the rockers came loose on the 97 gmc yukon i just bought and i need to re-set them and have never done this before.
so did some searching and think im going to use this method for setting lash.

wanted to clarify that i understood a few things.

1)When the cylinder is at TDC and spark is on number 1, i can adjust both the intake and exhaust rocker on that cylinder? and so on for each cylinder afterwards.

Other methods say to do the intake, then the exhaust while waiting for the valve to just barely be open. Hasnt this not happened doing it the way quoted?

2) it says to mark the 4 points, do these points need to be dead on or can i just guestimate it as close as possible?

3) stupid Q but rotating the engine in its normal direction is rotating it clockwise if you were looking at the pulley from the front correct? and i can just do this by putting a ratchet on the end of the crank pulley correct?

 

upon further reading this method while more time consuming seems like the easiest way to go

Adjusting Hydraulic Lifters for Proper Preload
In order to adjust the preload the lifter must be properly located on the base circle or “Heel” of the lobe. At this position the valve is closed and there is no lift taking place. You will need to watch the movement of the valves to determine which lifter is properly positioned for adjusting.

1. Remove the valve covers, and pick a cylinder you are going to set the preload on.

2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder’s intake rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)

3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)

4. Now spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the pushrod, you are at “Zero Lash”. Turn the adjusting nut down one half to one full turn from that point. Lock the adjuster into position. The intake is now adjusted properly.

5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.



i still need an answer to question number 3 in my first post.

 

That's the "EOIC" method; much better than the first one.

The engine turns clockwise viewed from th efront. Yes you can do that, if you don't mind maybe having to replace the bolt and Heli-Coil the crank halfway through the job. I highly recommend some kind of a turning tool, such as the ones I pointed out a couple of days ago in this thread.

 

lol well as much as i love helicoiling things that ive destroyed, i think ill stay away from having to do that to my crank. 20 bucks seems like a wise investment. im assuming that just slips over the crank pulley?

only other question was about this


so i want to start adjusting when the exhaust valve has begun to open so the pushrod will be all the way down, and as i turn will slowly be pushing up on the rocker. As soon as the exhaust pushrod starts to lift up, stop and set the intake rocker.

then rotate more until the intake lobe is almost closed, so the pushrod on the intake side has gone all the way up is going back down and you stop just before it is all the way down.

now if you miss it being almost closed and the intake goes fully closed, can i just keep rotating for another full cycle until the intake has opened all the way again and is almost closed?

EDIT: other question is im doing this on the used 97 yukon i just bought, put 5000km on it and the rockers came loose to the point one day it started ticking like crazy and was dropping a cylinder. only 3 rockers are loose. Should i loosen all the rockers on the whole motor and just do it all from scratch?

 

That tool bolts on by the pulley bolts; hard to say whether it will go on inside your pulley or not. You might have to take off the pulley. You wouldn't have to pull the damper though. The socket looking one is for when the damper is off.

I think you undertand it.... you adjust a cyl's intake as its exhaust just begins to open, and adjust its exhaust as its intake just closes. The abbreviation commonly used is "EOIC". Makes it easy to remember.

Yes I'd do the whole motor. I'd strongly recommend going by the hardware store and buying 16 3/8"-24 (fine thread) nuts, and putting them on top of the rocker nuts as jam nuts, so they don't back off again.

 

any sugestions for removing the bolt on the pulley? i dont think this motor has been touched since it left the factory and has 260 000 km on it that bolts gonna be welded on there.