Question(s) for those who've rebuilt their SN's...

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Originally Posted by Charged87GTA

well got everything back together yeasterday and the blower sounds pretty good, keeps blowing the pipes/hoses after the blower off lol. sounds like an airplane when its not hooked up to the motor

time to invest in some heavy duty hose clamps

the car was hard to keep in a straight line before, gonna be real tough now as long as i can keep it in boost

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Congratulations on getting the blower back together and on the car. See? These old Paxton's aren't so hard to work on, are they?

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Originally Posted by Charged87GTA

also if anyone knows the formula to see if your overspinning the blower i would apprecieate it if you could share it, been searching for it and cant seem to find it.

my sbc revs pretty high, i have a 7000 rpm chip in it and it gets there real quick with the blower on. just trying to make sure its safe, thanks

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Did the excel spreadsheet not work for you? I posted the link to it back in post #48 of this thread. All you have to do is enter the pulley sizes you're using and it will tell you how fast the blower is spinning @ the maximum engine RPM. If it's too fast, then look for a larger blower pulley that will spin it slower; input the pulley diameter into the spreadsheet to see what RPM it will result in.

If you're spinning the engine to 7000rpm, then it might be a bit high. Most of the GM V8s from the era of your GTA only spun to about 5500rpm, and the Paxton kits were pullied appropriately. Since you're spinning the engine 1500rpm higher, then you might want to consider changing the blower pulley.

Crank pulley \ SC pulley X 4.4 X Engine rpm = SC RPM

yea they dont seem that bad now, i mean the car is built to handel the rpms, not sure on the blower, bought the car the way it was and didnt get a whole lot of info on it, i do know he ran the blower alot and that that the car ran high rpms, so maybe the pullys are meant for the car, they are the triple belt type.

hopefully it all holds together when i get the piping all sorted out.

hows your 89 coming?

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Originally Posted by Charged87GTA

yea they dont seem that bad now, i mean the car is built to handel the rpms, not sure on the blower, bought the car the way it was and didnt get a whole lot of info on it, i do know he ran the blower alot and that that the car ran high rpms, so maybe the pullys are meant for the car, they are the triple belt type.

hopefully it all holds together when i get the piping all sorted out.

hows your 89 coming?

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The rebuild is not moving as quickly as I would like, but it's coming along. I've taken the H.O. impeller and ball carrier to a local shop that specializes in high-performance coatings. I'm getting the impeller ceramic coated and the ball carrier dry film coated. I'm hoping the ceramic coating on the impeller will help drop the inlet air temperature a bit, while smoothing out the incoming air flow and giving a bit more CFM and/or boost. I'm hoping the dry film coating on the ball carrier will provide some wear resistance over the long run. I've never seen or heard of anyone ceramic coating an impeller or applying dry film lubricant to a ball carrier before so this is going to be a bit of an experiment. Can't do any harm... I hope.

But once those parts come back (hopefully tomorrow, if not Monday), I'll be able to start the reassembly process. I'll post pics of the coated impeller and ball carrier when I get them.

I should also mention, I am working on having this shop become a forum supporter. I am working on a deal to give forum members here who want to ceramic coat their impellers a package deal. The price would include shipping to and from the shop anywhere in Canada and the U.S. We haven't talked about international customers yet.

The only unfortunate thing about this is I don't have any "pre coatings" data to prove whether they will make a difference. And since my blower is still a ways from being bolted up to my car, I can't say with any certainty when I'll be able to report anything. But if anyone here wants to try this experiment to see if a ceramic coated impeller will result in a drop in inlet temperatures and/or boost, feel free to send me your impeller and I'll have this shop ceramic coat it for you and send it back. Shouldn't take more than 7-10 business days.

Interesting idea playing with the ceramic coatings, with the surface area and mass of the housings I would think they would be a bigger source of heat and might help from heat soaking if coated as well? I guess it comes down to what is most of the heat source, the ball drive or compressing the air??

Have you hit them up if it is possible to coat the inner airways of the housings?

I thought about ceramic coating the scroll cover too. You're right - it is a much larger piece, and would probably prove to be a larger heat sink than the impeller. However, my fear is that ceramic coating it would promote heat retention within the blower itself (much like it does on an exhaust system); my thinking is that ceramic coating the impeller will help to deflect some of the heat created by compressing the air which occurs between the impeller and housing/scroll cover. Will it work? No idea, but it's worth a shot.

