Wondered if anyone can offer a quick answer to this. Am working something out in my head regarding these cams and need to know if they are symmetrical or asymmetrical (i.e. do they open more aggressively than they close - excuse the huge simplification).

Does anyone know off-hand?

 

Just look at the ramps ( lobes) if one side is steeper then the other---there is your answer. IE instead of being "A" shaped lobe design, the RT or opening side if looking at the intake cam from the frt will have a much steeper ramp then the exhaust-- if you cant tell the difference they are not asymetrical.

 

I know this, but I don't have the cams

I am trying to work something out before I purchase them so was hoping someone might have one of the cams and could check, or might know off the top of their head.

 

Yep---figured that out after the post....all i could find is some reference on the profile-- from Kelford, suggests they are asymmetrical, but doesnt call it our specifically.. Good luck. May want to just call them and ask.

"Because of camshaft ramp designs the valve events at a lift as low as 0.1mm are often asymmetrical this is why we specify checking valve timing at 1.00mm or .050" (in the case of imperial engines), it is more accurate for most people.

The problem with the centerline method is it has you finding the theoretical point of peak lift in relation to crank rotation. This method makes the assumption that the lobe or valve motion you are checking is symmetrical; with its opening side being the exact same shape as the closing side of the lobe. Most modern cam lobes are asymmetrical, with the opening side of the lobe being much more aggressive and the closing side being gentler. Therefore when you attempt to locate the middle (or centerline) of the asymmetrical lobe there is an automatic error. It could be as little as 2° or as much as 6° depending on the actual lobe design. Also, the centerline method does not really indicate if your camshaft was properly produced, as no confirmation of the duration at any given point. Our method will verify correct valve opening and closing and duration."

 

Yeah, might have to but I reckon they might be closed now until Monday

Reason I'm asking is because I'm looking at putting a set of Kelford 272s that were originally made for an Evo V-VIII onto my Evo III. I know the cams have to be switched and a new cut made into one of the cams for the CAS, but that's fairly simple. If the cam is asymmetrical... makes things probably unworkable.