valve depth

[superbike]

Hi all

If we were cutting valves into a 16v head obviously if we were not careful we could end up having one inlet valve a little deeper than the other.

With my Peg FM1 seat cutter (which by the way is working very well now) I usually end up with 0.05-0.10mm variation in height between valve tips. I'm asking is this an acceptable figure ? If not I could make some sort of depth control to get it more accurate.

[Guy Croft]

0.05 -0.10mm - that is perfectly acceptable Chris, very good in fact.

Obviously if you have rocker valve train it's a bit more critical to get tip heights equalised than with bucket tappet operation, but apart from the rather modest influence on cylinder head volume (and thus CR) a variation in tip height only really affects shimming up.

You can always correct the tip height (I call it valve setup height or VSH) by grinding the valve tips but with many heads it's not easy to measure the valve setup height to more than 0.2mm accuracy due to deviations in flatness of the spring platform (if that's what you're measuring to).

GC

[superbike]

I judge the height by eye
I must have 20/20 vision apart from the lump of steel they removed from my left eye last sunday LOL oops GOGGLES EVERYONE !