Custom Piston Order Form

XK-Engine
1

Just spent some hours, including physical measuring, searching greasy hard copies of books, e-material (including much time in the forum archives) for specification sources to fill in this form and all I really have left is some cam specs/info to discern:

I am running a ser3 head on a 1969 block, ser3 cams- I think this cam is .375 lift, but some archive material points to .395 (I read A LOT of the archives about this dimension(s) and am still confused)

Yet need for the form completion:

Gross Lift: _________(ahhh…is this TBD by the .375/.395 quandry solution?)
Lobe Separation: (As it is a DOHC engine this may be a moot issue)
Duration @ .050: Intake: Exhaust: _____ (no clue)
Degree in Std degrees: plus _______ degrees, minus _______degrees (no idea)
Valve Lift @ TDC: Intake _____, Exhaust _____(is this a math problem of degrees of a circle and then angle of attack, angle incidence, two trains leave Chicago at the same time, or finding out how good one’s measuring skills are, of late, and take a reading from the cams set into the head on a bench at the TDC marks and then measuring valve opening height?)

To those that can help, thanks much, in advance.

Huff
E-Type 2+2

2

Looks like I may have found the “Duration @ .050:” - from my web research it looks to be 225 degrees (would be same for Intake & Exhaust, I presume").

Thanks,
Huff

3

Many people don’t realize that the duration figures are not necessarily read at normal running clearance.

4

…as in valve lash clearances modified? (i.e…the late ser2, ser3 6 cyl cams are .012 to .014 int & exh, whereas the Ser2 are intake .004, exhaust .006)

Thanks,

Huff

5

…I may have also figured out the “Degree in Std degrees: plus _______ degrees, minus _______degrees” as that might be the advance/retard from 0 degree setup. In my case, it would be 0 (for both cams).

Huff