How do you adjust roller rockers? I think it's like a 1/4 turn past zero lash. But what is zero lash? Is it when the rocker doesn't move side to side? Or when you can't put a feeler gauge under the roller? Or when you cant turn the push rod? (the push rods are a pain in the butt to turn by hand) Any help would be appreciated!
Hello
I will give it a try. If your lifters are pumped up with oil the push rods will set firm on them. But if you are like me and mess around too long they will bleed down.
--- So rotate the crank shaft for the valve you are adjusting with no pressure on the rocker. Then adjust so you have zero lash--no more click as you try to rock the rocker--If you try to stop the push rod from turning you will get it too tight. Be careful because I think the lifters just have a little spring on the lifter seat holding it up so it easy to over tighten. [never had one of this apart so I am guessing].So no more rock ---that is zero lash. Then turn the prescribed amount of preload and tighten the nut.
Below is an old post--some say [Crane].060" to .100" preload is the best - [Comp Cams] say 1/2 turn which on their rollers give only .036". So I don't know for sure.
I wish some one would tell me!!
http://www.ls1truck.com/forums/mecha...tml#post106375
2002 GMC 1/2 ton Sierra,4WD, Xct cab, camed, mid-length headers, Nelson tune, electric rad. fan, trany cooler, Heavy 5750 lbs with topper.
On an LS1 type engine you just torque them down to 22 ft lbs unless the instructions say to set them by lash. If you are supposed to set them by valve lash like the old style Gen1 Chevy engines, remove all spark plugs, crank engine until you have full oil pressure on the pressure gauge before attempting to find zero valve lash. The most important thing about roller tip rockers is that they are centered over the valve stem. Take a black sharpie and color the top of the valve stem. Tighten the valve down to the manufacturers specifications. Cycle the engine a few times and then remove the rocker and check the wear pattern on the valve stem. You may have to shim the stands up or down to achieve a centered pattern. A longer or shorter pushrod can have the same effect on the wear pattern. Very thin wave washers are available to shim rockers. I get mine from my local VW parts retailer, old aircooled bug shops. Add shims to move the pattern towards the rocker body, remove shims to move it away.
Last edited by RedHeartbeat; 07-08-2008 at 04:38 PM.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
Thanks Red, but I think the question was for adjustable roller rockers. The instructions that come with the adjustable rockers are to find zero lash and then turn down the nut a certain degree.Originally Posted by silverado777
I guess one could do the magic marker with an adjustable one all so. But you would not need shims.
Does anybody have an Idea on what is the proper amount of preload?
I will yield the floor to the Honorable Red.
2002 GMC 1/2 ton Sierra,4WD, Xct cab, camed, mid-length headers, Nelson tune, electric rad. fan, trany cooler, Heavy 5750 lbs with topper.
Ok,ok...I will give this little dance a shot. I was considering some 1.8 roller rockers when I did my cam, but backed out at the last minute. From what I know about doing this, you put on the rocker arms on the studs and tighten the adjusting nuts to achieve zero lash (with no preload and no pressure on the valves). Be sure the setscrew in the adjusting nut does not contact the stud. After you have achieved no preload and no pressure on the valves after the first tightening sequence, rotate the crankshaft one full turn and adjust any loose rocker arms to zero lash. Rotate crankshaft again one full turn and adjust any loose rocker arms to zero lash.
Do not rotate the crankshaft anymore for a while--allow lifters to bleed down for at least 30 minutes. Those couple turns on the crank have loaded the lifters, but not much--so you have to make sure you allow proper bleed down time. After 30-45 minutes, adjust any loose rocker arms to zero lash. Now, tighten each rocker arm adjusting nut 1/16 turn. Allow the lifters to bleed down for 15 minutes. Repeat this procedure seven more times for a total of two full turns of the crankshaft. Be sure to allow 15 minutes bleed down time after each 1/16 turn. Those several steps should have just over 1/2 total turn. The lifters now have the proper preload. When holding the adjusting nut with a wrench, carefully tighten the setscrew in the adjusting nut of each rocker arm. Do not rotate the nut during this process. Allow another 30 minutes bleed down time for this final setting.
I know this is a painstaking process, but it is necessary to set a proper backlash on the rockers. If not, they will be out of adjustment and will clatter worse than a jar full of pebbles...
Last edited by txarkitekt; 07-08-2008 at 11:34 PM.
2000 ECSB 6.0L
TORQUER V2 CAM ● COMP 918's ● 7.4 HARDENED PUSHRODS ● K&N SERIES 77 CAI ● 80mm BBK ●PACESETTER LT HEADERS AND 3'' ORY ● SUPER 40 FLOW ● 3000 STALL ● 4.10s ● BUILT 80e ● VORTEC PERFORMANCE TUNE ● MSD 8.5mm PLUG WIRES● ELEC. CUTOUT ● UD & ALT PULLEYS ● FLEX-A-LITE E-FANS ● 22" CENTERLINE STINGRAY III's ● LUND FIBERGLASS TONNEAU ● 2" LEVELING SHACKLES ● 12K HID LOWS & FOGS ● LEDs ● DEBADGED ● WHITE-FACED ESCALADE GAUGES ● KICKER 450.1 ● 2-CVR 10's ● DS60's ● K693's
2002 GMC 1/2 ton Sierra,4WD, Xct cab, camed, mid-length headers, Nelson tune, electric rad. fan, trany cooler, Heavy 5750 lbs with topper.
what brand adjustable rockers? I've never used them on an LS1 type engine. Are these shaft mount or stud mount rockers?
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
They are Comp Cams Pro Magnum Roller Rockers. They are stud mounted.
Well, I guess I'll answer my own question. I read the instructions that came with the roller rockers. It say "Rotate the pushrod with your fingers and begin to tighten the polylock. When you feel the resistance on the pushrod, you are at zero lash. Rotate the polylock one half turn more and then tighten the set screw."
Crane Rollers?
Crane 1.8 Gold Roller Rockers...What horsepower & torque increases should we expect, on say an otherwise stock, 2001 5.7 LS1?
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