The search isn't working and i plan on redoing my rr's tomorrow night so bear with me.

What method do you all u se to set yours? post up please

TIA,

Dave

 

I find that rocking the rocker back and forth while turning the lock nut by hand is very good. Once i feel and hear the click is gone i turn the lock nut 1/2 a turn, tighten the allen screw and then tighten the locknut another 1/8 turn.Spinning the pushrod can be inaccurate for some people.

 

There are a few different methods that are used, so chances are you'll get different methods posted here. They can be divided into basically two methods - with engine idling and with engine off.

I use the method that the Pros use, which is with the engine off.

I do one cylinder at a time. I begin at the front, driver's side on #1 and work my way toward the rear on the same side. Then switch over to the passenger side front and follow the same procedure - front to rear.

I watch the intake rocker movement to set the exhaust, then watch the exhaust rocker movement to set the intake.

I begin with the #1 exhaust. Bump the engine - using the starter - while watching the #1 INTAKE rocker's movement. I back off the #1 EXHAUST adjusting nut until it's slightly loose. When the #1 INTAKE rocker completely opens the #1 intake valve THEN begins to close that valve - and is about 1/2 to 2/3rds the way closed - I STOP bumping and set the #1 exhaust. This 1/2 to 2/3rds approximation isn't too critical; anywhere in that range is good to go.

To set the #1 EXHAUST I back off the EXHAUST adjusting nut until it, too, is slightly loose, then begin to slowly tighten the nut while at the same time, using my fingers, I move the #1 EXHAUST pushrod up and down.

When I can no longer move the #1 exhaust pushrod up or down I know I've found ZERO lash. At that point, I make 1/2 turn more on the adjusting nut. Then, while holding the nut with a box-end wrench, I use an allen wrench to tighten the Allen screw.

I then move to adjusting the #1 INTAKE. To do this I again begin bumping the engine while watching the #1 EXHAUST.

When the #1 EXHAUST rocker JUST BEGINS to move downward (thus opening the #1 EXHAUST valve), I stop bumping. At this point I adjust the #1 INTAKE rocker using the same method as above.

I then move on to the next cylinder (#3) and do the same thing. Continue on until all are done.

When all are finished I go over all the nuts again by adding a little more torque to the nuts.

The ideal lifter preload is .030", which is pretty difficult to actually measure. So using 1/2 turn of the adjusting nut pretty much nails that setting.

Also, you'll find a very similar procedure in CompCams' and Crane's, etc. catalogs.

Just my way; others have others.

Jake

 

thanks guys...i hope some others post up too

mine have seemed to gotten a little loose and a few are making noise.

 

I agree with Jake with one exception - I don't bump the motor with the starter. I put a big-a$$ ratchet on the centerbolt of the crank and hand crank it. That way I'm sure when the lifter is "off" the cam lobe, it's more precise than trying to catch exactly when the rocker is free with the starter.

Sounds tedious, but with two people (one cranking, one playing with the RR) it takes maybe 30 min to an hour.

 

I am with Jake, also, with one minor exception on the lock screw.

Once I reach the adjustment I want, I back off on the adjusting nut by 1/16th to 1/8th of a turn. I then tighten the Allen headed lock screw so it contacts the stud, inside of the adjusting nut. THEN, I turn both the box end wrench, on the adjusting nut, and the hex wrench, engaged in the Allen lock screw, simultaneously the 1/16th to 1/8th of a turn I backed off on the adjustment, the get the lock screw, securely locked against the stud.

RACE ON!!!

 

I've found that detecting zero lash by twirling the push rod as I slowly tighten the polylock is very accurate. From the point where I just feel slight resistance to where I cannot rotate the push rod is only 1/8 turn on the poly lock. So I just tighten 1/2 turn plus an additional 1/8 turn, assuring that preload is set between 1/2-3/4 turn past zero lash.

I too prefer to rotate the carnk manually and use the EO/IC method of assuring the the valve being adjusted has its push rod on the cam's base circle.

If a valve "seems" to be loose after you've moved on to adjust other valves, do NOT go back and mess with them. Once you set preload and lock down the polylock, it's done.

