Is it as simple as putting a dial indicator on the retainer and turning the motor until the retainer is at its lowest point? Would that give you and accurate measurement? We are using stock rockers, pushrods, lifters with a a 2lb spring.

 

Yes, you should be able to mesure from the base circle to the highest point, then multiply by the stock rocker ratio to get the lift.

So if you mesured 0.358in then 0.358 * 1.7 you would have a 610 lift

 

Are you the same Dan that had his car in Pontiac mag a couple years ago?

I'd measure at the pushrod with the rocker off and mult. by 1.7. If you measure at the retainer, use an adjustable pushrod to get to 0 lash or your numbers will be off due to lifter preload.

 

Ok taking this a little further... We installed a G5x2 232/240 Duration & 595/608 Lift at 112 Lobe Seperation cam with stock heads. Installed DOT to DOT and called it good. We ran this combo for about 5,000 miles. This week we pulled the heads off to install a set of unmilled AFR 205's. I wanted to confirm PTV clearance just to see where we were. We clayed the piston, put the factory used head gasket back on, stock heads, snug them down, put the pushrods in, 2lb springs on, and then torqued the stock rockers to 24lbs. Turned the motor over clockwise and it cut the clay in 1/2 the 3 times we checked. My next step was to order a degree kit from comp cam.

Last night I mounted the wheel, located TDC. Put the Uncut AFR head on and new gasket and snugged to about 10lbs, put in valves train on as described above. Set the dial indicator up on the valve retainer, rotated clockwise until the valve was at max lift, reset the indicator to 0. I took readings at .050 before max lift and after, The readings were 78 and 142 which total 220/2=110. Shouldn't this be 112? I then took the valve back to max lift and reset the dial to 0. I turned the motor until the valve completely closed and measured that. Assuming thats how you measure total valve lift. I got .609 on the intake and .620 on the exhaust. I then checked ptv clearance with the dial indicator at 10-12 degrees b/atdc and have ptv clearance of like .005. I also checked valve drop at TDC which is at .035 on the intake valve. I guess that would explain why the clay gets cut in half. I assume the wrong cam was sent? and the scarry thing is we had this car running with this cam and there were no visual marks on the pistons that the valves ever hit the piston. Can anyone suggest anything else we need to check?

 

Yep that was me. I just came across this the other day. I guess they keep the arcives online for quite some time. http://www.highperformancepontiac.co.../0310pon_99ta/

I think I still have video of you and I racing at the f-body event!

I should clarify this is a friends car that I'm talking about...

 

Anyone?

 

LOL.....Wondered if you'd realize who I was. :o) Going to Memphis next month?

I have the solution to your problem. Just ran into a similar thing a couple days ago when checking P-V clearance on mine w/ clay. I did just as you said with a stock pushrod and light spring and had like .030" P-V clearance. I was like "WTF?" 'cause I had checked it with a dial indicator/degree wheel last year when I put the cam in and it was .080" or more.

It's due to the lifter preload. You need to get an adjustable pushrod and set it to 0 lash. The stock pushrod, when used with a light check spring, is holding your valve open approx. .070" (say .040" preload x 1.7 rocker ratio). That is screwing up all your numbers for P-V and valve timing man.

Once I put the adj. PR in and re-clayed it, I had .110-.130" clearance.