steel crank snout versus 8-71 blower

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steel crank snout versus 8-71 blower

Post  fastbarry on February 28th 2013, 8:03 pm

i just picked up a 8-71 blower to put on a 523. the engine has a standard snout eagle forged crank.

the engine makes 510 hp with a small cam and low comression.

here is a link to a thread on the motor. the engine was built for a turbo build and then run with a n/a cam.
http://www.429-460.com/t14437-523-dove-headed-stump-puller-update

i would like to make 10-12 pounds of boost. at what point should i be worried about the small diameter crank snout with regards to it breaking off from the loading by the blower belt.

i would like to hear from anyone with input.

thank you,
barry
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Re: steel crank snout versus 8-71 blower

Post  IDT-572 on February 28th 2013, 10:16 pm

I cant answer your question, but I will give you an idea, if you haven't thought about it, you can run a support bearing on the end of the crank to help carry the load.
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Re: steel crank snout versus 8-71 blower

Post  fastbarry on February 28th 2013, 10:33 pm

i had not thought about a support. that is not a bad idea. i am going to shorten the spacer up and get the balancer and pulley/belt package as close to the timing cover as i can in order to reduce the leverage of the blower pulley.

i may even be over thinking this.
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Re: steel crank snout versus 8-71 blower

Post  IDT-572 on February 28th 2013, 10:47 pm

Not having ever ran one, I can't give you a definite answer, but my gut feeling is with only 10-12 lb's of boost it will be fine if you bring everything back as close to the seal as you can.
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Re: steel crank snout versus 8-71 blower

Post  Paul Kane on March 1st 2013, 12:59 pm

IDT-572 wrote:...my gut feeling is with only 10-12 lb's of boost it will be fine if you bring everything back as close to the seal as you can.
x2. Just don't get hungry with pulley changes in search of more than 10-12 psi of boost.
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Re: steel crank snout versus 8-71 blower

Post  Paul Kane on March 1st 2013, 12:59 pm

Come to think of it, forum member Blown473 is running a cast 460 crankshaft with an 8-71 on a 0.030" over 460 making 10-12 psi and the engine runs great. With the steel snout, 10-12 psi ought not be a problem on the 523.
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Re: steel crank snout versus 8-71 blower

Post  fastbarry on March 1st 2013, 7:04 pm

i will try to resist the urge to drive the blower much harder than 12 pounds or so then.
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