I should mention, this shop does have a heat expulsion coating too, which helps to radiate heat away from the part itself. The owner of the shop said that he's applied the coating to a number of race car parts; the appearance of this coating isn't "pretty", so he's only used it when appearance/aesthetics weren't important. I would have had this coating applied to my entire supercharger, but frankly I like the mirror-finish look... LOL!!!

I think both the process of compressing the air, and the ball-drive produce substantial amounts of heat. The ball drive's heat can be kept in check by the use of an external cooler; the compression process will be more difficult to control.

I didn't ask about coating the inside of the housings, but I can do that next time I'm there. I'm sure they will be more than happy to do it... I'm just not sure if it will result in lowering the blower's temperature or keeping the heat inside.

Hi Michael,
I’m curious about the “dry film”. Could you expand on your idea of the benefit there?

Funny you should bring that up... I just got off the phone with the coating shop. Turns out the parts won't be ready until Tuesday for me to pick up.

My thoughts behind the dry film was that since the ball carrier itself doesn't actually place any pressure on the balls (that's done by the two bearing races), that by applying dry film lubricant it'll minimize the wear on the carrier itself.

Obviously, friction has to exist between the balls, the bearing races, and the impeller shaft, otherwise the ball-drive itself wouldn't work. Which is why I didn't have the impeller shaft and races coated. But the ball carrier just transfers (for lack of a better word) rotational (or sideways movement depending on how you look at it) to the balls and holds them in place as they spin.

I doubt there will be any performance benefit to this other than MAYBE reducing oil temps a tiny amount. All I was really looking to do was to give the ball carrier a longer service life by reducing wear; I doubt it will have any impact on the balls, races, and impeller shaft.

Now that I think about it, I hope I haven't screwed myself... if this coating DOES reduce friction with respect to the ball drive system, does that mean I'll see a different turning torque value when everything is back together? Oh oh...

Me and my bright ideas.

It will be okay. The resistance is all in the compression of the balls by the races. Otherwise the seals and misc. contribute a minor percentage to the rotational torque reading. I can’t see any reason dry filming only the carrier would impact your readings. It is a relatively soft metal, mines brass, and I do see wear. It would be interesting to see your coated carrier after some hard use.

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Originally Posted by Michael

...since the ball carrier itself doesn't actually place any pressure on the balls (that's done by the two bearing races), that by applying dry film lubricant it'll minimize the wear on the carrier itself...

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I'm confused on your statement, the ball carrier drives the balls from the input shaft so there is high pressure between the carrier and balls??

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Originally Posted by Buck-Strickland

It will be okay. The resistance is all in the compression of the balls by the races. Otherwise the seals and misc. contribute a minor percentage to the rotational torque reading. I can’t see any reason dry filming only the carrier would impact your readings. It is a relatively soft metal, mines brass, and I do see wear. It would be interesting to see your coated carrier after some hard use.

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I hope you're right. As I said, my logic was entirely based on exactly what you've said: all the compression on the balls is from the races (why else would they have shims and the belleville washer/spring?). The carrier just keeps the balls in place and transfers the rotational movement from the pulley. No real "drive" pressure.

The shop owner did say that the coating itself will "glaze" but it won't wear off. This is the same coating that you see on piston skirts for high-performance applications. I figure if it won't wear off of a piston skirt, it should be fine on the ball-carrier.

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Originally Posted by whodwho

I'm confused on your statement, the ball carrier drives the balls from the input shaft so there is high pressure between the carrier and balls??

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No, there is little pressure between the carrier and the balls. All the pressure exists between the bearing races, balls, and impeller shaft. The ball carrier only keeps the balls in place while transferring the pulley's rotational motion. If there IS any pressure between the balls and carrier, it's MUCH less than the pressure between the balls, races, and impeller shaft.

The pressure between the races, balls, and impeller shaft HAS to be there. Otherwise, the drive system wouldn't work. But other than the sideways contact between the ball carrier and the balls themselves, no pressure is needed between the balls and ball carrier which is why I decided to have it dry film lubricated.

Does that clarify things...?

I think your missing the connection between the input shaft and the ball drive assembly. The input shaft is connected to the ball carrier, the ball carrier drives the balls so they roll and the output/impeller shaft is driven from the balls at the 4.4 step up.

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Originally Posted by whodwho

I think your missing the connection between the input shaft and the ball drive assembly. The input shaft is connected to the ball carrier, the ball carrier drives the balls so they roll and the output/impeller shaft is driven from the balls at the 4.4 step up.

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I know the input shaft is connected to the ball carrier, and I know the impeller shaft is driven by the drive balls. Have you seen the photo below? Who do you think modeled it?

http://i49.photobucket.com/albums/f2...vesystem02.jpg

I'd like to think I have a decent understanding of the components within the ball drive and how they work.

