Isky adjustable rockers and valve lash

[Mpdave391]

Okay so I got my Isky adjustable rockers lined up. Correctly
Now I’m ready to. Put in my push rods what’s does any one know what the valve lash might me. I have the sequence to do it in I just couldn’t fine. The amount. I’m putting them on a hydraulic cam. I ran a set on my 383 years ago. But can’t find the info I used then

 

[PurpleBeeper]

I’m running Isky rocker and a hydraulic cam. Follow the adjustment order carefully and make sure you stay with cylinder #1 at TDC. I loosen the nut & put the pushrod in. Then, I twirl the pushrod with my left hand and turn the adjustment screw with my right hand back and forth until I hit the exact point I can feel some resistance to twirling the pushrod (that’s “zero lash”). Last, I eyeball the slot in the adjuster screw and tighten it 1/2 turn (lifter pre-load) and hold the screw adjuster in place with the screwdriver while I tighten the adjuster nut. Done

 

[pnora]

Most adjuster screws are 3/8 fine thread. So 1 turn from zero lash is about .042 preload and that is about what most company's want. Pretty sure Comp recommends .040 preload. I set most all to that spec unless the cam and lifter company says different.
https://www.compcams.com/pub/media/productattach/c/o/comp4-116.pdf

 

[HawkRod]

I’m running Isky rocker and a hydraulic cam. Follow the adjustment order carefully and make sure you stay with cylinder #1 at TDC. I loosen the nut & put the pushrod in. Then, I twirl the pushrod with my left hand and turn the adjustment screw with my right hand back and forth until I hit the exact point I can feel some resistance to twirling the pushrod (that’s “zero lash”). Last, I eyeball the slot in the adjuster screw and tighten it 1/2 turn (lifter pre-load) and hold the screw adjuster in place with the screwdriver while I tighten the adjuster nut. Done

Yup. What he said.

I sometimes wiggle the pushrod up and down. You hear and feel the slight tapping as it moves. at the point where it stops doing that, you are pretty much at "zero lash". Regardless of technique, with some practice, you can feel the point of zero lash.

 

[DPeltz]

Technically, you do not set lash with hydraulic lifters. What you are setting is lifter preload. I like.030 to no more than.060. As stated, when on the base circle, adjust until the PR snugs up, then 3/4 to 1 turn will give the proper preload. Hopefully you will only have 3 or 4 threads exposed on the adjuster. Check for any interference with the PR through the heads, PR to rocker, and rocker to retainer.

 

[pnora]

Technically, you do not set lash with hydraulic lifters. What you are setting is lifter preload. I like.030 to no more than.060. As stated, when on the base circle, adjust until the PR snugs up, then 3/4 to 1 turn will give the proper preload. Hopefully you will only have 3 or 4 threads exposed on the adjuster. Check for any interference with the PR through the heads, PR to rocker, and rocker to retainer.

Technically you are taking the lash out of a hydraulic lifter. Its part of the two part process. All lash is removed before setting desired preload.

 

[Bird 426]

And now, your geometry is off.

 

[RemCharger]

And now, your geometry is off.

How so?

 

[Bird 426]

I have been told by, will not mention his name, reputable engine builder, that when you make the switch to roller rockers, the geometry needs to be corrected. Witness marks on the top of the valve stem will say if this true or BS. We don't really need to argue about it. The OP can run it as is.

 

[RemCharger]

I have been told by, will not mention his name, reputable engine builder, that when you make the switch to roller rockers, the geometry needs to be corrected. Witness marks on the top of the valve stem will say if this true or BS. We don't really need to argue about it. The OP can run it as is.

Correct about the roller rockers, because of the wheel height.
But these are old fashioned pre- roller rockers.

 

[Bird 426]

I stand corrected. I am guessing that Iskedarian made something other than roller rockers. Was not aware.

 

[Mpdave391]

so if I set it up for .040 should I use feeler gauges while I’m making the adjustment on the rocker arm while spinning the push rod am I following that correctly

 

[Bird 426]

No, from zero lash, one more turn in. You don't use a feeler gauge on a hyd cam, usually. If you really want to know where the middle of the travel is, count the number of turns from zero lash until you get to the bottom of the lifter travel. You want to be in about the middle of that distance.