Discussion and questions related to the course How to Degree a Cam
In the Process of dialing in Skunk2 B series Pro 1+ cams in my Honda B18C5. Part # 305-05-5140
Performed initial timing and found true TDC. Locked VTEC mechanically on both intake and exhaust for cyl #1. And set dial indicator on retainer of intake valve. When looking at the cam card. The specifications are as follow for Intake.
Opening = .040" at 31⁰ BTDC
Closing = .040" at 47⁰ ABDC
Peak lift = 98⁰ ATDC/.498"
Valve lash set at 0.00"
However, when measuring with the dial indicator, opening starts at 11⁰ BTDC and close at 48⁰ ABDC. I adjusted the cam to start at 31⁰ however, I am still getting only 239⁰ of duration of the specified 258⁰. Am I missing something? Or is the cam not correct. Any help would be greatly appreciated. Thanks!
I always time my cams of the lobe centerline (what they call peaklift) as I find the opening/closing events rarely match up perfectly with the cam card. However if you are only measuring 239 duration at a valve lift of 0.040" (zero lash) then that is a very different cam to the quoted 258@040, if you are confident of that measurement I would be very suspicious that you have the wrong cam. Does the measured max valve lift match the cam card?
Just went through the same ordeal. Same cams. Same engine. I ended up using the centerline method.
The camcard does not state 258 duration @.040", 258 is total duration of the cam lobe. Using centerline method will not wrk as there is not a suggested centerline on the cam card to wrk with. You just need to set the zero point of the cam to the ivo, ivc, evo and evc @.040". You will get a lesser duration than 258 bcuz you are not measuring complete lobe duration. Also ensure the valve clearance is set @0 with solid lifters firstly bcuz if u use hydraulic lifters it will bleed out giving wrong readings.