 

any tips on turning the crank by hand? i ended stripping my stock crank bolt...pull the plugs??? am i missing something?

thanks again

 

Crap, I'm sorry. Yes, you need to pull the plugs to allow the pressure to escape.

I hope you can get it off easily!

 

That is the old, tried and true, published forever, method. And it is as good as gold. However, since I've been frequenting this forum, I have read of many cases where the person performing the task, missed the point of zero lash and kept tightening until he had the plunger bottomed in the lifter. That prevents the valve from closing. The resistance met when twirling the push rod varies with the strength of the plunger spring inside of the lifter. Not only can the spring to be weak enough to evade detection at zero lash by the uninitiated, it can also vary from lifter to lifer, leaving some lifters properly adjusted and others bottomed out.

For a final clarification it should be said that "zero lash" is more than just a condition in which the valve train has no lash. It is the precise point where the lash diminishes to zero and preload begins.

RACE ON!!!

 

One alternative way I've used to bump the engine is to connect a bump starter switch (available at most auto parts stores) to the starter solenoid and use it to bump over the engine.

Only downside is how difficult it is to make the connection to the starter with the car sitting on the floor. If the car happens to be on jackstands, then it's a piece of cake.

All the 1/4 drag cars I've worked on have a bump starter button bolted to the firewall. Pushing it bumps over the engine and is used when setting the valve lash (mechanical cams).

BTW, setting lash involves the same procedure except instead of setting preload - as you would with a hydraulic cam - you use feeler gauges to set the clearance between the rocker tip and valve stem tip.

Jake

 

here's an old post on the subject

http://forums.corvetteforum.com/show....php?t=1035253

 

lol...gee look who started it...the search wasn't working yesterday or the day before so i figured i'd ask since i'll be doing this later today

thanks again guys

 

BTW, setting lash involves the same procedure except instead of setting preload - as you would with a hydraulic cam - you use feeler gauges to set the clearance between the rocker tip and valve stem tip.

Jake[/QUOTE]

Ah, I miss the good old days of the 60's, solid lifters, and feeler guages. You could adjust those puppies down to a knats butt.

 

CFI-EFI - i agree with you because there is a point where the pushrod spins freely, then the tension slightly increases and it finally stops spinning. now if there is only 1/8 of a turn between spinning and not and i get them more or less correct and set a 1/2 turn preload, why does it clack?

Jake - i followed your method to the T last time and this time i twirled instead of moved up and down and got the same exact result = clack..

I will hopefully get someone experienced to come over tomorrow before i put it all back together.

thanks again

 

From what you describe, I can't explain it. Hydraulic lifter preload is much more forgiving than solid lifter valve lash. From what I read that you have written, you have somewhere between 7/16ths of a turn, and 9/16ths of a turn, worth of preload. Properly done, either should be quiet. You can alway go to my fool proof, stand by. Adjust them with the engine running. Pull just one valve cover and start the warmed up engine. Loosen one adjusting nut until it really clatters. If if doesn't get any louder, or once it does, start tightening, fairly slowly. The noise will get quieter and finally stop, all together. When the noise just stops, you've reached zero lash. You can add your desired preload from that point. Because the engine is running, you can do then in any order. It is easiest to keep track if you simply start at one end and work your way down the line. Once finished, go around and do the other side.

RACE ON!!

 

i actually think its just ticking that i'm not used to. i also eliminated an exhaust leak and it sounds pretty good now.

thanks for all the help guys,

dave

 

I guess I am old fashion but I do mine with the engine running. Initially I set mine as several have mentioned and use that setting for initial start up. Then I pull a valve cover and install a cover with the top cut out allowing access to the rockers. Loosen one until it clicks, tighten until it quits. Move to the next rocker. When all on a side are done shut down and tighten each 1/2 turn and set Pollylocks. A little more work but it works for me.

 

I guess that's another thing we should have mentioned. RR's are a lot louder than the stock rockers. There's a difference between a loose one clacking and the "ticking" you'll get. Wait until your knock sensors start retarding timing...what year is your car?

 

its a 93...i will have datalogs from the track on saturday