Rocker Arm Adjustment & Preload

95Vert383AOD · Oct 4, 2012

So i don't have chatter in my valve train but see that the procedure for preload is different than what i have done in the past.

I have Probe Shaft Rockers. 1.72

The way a speed shop told me to adjust them is so that the push rod still spins. There is still some pressure on the lifter. I have never gotten chatter this way. Things have worked fine.

Now i see some videos where they take the play out of the pushrod and tighten the adjustment nut 1 full turn. These videos were stud mount with poly locks.

My adjustment is right where the push rod meets the rocker. Not sure if this has any effect.

If anything i would think my adjustments may be too loose. But i don't have any valve train chatter. Shaft rockers dont have any play in the the mounting area. So how is everyone else adjusting theirs??? Should i go and readjust my valvetrain if its working just fine?

jrichker · Oct 5, 2012

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

Gearbanger 101 · Oct 5, 2012

Not a tuning issue. Moved to Tech.

95Vert383AOD · Oct 5, 2012

jrichker said:
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.
__________________
Michael Yount - K'ville,TN 82 Volvo 242w/5.0L; 2000 Suzuki Bandit 1200

I use shaft rockers. They are already bolted into place before i adjust them. The adjustment is at the pushrod end.

jrichker · Oct 5, 2012

95Vert383AOD said:
I use shaft rockers. They are already bolted into place before i adjust them. The adjustment is at the pushrod end.

Sorry, I missed that when I read your post..

louieb · Nov 30, 2012

if i cant get this thing running right im about to hang up the towel.

i had a rocker arm stud break on exhaust valve. after pulling it apart 5 times i get it running.

300 hundred miles later the intake stud breaks. what is the deal with that?

The stud broke on the intake side this time. the one i replaced is fine. they are side by side.

also same thing happened when it broke, i was idling in dunken donuts waiting on a bagel, and i hear it snap. this time tons of smoke. i pulled the intake off again, and yup broken.

inside the intake was unburned fuel also,

any suggestions, thanks.

Gearbanger 101 · Nov 30, 2012

No sales ads in Talk/Tech Forums please. If you'd like to list a vehicle for sale, please do so in the appropriate Classifieds section.

louieb · Nov 30, 2012

Gearbanger 101 said:
No sales ads in Talk/Tech Forums please. If you'd like to list a vehicle for sale, please do so in the appropriate Classifieds section.

ok sorry, i was just trying to get more reads. i love my car. i have it up and running again.. this all started after i changed thermostat to 195 degree. the 180 keeping it from reaching proper temp.

whould you advise me to go back to the 180 thermostat? it probbly stay in open loop though?
thanks..

65ShelbyClone · Nov 30, 2012

louieb said:
whould you advise me to go back to the 180 thermostat?

I wouldn't. It's highly unlikely that the thermostat is at all related to breaking valvetrain parts. Can you be sure there is no coil bind or parts hitting other parts? You didn't provide much info regarding how your top end is set up besides what rockers are involved.

To adjust hydraulic lifter preload with polylocks, it's fairly easy(if not messy) to back off the rockers with the engine running until they start making noise, and then tighten them back down between ½ and one turn. You're looking to compress the lifter plunger by 0.030"-0.060" from the fully extended position. That's with a polylock, though; the thread pitch determines how many turns equate to X amount of compression and I don't know what your rocker adjusters have.

louieb · Nov 30, 2012

It is a DSS rocker black aluminum. a bit heavy if you ask me. It does use Poly lock with Alan key

this is what i have. the first rocker stud to go was the ex side. i replaced it with a 3/8 arp stronger bolt. i see there is improper geometry. on the roller there is a line off to the right side. its very close to the edge of the roller. so yea something is not right with the geometry. would that mean the push rod is to short, or to long?

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