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Perpetual Reassembler
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Valve Springs Upgrade Worthwhile? 3.0 SC
I am about to start reassembling my 3.0 motor and am trying to plan ahead on the head work.
Motor has 200K miles on it. Case, crank, and rods checked out ok, crank was polished and rods have been rebuilt. 9.5:1 JE pistons will be going in and I will keep the CIS. I might do 964 cams when I get to the top end of the rebuild. Car will mainly see spirited canyon driving and autocross. With my main goal of making sure the motor lasts another 200K miles, is there any value in upgrading the valve springs for the sole purpose of protecting the valves during a missed shift? I am not interested in raising the redline or tracking the car. I guess the downside is shortened cam life, correct? Thanks in advance.
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Jose - 1983 911SC Coupe Instagram: @joe_engineer 911 D I Y Blog: joe-engineer d o t c o m D I Y Vids: https://www.youtube.com/joeengineer |
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abit off center
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I would run stock springs which are very good! and work on not missing a shift, maybe update the shift mech?
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______________________ Craig G2Performance Twinplug, head work, case savers, rockers arms, etc. |
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Jose,
I would not install aftermarket springs in an engine that will not be raced or see any track days. What I WOULD do is test each & every valve spring to make certain they still meet specification. Naturally, one replaces the ones that don't. ![]() If you are concerned about a missed shift and the ensuing consequences, the VERY best thing you can do to prevent that is by installing a Wevo shifter and replacing the shift coupler and shaft support bushing with new factory ones. I've found those items are more effective in preventing missed shifts than anything else I've used.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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Perpetual Reassembler
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Thanks for the feedback. I was just trying to think of all the possible safeguards to put in place "while im in there".
Ill proceed with stock springs on my heads rebuild!
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Jose - 1983 911SC Coupe Instagram: @joe_engineer 911 D I Y Blog: joe-engineer d o t c o m D I Y Vids: https://www.youtube.com/joeengineer |
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Registered
Join Date: Feb 2007
Location: Northeast
Posts: 463
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I'm in agreement with Cgarr and Steve-stock springs are what you need and it's a moot point
whether you should replace them at 200K-don't waste time checking them-the're not expensive, esp if one broke somewhere down the road!
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Mark www.exotechpower.com 1981 Targa-messed with. 91 C2 supercharged track rat Radical Prosport-irritates the GT3 guys 40 years of rebuilding services |
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