Engine: DIY supercharger rebuild?

[Ron Dame]

I need a reality check fr those who have done it.

I've been advised by John Erb and others that no matter how good the supercharger looks, how clean the fluid, one that has been sitting for 16 years should be rebuilt. Despite oil, dissimilar metals touch inside, springs can add flat spots to the balls and races, and best practice is to go through it all including new balls, races, shaft, and bearings, etc.

I've rebuilt engines, manual transmissions, carburetors, and so forth... but never touched a supercharger ( SN-60). This one turns smoothly and there is no oil leakage on the output side, and in fact looks like it has been rebuilt in it's past, as it is black and cleaner than the rest of the engine bay.

So, is this a DIY job for someone like me? How many of the special tools are really needed? Or do I need to stand up to my CASO leanings and let a pro do it?

[BobPalma]

I need a reality check for those who have done it.

I've been advised by John Erb and others that no matter how good the supercharger looks, how clean the fluid, one that has been sitting for 16 years should be rebuilt. Despite oil, dissimilar metals touch inside, springs can add flat spots to the balls and races, and best practice is to go through it all including new balls, races, shaft, and bearings, etc.

I've rebuilt engines, manual transmissions, carburetors, and so forth... but never touched a supercharger ( SN-60). This one turns smoothly and there is no oil leakage on the output side, and in fact looks like it has been rebuilt in it's past, as it is black and cleaner than the rest of the engine bay.

So, is this a DIY job for someone like me? How many of the special tools are really needed? Or do I need to stand up to my CASO leanings and let a pro do it?

Ron, you are wise to proceed with caution, but it is certainly do-able for an amateur with your mechanical experience. The special tools are not necessary.

The most important thing (things, actually) are cleanliness, cleanliness, and more cleanliness. It is critical that you not handle the new ball races and drive balls with your bare hands; wear plastic gloves when handling those to avoid your body acids, however slight you may perceive them to be, from getting on the ball or race surfaces.

Other than that, follow the instructions in any applicable Studebaker Shop Manual. SN-60s are duck soup compared to VR units. Good luck. BP

[PackardV8]

I've been advised by John Erb and others that no matter how good the supercharger looks, how clean the fluid, one that has been sitting for 16 years should be rebuilt. Despite oil, dissimilar metals touch inside, springs can add flat spots to the balls and races, and best practice is to go through it all including new balls, races, shaft, and bearings, etc.

If this were an engine, about now, several would come in saying a rebuild is not necessary. It's not usually my advice, but just trying to learn something here; what would Ron be risking by changing the oil and running it? What could be damaged that wouldn't have to be replaced in a rebuild anyway?

jack vines

[WCP]

I'm with Jack on the need for a rebuild. However, it is prudent to separate the halves to check the function of the oil pump, as described in the manual. Clean the screen of any congealed oil and reassemble the unit. Don't mess with the spring pack, balls and races.Do all this with the unit lying on its back, so nothing falls out. Tease the halves apart carefully. I use a thin putty blade initially to lift the top sufficiently to allow a couple of tongue depressors as surface protection as a blade screw driver is inserted between them. Takes bit of time but be careful not to damage the housing o-ring grooves. SN60s are fairly easy, SN92s can be more difficult.
The life of the blower will depend on the level of ball load drive. Assuming it turns smoothly, at 20 in.lb. it will run a long time - at 30 it should last several years and at 40 in.lb. the life will drop significantly. An early SN60 that had been rebuilt some time later, had had the springs changed as specified by a factory upgrade, but the rebuilder left the shim washers in place. It checked out at 45+ in.lb. torque - very stiff to turn over by hand. OK for drag racing but- !
Change the oil every 3000 miles and check the feel for roughness at least yearly. Don't run the blower until it seizes. That could get very expensive and require a lot more than balls, races, springs and ball driver. Good luck!

[Ron Dame]

Honestly, my inquiry was hoping a minor service was all i needed to do, worst case being that a rebuild would be be
necessary and obvious prior to significant damage. My fear is/was that serious damage could hapoen before i realuzed it.

[64Avanti]

I know John very well but I have to disagree. The balls are 52100 steel and the races are M50 tool steel and are very hard,about RC62. The strength is very high and I would not expect any yielding as they are through hardened. Some older outer races may be a surface hardened material and could yield some. I would just run it. The worst that will happen is that it will fail fairly quickly and then it can be rebuilt.

If it fails then you can someone like John Erb rebuild it if you don't want to do it. It really isn't that hard to do. There are a few things that need to be done correctly such as shimming the impeller to get the proper clearance. If that as an example is not done right and there is too much clearance you will loose boost. Anyway a competent mechanic can do it. It is really a simple device.

[sailingadventure]

Not much inside one of these, easy to rebuild if you have any mechanical skills. Don`t be afraid to give it a try. You will need an inch pound torque wrench tho.

[Buzzard]

Holy crap, sailingadventure. Your pictures just reminded me I had some special, heavily curved impellers made many, many years ago in an attempt to increase the boost. The vanes had a very pronounced curve in order to "scoop" the air. Now with old age, where the hell did I stash them?
Thanks guys for this great info.
Bill

[WCP]

Ron, you may have misunderstood my opening comment. You are not risking anything by running the blower, after you take care of the oil pump check and/or cleaning. You may get many years of operation from it with proper maintenance before you have to spring for a drive system rebuild. BTW, drain the oil by syphoning from the unit and before you lay it on its back and don't turn it upside down to drain - it won't drain. You want to keep any crud, settled around the pump pickup at that location.

[Ron Dame]

Thanks everyone, I'll clean the pump screen and give it a try. Thanks for the tip on not turning it upside down to drain it. Other than the inch-lbs torque wrench, no special tools are really needed?

[SScopelli]

Here is a national service data repair manual which includes the SN60 rebuild. Search for Paxton.

https://drive.google.com/file/d/0B_wGFoUR75qTckhFcXlVOVVNSW8/view?usp=sharing

[WCP]

No special tools, just patience. Tease the upper half as suggested by working gradually around the circumference and lift straight up. Once apart, you will see why it shouldn't be inverted. The webbing traps the oil and refuse, ready to drop it back down on the pump and drive assembly.. You may wish to lift the spring pack to examine the ball & race section but don't touch balls or races. To lift the pack I use a piece of wire coat hanger fashioned to span the pack and hook into diametrically opposed radial drain holes. BTW, there is no need to remove the rear impeller cover. That can be done later, if you feel you are not getting adequate boost and to check the impeller clearances. To remove the impeller to adjust clearance, you will need to make a impeller lock as illustrated in the manual and acquire a piece of drill rod and the appropriate capscrew size to draw off the impeller.

[DougHolverson]

[ATTACH=CONFIG]67387[/ATTACH]

I'm digging this picture. Sort of like a Frank R. Paul fantastic technology illustration for one of Hugo Gernsback's pulp magazines or sort of like a mysterious Krel machine.

[Ron Dame]

Big bummer yesterday. I was hoping to start work on the Avanti this weekend, but the clutch disk in the truck disintegrated. Since I have room for only one car at a time in the garage, I'll be doing a clutch job instead. This clutch has only 10,000 miles on it too.

[jclary]

Bummer Ron...do you think all that raw added horsepower by converting the engine to 185ci had anything to do with it?