what is zero lash ,and is there any special tools i need to this. it has to be my problem.

 

"Lash" is short for "valve lash", and is a reference to the gap between the rocker arm and valve stem when the lifter is on the heel of the cam lobe. In the days of solid lifters, you needed a gap to insure the valve would fully close.

"Zero lash" is how you adjust hydraulic lifters - in other words, no gap between the rocker arm and valve stem. The lifters "self adjust" every cycle to reduce noise and maintenance.

On Chevy V8's, when you first assemble, you adjust the rockers so that there is no "lash" or gap, and then give the adjusting nut an additional bit of a turn (the factory says 1 turn, a lot of people use less, like 1/2 turn). This centers the plunger in the lifter to give it the latitude to self-adjust during operation.

 

thanks man for explaining it .some people think its the module ,so i went and exchanged mine for a new one if that doesn't do it then its time to mess w / the lash.

 

What sort of problem are you having? Ignition or compression?

 

the other day after finally getting the car started (ran strong for two days)i went out to put it in my garage,no start just cranked and cranked. its getting plenty fuel ,but only producing a yellow spark at spark plugs.

 

I wouldn't think that would be a problem with rocker arms then. Usually your local parts store can check an ignition module. Have them run it two or three times to simulate operating temperatures.

 

coil not valve lash,make sure you got 12v getting to primary of coil

 

well, i took the distributor back got a new,still only yellow spark. the coil is new also.but i'll check the voltage.