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Join Date: Feb 2012
Posts: 246
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Choice of valve springs for camshaft
I have a question. Is it safe to use genuine Porsche valve springs and retainers with the Webcam 120/104 camshaft profile? Or is it an absolute must to use performance springs and TI retainers?
After what I have read the genuine springs handles up to 11,8mm / 0,465 inch lift. A friend of mine has been using genuine springs with no problem for 6 years in a 3.4 short stroke Carrera engine toghether with a cam profile that has 0,490 inch /12,446mm lift 
Last edited by Litle brother; 08-01-2019 at 01:31 AM.. |
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08-01-2019, 01:18 AM
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Registered
Join Date: Feb 2012
Posts: 246
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Here’s the specs on the 120/104 cam:
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08-01-2019, 01:25 AM
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Registered
Join Date: Jul 2005
Location: Atlanta
Posts: 1,241
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I am running a very similar cam. Dougherty DC65. I run Cat cams 911 springs which are only a very slight amount stiffer than stock, yet certainly not as stiff as Aasco springs. You're in Europe so it will likely be easier to obtain. Highly recommend Cat cams springs.
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No physical quantity completely explains its own existence |
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08-01-2019, 09:04 AM
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Now in Florida !
Join Date: Aug 2012
Location: York Beach, Maine and Anastasia Island, Florida
Posts: 406
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Good tip on the CatCams springs. Sounds like a great compromise between stock and the super stiff race springs. I've always been concerned with the pounding the valve seats, retainers, rockers, etc receive when running race springs.
I recall a similar question in an earlier thread. Fred Apgar had responded that he always used stock springs that had been cryo'd in his race motors. Thread link: Large Port SC Valve Spring Retainer?
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1983 911SC Coupe Hot Rod - Platinum - Twin plugged 3.4, DC-60 cams, PMO 50's, 1 3/4 headers, Bill Rader 915 w/LSD 1976 914 2.0 Lime Green Metallic - Completely stock Last edited by Tom_in_NH; 08-01-2019 at 12:12 PM.. |
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08-01-2019, 11:59 AM
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Registered
Join Date: Mar 2004
Location: So. Ca.
Posts: 521
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When I was looking for springs I measured the Stock spring at 315 lbs per inch a increase of 45 lbs per inch (360) was not considered detrimental at all. The folks that use a spring from another application particularly a spring used for a push rod motor with inordinately heavy seat pressure is what gives springs a bad name when wear is considered. It also didn't help when Web Cams had their hard face overlay issues which I since believe they rectified.
regards |
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08-02-2019, 06:51 AM
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