Valve geometry hell |
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Valve geometry hell |
malcolm2 |
Jun 25 2020, 09:19 PM
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#1
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Advanced Member Group: Members Posts: 2,738 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
Help me out here. Working on the subject and can’t figure it out.
9590 cam. 0.426 lift on the card. Adjustable pushrod tool. I get to 0.426 lift. But the geometry between the swivel foot and the valve is wack. That is shortening the PR. Stretch out the PR and i get 0.430 lift and almost straight valve to adjuster. The foot is too tight to the 1.7 rocker boss. Bought some shims to lift the rocker stand and try that. Question is: why am I so far off the card lift? Does it matter? |
Jake Raby |
Jul 4 2020, 06:24 PM
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#2
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
With the 9590 you should dial in around a 27.1cm pushrod on the intake, to net .434” lift~
The exhaust side will usually never net more than .410” lift due to the rockers. Typically the pushrod on the exhaust side will run around 27.0Cm in length to net the most lift. These are examples, but usually pretty close. There’s 11 variables that play into this, the biggest being flycut depth and cylinder shim figures. I have taken up to .080” off of rockers, then lightened the 35 grams, with no issues. Those were for the 2563cc in my 356C, which has been together since 1999 and I haven’t broken a rocker yet.. |
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