Setting Valve Lash

[gedmeyer]

What is the best method to adjust valve lash on my '81? I'm getting some clicking that I would like to fix. The motor and heads were rebuilt last year, but I must've been a little off on my valve adjustment during reassembly.

Am I correct that I have hydrualic lifters? Can I adjust the lash with the engine running? I figure this would be the surest way to make sure I got them adjusted the first time without having to go back...

thanks!
-gedmeyer

 

[RodsnRides]

Yes-you can do it with the engine running, and it is perhaps the "surest" method.

First, get yourself those nifty little rocker arm clips that cover the oil holes in the rockers and help avoid oiling down the engine compartment. Next, get the engine to normal operating temperature. Remove the cover, start engine, let idle. Back off the rocker arm until an audible 'clicking' is heard. Slowly tighten rocker nut until the moment the click goes away. Note position of ratchet handle (I like to bring handle back to six or twelve o'clock). Slowly tighten another 1/2 turn. Books typically recommend 1 full turn-I think it's too tight. Racers will go 1/4 turn to allow the free revving of the engine. I like 1/2 turn as I think it's the best of both worlds-tight rocker, free revving. Continue with each rocker on that side. Shut off engine, remove clips, wipe down, install cover, go to other side, repeat procedure. Finish at car wash to remove excess.

Let me know if you need the 'cold' or 'start' procedure. It's a little more involved. How "basket of snakes" is that engine bay? I shudder....I have good access on mine. Good luck.

I hope John Z approves...

Rick

 

[JohnZ]

I hope John Z approves...

Rick

 

[wishuwerehere82]

I have used the Vacuum gauge techniqe with good success.
Put a Vacuum gauge on your intake manifold source and back off the rocker until the vacuum drops, then turn the nut in until you get the highest reading on the gauge. The proper setting is between 1/2 and 3/4 turn from the clatter point, but using the guage helps you find the exact backlash point.

 

[gedmeyer]

Thanks Rick. Other than being messy, sounds fairly straight forward. I used the shop manual for the initial setting of the lash last year. Looks like I have myself a weekend project.

...slowly working up to the sidepipes in the next couple weeks! After the valve lash comes the squeeky LF caliper. YIKES

-gedmeyer

 

[wishuwerehere82]

not a big job. The hardest part is getting the valve cover off the A/C side.

 

[Hib Halverson]

First, know that not all clicking you hear from the valve gear is lash-related. Even hydraulic lifter valve trains that are perfectly adjusted sometimes make noise, however, a stock 81 cam and valve train which are in good condition should not make noise.

Pull both covers, turn the key off and connect a remote starter button to the starter. Do one cylinder at a time. Adjust the intake when the exhaust just starts to open. Adjust the exhaust when the intake just begins to close. Back off the adjustment until you feel the rocker arm loosen. Twirl the pushrod with your fingers and, at the same time, tighten the rocker nut slowly. As soon as you feel resistance to the twirling, stop turning the nut, then back off just until the resistance to twirling goes away. Move on to the next pair of valves and repeat the procedure. Once you do all 16 valves like that, go back and give each nut an additional 1/2-3/4 turn. That will properly preload each lifter. Put the covers back on and go for a road test.

 

[AKRAY4PLAY]

What is the best method to adjust valve lash on my '81?

i would get some old valve cover from a junk yard, cost you next to nothing. cut the top out so you can reach the adjusting nuts. as stated, set them at 1/2 - 3/4 turns from clacking with the motor warm and running. the cover will keep the splashing oil under control as long as you don't rev the motor to the moon. good luck with it, Brian.

 

[rgtrough]

Hey RodsandRides, where would one obtain the clips you mentioned?

Bud

 

[gedmeyer]

I reset the lash yesterday afternoon. I bought those clips from a local parts store (mom and pop operation b/c the chain automotive store didn't carry them). In any case, I first tried to set the lash w/ the car running, but it was making more of a mess and I was not confident that I was doing it right. So I turned the car off and did it the other way.

Sounds like I got rid of the clatter, so I'm happy. The only problem is that I spilled oil on the exhaust pipes, so it stinks when it is burning off!

Thanks for the help guys.