Changing LSA

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Mar 23, 2015 | 01:02 PM

c66vet

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Changing LSA

Looking for feedback on advancing a cam. I want to know what will happen if I install a cam that has a 109 LSA and install it at a 112 LSA.

Will installing the cam at 112 LSA lower the power band and smooth the idle out. Or the difference of 3 degrees between 109 and 112 degrees is not noticeable at idle. Strange question I'm sure.

Thanks

Mar 23, 2015 | 01:06 PM

MelWff

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You cannot change LSA it is ground into the camshaft. What you can do is advance or retard a cam. Read these two links.
http://www.compcams.com/Pages/413/ca...ion-angle.aspx

http://www.superchevy.com/how-to/eng...formance-test/

Mar 24, 2015 | 06:13 AM

c66vet

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Quote:

Originally Posted by MelWff

Thanks for the feedback.

Mar 24, 2015 | 06:18 AM

c66vet

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Quote:

Originally Posted by c66vet

Thanks for the feedback.

I was trying to determine how rough/radical the idle would be with this cam in a 540. Cam spec's 250/254 @.50, 714/680 LSA 109.

Mar 24, 2015 | 09:38 AM

427Hotrod

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Hmmmn...that depends on your idea of rough and radical.

I ran a 266/272 on a 112 in my 540 for years and considered it sort of "wussy" sounding even with 11.5 compression. Ran like a **** though! It idled around 1100 comfortably...could go lower...but I liked it there.

I've got a little 248/248 on a 114 in it now with the twin turbos. Interestingly doesn't sound a whole lot different to me,,,but I took out 2.5 points of compression also.

Is this a solid roller or a hyd roller?

Either way, I wouldn't expect it to idle bad at all. It will have very sharp throttle response and strong mid range pull.

What trans will be in it...stick or auto?

JIM

Mar 24, 2015 | 11:27 AM

1Hotrodz

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Advancing/ retarding the cam will change the intake centerline.

Mar 24, 2015 | 06:04 PM

427Hotrod

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To specifically answer your question....retarding the cam from a "straight up" installed ICL of 109 to 112 (assuming this IS a 109 LSA cam)...you'll move the powerband upwards...not downwards. It will likely make a little more HP at higher RPM...a little less at lower.

3* won't typically move things a lot...but it will show the trend.

You'll still have the same overlap...yet with a later intake closing point...which will tend to lower cranking compression slightly and possibly make it idle a little worse.

Nothing dramatic...but typically that's the wrong way to go. Advancing it would build cylinder pressure at lower speeds an increase vacuum by closing intake a little earlier...which tends to help low speed operation.

JIM