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Thread: Installed valve height

  1. #11
    Join Date
    Jun 2007
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    Hudson, MA
    Posts
    8,811

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    Quote Originally Posted by kcabpilot View Post
    Hope I'm not boring you guys with this stuff but it is kind of quiet around here.
    Nope, not boring us! We're all still here, we just don't post a lot of stuff as many of us talk offline as well as here.
    I enjoy talking to you. Your mind appeals to me. It resembles my own mind except that you happen to be insane.
    ― George Orwell, 1984

  2. #12
    Join Date
    Sep 2009
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    In the big house
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    7,068

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    Quote Originally Posted by kcabpilot View Post
    Another update: After going through the intake side of the 1-4 head I'm in pretty good shape, they are all within spec and I'll be able to use the shims I have. Looking back at my initial measurements that I took when I first started disassembling the engine I mentioned that all of my exhaust clearances were tight. Radioman said this is normal due to valve recession and to be expected. Just running through the calculations of what shims I would have needed at that time if I were just doing a valve clearance adjustment and had not done any head work I can see that many of them would have needed shims in the 3.75 to 3.80 range which were already under the ideal range before any machine work was done. As it sits now I would need at least two 3.40 shims, the rest (so far) in the 3.55 to 3.75 range. the rim of the bucket averages about 3.00 so a 3.40 shim still sits 15 or 16 thousandths above it as opposed to a 4.00 shim that would sit 40 thousandths proud.
    Valve seat recession is normal, as well as wear on the face of the exhaust valve. But, there are limits. It is rare that I replace valves seats while doing heads. It is common for me to replace valves, particularly exhaust valves. If the "margins" on your exhaust valves are too thin, they will dissipate heat poorly and wear quickly. With that said, You're on the right path. I try to always stay above 3.75 mm and below 4.25 mm. Yes, this is tedious work. But, when it's right, it's right!
    Sarasota Italian Garage, LLC
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