924Board.org

[MikeJinCO]

Has anyone come up with replacement valve springs that fit our retainers? Or valve springs and retainers for the 9mm stem valves. My old used ones seem to be down about 18% on open pressure.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[MikeJinCO]

I was looking for replacement with a higher closed pressure than stock, about 110 vs 63 and similar open pressure of about 230. After hours going thru old paper valve catalogs I found only one Comp Cam small block Chevy single valve spring with damper that might work with our retainer and no guarantee on that due to the damper. Our spring wire size is generally a lower spring rate than we have. I'm currently working with RD Spring on a setup similar to a high performance 944 setup as they also use 9mm valve stems and valve locks of similar OD for the retainer. An expensive setup, but would give 115 closed and 240 open pressure. This can be made to work as the 931 has rotators on all valves so deep valve pockets for shims as needed. The NA head I believe has rotators on exhaust only so they could be more difficult to set up.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[MikeJinCO]

I only had access to US spring makers catalogs and could not find any European of Japanese spring makers on line. I might expect some old Volvo, Alfa or even Porsche/VW springs might be much closer to working.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[Fifty50Plus]

Someone on this board in Australia had some made 6-8 years ago as part of a group buy. They were for the stock NA valves and I bought some. The quality control for spring pressures wasn't as good as stock.
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1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA