I degreed my cam and checked my piston to valve clearance today;; I have a 454 with a ultradyne solid flat tappet 288/296 cam. it was "supposed" to be ground on a 112 lobe seperation. I mocked up the engine with a head gasket tightened down the head, put on (2) checking spring on the number one cylinder, I then put a rocker on the intake valve and adjusted the valve for "zero" lash. I then mounted the dial indicator on the retainer and made sure the geometry was correct. I then found top dead center using a piston stop tool, i turned the motor around until it hit and then went counterclockwise until it hit, i then adjusted the degree wheel accoridingly and then double checked "twice"! to make sure that each time i turned it around i got the same exact number once on ATDC and then again on BTDC. I then turned the motor around and watched the intake valve open all the way, once at full lift i zeroed out the dial indicator, i then turned the motor counterclockwise until i reached .050 before max lift, i marked down 73 which was what the degree wheel read, i then turned the motor over clockwise until the valve opened and then started closing until i just reached .050 before max lift, I then marked down 141. so if i do themath 141+73= 214 /2 = 107, so this means my intake centerline is 107 if i am correct. The confusion starts that Harold at Ultradyne personally told me that his cores have 2 degrees already ground into them, then i had my cam ground at 112 lobe seperation right? so wouldnt that make my intake centerline 110?? Am i missing something here??

I then turned my engine over to 20 degrees before top dead center on the intake stroke with my dial indicator and checkign springs installed on the intake valve with Zero lash. I then proceeded to check the piston to valve clearance by pushing down on the valve until it hit the piston, I started at 20 degrees after, and went every 5 degrees down until i hit TDC, i then went 20 degrees after top dead center checking along the way, the minimum clearance on the intake valve was .093, I then did the same thing on the exhaust and cam up with .0110 clearance. My questions are did i do everything right, do the numbers sound okay, and should i do anymore follow up or any more checks on the cam?? thanks a lot!

Do you mean .110 or .0110 for the clearance on the exhaust valve? I hope that you mean .110 in. How did you push down on the valves? I used clay on mine and just turned the engine over. If you mean .110 I would say you are O.K., the .093 is getting close but I believe since it is on the intake you will be O.K. also. I'm sure that someone smarter than me will chime in to correct any misleading info. that I have given. I run a hyd. cam so you need a solid guru for info.

I'm not sure how much difference it would make, but I think when you're checking the cam position at .050" below max lift on the opening side of the intake lobe you should turn counter-clockwise past .050" below max lift and then turn clockwise to come back to .050" below max lift (so you're always turning the engine in the direction that it runs in when you stop and take your readings).

Have you put the dial indicator on the lifter and checked both the exhaust and intake opening and closing points (both advertised and at .050" lift) and compared them to the cam card to confirm the rest of the numbers?

I prefer they clay method too. It not only gives you the clearnce with 720 degrees of rotaion but shows you were the problem is.

Cody,

BobT is correct in stating that you always want to turn the engine over in the direction of running rotation ( clockwise). Even with a new timing chain there is a minimal amount of slack.In turning clockwise you reduce error due to slack in the chain. As far as the centerline goes,it depends on if the cam lobes are ground symmetrical ( same on opening side and closing side) or asymmetrical ( different opening and closing sides). The better way to check centenline is to measure .050" before maximum lift the number of degrees and add .050" after maximum lift the number of degrees and divide by 2 to give you the actual centerline.Do the intake side then exhaust side,then add the two centerlines together and divide by two to give the lobe seperation.Hope this helps. :confused:

[ 07-14-2003, 04:18 PM: Message edited by: usa z28 ]

Thanks, the cam is assymetrical(spelling?) it is a dual pattern cam, i am going to check the lobe seperation, that does make sense!