so are there any disadvantages of running the valves close to zero lash?

 

I agree, it sounds a lot like a spring issue to me, with impropper lash (too much) as soon as the lifter is oiled up it will act poorly no matter the rpm.

 

Maybe Bret or someone else with knowledge and experience with these lifters could chime in about the disadvantages of running less lash, for example 1/4 turn past compared to 2/3 turn?
Chris

 

The only advantage is that if ya float the valves or they bounce off the seat or they are tossed away from the cam they don't pump up as far and relief time is shortened.

It doesn't make ANY difference if the PR cup is .025 or .100 in the lifter as far as adjustment goes.(There is about .100 thousands adjustment in a lifter.
The lifter will take up ANY slack that is in the train for whatever reason and hold that slack until the reason for the slack passes and bleed back down to where it is adjusted too.

We were doing the 1/4 turn thing back in the early '60's so that trick is not new.We would even set the lash at .001 with a feeler guage on race day to gain some RPM's without the lifters pumping up making it miss.

 

Lloyd recommended 1/16 past zero to me. Just enough to get zero lash, and a little bit of preload. At least that way you know you dont have too much preload and are holding valves open.

 

Ya would have to go .060+ to have TOO MUCH preload,as to hold the valve open all the time.In other words bottoming the lifter adjustment space.
It would however shorten the time for the lifter to pump down if there were ever any slack in the system and would not hold the valve open as far if it pumped up to take up any slack.

 

Josh, do you have Morel's or comp r's? Also was 1/16th of turn your final adjustments? Are you using stock length pushrods?

 

I have Morels with 7.125" pushrods. I havnt got it running yet though as I keep running into little problems. Hopefully it will run very soon.

 

Josh, what is stock length? Also, does the length of your pushrod matter how much or how less lash you can run?

 

Stock is 7.200". If you have milled heads, decked block, or aftermarket valves you need to check and install proper length push rods. I think the morels may be a little taller than stockers too. If so that would change things too. It has nothing to do with lash, it has to do with the wear pattern between the rocker arm and valve tip. You want it to be just right to minimise wear, and reduce side load on the valves.