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Milling heads, DCR

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Old Dec 9, 2006 | 07:04 AM
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Question Milling heads, DCR

A little background info: I installed AFR 205 heads w/ 66cc chambers and a Crane 220/224 .583 114 cam a little over a year ago. Now, I am thinking of milling my the heads the necessary .024 to get a 63cc chamber and bump my compression up to 11.21, right now it is 10.79. All of that being the easy part, here come the questions...

Pushrods, since the heads will be milled, in theory a shorter pushrod should be used. But, I have the Crane gold adjustable rocker arms, so could I just adjust my preload, insted of the 2 full turns only go 1.5 turns?

Intake and Headers, since the heads will be sitting a hair lower, I assume that it will not cause any isues with these components, but I just figured I would ask.

DCR, I am using Pat Kelley's DCR calculator to plan all of this out. It calls for the advertised duration 282/286 (@.004), LSA 114, and ILC 110. When I enter all of these numbers it tells displays vavle events, overlap, and advance. The problem is that the valve events that it lists do not match the ones on my cam card card says IVO 27, IVC 75, EVO 77, EVC 29, program says 31, 81, 71, 25 respectively. It also indicates that my cam is advanced 4*. If I change the ILC to 114, then the valve events match and there is no advance. I installed the cam with no advance, so does this mean that the cam has 4* of overlap ground into it? I tend to think that that is correct as hp peaked at 5800 on the dyno. If it is my current DCR is 8.15 and with a 63cc chamber it would be 8.46.

What do you all think? Any and all assistance or ideas that you all have are greatly appreciated!!

Last edited by Blk02Ls1A4; Dec 9, 2006 at 07:13 AM.
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Old Dec 9, 2006 | 07:54 AM
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shorten the pushrods, these motors like preload. as fas as dcr/scr calculator try www.kb-silvolite.com that should help., oh and if you have dyno numbers on that cam let me know, i want to see if it compared to the last one one i did for a customer. your cam should be a crane 144hr00067, and with 1.8 cranes it's .589 lift. my combo made power to 6000rpm. 401/hp 381trq
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Old Dec 9, 2006 | 09:15 AM
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Originally Posted by JPH
...as fas as dcr/scr calculator try www.kb-silvolite.com that should help.
It has one glitch. Do not add 15 degrees to your .050" ivc as they request. For example w/ XE-R lobes you need to add 24.5 to get the .006" number and the correct DCR. The 15 degree they show is for a solid roller cam.
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Old Dec 9, 2006 | 12:29 PM
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Here is a link to the calculator... http://members.uia.net/pkelley2/DynamicCR.html
I also tried the excel sheet at the top of the Advanced section and achieved the same results.

JPH, That is the cam... Do you know if it has 4* of advance ground in or any other info, other than what the cam card says? I dynoed before the Fast90/NW90 and underdrive and made 385/374 with the converter locked. I am hoping to have gotten those 15 ponies with the intake and pulley, dang ole A4.

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Old Dec 9, 2006 | 12:44 PM
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yes, 4* is it. your intake centerline should have degreed in at 110. #'s look good for an a4 car.
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Old Dec 9, 2006 | 04:47 PM
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Just make sure your rocker arm geometry is still correct after you adjust (aka, check the swipe pattern on the valve tip.)
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