Hey guys I've got a Willy's show car apart in my shop with a 6-71 BDS large diameter blower on it. The customer wants me to set it up for pump gas. This thing from what i can figure is making about 12 lbs. of boost on an 8.5:1 350 chevy with a 1:1 drive. So I am figuring on about 15% under. My burning question is...... How do I determine whether or not this blower has any life left in it? I can rock the screws side to side quite a bit. How much is too much slop? I asked the guy in the BDS tech department, He said it can only be determined with a "Trained Eye". If any of you have any info or experience with these it would be greatly appreciated.
A "trained eye" might be good - but a set of long blade feeler gauges to check the rotor-to-case and both (C & CC) rotor-to-rotor clearences will get you a lot closer to the answer.
I'm running an OLD BDS large port 6;71 on my 355 SB Chevy w' 8.5 pistons, ,,in my Daily Driven '27 T ,,it has two Blower Specific 600 Holleys on top and i'm running it 1 to 1 on pump gas ,,91 octaine mostly ,,but i've also used 87 when i'm short on cash ,,timing is the key ,, BUT ,,my BDS is pretty worn,,at the edge of the limits ,,i still get good boost 12 to 14 lbs runnin' it 1 to 1 ,, it ate the front bearing last fall ,i called BDS and they gave me a bearing part number ,,the local O'Reillys had it in stock ,,BUT ,,it was WAY too small ,so i sent mine to O'Reillys and they came up with the right one ,,i called BDS and told em they gave me the wrong part number ,,told em what fit ,and lo n behold ,,they said they haven't used this big bearing since 1969 ,,,i got this Blower used ,,second or third or >??/ hand ,,no tellin' if it was rebuilt along the way ,, So ,,long story short ,,if yours is halfway tight ,within the tolerances ,,run it ,,but i would stay with the 1 to 1 pulleys ,,ALSO ,,check BDS' prices on rebuilding that 6;71 ,,pretty darn cheap for what all they do ,, just my .02 werth ,,
I don't know much about BDS blowers but my experience with any type of a screw pump is that if you can move the screws from side to side very much you have too much end play. Or you may need new bearings.Once they start hunting themselves it usually isn't long before they get into the case. Call BDS again and if the techy tells you the trained eye thing tell them that your machinist just needs to know the clearances and tolerances. if that doesn't fly ask to speak to his super. I know that they'll tell you what you need to know if you are just persistent.
If you can rock the screws side to side AT ALL ,,it needs new bearings ,,,piece o cake to change ,,call the BDS tech guy ,,get all the part numbers for the bearings ,,buy em locally ,,Cheap that way ,,my new front bearing from O'Reillys was under $15 bucks with my shop discount ,,retail was $20 sumthin' ,,
A properly "clearanced" blower, is not done with a trained eye, period. The great guys at BDS, will use thier trained eye to simply establish the fact that you probably need a tear down and complete inspection of the unit, and rightly so. If your able to move your screws side to side by hand, " quite a bit", take it apart, or have it taken apart and correct the issue/issues before the case is destroyed. Do your screws have teflon strips, and if so, what are the condition? Scoring inside the case? Rotors pinned? New bearings? Clearanced? Many, many questions to be answered regarding a roots type blower. Please dont judge the condition of your huffer by how much boost it is still capable of making. Best of luck.
Since you're in the midwest, I recommend that you take/send it to 'Fowler Engines' in Columbus, OH -- they are a top-shelf operation and have dedicated staff to rework blowers . . . of ALL kinds. They're one of the few places on this side of the country that services blowers, manufacturers drives, etc.. Most of their work is for the race boys, but they'll do stuff for us hotrodders and their quality is very high. (They do all my machine work and blower work). They really know their stuff and deal with the facts -- no BS here of any kind. If something is hosed, they'll tell you and they won't put junk together to push it out the door. Anyway, here is their contact information - ask for 'Chris' at the front counter: Fowler Engines, Inc. 3021 Switzer Avenue Columbus, Ohio 43219 (614) 258-2924 Tell them 'Flathead Hays' sent you . . .
