Valve lash

[71Duster]

Checking the adjustment on my valves in the 340. It has a Hughes #HEH2328AL hydraulic cam with crane gold rockers.

On the cam card it reads .000" Valve lash Hot

On the Hughes website under the install directions it reads: "Hydraulic lifters should have approximately .040” to .080” lifter
pre-load, (1 to 2 turns on the rocker arm adjusting screw)."

Heres the link. http://www.hughesengines.com/Upload/productInstructions/New_Camshaft_InstructionsMar2010.pdf

Not sure how to set this correctly.

 

[fishy68]

Lash is a term only used with mechanical cams because it is an indicator of clearance. You don't have lash with a hydraulic cam. You have preload with a hydraulic lifter. That means you take the adjustment down to zero lash (all the play is adjusted out with the cam lobe on the bottom, i.e. not lifting the lifter at all) then turn it the amount required to compress the hydraulic lifter however much the manufacturer says. In your case they say they want .040~.080 preload. To achieve this you can either measure preload via dial indicator or if you know the threads per inch the adjusters are (3/8" adjusters are 24 threads per inch) you can calculate how much to turn it after zero lash. With adjusters that are 24 threads per inch .040"~.080" preload would = 1-2 turns, just like they said. In most cases standard hydraulic flat tappet cams work fine when all the lash (slop, play, clearance) is adjusted out then turn the adjuster exactly 1 turn more then lock it down.

 

[camd64]

lash is a term only used with mechanical cams because it is an indicator of clearance. You don't have lash with a hydraulic cam. You have preload with a hydraulic lifter. That means you take the adjustment down to zero lash (all the play is adjusted out with the cam lobe on the bottom, i.e. Not lifting the lifter at all) then turn it the amount required to compress the hydraulic lifter however much the manufacturer says. In your case they say they want .040~.080 preload. To achieve this you can either measure preload via dial indicator or if you know the threads per inch the adjusters are (3/8" adjusters are 24 threads per inch) you can calculate how much to turn it after zero lash. With adjusters that are 24 threads per inch .040"~.080" preload would = 1-2 turns, just like they said. In most cases standard hydraulic flat tappet cams work fine when all the lash (slop, play, clearance) is adjusted out then turn the adjuster exactly 1 turn more then lock it down.

x2