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Registered
Join Date: Sep 2015
Location: Costa Rica and Pennsylvania U.S.
Posts: 3,301
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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 |
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06-07-2018, 06:19 PM
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Registered
Join Date: Dec 2001
Location: Santa Cruz, CA
Posts: 907
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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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1972 914-6 2.5L Gemini Blue 1973 914-6 MetalCraft Racing C-Prod/TransAm/IMSA history |
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06-07-2018, 10:13 PM
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Registered
Join Date: Sep 2015
Location: Costa Rica and Pennsylvania U.S.
Posts: 3,301
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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
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06-08-2018, 03:37 AM
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Registered
Join Date: Dec 2014
Posts: 13,862
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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 ?
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06-08-2018, 04:58 AM
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Registered
Join Date: Jul 2005
Location: Atlanta
Posts: 1,241
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That sure is purdy.
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No physical quantity completely explains its own existence |
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06-08-2018, 08:45 AM
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Under the radar
Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
Posts: 7,129
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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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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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06-08-2018, 10:09 AM
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Navin Johnson
Join Date: Mar 2002
Location: Wantagh, NY
Posts: 8,783
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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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Don't feed the trolls. Don't quote the trolls  http://www.southshoreperformanceny.com '69 911 GT-5 '75 914 GT-3 and others |
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06-08-2018, 03:13 PM
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Registered
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Fred, who makes the crank on the left and what cam are you running with it?
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06-08-2018, 03:22 PM
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Under the radar
Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
Posts: 7,129
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Quote:
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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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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06-08-2018, 03:42 PM
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Puny Bird
Join Date: Nov 2002
Location: Port Hope (near Toronto) On, Canada
Posts: 4,566
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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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'74 Porsche 914, 3.0/6 '72 Porsche 914, 1.7, wife's summer DD '67 Bug, 2600cc T4,'67 Bus, 2.0 T1 Not putting miles on your car is like not having sex with your girlfriend, so she'll be more desirable to her next boyfriend. Last edited by Mark Henry; 06-08-2018 at 05:48 PM.. |
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06-08-2018, 05:28 PM
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Registered
Join Date: Jun 2003
Location: Camarillo, Ca.
Posts: 2,418
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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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Aaron.  F.S. 1965 Solex engine w carbs/cleanerBurnham Performance https://www.instagram.com/burnhamperformance/ |
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06-08-2018, 05:31 PM
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Registered
Join Date: Sep 2015
Location: Costa Rica and Pennsylvania U.S.
Posts: 3,301
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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
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06-08-2018, 05:37 PM
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My Garage
1971 Porsche 911
Baja Bug
