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930 rebuild
I am going to have to open up the motor on my 930 as I strongly suspect a bad bearing.
In contemplation of this large and expensive project I had a few questions. What are my bearing choices for a 930 crank? IIRC I have ready several post where the bearings currently available are not what they used to be? I was thinking about going to a 964 or GT3 crank should my 930 crank need work. Thoughts on that? IIRC the GT3 crank will need more clearance in the case. How good is a crank repair of welding, turning back to correct size, and hardening? The use for this car is street only with some spirited hill country roads in a 78 sunroof delete mostly stock Euro 930 (has SC cams and 993 heat exchangers). Thank you in advance. John
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John- 78 Slick Top 930 "Illegitimi non carborundum" |
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01-18-2015, 09:08 AM
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,249
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You should also ask this question on the engine rebuild forum. There's some helpful people there that know what they are talking about.
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01-18-2015, 09:35 AM
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Chain fence eating turbo
Join Date: Dec 2008
Location: Austin, TX
Posts: 9,125
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John, IIRC, a Carrera 3.2 is the same exact crank as the 930. This should open up the search for a good used one.
When I tore my 3.2 down, the journals were perfect after a hard life over 500hp. I almost reused the bearings they were so pristine. Opposite of classic American iron where the journals show wear in a short timeframe. |
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01-18-2015, 10:20 AM
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beancounter
Join Date: Jan 2008
Location: Weehawken, NJ
Posts: 3,593
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A mentioned by Tippy, 930 shares a crank with 3.2 Carrera, so you can find STD/STD cranks. When I did my rebuild, the rod journals were marginal (under spec but above wear limit). I have the crank re hardened (nitriding process) which actually increased the dimension back to spec. This is documented on my rebuild thread (easy to find on this forum).
Best, Jacob |
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01-18-2015, 10:25 AM
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3 restos WIP = psycho
Join Date: Feb 2005
Location: North of Exit 17
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It is the rod bearings that are crap, not the mains
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- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
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01-18-2015, 11:32 AM
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Location: new jersey
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Quote from Mike Bavaro when he was rebuilding mine.
"Steve,*Crank is back, balanced and polished. It measures within .0005" of new!Remarkable, I take liquid coolers apart with half the horsepower and half the miles and they are worn almost to the limit!" My rod bearings were smoked but the mains were fine. They don't make stuff like this anymore.
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1981 911SC Black metallic, no sunroof. Sold(damnit)2005 987Guards Red, Stuttgart build. Sold1978 911SC Bahama Blue, M491 look E class PCA race car.Sold with help from Pelican. Thanks! 2005 997 Black. Sold1988 930 Grand Prix White. Keeper. 2008 957 Basalt Black, Pneumatic suspension and PDCC. |
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01-18-2015, 12:53 PM
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3 restos WIP = psycho
Join Date: Feb 2005
Location: North of Exit 17
Posts: 7,665
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50% more main bearings than a V8 = no surprise
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- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
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01-18-2015, 01:00 PM
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Chain fence eating turbo
Join Date: Dec 2008
Location: Austin, TX
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Quote:
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01-18-2015, 03:19 PM
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Registered
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Quote:
Yes, that's what I have read is the rod bearings are not as good as they used to be. They seem to wear quickly. I have read some turn the rod journal down, IIRC to a smaller size and use a GM bearing which would require a different rod, again IIRC.
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John- 78 Slick Top 930 "Illegitimi non carborundum" Last edited by sundevil64; 01-18-2015 at 05:58 PM.. |
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01-18-2015, 05:55 PM
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Chain fence eating turbo
Join Date: Dec 2008
Location: Austin, TX
Posts: 9,125
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At least you can reuse your dizzy gear then and swap between the 2.
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01-18-2015, 06:40 PM
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