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Education time....what were these used for?

General engine tech -- Drag Racing to Circle Track

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shoedoos
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Education time....what were these used for?

Post by shoedoos » Thu Nov 28, 2019 1:01 pm

First time I have seen one of these, anyone care to educate on their usage pros/cons?

https://www.ebay.com/itm/L-A-BILLET-3-7 ... SwO0Vd1bd8

peejay
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Re: Education time....what were these used for?

Post by peejay » Thu Nov 28, 2019 6:26 pm

Wow that is wild! It looks like the pins are split roughly the same as a 90 degree V6 gets split to make it even fire. Except... wow, that is wild.

It looks like 1/3/5/7 would all be retarded relative to the other bank, or rather 2/4/6/8 would be advanced. So, thinking this out, with a standard cam the firing order would be

1-8--4---3-6---5--7-2---1-8--4---3-6---5--7-2---1.....

Maybe an attempt to break up the firing order for more acceleration on slick tracks without going to something that would have lots of vibration problems?

Did they ever make a narrow angle SBC block? That crank in say a 60 degree block would be even fire, although I can't say I'd ever heard of anyone doing it...

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Re: Education time....what were these used for?

Post by hoodeng » Thu Nov 28, 2019 6:45 pm

Possibly for exhaust tuning without the flat plane??

Cheers.

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Re: Education time....what were these used for?

Post by rebelyell » Thu Nov 28, 2019 8:21 pm

At nearly 67 lbs ... too heavy

Mark O'Neal
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Re: Education time....what were these used for?

Post by Mark O'Neal » Thu Nov 28, 2019 10:55 pm

Crankshaft angles...firing pulses...balancing....and a theory.

Never figured out what the theory was....but someone identified a problem and used a 6 cylinder crank design to solve it.

Walter R. Malik
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Re: Education time....what were these used for?

Post by Walter R. Malik » Fri Nov 29, 2019 12:07 am

shoedoos wrote:
Thu Nov 28, 2019 1:01 pm
First time I have seen one of these, anyone care to educate on their usage pros/cons?

https://www.ebay.com/itm/L-A-BILLET-3-7 ... SwO0Vd1bd8
I remember an 80 degree V8 Indy Chevrolet but, I can't say this is one of those cranks.
http://www.rmcompetition.com
Specialty engine building at its finest.

mag2555
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Re: Education time....what were these used for?

Post by mag2555 » Fri Nov 29, 2019 7:14 am

They look like they are for making atrue V4 out of the V8.

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Re: Education time....what were these used for?

Post by Walter R. Malik » Fri Nov 29, 2019 10:45 am

Walter R. Malik wrote:
Fri Nov 29, 2019 12:07 am
shoedoos wrote:
Thu Nov 28, 2019 1:01 pm
First time I have seen one of these, anyone care to educate on their usage pros/cons?

https://www.ebay.com/itm/L-A-BILLET-3-7 ... SwO0Vd1bd8
I remember an 80 degree V8 Indy Chevrolet but, I can't say this is one of those cranks.
GMC truck & buss offered a 60 degree V8 engine from 1966 through 1972 but, it was based upon the 478 cubic inch V6 with two cylinders added.
It ended up as a 637 cubic inch engine. That stroke was 3.860" though with a 5.125" bore.
I can only imagine that someone maybe built an aluminum SBC based upon this design.
http://www.rmcompetition.com
Specialty engine building at its finest.

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Re: Education time....what were these used for?

Post by SchmidtMotorWorks » Fri Nov 29, 2019 11:55 am

Possibly the same reasoning as the Yamaha cross plane crank on 4 cylinder.

http://www.schmidtmotorworks.com Prototypes, Tooling, Molds.

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Re: Education time....what were these used for?

Post by jacksoni » Fri Nov 29, 2019 1:27 pm

Well, if Gaerte built it they probably had a reason (might have worked, might not). Someone should ask them.

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Re: Education time....what were these used for?

Post by dannobee » Fri Nov 29, 2019 3:23 pm

Gaerte is out of business and the assets auctioned, so no help there. Earl passed away years ago.

But they were big in circle track racing, specifically sprint cars. If we go in knowing that, the 3.76" stroke with a 4.155" bore gets us 408 inches, pretty close to a 410 sprinter, with a tad left for an overbore before resleeving it. It sounds like a 72 or 60 degree V8 project. And Brodix made most of the blocks used in sprinters, so it wouldn't be too hard to have them help you out with special projects. Don't know what benefit it would have in a sprinter though.

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