I think the 6v-71 is what my buddy has, thanks for the info I will get him to contact Dyers sounds like they should be able to help.Thanks again.
Hey dude.....Krooser and the guys that run blowers have given you solid advice......I'll do ya a quick and dirty Blower 101.........ready?????? 1. If its freshly off a diesel and is in good shape, get everything to the correct end. Want the drive bolted to the gears. Mill off the flange or you can grind if off if your precise and careful enough. Be careful not to get any grit, filings and/or shavings into the blower. V-belts or Gilmer....hey, thats your business. Gotta run matched v-belts if ya run V's cause there's a smiggen of difference in the dia.'s. If they're close....they'll burn in..... 2. The guys are correct....its all about the bearings and the seals. Try making about 6 to 8 lbs of boost....your OK, 10.....is the most generally speaking.....12 to 14, this is serious territory (o'ringing the heads are a callin' soon!) , anything above that is professional builders generally. Boost is made by your rpms, don't overspin the 6-71. Shoot for about 15% underdrive with a good, tight blower. Looser ones, you can run straight, if you run v-belts (will slip if too much pressure is put on them), and don't turn the engine above 5000 RPM. 3. Gotta run oil to your bearings. The Pro shops can fix you up with lines....if your mechanically inclined....you can tap in and do it yourself, IF THATS WHAT YOU WANT, just be sure you have a drain line somewhere to return your oil. It's not necessary if the blower sits flat. Now if your gonna hang one off the side of a 6 or a 4....you might need to have lines so both bearings get oiled if you don't have a oil slinger setup under your covers..........drive gears in the front cover usually do a good job.... 4. Run a screen under your botton gasket or intake gaskets....you'll be suprised what gets sucked past your air cleaners. PLEASE NOTE THIS>>>>the choke rods on your carbs have a little plastic piece the keeps crap out of the airhorn area. This is a open hole on a lot of carbs. That blower is like a big vaccuum cleaner.....its pulling air in with quite a bit of force! I've had elements collaspe, air cleaner housings distorted, carb bottom gaskets sucked in. If everything isn't sealed up, you can and will suck in dirt. I normally remove the chokes anyway and seal that hole up....just pump it a couple if times before you hit the key and she'll light off. 5. If you've got a blower manifold, check and see if you've got a bust plate or a popoff valve. That'll be a plate with 2 bolts holding it down at the front of the intake, or a plate with 2 bolts with 2 springs holding the plate down. Be sure to run this!!!!!! Don't bypass this feature!!!!! 8 to 10 PSI of compressed fuel mixture and a backfire....well.....have you seen a Top Fueler have a blower explosion.......welll......you get the idea. 6. If you don't feel comfortable doing ANY of this yourself......get one of the guys off the board that does run a blower to help ya. Buy him dinner, some beer or do some service for him....he'll help ya out. Thats a lot cheaper than having a blown engine with couple of rods hanging out the side of your block.... 7. Please don't think about putting a good, tight blower on a 100,000 smallblock. It ain't a good idea. Up to about 40,000 miles of good periodic maint. on a engine, you should be safe. Hi-Perf. rebuilds with less than 8to1 on compression and 5000 miles, you should be safe. 8. Run a blower cam......it works better usually. A racing cam will sound relatively stock with a blower, reason being the valve lift and duration at lower speed makes the engine sufficate. That lift and duration is so the engine can take massive gulps of fuel and air at 5500 rpm or higher and be more effecient, making more horses. A blower is cramming many more times atmospheric pressure into the cylinders.....so the cam isn't causing a suffication effect on the engine. 9. Don't do any pulleys that bolt to your stock harmonic balancer, its a good way of breaking things, loosing a radiator, not to mention other things...... Be Safe, It ain't rocket science.....they've been helping power trucks and industrial engines for better than 70 years, and we've been playing with them for almost that many......they're cool, they're durable, but ya gotta give them some respect and maintenance.
As long as its oiled and sits so that fuel won't fall out of suspension and puddle up.....you should be OK.
