Push rod length checking and lifter collapse
Thread Starter
Racer
Joined: Jan 2008
Posts: 291
Likes: 15
From: Virginia Beach VA
Push rod length checking and lifter collapse
Something I've always wondered about is the use of checking push rods and hydraulic lifter collapse. What stops them from just collapsing and throwing off your geometry when your doing the valve stem felt tip pen test? I've seen light "checking springs" but have never used them. How do the methods that Comp Cams and Crane recommend for length checking account for lifter collapse?
I used one once without the checking spring... and ended up going with 7.15's for my ZZ4 with angle milled AFR 195's... I ran the motor about 200 miles then checked the valve stem wear pattern and found it ran from center of the stem outboard to near the edge on some of them... I quickly replaced them with 7.10's and now the wear pattern centers nicely...
I also used one of those Proform length checkers (the ones that look like rockers) and used this procedure and 7.10 was pretty close...
What are your thoughts?
I used one once without the checking spring... and ended up going with 7.15's for my ZZ4 with angle milled AFR 195's... I ran the motor about 200 miles then checked the valve stem wear pattern and found it ran from center of the stem outboard to near the edge on some of them... I quickly replaced them with 7.10's and now the wear pattern centers nicely...
I also used one of those Proform length checkers (the ones that look like rockers) and used this procedure and 7.10 was pretty close...
What are your thoughts?
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
With the light checking springs there should not be enough pressure on the lifter to give you a false reading. Some use solid lifters with the same dimension while others take a hydraulic lifter apart and put something like a stack of dimes inside or the correct size piece of metal inside to hold the plunger up. 
Last edited by MotorHead; Dec 19, 2008 at 12:51 AM.
Instructor
Joined: Nov 2005
Posts: 160
Likes: 0
From: Hamden CT
I use a washer that sits on top of the lifter body, with a 5/16" hole for the pushrod to fit through. I just let the pushrod sit on the lifter cup and tighten up a 5/16" lock collar around the pushrod just on top of the washer. Acts just like a solid. If you're working with a retro roller lifter with a link bar, you'll have to grind a flat on one side of the washer to clear the link bar pedestal on the lifter.
Lock collars like this are usually available at Home Depot or any reasonably well-stocked hardware store:
http://www.lucasindustrial.com/produ...solid_collars/
Lock collars like this are usually available at Home Depot or any reasonably well-stocked hardware store:
http://www.lucasindustrial.com/produ...solid_collars/
