Re: value lash

Posted by Tim Cole On 2016/2/21 16:22:24

I always preferred to not run clearances too tight as that can cause compression problems, but when I checked the clearances running I would check to see what gauge would fit, record the result on paper, and adjust with the motor off. That avoids the oily mess and burns.

For example: if running clearance on valve #1 is .008 then reduce the clearance by .002 with the motor off.

This method avoids problems with where the cam lobe is because it simply reduces an existing clearance.

As for what is a "clearance" the gauge should slide readily with only a slight feel of drag.

As mentioned, all of this is academic in the absence of precisely milled tappets. When Packard built those motors the valve guides were bored in a mill to be precisely perpendicular to the individual tappets. This is beyond the resources of almost all motor rebuilders and why those motors were dead silent when new.