Not to Hype BDS here ,,but for $234.20 ,they'll replace all the bearings ,,new teflon strips ,clearance and set it up like new ,,but,,you gotta ship it there ,,turn around time is only a couple days ,, they helped me a bunch a couple years ago finding old vintage 2 inch drive belts i needed ,,2 for $100 shipped ,,,not very many guys run the old 2 inchers anymore ,,gave me one to run anna spare ,,
+1 on the movement, any is cause for bearing replacement. I run my 6-71 at 1:1 with 8.5 :1 on 93 octane and 87 when money is tight or I know I'm going on a long trip and not getting on it. Fowlers is a great shop as stated above. The price at BDS isn't all that bad either. But you can change the bearings yourself and save some money. Like others take the bearings to a local part store and match them up, all they need is the number off of them and from there its a simple press and replace job.
My guy will tear down, inspect and set up a blower for about the same as BDS, but you have to ship it to Oregon. (BDS is in California, so not much diffrence.) Rick Dean Blowers 360 451 2119 BDS does great work also, but the tech guy "Craig" is not a real fun guy to talk to. Either way, for about 250 bucks you can have some piece of mind. Good lulck, -Abone.
how are you rocking it ? moving top pully back and forth if so the rotors do have play in them if you are actually pushing the rotors by hand sideways your bearings are toast. my old blown car was street driven for thousands of miles and you could roll the top pully and hear the rotors clunking it was that way new. wayne
After i replaced the main drive bearing on my 6;71 , ,,you couldn't move the rotors side to side AT ALL ,,NONE ,,NATA ,,,my Blower is also a little different than most 6;71's ,,since i needed room for my AcCel Electronic Dist ,,i made a rear flat plate with grease jerks for the rear bearings ,,i shoot a little grease at em every so often ,,,,BDS didn't approve ,,but it werks for me ,,and my 6;71 ,, 5000 miles plus later ,,they're still good n tight ,,,, there shouldn't be ANY Slop in the side to side on those bearings ,,if so ,,they're junk and need replaced ,, BUT ,,like whats been said ,,you can replace those bearings yourself ,save time n money ,,
but the tech guy "Craig" is not a real fun guy to talk to. Good lulck, -Abone.[/QUOTE] I'll second that comment. Got tired of not getting answers and went to Mooneyham.
I'll second that comment. Got tired of not getting answers and went to Mooneyham.[/QUOTE] To me - it is ALL about customer service! If the people you put in front of the customer are a PITA, says something about how you view your customers. As a technical person, I expect to be able to talk to somebody who has a clue about what I'm talking about and will respects my time, money and commitment to their brand as much as I do. They SHOULD know more than I do about their product - they should educate, teach and mentor those of us who spend our hard earned $$$ on their products. If not - then be willing to lose their customers to somebody who goes the extra mile. When I find that the guy on the phone brings "drama" to the conversation and I have to step around his/her moods . . . time to let them know -- and if they don't fix the problem, I'll talk to their boss/owner . . . and if they don't fix it, go someplace else. I've found that very few people will actually confront a person/problem in the face -- they're only brave on eMail, talking to others and NEVER talking to the person they had an issue with. Let Craig know what you think - and if he doesn't change his ways, tell his boss . . . and if the company doesn't give a shit, find somebody else who does. Whew . . . time for a big bag o' popcorn, another big ass drink and send this fat-boy to bed. After all -- I plan on running around Columbus GG tomorrow, drink a few beers, maybe grind on a Turkey leg or two . . who the Fuck knows
Try l-m blowers in colorado, small guy does nice work, i would not teflon the rotors for street use, tighten up the clearance too much and you will MAKE too much heat
[ I've found that very few people will actually confront a person/problem in the face -- they're only brave on eMail, talking to others and NEVER talking to the person they had an issue with. Let Craig know what you think - and if he doesn't change his ways, tell his boss . . . and if the company doesn't give a shit, find somebody else who does. [/QUOTE] Problem is, Craig IS the owner!!
Now that is a problem ! When the guy at the top has a bad attitude, then I usually take my business elsewhere. If I have a choice, I'll use it . . . AND I'll let them know what my issue was (they deserve to know). They might not give 2 shits . . . which then tells me they don't care about their business.
Gents, I have a 6-71 Blower and plan to use it on a 454 BB on the street. Is there a publication that spells out how to set up the pulleys used for the water pump and alternator? Thanks! BiG DawG
Gents, I have a 6-71 Blower and plan to use it on a 454 BB on the street. Is there a publication that spells out how to set up the pulley set up for the water pump and alternator? Thanks! BiG DawG
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