But I don't understand what you're getting at, and what it has to do with applying dry film lubricant to the ball carrier?

Sorry to have upset you it was not my intention at all. It is just a friendly discussion of a different view on something and sorry if I am not explaining it well and let me know if you are not wanting to discuss it.

It didn't have any to do with the dry film it had to do with the comment "since the ball carrier itself doesn't actually place any pressure on the balls"

As we agree there is good amount rotating resistance of the ball assembly, what and how makes that assembly rotate?

Again feel free to tell me to STFU and delete my posts, it is just meant as a discussion and not an attack :sick:

I'm not upset, and there's no need to apologize.

You're right. My comment about the ball carrier not applying pressure to the drive balls was incorrectly worded. It does indeed apply force to the drive balls as it pushes them around the bearing races and impeller shaft. But that force is linear, along the side of the drive balls. The bearing races apply an axial force to the drive balls which is transferred to the impeller shaft as the balls rotate.

The bottom line: friction between the bearing races, drive balls, and impeller shaft is needed, otherwise the impeller shaft wouldn't spin; friction between the ball carrier and the drive balls isn't needed (or wanted). Or is it?


I'm going back to designing airplanes. At least stuff made sense.

I agree, the friction between the balls and carrier is not needed or wanted I think your attempt at lowering it is a great idea.

With the balls rotating as the carrier is driving them would seem to have a high friction potential between them. It will be interesting the next time you have it apart if the coating will have held up.

I know they switched between an aluminum carrier and brass/bronze, not sure if that was any attempt at this or just durability?

Again I appreciate your efforts here and documenting it and your CAD project. I have had that pic above as a desktop background since you posted it! :laugh:

And now back to your regularly scheduled program...sorry for the extended detour.

The carrier that I took out of my SN89 was aluminum (probably the original one from the factory) the replacement one that I'm having coated is brass. The reason for the switch was because brass is soft (softer than aluminum and certainly much softer than the drive balls) so it won't score or wear the balls themselves (they see enough pressure from the races and impeller shaft). Durabilty? Don't know... probably more to do with mitigating parts wear. If a drive ball gets scored, it can easily (and quickly) damage the races and impeller shaft. If the 'soft' ball carrier wears, there's little likelihood of that damage propagating anywhere else since the drive balls are harder than the carrier.

Of course, once any damage occurs, it's only a matter of time before everything has to be torn down and rebuilt anyway.

But I agree. It will be interesting to see how the DFL holds up after some time in the blower with regular use. It's too bad I don't have any previous data (oil temps, discharge air temps, etc...) to compare to with respect to these coatings. Would have been great to actually quantify these changes with real numbers. Maybe one of the members here can provide their oil and discharge temp numbers as a comparison? Of course, they'd have to be running the same setup as mine (ie. same pulley sizes, comparable sized engine, same fluid, etc...) to make the comparison of any value.

I'm glad to hear you liked the rendering so much that you've made it your desktop background. But if you like that one, then stay tuned... I've got more renderings coming soon which will blow that one away!

Well, I got the impeller and ball carrier back from the shop today. They look FANTASTIC too! Great work.

Take a look at the ceramic coated on the impeller:
http://i49.photobucket.com/albums/f2...d/P1080162.jpg

http://i49.photobucket.com/albums/f2...d/P1080163.jpg

And here's the ball carrier with the dry film lubricant:
http://i49.photobucket.com/albums/f2...d/P1080165.jpg

http://i49.photobucket.com/albums/f2...d/P1080166.jpg

Now it's time for the reassembly process to begin.

Looks nice. It's a shame to hide the impeller.

What was the cost for the dry film coating on the ball carrier? I'm interested to see how that holds up.

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Originally Posted by Buck-Strickland

What was the cost for the dry film coating on the ball carrier? I'm interested to see how that holds up.

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The dry film lubricant cost me $80. A relatively inexpensive experiment all things considered.

so if anyone was wondering what would cause a loud buzzing noise from your sn89, this is a pic of the old impeller shaft out of mine lol

This is going to sound like a real 'novice' question, but what do you guys use as an inch-pound torque wrench?

I'm asking because the bolts that hold the input shaft to the ball carrier (which is where I'm starting the reassembly process) need to be torqued to 50 inch-pounds. How are you guys ensuring that torque level? Beam-type torque wrench? Clicker-type? Any particular tool brand you guys favor or use?

