Camshaft lobe overlap

[sbw9056]

I am looking at purchasing a cam with these specs:
duration 208/217 ,lift .508/.509 ,LSA 114
I plan on using 1.8 ratio rockers, which will change the lift to .538/.539. I don't know how much the duration will change.
My concern is, how much overlap does this cam have, and how will it effect emmisions? Will I still pass a sniffer test?

[farmtruc]

<div class='quotetop'>QUOTE(sbw9056 &#064; Jan 22 2007, 09&#58;18 PM) [snapback]80824[/snapback]</div>

I am looking at purchasing a cam with these specs:
duration 208/217 ,lift .508/.509 ,LSA 114
I plan on using 1.8 ratio rockers, which will change the lift to .538/.539. I don&#39;t know how much the duration will change.
My concern is, how much overlap does this cam have, and how will it effect emmisions? Will I still pass a sniffer test?
[/b]

It&#39;ll have approximately -15.5 overlap, so no overlap.

It should pass with no problems.

allen

[misterp]

<div class='quotetop'>QUOTE(sbw9056 &#064; Jan 22 2007, 09&#58;18 PM) [snapback]80824[/snapback]</div>

... I plan on using 1.8 ratio rockers ... I don&#39;t know how much the duration will change. ...[/b]

When you swap rocker arms you will increase duration, the exact amount depends on the cam grind but in general the motor will act like it has another 3-4 degrees duration, along with the 6% increase in lift.

Mr. P.

[Ascrap2003]

Sounds like a pretty mild cam, I think it should pass no prob. To get the exact overlap you need to talk to the cam manufacturer or consult the cam card.

[farmtruc]

Even with the increase in duration because of the higher ratio, it&#39;ll still be ok.