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technical quiz

Which crank will spin the motor quicker from point A to B.The 22.5 lb.Chrome-Moly on the left or the 32 lb.boat anchor GT-3 crank on the right.

Crank on left is 66mm stroke with late main bearings with 2 inch chevy rod journals and 9 bolt flywheel flange for a SS 3.0. 66 X 98mm bore
Old 06-07-2018, 06:19 PM
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formerly dug@project914
 
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Sweet stuff Fred! I'm building a motor around a similar setup now...
66mm 6-bolt S crank with rod journals turned down for Ti GT3 rods that will go in a 3.0 turbo case.
How fast have you spun yours?

cheers,
dug
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Old 06-07-2018, 10:13 PM
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spin it up

You will like that setup.Your Ti rod is 1mm longer at 130mm.I have one built on 76 turbo 3.0 case that spins to 9300 rpm.I like 132mm Ti rods that make the rod / stroke ratio 2 to 1.What heads are you using?Enjoy your build
Old 06-08-2018, 03:37 AM
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Sounds pricey, I'm getting ready to build a 3.0 any suggestions other than the usual stock crank, 964 cams et ?
Old 06-08-2018, 04:58 AM
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That sure is purdy.
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Old 06-08-2018, 08:45 AM
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Interesting. Who made the non-counterweighted crank? Why no counterweights?

Seems that the extra 10 pounds could be subtracted from the flywheel with equal results?
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Old 06-08-2018, 10:09 AM
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The T crank will spin up faster..MOI is less without those pesky counterweights..

Good short stroke T cranks, that measure within spec and ring true, are desirable to certain small displacement class racers..
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Old 06-08-2018, 03:13 PM
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Fred, who makes the crank on the left and what cam are you running with it?
Old 06-08-2018, 03:22 PM
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Quote:
Originally Posted by TimT View Post
The T crank will spin up faster..MOI is less without those pesky counterweights..

Good short stroke T cranks, that measure within spec and ring true, are desirable to certain small displacement class racers..
Porsche put the counter-weights on for a reason. Surprising that someone would make a modern crank like the old T cranks.

FWIW, I ran a SS2,5 based on a T motor for years. My new 3,0 L revs up just as fast.
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Old 06-08-2018, 03:42 PM
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The non counterweighted will spin up faster, but the counterweighted will beat it for longevity.
There's no such thing as a perfect engine, everything is a compromise.
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Last edited by Mark Henry; 06-08-2018 at 05:48 PM..
Old 06-08-2018, 05:28 PM
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Factory 66mm 9 bolt on the right and modern equivalent on the left. I want as much counterweight as you can give me.

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Old 06-08-2018, 05:31 PM
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22.5 lb.crank

Crank was made in South America.I have a friend Peter Dawe who has used their 4.0L Crank for many years with no issue.I will choose cam after the heads are flowed with intake and exhaust pipe.I use early 3.6 head and narrow the stud spacing.The early heads that have not been machined fit right on the 95 or 98mm cylinder.I will post some more pics tomorrow.Ciao
Old 06-08-2018, 05:37 PM
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