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Old 04-09-2012, 06:25 PM   #1
rskrause
 
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Default Short deck 632 feasible?

Anyone built a short deck BBC with a 4.75" stroke and a 6.135" rod? The rod length would allow a shelf 1.290" CH piston to be used. I suppose another possibility is a custom piston with a 1.040" CH and a 6.385" rod.

Yeah, I know the rod ratio is "bad" at 1.29/1, that's why I am asking the question. The 6.385 would be better at 1.34 but that's not a of room for the ring package. Hopefully, someone has tried it and can report on results. I know the theories about rod angularity and side loads, but I'd like to find out about about real world experience with that or a similar combo.
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Old 04-09-2012, 06:47 PM   #2
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Quote:
Originally Posted by rskrause View Post
Anyone built a short deck BBC with a 4.75" stroke and a 6.135" rod? The rod length would allow a shelf 1.290" CH piston to be used. I suppose another possibility is a custom piston with a 1.040" CH and a 6.385" rod.

Yeah, I know the rod ratio is "bad" at 1.29/1, that's why I am asking the question. The 6.385 would be better at 1.34 but that's not a of room for the ring package. Hopefully, someone has tried it and can report on results. I know the theories about rod angularity and side loads, but I'd like to find out about about real world experience with that or a similar combo.
Someone point out the issue of skirt to crank clearance. Dumb of me not to think about it. A custom piston with a 1.100" CH would work with a 4.625" arm and a 6.385" rod. More feasible?
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Old 04-10-2012, 01:44 AM   #3
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Your biggest problem is getting a crankshaft counterweight to clear the piston skirts. The second problem will be balancing the crankshaft.
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