Help With Rocker Arm

The Allen set screw is the last thing you tighten when you are setting the rocker arm. Make any adjustments after that to the same rocker and you need to go back and set the Allen set screw. It's function is to lock the nut so that it doesn't turn.


Michael Yount’s valve adjustment procedure

Here's an easy way to determine this. Start with the #1 cylinder. Rotate the engine with a ratchet on the crank bolt clockwise. Watch the #1 pushrods. First the exhaust pushrod will rise and fall signaling what would be the exhaust valve opening and closing if the rocker were on. As it closes the intake pushrod will rise -- keep rotating clockwise until the intake pushrod falls and is level with the exhaust pushrod - both at the same height. Both lifters are now on the base circle of the cam - both valves would be closed if the rockers were on.

Now, install both rockers. Tighten the bolts with one hand while rocking the rocker with the other hand - continue until you reach the point where you can't 'rock' the rocker any more because there's no gap on the valve stem end or the pushrod end. You are at zero lash - i.e. - no gaps. Stop tightening just as you reach this point.

Now, put your torque wrench on the bolt and tighten it to 18-20 ft-lbs while counting the number of turns it takes to reach the torque. You should hit the torque within 1/4 to 1 turn of the bolt. If it takes more than 1 turn, use a shim to raise the rocker -- each .030" shim will reduce the number of turns to torque by about 1/4 turn. If you reach the torque in less than a 1/4 turn, or you have trouble reaching zero lash even at full torque, then you'll either need longer pushrods, or to CAREFULLY remove some material from the bottom of the rocker fulcrum. Using the procedure described above, you will work through the remaining 7 pairs of rockers. If you follow the firing order, it will minimize the manual cranking you have to do to get the lifters on the base circle of the cam prior to installation of the next pair.

When I first went through mine, 13 of them took no shims; 3 of them took 1 .030" shim. Upon cranking it up, one or two of them sounded a bit noisier than I thought was right, so with the engine hot, I pulled the upper off, and the valve covers, and went through the installation procedure again. That time, 11 of them took no shims; 4 of them took one .030", and one of them took one .060" shim. And they were very quiet running.

Good luck with it.
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Michael Yount - K'ville,TN 82 Volvo 242w/5.0L; 2000 Suzuki Bandit 1200

I think there's some confusion going on here. The procedure jrichker posted appears to be for pedestal-mount rocker arms. It sounds like you have stud-mount rocker arms. Installation of the two types is different. There is no use of a torque wrench for installation of stud-mount rockers.

The sequence for setting stud mount rockers:

1. Turn over engine until the "valve" you're working on is on the base circle of the cam (zero lift).
2. Drop the rocker on and spin the stud-nut down by hand until you're at zero lash (no push rod jiggle).
3. Crank the stud-nut down 1/2 turn (more or less, depending on preference) past zero lash.
4. While keeping the stud nut from turning with a wrench, crank down the allen-head set screw down TIGHT. This is what keeps the stud nut in place while the engine is running and locks your lash in at whatever you set it to.

Do the other 15 valves in the same manner. You're done.

If you need more info, there are some really good tutorial videos on youtube.

NIKwoaC said:

I think there's some confusion going on here. The procedure jrichker posted appears to be for pedestal-mount rocker arms. It sounds like you have stud-mount rocker arms. Installation of the two types is different. There is no use of a torque wrench for installation of stud-mount rockers.
If you need more info, there are some really good tutorial videos on youtube.

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When the OP doesn't know what he has, there is an opportunity to make a wrong guess. Indeed, this may have happened. Without a photo of the rocker top and full side view, it would be difficult to determine exactly what he has. People have been known to throw all kinds of odd hardware at a job and not give it any thought.

jrichker said:

When the OP doesn't know what he has, there is an opportunity to make a wrong guess. Indeed, this may have happened. Without a photo of the rocker top and full side view, it would be difficult to determine exactly what he has. People have been known to throw all kinds of odd hardware at a job and not give it any thought.

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Yep, I had to read his post a few times before I saw what was going on. I wasn't trying to make jabs at anybody, just trying to clear it up for the OP.

louieb said:

ok guys I found another variable when setting the valve lash. Here is the mistake everyone keeps on making, i did.
when u set lash they say turn the polly lock till hand tight, or when pushrod stops spinning. this is wrong.

the correct way is to lift up the push-rod until it just hits the rocker cup. in other words you may compress the lifter if you are not careful.
instead of spinning the push rod until it does not spin, you will lift up, and down on the push rod until it just touches the rocker arm cup. no up and down play in the push-rod is 0 lash this is the correct way to do it. you will not end up compressing the lifter if you do it like i had said.

cheers.

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Notice above I said:

NIKwoaC said:

2. Drop the rocker on and spin the stud-nut down by hand until you're at zero lash (no push rod jiggle).

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I don't know why the "spin" method is so commonly quoted by people... Because if you can't spin the pushrod by hand, that actually indicates that you've gone past zero lash and have actually begun to "load" the pushrod, AKA preload the lifter. There are probably some builders who can tell when they've hit zero lash by turning the pushrod and feeling when it starts to drag, but most other people are probably just doing it wrong.