283 rocker question... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

revjim · 04-18-2011, 07:03 PM

What are the torque specs for the nut that goes over the rocker? Thanks..

*blackedoutharley* · 04-18-2011, 07:26 PM

There is no "torque spec"... you tighten the nut until you get the desired lash setting on the lifter/valve.

**PGSigns** · 04-18-2011, 08:32 PM

With the chevy rockers you would run the nut down with the cylinder on tdc until the slop was gone and then just a little more to get them close. Then they make these little clips that you put on the rockers to deflect the oil and with one valve cover off at a time start the motor and adjust the lash. If needed tighten any that are making a racket to shut them up first. Back off the nut till the rocker begins to tick and slowly tighten it up till it stops. Depending on who's lifters you have go between a 1/2 and a full turn down to get the preload in the lifter. 3/4 is a good setting. The engine may try and stall as you tighten them and if it does just wait a second and slowly continue. Finish that side and put the valve cover on and go to the other side.
Jimmy

andyh1956 · 04-19-2011, 12:10 AM

one other thing, and this confuses a lot of people. in a four stroke engine there are TWO top dead center events per a particular cyl making the power stroke, or put another way the piston travels up & down twice per revolution & needs two revolutions to complete a whole power cycle. 1st, intake, 2nd, compression, 3rd, power & 4th exhaust. so it's important than when you adjust the valves on a four stroke-cycle engine like a sbc that the valves get adjusted on tdc COMPRESSION. if the valves are adjusted on the other tdc they will be between the exhaust stroke & intake stroke. this is called the "over lap" when both valves are off their respective seats. the way i have always done the valve adjustment is to rotate the engine & watch the #1 intake rocker. when it goes down & comes back up then that is the start of the compression stroke. keep rotating until the line on the damper lines up with 0deg on the pointer. this will be #1tdc COMPRESSION. adjust both rockers on #1. now mark three more equally spaced lines on the damper from the factory line, or another line every 90 degrees. then rotate to the next line in engine rotation direction & adjust the next cyl in firing order. hope this helps.
andy

04-18-2011, 07:26 PM	#2
blackedoutharley Account Suspended Join Date: Jul 2007 Location: Plumas Lake, Ca. Posts: 1,009	Re: 283 rocker question... There is no "torque spec"... you tighten the nut until you get the desired lash setting on the lifter/valve.

04-18-2011, 08:32 PM	#3
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: 283 rocker question... With the chevy rockers you would run the nut down with the cylinder on tdc until the slop was gone and then just a little more to get them close. Then they make these little clips that you put on the rockers to deflect the oil and with one valve cover off at a time start the motor and adjust the lash. If needed tighten any that are making a racket to shut them up first. Back off the nut till the rocker begins to tick and slowly tighten it up till it stops. Depending on who's lifters you have go between a 1/2 and a full turn down to get the preload in the lifter. 3/4 is a good setting. The engine may try and stall as you tighten them and if it does just wait a second and slowly continue. Finish that side and put the valve cover on and go to the other side. Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

04-19-2011, 12:10 AM	#4
andyh1956 Registered User Join Date: Mar 2010 Location: thomastown mississippi Posts: 1,261	Re: 283 rocker question... one other thing, and this confuses a lot of people. in a four stroke engine there are TWO top dead center events per a particular cyl making the power stroke, or put another way the piston travels up & down twice per revolution & needs two revolutions to complete a whole power cycle. 1st, intake, 2nd, compression, 3rd, power & 4th exhaust. so it's important than when you adjust the valves on a four stroke-cycle engine like a sbc that the valves get adjusted on tdc COMPRESSION. if the valves are adjusted on the other tdc they will be between the exhaust stroke & intake stroke. this is called the "over lap" when both valves are off their respective seats. the way i have always done the valve adjustment is to rotate the engine & watch the #1 intake rocker. when it goes down & comes back up then that is the start of the compression stroke. keep rotating until the line on the damper lines up with 0deg on the pointer. this will be #1tdc COMPRESSION. adjust both rockers on #1. now mark three more equally spaced lines on the damper from the factory line, or another line every 90 degrees. then rotate to the next line in engine rotation direction & adjust the next cyl in firing order. hope this helps. andy

04-18-2011, 07:03 PM	#1
revjim Registered User Join Date: Feb 2011 Location: Sales Posts: 89	283 rocker question... What are the torque specs for the nut that goes over the rocker? Thanks..



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