Blower re-stripping

How many of you do your own blower strips . Most can do whites but how many of you do your own blacks also , how often do you do the blacks . I had mert strip my last blower ( his own ) both black and whites and it lasted about 15 runs without falling off , I had it stripped by another blower mfg. and it lasted 4 1/8th mile runs and it was falling off big time , grab the top pulley and whirl it around with no problem .

 

This is going to be a interesting post to watch.

I was under the impression that the black stripes on the apex of the rotors are not as critical as the whites. I also understand that the only way to correctly do the blacks is to have them trimmed after they are on the rotor on a lathe so they fit the case correctly. The blacks actually help you back boost

And the whites are more important since the rotors turn opposite directions toward the case that the whites stop the air that has already been compressed from leaking back up between the rotors in the middle. So they don't actually make boost they stop you from loosing it.

If all that is true then does that pretty well stop the local racer from changing his own blacks?

Also, there are several differenet types of lubricant out there that racers swear buy that keep the performance of the blower up. I have seen people spray WD-40 into the blowers and I have seen people use the expensive gel lubricant. I have also heard that the expensive gel lube can be a problem because it makes the belt dust stick to the rotors and cause trouble. Any thoughts or experience on that.

 

Well Here Is My Two Cents On The Subject. Most Blowers Are Different On The Case Dimesions Requiring As Mike Says Fitting The Rotors To The Case. Putting Blacks In Your Own Supercharger Is Not Hard But Can Be Tedious As Anyone Who Has Done It Knows Pulling Them In Can Be A Real Hard Thing To Do. You Must Also Have A Lathe That You Know Is Square From End To End Or You Will Be Cutting Your Rotor On A Taper Which Sometimes Must Be Done As Alot Of The Older Mag Cased Blowers Have Severe Taper In The Case.also It Is Critical That You Dial In Your Rotors On The Bearing Surface Of The Shaft So You Know It Is Running Concentric To The Rotor. I'm Doing A Bowers Right Now For A Tractor Puller Has .012 Taper From End To End On A 8-71.typically You Are Looking For A .001 Clearence On A 19in Long Rotor On A 14 When It Is All Done. If It Is Teflon Typically We Go For A .001 Crush. On The Ssi Blowers It Is Nice As They Grind In The Size Of The Blacks On The Rotors And Usually Between The Two Rotors There Is A .001 To .0015 Difference. Know As Far As The Teflon Gel Lube I'm A Firm Believer In It As I Think It Helps Keep The Teflon Plyable As The Alch. Can Try To Dry Everything Out And Also After Getting A Blower Back That Has Run It It Usually Is Packed Up In The Top Of The Case Which Is Somewhat Dead Air Space From The Double Bore On The Blower Case Allowing The Blower Rotors To Make A Tighter Seal When Swooping The Air From The Top Of The Case.i Get Asked All The Time How Long Should It Be Before Restrips On My Blower Well In A Prefect World The Blower Will Usually Go Out And After A Couple Passes Take A 1 To 3 Pound Loss Then Maintain And Stabilize. But Then There Is The Variables Such As When Was The Last Time The Blower Manifold Was Lapped To Insure Flatness That Is Probaly The Number One Killer On Ruining Fresh Or New Blowers Is Unflat Manifolds. Even If The Blower Manifold Is Brand New It Needs To Be Checked.second If The Motor Goes Out And Unloads Say In The Middle Of The Pass And The Motor Does An Over Rev Chances Are The Rotors Will Rub The Case And The Blower Will Be Down And Third Proper Fuel Going Thru The Blower Is Also Critical. This Year Had A Boat Customer Tell Me The Restrip Job I Did Was Poor So I Said Send It Back And Lets See. When It Arrived First Thing I Noticed Was The Stripping Was Cracked A Lot And Some What Melted. I Called And Asked Was There Any Other Problems That Weekend He Said Well We Did Sink A Few Pistons. Well It Was Obviuos That The Fuel Pump Was Going Sour. A Quick Flow Check On The Pump The Same Blower Restrip And It Was Back To 38 Pounds Of Boost With A Happy Customer. If Anyone Would Like To Buy The Materials To Do There Own Supercharger We Carry All The Stripping And Seals And Gaskets For The Superchargers.

 

Nice post. So how do I lap the top of my intake correctly? I would guess it foirst has to be torqued down correctly but then what do I use that is big enough to run across the top? Do you sell such an item? If not then where do I get this tool? I would imagine that it is some failrly stout machined block that has some kind of abrasive material on the bottom. How do you do it, in small circular patterns moving from one end of the intake to the other? How do you tell when it is lapped in? How often should one do it?

 

And one more question.....(for now)....do you flip the bolower over and also lap in the blower bottom mounting area?

 

WE DO SELL THE MANIFOLD LAPPING PLATE. IT IS A THICK ALUM PLATE WITH SELF STICKING SANDPAPER TO THE BOTTOM YOU CAN SEE PICS OF IT AT WWW.RBS SUPERCHARGERS.COM. I LIKE TO TRY AND DO FIGURE 8'S ON THE MANIFOLD. SEEMS TO WORK GOOD. ONCE YOU START USUALLY AROUND THE STUD HOLES AND SOMETIMES TOWARDS THE CENTER OF THE INTAKE YOU WILL SEE YOUR HIGH SPOTS AND ONCE YOU HAVE AN EVEN PATTERN OVER THE WHOLE INTAKE THAT SHOULD BE GOOD. YOU CAN DO THE BOTTOM OF THE SUPERCHARGER AS WELL AS THE TOP. WE HAVE A LARGE DOUBLE DISC GROUND PLATE THAT WE LAP THE FRONT COVER BOTH SIDES AS WELL AS THE TOP AND BOTTOM OF THE CASE WITH THE FRONT BEARING PLATE IF IT IS A HI HELIX THAT USES THE FRONT BEARING PLATE AS PART OF THE SEALING SURFACE WHEN WE DO A BLOWER RESTRIP FOR A CUSTOMER.

 

The o ring alone will distort the case badly , most grooves were never deep enough to begin with!

WE also are experts in Roots technology, and service them as well!

 

We made one years ago out of 2in thick steel I think, machined relief grooves about every .375 to .500 to make small squares on the plate then used lapping compound to lap in the manifold.
I've seen a picture of RBS's lapping plate and there plate would be a lot easier to use than the one we made.
It's important to tork the manifold down using a tork wrench and using the same pattern you used to tork the manifold down when you lapped the manifold in. We also used an inch pound tork wrench to tork the nuts on the blower studs using the same pattern every time.
One other thing you can do after lapping the manifold, is to buy or make a plate with dial indicators to tork down the manifold to keep it flat like the fuel teams use or use to use.

Bob Kraemer

 

We strip our own blowers, teflon and nylatron- as well as customers. We do the nylatron once or twice a year, do the whites every 10 runs or so.