View Single Post
Neil Harvey Neil Harvey is offline
Registered User
Join Date: May 2004
Posts: 218
If you have the bracket that holds the dial indictor to set the valve timing,(cam timing) use it to measure the retainer heights.

Without the need to destroy anything, get a round "tube" of a known exact length that fits inside the spring base outer platform and the retainer outer face. 1.00" or 25.40mm is a good size. Assemble the valve with its base, this tube and the retainer and locks. With your dial indictor set up on the 90 degree holder, measure the distance the retainer travels from the valve seat to the "tube". If you use a 1.00" spacer tube, the total distance will be approx. 1.400 - 1.500" typically.

This way I believe the accuracy will be higher. Then if you do set up the springs by installed height only, I think the spring installed height on some engines is 46.00mm or similar. Do some simple math and the difference between what you measure and 46.00mmis the shim thickness that needs to be installed.

But, remember, without measuring the springs, the seat pressures can be all over the place with only the installed heights used. Does this make a difference. A huge one at engine speed. At 6800 RPM, you would be horrified at the differences. Any speeds over 2500 RPM, the spring pressures affect the valve motion. At higher engine speeds, the cam timing goes nuts. Each valve has to be considered individually here as the seat pressures and nose pressures are different. Add in the differences in each spring and your hope of controlling the valve timing is basically out the window and its all down to a hope and prayer it all stays close.

These are one of the many little build things that make the difference in why one engine performs at a higher efficiency over others.
Old 06-01-2018, 05:26 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)