OK who knows what about blower motors

OK guys I have the opportunity to build a 540 cid A460 head  8-71 blower motor too run in our Modified 4x4 class here in Wisconsin.
Just need to know how strong do I need to build the lower end of this motor. Is a 4340 drop forged crank strong enough or is billet the better option. I don't want.to have to spend 20,000 on the short block if I can get.away with it holding together on 10,000 .
Also plan to run this with two Dominator carbs with race gas.
So what kinda of cam does a blower motor use everything I built and had built was nateraly aspirated.

I'm looking to have good off the line manners also. This will be going into a pulling truck.


Looking for info

Dan

ShaZam

Forged Crank should be fine, would want to use a boss snout, the regular one is a little long. May also want to consider a bigger snout if your going to be running big boost or some kind of support.

Definetly consider the 18 bolt heads too, especially if you are starting from scratch.

Is an 8-71 as big of blower as your allowed to run? Its a little on the small side IMO on a 540" engine.

I'd talk with somebody like Dyers, Littlefield or your choice of a number of others before starting.

A forged crank with will work fine.  
I went with a chevy snout on my Bryant billet crank... (with that you have to run a chevy damper) no big deal...
Adney can fix you up a real nice piece!!!



I also had to open up my timing chain gear.


i'm running blue thunder heads,,,  reason is because blower intake choice.


A-Heads you have to cut up a tunnel ram and weld a plate.
Or get the adaptor plates for a Blue thunder blower intake too A-head deale-o..



this application was a lake boat 12-71 Hampton blower, 10lbs boost on gas.. never have an issue one.

going 14-71 alky,

An 8-71 really isn't near big enough with a 540 inch engine; Straight, 2 lobe rotors are definitely needed for the extra volume IF rules restrict the blower to an 8-71.

And drive the piss out of it......   the blower rating is how many 71 cu in cylinders could the blower evacuate.  The original application was an exhaust scavenger for diesel engines.  6-71 8-71 etc.   In the application of a roots style blower an 8-71 is best suited on a small block.  Most big blocks would look at a 12 to the big daddy 16-71

May want to run a crank hub instead of a balancer, may also want to double key the crank shaft with a 1/4 key for the second key way. There is alot of load on the snout and keyways ect. and I have personally had a FluidDampner split on a 6/71, on a SBC application. The BBC snout option, mentioned above, sounds like a good idea too, if you are buying a new forged crank. A billet crank seems overkill to me, and a 8/71 does seem small for the cubes you are running, as also mentioned above. BDS provided my crankhub, give then a call, they can point you in the right direction, as well as the other big name Roots style blower companies.

Definitly want to look into a custom ground cam on a engine like this, and match the combination to your needs, and parts you plan to use, ie, cyl. heads, exhaust ect. BDS lists or use to list cams in their catalog, so you could get a general idea of the grinds and RPM ranges and go from there. They are probably based for a 460ci., so this where the custom grinds will come into play with a 540ci. engine. Came back to add this. By the time you spin that 8/71 fast enough to make much boost on a 540 the air will be so hot, you won't make much HP, but you can try it if you allready have it, and upgrade latter if you want to. Alky is where the Roots shine, and gas/Roots, is more for show now days. Screw blowers, are where the powers at. I doubt you will gain much more than 100 HP with the 8/71 on gas with a 540.

I've got a Scat 4.5" forged standard weight crank ( 4-460-4500-6700-2200 ) and would like to build blower engine. I want to run a 1271-1471 The Blower Shop kit.

Is this crank ok to use? I will run E85 and keep the revs down ( 7000-7500rpm max ). Would prefer to run more boost and less rpm. Not looking for earth shattering power ( 1000-1200hp ), just something that will hold together, run hard, look good and sound off tap.

busta wrote:I've got a Scat 4.5" forged standard weight crank ( 4-460-4500-6700-2200 ) and would like to build blower engine. I want to run a 1271-1471 The Blower Shop kit.

Is this crank ok to use? I will run E85 and keep the revs down ( 7000-7500rpm max ). Would prefer to run more boost and less rpm. Not looking for earth shattering power ( 1000-1200hp ), just something that will hold together, run hard, look good and sound off tap.

Be sure to run enough "clamping" force on the front parts on the snout to keep flexing to a minimum. THAT is key to making the Ford snout live

rmcomprandy wrote:

busta wrote:I've got a Scat 4.5" forged standard weight crank ( 4-460-4500-6700-2200 ) and would like to build blower engine. I want to run a 1271-1471 The Blower Shop kit.

Is this crank ok to use? I will run E85 and keep the revs down ( 7000-7500rpm max ). Would prefer to run more boost and less rpm. Not looking for earth shattering power ( 1000-1200hp ), just something that will hold together, run hard, look good and sound off tap.

Be sure to run enough "clamping" force on the front parts on the snout to keep flexing to a minimum. THAT is key to making the Ford snout live

Randy can you please explain further? How do I run enough clamping force to minimize flex? I will not be building this engine, but I'm doing as much research as I can as there aren't many people that specialize in BBF stuff over here.

My only knowledge of blower motors is that they don't wanna work as well after saying "I do", then eventually quit working altogether   

 quote="HorsinAround"]My only knowledge of blower motors is that they don't wanna work as well after saying "I do", then eventually quit working altogether   
[/quote]