vettenuts

iTrader: (4)

I am getting ready to do my valve spring and rocker setup. The spring shims come in 0.015, 0.030 and 0.060" thicknesses. Seems reasonable to me that the original machining on the head must be within 0.015" between spring pockets. If that is the case, then shims wouldn't be required to get the same installed height.

Does everyone measure their installed height, or just install out of the box?

3rdgenguy

iTrader: (1)

what does the directions suggest as the installed height? assuming you are going with aftermarket springs and such?

vettenuts

iTrader: (4)

The Cranes that I bought install at about 1.76" on an LS1 if I remember correctly, about 125# seat pressure.

383LQ4SS

iTrader: (33)

I am putting some different springs in right now. Mine are Comp 923s ( I think that was the PN) They are 200 lbs at 2.00 install height. I am installing them at ~1.940 which will put seat pressure right around 230 or so. Coil bind on the box sais 1.090. But you really need to actually measure coil bind with a retainer in the spring. The coil bind of the 923 with my Comp Titanium retainers was 1.130.
SO:
1.940 install height (measure with height mic)
1.130 coil bind measured with travel mic
= .810 available lift
subtract .060 to leave room before coil bind
Thats .750 usable lift
My cam is approx .735 lift.


I also measured the actual spring pressure on the new springs. At the 1.940 installed height they are approx 230. Open pressure at max cam lift is about 550 lbs

I suspected some valve float or seat bouncing with the old Comp 999 springs so I measured the actual spring pressure on the ones removed. They measured at 170 lbs at the ~ 1.860 that they were installed. They are supposed to be 200 lbs at 1.900

So having said all that...if you have machined the spring pockets, changed a few things around, are using a new spring that you havent used alot (like a 918) I suggest checking EVERYTHING.

I have found spring charts to be wrong lately too. Lots of bad info out there..or atleast inaccurate. Couple that with mediocre quality control......and you get the picture.

If you want it done right....youll have to do it yourself and check everything twice.

I just finished the driver side...Ill do the passenger side thursday.

krexken

I've gotten by using a 6" scale to measure installed height. You should be able to get it to within 1/64 (.015) using one properly. I'd never assemble something and not check them all. Depth of the valve seats and different retainers can change the installed height drastically. Like some wiseass once said, "let your conscience be your guide".