Cam Specs

[Smeado]

I posted this on Prelude Power but i figured i would post it here too because there lots of 3geez guys that aren't over there and we have the exact same engine.

Anyway, I have been slowly working on rocker arm designs. I'm trying to figure out exactly how much room there is in the rocker area and how much lift we could potentially get out of the engine. However the only cam i have access to right at the moment is a stock one. Hopefully you all can help me, I am trying to figure out the exact dimensions and specifications of various cams on the market for the A series engines. I was wondering what the factory figure for valve life on the engine is? If anybody has a aftermarket cam and a micro-meter I was wondering what is the max height of the lobe and what is the minimum height of the cam (zero lift). I was also wondering this to figure out if when a company like web-cams makes a regrind that adds say like a MM of lift (at the cam) do they just add that lift to the lobe height or do they add say .5MM to the lobe and reduce the radius by .5MM?

Anybody that can make measurements of a non-stock cam it would be a big
help.

For example:

Stock Cam:
Min Diameter:31.75MM
Max Diameter:38.90MM

From this you can figure that a stock cam has a lobe height of 7.15mm total
and I can guess that the total lift at the valve is about 8.5, but I'm not sure of that.

Thanks for all your help.

Smeado

[Ichiban]

I think instead of simply measuring lobe height with a micrometer you're looking for actual lift as compared from the base circle. An easy way to check this is with a dial indicator, and leaving the cam in the engine, zero the indicator on the base circle (no lift) and rotate the cam, recording the reading at max lift. If the cam is out of the engine, you could support it between centers on a lathe, and do the same thing. I'm pulling apart an A20A3 next week, so I can look into it for you sometime soon.

[2ndGenGuy]

Intake cam is the same Honda part number as the B20A5. So look through the 3rd gen section on PP.com for stock B20A5 cam specs. Not sure about exhaust, the part numbers are different, I'd imagine that they're getting the extra 20hp partially from that.

[Ichiban]

Intake cam is the same Honda part number as the B20A5. So look through the 3rd gen section on PP.com for stock B20A5 cam specs. Not sure about exhaust, the part numbers are different, I'd imagine that they're getting the extra 20hp partially from that.

?

He's looking at A-series hardware, Johnny!

[2ndGenGuy]

Oh Christ! It's like I think everybody has B20A engines now.

[MessyHonda]

Oh Christ! It's like I think everybody has B20A engines now.

lol...thats true..but i still rock my a serries