Valve Lift Rule Question

[Stan Clayton]

Here's one for you old timers in FC/S2. What is the origin of the two different valve lift specs in the FC/S2 engine rules? If you take a look at paragraph B.3.a. on page 193, the valve lift is set at .400" +/- .005". Now flip to page 195 and look at the table in paragraph "i.". If I measure my valve lift with a metric caliper I can use 10.442 mm. That converts to .411". Woot!

[R. Pare]

Most likely an oversight when some re-wording took place - pretty common all over the GCR.

[Stan Clayton]

You could be right, Richard...I only started keeping GCRs in '99. It's in the GCR at least that far back.

[R. Pare]

It's in the '98 version also. I may have some earlier ones around here somewhere, but not a clue as to where they are at the moment.

The real questions are these:

Why have no engine builders noticed this years ago?

What lift are they actually going to?

Which lift will the club make the legal one? ( I suspect that the .411 lift is the correct one)

[Stan Clayton]

Richard,

I have just been told by a former CRB member that he thinks the table in "i." was added in 1994 to describe the cams Crane was making for Ford Motorsport at the time, but he's not 100% certain of that. And I'm told that over the years we've had OEM Ford cams, Ford Motorsport cams, Crower cams, Crane cams (both under their own name as well as with a Ford logo), and a couple of English cams (again either with or without a Ford logo). As long as they meet the spec geometry (profile, max lift, heel-to-toe length and lobe separation angle) we haven't really cared all that much where they came from (hence the line in the FC/S2 specs about the "approved supplier"). In any case, I see nothing in the GCR that deliniates the cams. Just that if you measure it in inches it can only be .405"...but if you measure it in millimeters it can be .411".

I have only talked to Steve and Jay about this so far, and they both say they've known about it for years. Each said he raised the issue to the CRB years ago, but that nothing was done about it. Each also said they build engines to .400" lift and recommended we delete paragraph "i." from the 2009 GCR.

I strongly suspect that if a competitor shows up at the Runoffs and his cam checks out at 10.442mm we would have to concede that it's compliant.

Stan

[R. Pare]

I'd talk with the other builders, JJ, Sandy, Williams, Arnie, etc., to see what they have been doing - if I were building a motor and saw the table, I'd expect that it is the the "more official" specification for no other reason than the fact that it gives much more detail. If indeed even one builder has been using the higher lift value, then just change the .400 lift figure to .411, or drop that earlier lift reference from the specifications - why have the same spec in 2 different areas?