Knocking at idle
Road Master
Joined: Jun 2009
Posts: 1,062
Likes: 18
From: Beautiful SW Missouri Ozark Mountain Country
OK guys, I don't want to hijack this thread, but I have a question since you're on the topic.
Are you suggesting adding a cam with no other mods? The reason I ask is because if I were to add a higher lift/duration cam to a V8 I would do a bunch of head work, better intake and more fuel. Port and polish, bigger valves, better rockers, high flow intake, bigger carb, etc. I realize that this Evo is not a V8, but I would think the principles are the same. Or maybe this EV27 is equivalent to an RV cam in a V8?
Just asking guys. I was thinking about a cam change myself.
Are you suggesting adding a cam with no other mods? The reason I ask is because if I were to add a higher lift/duration cam to a V8 I would do a bunch of head work, better intake and more fuel. Port and polish, bigger valves, better rockers, high flow intake, bigger carb, etc. I realize that this Evo is not a V8, but I would think the principles are the same. Or maybe this EV27 is equivalent to an RV cam in a V8?
Just asking guys. I was thinking about a cam change myself.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
The EV27 is designed to be a bolt-in cam, that should have at least a better air cleaner and exhaust to realize it's potential. Like any engine it could also benefit from any of the mods you mentioned providing they are within the parameters for the level of work done on a particular engine. Bigger isn't always better, even though a lot of owners think it is.
Last edited by miacycles; Mar 9, 2012 at 10:07 PM.
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,077
Likes: 2,148
From: Ohio
John condensed alot of info into that single paragraph and a good guideline . EV27 is a compression builder with early intake closing and some steeper ramps to get some fuel in, the Woods 6 has the same numbers but the lobes are extremely steep and needs detail in installing, most of the time the lifters need set deeper to tame the clatter but produces alot of power.
Ev46 is a popular cam in light bikes but will be alittle softer on the bottom side than the Ev27 but should finish off nicely, the Andrews cams are install and ride it and the Woods will need some tinkering but good rewards.
Ev46 is a popular cam in light bikes but will be alittle softer on the bottom side than the Ev27 but should finish off nicely, the Andrews cams are install and ride it and the Woods will need some tinkering but good rewards.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
Woods cams make a lot of power with their "high lift, shorter duration" cams. We like to pull the heads and freshen them when we install a Woods cam, but it is not mandatory.
Ok since I have shut my shop down up north and plan on just finding older bikes and restoring them here is a free tip that we use to reduce the valve train noise in these cams. The roller hydraulic lifters have about .200" of travel and were originally designed for automotive use. Cars run more oil pressure than an EVO, so they work well in a car. When we put them in an EVO they work in stock applications, but basicaly it is marginal because of the difference in oil pressure and supply. We are told to adjust the pushrods to about .100" or half the travel. The cylinders in an EVO grow about .040" so now you are down to .060" or less. What we've been doing is setting the to about .140-.150" and this seems to go a long way in noise reduction. We feel that part of it is the fact that we are allowing for the .040" of growth and part of it is it the fact that you are setting close to being a solid lifter but still having hydraulic compensation left in it. The second part helps reduce the noise from the front exhaust which is a common source of valve train noise because of the angularity of the pushrod. Hope this explains and makes sense of the problem and helps some of you out there
Ok since I have shut my shop down up north and plan on just finding older bikes and restoring them here is a free tip that we use to reduce the valve train noise in these cams. The roller hydraulic lifters have about .200" of travel and were originally designed for automotive use. Cars run more oil pressure than an EVO, so they work well in a car. When we put them in an EVO they work in stock applications, but basicaly it is marginal because of the difference in oil pressure and supply. We are told to adjust the pushrods to about .100" or half the travel. The cylinders in an EVO grow about .040" so now you are down to .060" or less. What we've been doing is setting the to about .140-.150" and this seems to go a long way in noise reduction. We feel that part of it is the fact that we are allowing for the .040" of growth and part of it is it the fact that you are setting close to being a solid lifter but still having hydraulic compensation left in it. The second part helps reduce the noise from the front exhaust which is a common source of valve train noise because of the angularity of the pushrod. Hope this explains and makes sense of the problem and helps some of you out there
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purcell06
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