Since alot of people seem to be having problems adjusting rockers/pushrods lately, I am here bored at work with my 1991 GM Helms Manual. I will try to re-type what it says.

1. Install pushrod properly, and install rocker, pivot ball, nut

2. rotate engine until mark on torsional damper lines up with 0 timing mark with engine being in #1 piston firing position.

3. In #1 FIRE position, adjust Exhaust valves 1,2,3. Intake valves 1,5,6.

4. Adjust tell all lash is removed (do this by spinning pushrod with fingers) and then turn nut 1.5 turns more

5. rotate engine to #4 fire, 0 timing mark.

6. In #4 FIRE position, adjust Exhaust valves 4,5,6. Intake 2,3,4.

7. Adjust lash (see sequence 4)

 

I'm going to have to point out that using vague terms such as "Adjust till all lash is removed" is the problem people are having adjusting their timing.

 

I have seen many debats on weither to turn it .5 turn, 1 turn, 1.25 turn, 1.75 turn.

Also this book in aspect your saying "lash" is vague itself...

... back out adjusting nut untill lash is felt at the pushrod, then turn in adjusting nut until all lash is removed (see fig 10, which shows spinning rod between fingers). This can be determined by roating pushrod while turning adjusting nut. When lash has been removed, turn adjusting nut 1.5 additional turns.

So I guess the problem is people dunno what "lash" is.

Dictionary.com says....

"To move swiftly or violently; thrash"

IMO, lash=slight drag

 

lash=slight drag

Yep like setting points with a feeler gauge.
A slight drag is right, not to tight or lose.

I think most people expect some sort of solid feel when they hit 0 lash and over tighten.

 

Lash as defined for an engines 'valve lash' is the gap between the end of the rocker tip and the top of the valve stem. Mechanical cams get lashed with a spec such as 20-thou or 30-thou (.020" or .030"), done hot with a feeler gauge.

The '92 Helm manual says the same about spinning the push rod and the 1.5 turns after 0 lash.

Finding that zero (0) lash is the tough part. I like to grasp the pushrod and move it up & down to check for lash. It is easier to feel the lash that way. A pushrod that has been run for a while is so polished on the ends that they spin real easy. They spin too easy to tell when pressure is on it.

HTH's

RBob.

 

I followed those directions to a T when i did mine, started it up and it sounded like i had loose change in the valve covers! The only way i got them right is by removing the valve covers( while i left the plenum, fuel rail on!) and adjusting them with the motor running. This way sucked also because i had to remove the egr to slide the passengers vc out and when i started the car and went to adjust the pass side valves i had open exhaust shooting up at me

 

Those are identical directions to the Chiltons Directions. They are NOT accurate. I followed that procedure to a "T"....in short, It's not right. Every valve stayed open and I had no compression, EVERY valve was open. Bear in mind this was on a 3.4 but, the procedure is identical for all three motors. Being that they're hydraulic lifters, there is some play if they are a little looser than norml. Next time I'm just gonna count threads...

 

I have adjusted two motors to these exact specs with no problems.

Hopefully adjusting a 3rd in few weeks

 

I had a bad experience, If you made it work, awesome . I'll never do it again though! LOL

 

May the G0ds Smile On You as you adjust your valves!
I still need to do my Blazer valves on the 3.4 conversion.
I wish someone here would tell how they do this valve adjustment on the assembly line & always "get it right".
I know they use an electric motor to spin over engine, but.....
I used compression guage & that was biggest assist I could give myself.
Before using the Compression guage, I kept tightening too much, leaving a valve open which gave me no compression or ignition.

 

My boss says just count the threads before you pull the rockers put the motor in with the startyer. Just leave the lower plenum and injector assy off. and turn the motor over while testing compression to make sure. Then put the plenum and stuff on. They won't make noise, I promise.

 

bringing this back to the top.

As I adjusted the rockers on my swap, I took mental notes.

Here is the questionable "lash" explained!

Their is a spot where the pushrod can be moved up-down. then a spot it wont move up-down, but can spin (not firm grip, but spinning like pencil in your hand), then no movement at all.

That middle spot is "lash". It is very touchy as less then 1/4 turn on ratchet moves over this spot from up-down movement, to no movement of anything.

On phase one, most of the adjustments will be on the passenger side of the engine (4 out of 6)

Phase two, the exact opposite, most will be on drivers side (4 out of 6).

Dont forget to "set" your rockers then. Myself this time I set them 3/4 of a turn. Next time I'm going to go 1 or 1.25 turns.

 

I used the same method RBob described- wiggling the pushrod up/down instead of spinning it. As you shake the pushrod up/down, you can "feel" the taps as the pushrod hits the lifter (down) and rocker arm (up). When that pushrod doesn't bounce up/down anymore, there's no more lash.

I might have a better grip on the pushrod, and could spin it more than someone else... or, someone else might be able to keep spinning the pushrod for longer than I could. Wiggling it up/down doesn't depend on the strength/grip of the person, or how much oil is on the pushrod (preventing a good grip).

 

Actually, you've got the verb definition. AskJeeves' definition for the NOUN is:

5. the clearance or play between adjacent movable mechanical parts

 

Tom, I failed english, so I dont know what I got.

I was just going by the repair books, they say spin. But I understand completely on the grip/oil on the part.

Hopefully people can search and see this post. All good usefull information.

 

I was originally going to use the spin method too, then I was told about the up/down method from the guys on the tech forum.

There's an even more exact way to do things involving a dial gauge, but (A) I didn't fully understand the method and (B) it wasn't my engine so I didn't bother. Plus I think I needed a different dial gauge than the one I have.

 

Yeah the gauge reads "cam lobe peak" via rocker arm.
I think the big problem for me was the lifters "drained" out oil.
I'm gonna warm up engine, let cool, remove covers & go forward then.
Sun is out time to get to work again!

 

This is a "for what it's worth tip". I've found through many years of rocker arm adjustments that using a 3/8 breaker bar for this job gives you a much better feel. You can go back and forth as many times as you need to find the "sweet spot" without having to let go of the push rod to reverse the ratchet. Using this small change in method will result in a very experienced, trained feel in the coarse of one job. FYI