I would check this way...

I would check this way...using the intake valve as an example.

Set the intake valve preload when the exhaust valve on that cylinder is just starting to open. This will insure the lifter is on the heel of the cam lobe. (You set the exhaust valve when the intake valve is starting to close.) When you get there, use your pushrod length checker, rocker arm, and polylock, and set the preload on the lifter. You will want to go to zero lash, plus about a 1/2 turn.

When you check for zero lash, a lot of people will tell you to twist the pushrod back and forth to gauge the drag. I've never liked that method and prefer to move the pushrod up and down axially until there is no play left. You can feel the instant when everything tightens up, but before it starts to compress the plunger.

Now...

You are correct in that the plunger will compress and bottom out so that you won't be able to get a mid/full lift reading. If the intake is on and you don't want to change over to checking springs, then you really don't have much of a choice. However, if you mark the top of the valve stem with a marker, you will be able to get a witness mark of where the rocker roller started before movement, then what kind of progression it made as it at least moved a little bit.

If it were mine, I'd take 10 minutes and pop the first two valve springs off and put some checking springs on.



Brent Lykins
B2 Motorsports, LLC