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Old 03-04-2011, 04:09 PM
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Flug540 Flug540 is offline
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Location: Hayward, CA
Join Date: Nov 2009
Posts: 606
Mein Auto: 1998 BMW 540i 6-spd
Originally Posted by franka View Post
The spring load is important to prevent the valves from 'floating' at less that the engine's rpm limit. It is not about preventing the valves from leaking. Even a very weak spring will close a lapped and stationary valve and prevent it from leaking.

A spring load tester, the equipment and not the person, will read-out the lbs of force it takes to compress the spring at two different hts. One height is when the spring is installed and the valve is closed, and is called the seat load, and the other is when the valve is fully opened. The load at each of the two specified hts is important, though the open load figure is most important.


I don't mind the long post at all, thanks a lot for taking the time to go into details. I'll have someone evaluate my springs when they are out (this weekend, I hope).

I read a couple of articles about back-cutting and (correct me if I'm wrong) it seems that it's mostly done to a "penny-on-a-stick" type of valves, not the tulip type that BMW uses.
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