Technical 6-71 blower

I recently bought a 6-71
The seller told me it is a big bore BDS
There is no name on it
on the inside it is stamped Drmi 12r8 5155866
Hope somebody can help me decoding it
Thank you
Claes

 

How about some pictures?

 

X2.
Go to BDS web site , is it aBDS case or One converted by BDS?
Pics will help us,

 

that's the GM casting number for a 6-71. Does it have end plates, etc? my BDS blower says BDS on both ends of it...but they changed how they did things, over the years. Pictures will help us figure it out, of course.

and you're supposed to ask these questions before you buy

 

ok i will try to post some pictures asap
Claes

 

I think the Drmi might be DRM1. The 5155866 is most likely the GM number that identifies the casting and the part number for the case, once machined, would be different than that. Sounds like an OEM GMC/Detroit Diesel blower that was set up by BDS.

 

Some info here: http://www.jalopyjournal.com/forum/threads/is-this-a-big-bore-or-small-bore-6-71.997042/

 

Ok i understand
So in the beginning Weiand. Bds and other companies took OEM blowers
and rebuilded them.
Any idea what DRM 1 stands for

 

probably something to do with the casting process, or tooling. I doubt it's important.

this is what my BDS blower says underneath.

 

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Thank you all for you
Help
Next spring i will put it on top of my CBB


Sent from my iPhone using The H.A.M.B. mobile app

 

Sent from my iPhone using The H.A.M.B. mobile app

 

If it doesn't say BDS on it anywhere, or have their stamp (circle with BDS inside) and a serial number stamped by them, then it is probably not a BDS rebuilt unit. That is not a bad thing, it just means that the seller was telling a fib, which is pretty common.

Looks like a fun thing to do! Might want to use a square tooth, 1/2" pitch belt and pulleys, for the old time look.

 

I like where your putting the blower.....

 

That looks like an 8MM pulley on there now with a nice billet snout. the front bearing housing is original Detroit diesel unit, the triangle shaped plate is where the injector pump once was. those original housing ends are desirable with the nostalgia racers.
Do the rotors have any strips in them ? you just need to make sure that the clearances are set up for gasoline and not alcohol, they actually machine the ends of the rotors for expansion.

 

No strips on the rotors


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That triangle plate was where the fuel transfer pump was, the injectors in the head developed the high pressure. but i'm just splitting hairs.

 

There was two sizes of GMC 6-71 blowers. Rotor diameters.

 

The HAMB search engine is fairly literal. You will likely have more and better result if you search on the term 6-71, rather than the mathematical ratio 6:71.

 

http://www.jalopyjournal.com/forum/threads/tech-week-6-71-blower-rebuild.367403/

 

I thought search engines ignored those funny characters like - and : and only look at the numbers and letters? but the HAMB search only works on longer numbers than 2 digits.

But yeah, the colon bugged me too

 

A trio of GMC blowers: 3-71, 4-71, 6-71.

 

if you want real old school you use primary chain.

 

What are you going to do with it? Is it show or go? If it is a "show" puffer then it will work without rotors. If you are going to race then you need to start over. Rotors need strips and end clearance setup etc.

 

I would not run an empty blower. I set up a 6-71 on my Hemi. Might put the 3-71 or 4-71 on Dodge Hemi. Clearance no problem. You don't need strips on street motor, They wear out in time. without strips can make over 7psi boost or more with pulley change. Don't need much more on street motor.
Have over 20,000 miles on my blown 354 Hemi 7psi.