Cam timing
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TECH Apprentice
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Joined: Aug 2014
Posts: 361
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From: Jupiter Florida
Cam timing If this is a rookie question, please forgive me. ..
I calculated my statuc and it comes out to 11.7:1.
Is there any way to tell by my cam specs if I have enough overlap to bleed off enough compression where I won't be so close to "no margin for error". And is this dictated by how early the exhaust valve opens? It's a TSP Ls7 2.2 cam and my heads are coming in at 66cc's . Pistons are .001 in the hole. I plan on using 93, but I'm not sure I got the right cam. I guess I'm trying to figure out if I need a custom cam. Oh, and the pistons are flat top with 5cc valve reliefs. Any advice would be appreciated. Thanks
I calculated my statuc and it comes out to 11.7:1.
Is there any way to tell by my cam specs if I have enough overlap to bleed off enough compression where I won't be so close to "no margin for error". And is this dictated by how early the exhaust valve opens? It's a TSP Ls7 2.2 cam and my heads are coming in at 66cc's . Pistons are .001 in the hole. I plan on using 93, but I'm not sure I got the right cam. I guess I'm trying to figure out if I need a custom cam. Oh, and the pistons are flat top with 5cc valve reliefs. Any advice would be appreciated. Thanks
TECH Enthusiast
Joined: May 2008
Posts: 642
Likes: 572
From: Carnation, WA
Specifically, the intake closing event as measured at .006” (“advertised” duration vs. .050” duration).
If you don’t have this number, adding 25-26 degrees to the .050” number should be pretty close. Then go plug your numbers into the Wallace Racing DCR calculator online. You want a DCR < 8.7:1 to run pump 92 octane.
If you don’t have this number, adding 25-26 degrees to the .050” number should be pretty close. Then go plug your numbers into the Wallace Racing DCR calculator online. You want a DCR < 8.7:1 to run pump 92 octane.
