Cam Explanation
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
Cam Explanation
I'm concerned how changing a cam will affect CR.
I currently have an Isky 256 cam, 450 lift, 202* duration @ .050 lift, 112 LSA. Nice, mild cam.
I'm considering the Howard 263 cam, .448 lift, 209* duration @ .050 lift, 108 LSA. I have to admit I long for the lope at idle. Also, with this cam it is my understanding I should still be able to tow/haul.
I need to know with the 4* diff. in lobe separation, is that going to change my CR much/any?
Thanks for the help.
I currently have an Isky 256 cam, 450 lift, 202* duration @ .050 lift, 112 LSA. Nice, mild cam.
I'm considering the Howard 263 cam, .448 lift, 209* duration @ .050 lift, 108 LSA. I have to admit I long for the lope at idle. Also, with this cam it is my understanding I should still be able to tow/haul.
I need to know with the 4* diff. in lobe separation, is that going to change my CR much/any?
Thanks for the help.
Senior User
Joined: Jan 2013
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Not going to be much change between those two at all. The new cam might have a touch better low end power due to the lsa, but the tiny duration difference likely won't even be noticeable unless you put it on a dyno.
What are your goals?
What are your goals?
Senior User
Joined: May 2014
Posts: 212
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From: auburn, ca
the tighter the lsa, the choppier the idle. the only thing about a cam profile that will effect your cr is overlap(having both valves open at the same time) lots of overlap usually means a higher rpm cam.
usually a cam with 210* of duration @ 050 and higher will make it lope. maybe a cam between 215~225 with definitely lope on a 108 degree lsa. get above that and you will have a more agressive idle. in my '56 Ford f-100, my cam is 242* at 050 and its pretty rowdy( setting off car alarms in parking lots!!)
usually a cam with 210* of duration @ 050 and higher will make it lope. maybe a cam between 215~225 with definitely lope on a 108 degree lsa. get above that and you will have a more agressive idle. in my '56 Ford f-100, my cam is 242* at 050 and its pretty rowdy( setting off car alarms in parking lots!!)
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Joined: Apr 2004
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Static is fixed, dynamic depends on the cam:
Static Vs Dynamic Compression Ratio | Piston Ratio
A lumpy, long duration cam in a low compression engine is a mistake.
Static Vs Dynamic Compression Ratio | Piston Ratio
A lumpy, long duration cam in a low compression engine is a mistake.
Super Moderator
Joined: Apr 2004
Posts: 34,475
Likes: 2,800
I'm concerned how changing a cam will affect CR.
I currently have an Isky 256 cam, 450 lift, 202* duration @ .050 lift, 112 LSA. Nice, mild cam.
I'm considering the Howard 263 cam, .448 lift, 209* duration @ .050 lift, 108 LSA. I have to admit I long for the lope at idle. Also, with this cam it is my understanding I should still be able to tow/haul.
I need to know with the 4* diff. in lobe separation, is that going to change my CR much/any?
Thanks for the help.
I currently have an Isky 256 cam, 450 lift, 202* duration @ .050 lift, 112 LSA. Nice, mild cam.
I'm considering the Howard 263 cam, .448 lift, 209* duration @ .050 lift, 108 LSA. I have to admit I long for the lope at idle. Also, with this cam it is my understanding I should still be able to tow/haul.
I need to know with the 4* diff. in lobe separation, is that going to change my CR much/any?
Thanks for the help.
Wallace Racing: Dynamic Compression Ratio Calculator
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