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racing97 racing97 is offline
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Join Date: Mar 2004
Location: So. Ca.
Posts: 431
Lightly tap the Teflon seal into place with a suitable socket be careful not to over do it it probably goes down about 8mm or so. Usually there is a piece of formed plastic in the Gasket kit that goes over the valve to protect the seal on the valve stem from being damaged in the process.
In regards to the Springs, Porsche makes a tool that one would use in conjunction with the top retainer and the bottom pearch to arrive at the preload. If you do not have such a tool you can resort to what many Performance Engine Builders do, and that is to set the Tension at Full lift a given distance away from the spring bottoming. This clearance is generally 1.25mm. To do this install one Top Retainer together with the Keepers on one valve, pull the retainer into the intalled position and measure to the bottom of the head without the spring seat installed. This measurement should be done with a Venier Caliper as square as possible to the Valve Axis. Repeat for the opposite valve and record.
This will provide the measurement of the Installed Height. Now for preload you will need cam lift and if you don't have that measure (subtract) the small side from the tall side of the cam lobe and multiply it by rocker ratio I think 1.425 will do. With your Cam lift figure in hand go to a Vise and compress the Spring to your Installed Height (first measurement) also use your same Caliper and Subtract your Cam Lift (your second measuremnt) by compressing the Vise remember you absolutley must have 1.25 for clearance before the spring coils touch and the rest should be made up of shims for your preload. This should be as good as it gets since all compression springs are design to a given Clearance before the coils touch and in the case of the Porsche 1.25mm is a proven safety margin and the spring rate is what it is by the material and size of wire and it will not change, but this installation will affect the seat and nose pressures in acoordance with your shim pack
This can be done with simple tools but does not provide information in regards to the spring rate and or the condition of the springs.

Kindest regards
Old 01-03-2005, 01:37 PM
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