Hello all! I'm attempting to degree a camshaft (Scott Brown turbo grind) into my used engine and I'm running into some confusing numbers. Please note that I've never degreed a cam before so forgive my ignorance! Here is the cam card: I know that Jim Weise's thread over in the 455 section encourages the use of the duration method, however I am trying to use the centerline method for simplicity. I figured out that with the cam installed +2 degrees advanced, the open and close measurements match those on the cam card: #1 intake lobe opens to .050" at -2 BTDC (2 ATDC) and closes to .050" at 46 ABDC. However, I read 71 ATDC and 162 ATDC when I zero the indicator at max lift and then go down .050" on each side of the lobe. My math looks like this: 71 + 162 = 233/2 =116.5 According to the card this cam should be degreed at 114. So am I really 2.5 degrees off or should I believe the lift events? Am I doing something wrong? Any help is appreciated!
Bump Anyone out there who can help? I'm inclined to call it good but I just want to be sure before I start buttoning this engine up!
I'm not big on cam degreeing but I'll take a stab at it. Adding the opening and closing events at .050, you get 2+46+ 180 =228. The cam card calls for 224* duration. That's 4* off. Then subtracting the intake opening from 228/2 =114-2 =112*. That's 2 advanced. Something isn't right. Your centerline method says it is 2.5* retarded. Maybe shoot Jim Weise a PM and ask him to look.
OK, I missed that negative sign on the intake opening. -2 + 46 + 180 = 224. That agrees with the card 224/2 - (-2) = 114 That's dead on. So the discrepancy is with the intake center line method. Maybe run those numbers again?
Oh sweet! Ok I'm sure I'm making a mistake somewhere then. Maybe I'm not getting the cam to full lift before I zero my dial indicator . . . Thanks for your help! I will report back.
Ok so I took centerline methods measurements again after resetting my dial indicator on max lift (it was off by .001" or so) and got: 71 (open) + 158 (close) = 229 229/2 = 114.5 So I'm going to call that good. Again this is with the cam advanced 2 degrees. I also took readings for the #1 exhaust lobe valve events and they were about 1 to 2 degrees off but I think close enough. I'm pretty sure there's still some measurement error going on, might be excess lube on the lobes that I tried to wipe off or some other discrepancy!
