Valve Length

Thanks to Warren I was able to start measuring and adjusting spring lengths. Thanks Warren, you're right I ran out of springs. I will get some more this weekend.

I found another intersting situation and I'm not sure if it's a problem or not. I bought some new stainless steel valves, intake and exhaust,and while measuring them tonight I noticed the intake valves are .020 inches shorter than the valves that came out. The "c" dimesion for intake valves is 4.338 plus or minus .010 if I did the math right. The new valves are 4.312. Is the fact that they are out of spec. significant or does Stainless have a different spec. The exhaust valves are within spec. Any words of wisdom here??

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78 3.0L CIS 911SC

OOOOPS! Ran out of Shims, Not Springs...

David,

Until you know what the 'A' dimension turns out to be after the grinding or cutting of the seats, I don't even think I can comment. You can measure the 'A' dimension with a dial caliper and just the valve sitting on the seat with stem sticking up.

Just a couple of notes ... according to my calculator, your nominal Intake valve length is 4.325" +/- 0.010" yielding a min. value of 4.325" so your valve is 0.013" short, but that may not matter, depending on what you measure as an 'A' value. And why do I say that? Because I have some new TRW 3063/1 valves that measure 0.015" long, however in a new head the 'A' value is within spec ... and the 'A' value is the critical value that speaks to how the 'fit' is in the head!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 02-22-2001).]