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Reply to "A(nother) Bridge Too Far"

You had me at beehives, Stan.  I love this stuff, this kind of detailed thinking and building, seeing the way you and your builder are sweating the details. Magnificent!

I love the way springs behave. How, say a different number of coils over the same distance at the same spring rate changes everything. I got into it through race bike suspension set up, not valve trains, but things can get really crazy really quick.

I'm also glad I decided to go Suby before this post was up.  It's like Stan is standing just down a side alley saying to me, "Hey, kid, come here. I got some candy for ya."

Thanks (I think), Michael. It's apparent that God made (at least) 2 of us. It's the small things like these springs that get me all worked up.

A standard "HD dual" valve-spring for a VW has about a 1.54" install height. The springs have 5 coils and an interference fit to keep harmonic vibrations under control. That friction increases oil temperature.

The beehives are installed at 1.7", with a funky looking retainer set-up that brings the spring almost all the way out the the lash-cap. They wires are oval-shaped, with 6 coils per spring. This means that each coil moves less with each compression. There are no inner springs, so there is no friction. The nose pressure is about the same as the standard HD dual springs (295 lbs), but the seat pressure is lower (about 110 lbs).

The part of the spring that moves the most (the top) is lighter than the duals, so it's easier to keep under control. There are two reasons to love the idea of these things: the reduction in friction, and the reduction in valve-train weight. The benefit of the first is obvious, but it's that second part I'm really excited about, as it's kind of a new way of thinking for me. This will be my first engine with smaller (40 mm) intakes, lighter lifters, light retainers (12.5 grams), and aluminum push-rods. I'm really hoping to be able to spin this out to 7000 RPM, as the cam will still be making power up there.

It's a big engine to spool up that far, but that's why we're doing what we are with the bottom end. But that's a story for another night. 

Last edited by Stan Galat
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