All the torque wrenches I've found at the usual retail outlets are all foot-pound units. I already have two foot-pound units, one 3/8" drive and the other 1/2" drive. I just can't seem to find an inch-pound wrench.

found one new on ebay $60.00 0-60 inch pounds brand Consolidated Devices Inc. it's a bar type.

You need to check a Ball in the Bronze Ball Driver(Carrier) slots. Sometimes they are a little tight when brand new. It can throw off your inch pound measurement with all brand new parts.

I 've had to open the slots up just a little to allow the balls to spin smooth when the Ball Driver pushes them.

The best inch pound guage is one with a needle.

You have to turn the blower with the inch pound gauge at a consistent speed and note where the needle is.

I marked my inch pound gauge with a red line in the target tension area so I could see where it was reading easier.

Harbour freight tools have them for 20 bucks

one like this http://cgi.ebay.com/Proto-Dial-Torqu...item3a6703a48a i scored my snap on 150 inch# torque-o--meter used in good shape for around $40, i have a 1/2" unit too that works great and they hold their calibration well, i get about 6-7 years of shop use out of it between rebuilds before the head slips

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Originally Posted by Michael

This is going to sound like a real 'novice' question, but what do you guys use as an inch-pound torque wrench?

I'm asking because the bolts that hold the input shaft to the ball carrier (which is where I'm starting the reassembly process) need to be torqued to 50 inch-pounds. How are you guys ensuring that torque level? Beam-type torque wrench? Clicker-type? Any particular tool brand you guys favor or use?

All the torque wrenches I've found at the usual retail outlets are all foot-pound units. I already have two foot-pound units, one 3/8" drive and the other 1/2" drive. I just can't seem to find an inch-pound wrench.

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sn92 here, new balls and used impeller shaft from cund lasted a whole 2k miles

http://www.fileden.com/files/2006/11...0/da-shaft.jpg

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Originally Posted by Charged87GTA

so if anyone was wondering what would cause a loud buzzing noise from your sn89, this is a pic of the old impeller shaft out of mine lol

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Little update on my rebuild progress...

I got myself an in-lb torque wrench yesterday! Took advantage of the Father's Day sales and got myself a nice clicker-type torque wrench from Mastercraft (the Canadians will know the brand well. Exclusively sold through Canadian Tire, these are very good tools and reasonably priced). It was 50% off, so I got it for just over $60. Not bad at all. Check it out:
http://i49.photobucket.com/albums/f2...d/P1080263.jpg

The Mastercraft Maxium line is the "professional grade" of the Mastercraft brand of tools. They are almost up there with Snap On in my opinion, and definitely better than any shade tree mechanic would ever need. Most of my tools are Mastercraft. And 3/8" drive means I won't need to use adaptors to step down from a 1/2" drive wrench. Nice.
http://i49.photobucket.com/albums/f2...d/P1080260.jpg

Adjustment range between 30-250 in-lbs is perfect for rebuilding a Paxton ball-drive supercharger.
http://i49.photobucket.com/albums/f2...d/P1080261.jpg

Lifetime warranty... can't beat that. If anything goes wrong with the wrench, I can walk into any Canadian Tire store and get a free replacement on the spot - no receipt needed and no questions asked.
http://i49.photobucket.com/albums/f2...d/P1080262.jpg

Even comes with it's own plastic case too! Sweet. (I know, I know... most torque wrenches come with their own storage case. Hey, it's a new tool and I'm excited!).
http://i49.photobucket.com/albums/f2...d/P1080264.jpg
http://i49.photobucket.com/albums/f2...d/P1080265.jpg

The calibration tag that came with the wrench shows this is a fairly accurate unit too!
http://i49.photobucket.com/albums/f2...d/P1080266.jpg

So now it's about time to start the rebuild!

But before I do, I have to ask a couple of quick questions:

1. The assembly drawing that's floating around this site shows that Loctite (or Locktide... whatever the hell that is) is supposed to be used in various locations. Which Loctite did you use? Did you use any Loctite on bolt threads (ie. between the drive shaft and the ball carrier, on the impeller bolt, etc...) and if so, which Loctite?

2. What kind of assembly lube did you use? Did you just coat the various parts in Type 'F' fluid, or did you use a specific prelube? Did you do this BEFORE or AFTER establishing the proper turning torque for the impeller?

Always install the parts lubricated in F type oil not dry.
I use locktide on the bearings for extra securety they will not spin.
I do not use threat locktide on the bolts exept for the impeller bolt. I really do not want that bolt to come lose at high rpms.

Locktide is a sort of glue that keeps bolts from comming lose (threat locktide)
There is also Locktide for flat surfaces, I use that for the bearings.