You don't need to pressure oil these things. If you put in the proper sealed bearings and the proper seals in the end plates and housings they will run forever on 85-90 gear oil. My race partner has put over 300,000 miles on his hot rods on the street running like this. None of the blower companies, ie: BDS, WEIAND etc. have pressure systems on them.
Your so right.....some folks are just extra cautious......I prefer not to run lines to them.....just a bath in the front and rear covers......I make a small hole with a small dipstick so I can check the levels. If your not cautious....you can really screw things up by forcing oil past the bearing seals in the front and rear plates, if the drain system gets screwed........As a professional, I've only setup 3 systems that the owners wanted pressure systems........they're not really needed........now turbos are a completely diff. story......
In some specialized systems, because of the way the blower sits, you might have to run lines to them.....but normally sitting on a v8 engine the way it looks best....sitting flat........no oil lines needed.
6-71 vs 6v71 is there any difference in rebuiling them, or on parts i'm looking at machining a potvin style setup and i think it would look cleaner
They are different but work the same... the rotors won't interchange. When running any GMC blower on the street you change the rear cover to accomodate sealed bearing... no extra lube needed. The front cover is filled with gear lube.
Well guys, been infomative and I've looked at all the links and tracked down and ordered Pat Ganaals book, But still no pics of a 6v71 ready manifold. Someone must have a couple along with some practical info to mount rhis blower. Cheers fella's. Simon.
I know the popular GMC blowers are the 471 and 671, but this Deuce roadster in Lake Havasu, AZ is the ultimate. I've been told it is a 871 with three 4 barrels on a huge Hemi motor (out of a AA/G dragster). It runs as good as it looks. Does anybody have more info on it??
GMC never made an 8N-71 engine (inline)... the 8-71 blower is an aftermarket design using 8V-71 GMC rotors in a custom case... FWIW.
Hard to believe I'm answering a 4 year old post... again. To Kerry and Tudor... Yep the valley has an oil plug... small but it's there but I have a plan B in my arsenal... and I still haven't put any holes in that aluminum plate... but that's coming, too. As far as four 97's not having enough cfm's they are 175 each so that's 700 for the quartet. Not enough for any power at 6 grand but enough for regular crusing. Since I'm running stock manifolds I can't enough flow anyway so theres no point in having two 500's bolted to the blower. I'm actually using a Carter 750 to start with. BTW... this project has been on hold for four years but WILL be running and driving for the Shakedown this August...
On the coupe earlier I welded a filler onto the stock valley pan. It came from an old Massey Ferguson combine. Here's what I did on the digger for the oil filler.
Tudor pretty much ran it down for you. Some other guys added a lot of good info for you. About the only thing I could add is that I've all ways been told that leaking oil into the blower will be a disaster. I use syntetic lubricant so if it leaks it doesn't blow up your engine. Blowers are way more fun then any other way of doing it. As they say injection is nice but I'd rather be blown.
Yep... Since I still don't have my Peterbilt roadworthy after last August's altercation with Jose the drunk, illegal alien I've actually been working on the damn F100... four years in cold storage had me a little concerned about moisture in the fresh engine but it's nice and shiny in the cylinders and it turns over easily. I've been messing with the engine accessory stuff...alternator mounts, fan pulleys, blower drive and such. Seems to be going together pretty good... so far. I'm sure something will screw THAT up... I also think I found the answer to my oil fill problem... I have an old Imperial valve cover with a big hole punched in it... should be perfect for adding an oil fill tube. Film at eleven.
Jeff, Here's PROOF I'm working on it....OK... it's only a photo of my rear end. Here's my new Rick Dean-built top plate for the single Edelbrock 750... I like the fact that it's "shop built" not made on some modern CNC machine... it has "character"... THIS story has a sad ending... more later.
Cool he's the guy i was planning on sending mine to, but a buddy had some issues with him....but he's seems like a decent guy on the phone... you can see new toy on the backround...
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