powder coating kit from Eastwood company? You can powder coat everything from pullies to bolts and stuff, a guy on the mustang website did allt he small things on his engine, looks really nice.

They are onyl about $100-200 US for a chepa kit, enough for what we will need, plus I gota stove we could use:) Let me know guys!
 
Sean, here is an article that in spite of its "tongue in cheek" atitude, gives a real insight into what is needed in a blower case porting.
http://www.theoldone.com/articles/damaged-blower/
The big gain is on the inlet side where you are fighting cavitation. Rotor timing is important so don't grind too high in the rear opening but I found I was able to open the width up 0.250" on both the case and the plenum. The plenum needs as much work as the case in my opinion.

Incidently (and embarasingly!) I finally have my car on the road. So much going on and not enough time for my own projects. Car started first thing and runs OK but power is WAY down, lazy. I get a code 332 for EGR flow (vac lines wrong?) but nothing else. Hmmmm....


Steve Best
SVO: http://sbest4.tripod.com/
SC 5spd: http://stevebest1.tripod.com/
4x4van: http://www.glinx.com/~sbest/
 
Thanks, Steve. I rather enjoyed reading that article!

I'm glad to hear that you're driving your SC again. I hope you manage to work out the remaining bugs.

Cheers,

Sean
 
rear bearings

I have been using bearings for a GM alt. for the rear case half. they have the seal and come greased. Also they are dirt cheap, i think 6 bucks a pair.
 
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