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Discussion Starter #1
I am looking to learn how different cam grinds affect performance and what all the numbers mean. I am pretty mechanically inclined but I would like to find a site that kinda dumbs it down a bit to help me understand it all. I have found some decent info so far but would like to fastlane to an answer and cut out a lot of the searching process. please let me know if you have any suggestions. I want to drop a set of cams in my 15 but want to understand the numbers when I look at the specs. Thanks..
 

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Do a search on the Hot Rod Magazine website and you will come across some in depth articles on this subject. Also I remember seeing a chart in the Screamin Eagle catalog that puts the information from the Hot Rod articles into V-twin perspective.

http://www.hotrod.com/techarticles/113_9604_choosing_the_right_camshaft/

Page 4 on this Screamin Eagle catalog PDF
http://www.harley-davidson.com/en_us/media/downloads/racing/us_se_p.pdf


After I wrote the post I thought "oh hell I know what im lookin for i'll just find it and link it" Hope it helps
 

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One of the better articles explaining cams that I found was in the V-Twin forum.
Go to the V-Twin forum and click on "Twin cam performance mods" and there is a sticky on the top of this section titled "Explaining how cams work and what the numbers mean".
Check it out there is some good info there.
 

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The link Ironmark mentioned is a good one to read. Plenty of info, but written where the average person can understand it.
 

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Does anyone know what the columns ".053 Timing" and "Duration .053" mean in this link?

http://www.fuelmotousa.com/performance-cams.html

Especially since there's another column that just says "Duration" with two numbers (presumably degrees?), both the same, for each cam in that column?
The .053 (more often measured at .050) is a standard measurement to accurately compare different cam's lobe design. The term .053 means the cam's duration is being measured at .053 inch of lift on the opening ramp to .053 inch of lift on closing side of the cam ramp. When you see the term 228 at .053 it is telling you the crankshaft was rotated 228 degrees between the opening and closing .053 cam measurements. If you find a cam spec sheet with two different numbers (such as 228/234 at .053) it is telling you the intake lobe is slightly narrower than the exhaust lobe. A cam of this design is referred to as a dual pattern cam and is often used to help equalize differences in cylinder head intake to exhaust flow ratios.. The column for .053 timing tells at what degree of crank rotation the cam is opening and closing the valve. In this case the intake valve would open at 14 degrees before top dead center of piston travel and close at 34 after bottom dead center. There are two sets of numbers, the first for the intake and second for the exhaust. Hope this helps, sometimes my explanations aren't the greatest.
 

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Discussion Starter #10
Thanks so much for all the responses. I have started looking through some of the links and there is some excellent info. Its a difficult thing to wrap your head around at first but gets a bit easier as you read more. Thanks again..
 
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