Visit The Dirt Forum for More Information

Author Topic:   Lifters At Zero Lash
69-er
Member
posted July 14, 2003 09:02 PM
In order to get the vacuum high enough on my motor to pass tech, the cam manufacturer told me to adjust the lifters at zero lash. They are hydraulic lifters. Sure enough, the vacuum increased by about an inch.

My question is: Other than the valves running a bit noisy, is there any other problems I should worry about?

Also, how does running the lifters at zero lash increase vacuum? When hydraulic lifters are adjusted the normal one turn from zero lash, they automically run at zero lash when the motor is running anyway. I also experimented and there is a very fine line between "tighter than zero lash" to "zero lash" to "looser than zero lash". Looser seems to increase the vacuum even more, although I don't think it would be a good idea.

Thanks!

Larry

Pickel
Member
posted July 14, 2003 09:23 PM
When I ran hydraulic lifters I always set mine with a compression gauge..I set them to the highest compression and left it alone .. seemd to work well..


69-er
Member
posted July 14, 2003 09:34 PM
Pickel,

Could you go through that procedure for me? I've never heard of adjusting the valves that way before.

Larry

Mell00
Member
posted July 15, 2003 09:15 AM
Unless you have 'anti pump up' or 'hi rev' hydraulic lifters i would be careful running your valves very loose. I would set them at exactly zero lash, or when you just start to feel a little resistance when you spin the pushrod and thats it. Without the extra half turn to center the plunger the plunger in the lifter will pump up and run against the clip in the end of teh lifter body, effectively like a solid. Regular lifters just have a small wire clip here and will pop out easily and the lifter will disassemble itself inside your engine....not good. The 'hi rev' lifters have a steel circlip or similar clip to hold the plunger at zero lash. In fact they are set with a few thousandths lash.


69-er
Member
posted July 15, 2003 05:14 PM
Mell00,

I had that same thought, so to try it out, I swapped the 1.6 rockers with 1.5's figuring the smaller rockers would fool the engine into thinking it had smaller cam. Same results. Maybe using smaller rockers isn't the same as looser lash.

dirtbuster
Member
posted July 15, 2003 06:28 PM
69 er
Changing rockers doesnt affect duration the way lash does. With the same lash the valve will still open the same time with 1.5 or 1.6 rockers, The 1.6 will just open it farther overall and at a faster rate. that is what makes it think it is a bigger cam.


Mell00
Member
posted July 16, 2003 09:15 AM
Like dirtbuster said that's not good,everytime i tried that(zero lash)they blew the top out of the lifter,anti-pumpup style lifters have the internal c-clip instead of the little wire to run zero lash.


Back to the Archives