Hydralic Valve Adj help

[67chevemall]

Going to go over all my valves because a few are getting loose.

Never had to do this before. Want to do it right with the engine off for my
first time. And keep my intake on cause I'm poor.

Does this guy have it down right? I like how simple he has put it.

TDC

then

# 1 IN adj... 1, 2, 5, 7
EX 1, 3, 4, 8

turn over 360 deg ( the timing mark one full turn around)

on #6 now adj IN 3, 4, 6, 8
EX 2, 5, 6, 7

losen off then feel it get tight and tighten 1/2 a turn
Then tighten the lock nut with allen key and wrench.

‪hydraulic valve lash adjustment small...

I this is the right way....then I can do it and save some cash.

[67chevemall]

Well I am going to put down as much info on the subject as I can find....


When I had adjusted the tappets, I wasn't happy with the procedure, it just didn't feel right. This webpage is going to discuss 3 different methods of adjusting hydraulic tappets for a small bock chevy (SBC) which could be applied to almost any model of engine.


Rotate pushrod method

In this method, each pushrod is rotated lightly by hand while its rodnut is tightened (in a specific order). When you cannot easily rotate the pushrod with your fingers, then supposedly you are at 0 freeplay. At this point, tighten the rod nut, 3/4 turn.

I use lots of engine lube when I build an engine. The top of the lifters have lube and the rocker arm had lots of lube. The engine is also pre-oiled by running the oilpump with an electric drill. So oil is everywhere. I could tighten the rod nut until the cows came home and still easily turn an oil drenched pushrod. I know that I overtightened most of the tappets. It doesn't take much as hydraulic lifters only allow about 0.050" of adjustment from what I've heard.

This is the method that most engine building manuals suggest but I know from experience that it is just not conclusive enough.



--------------------------------------------------------------------------------


Adjust while running

This method has you adjust the tappets while the engine is running. I have a set of tappet oil plugs which clip on the rocker arms and stop the oil from being sprayed all over the place. The procedure is to remove one valve cover, plug up the oilholes on the eight rocker arms and start the engine.

With the engine at idle, each rocker stud nut is loosened until it starts to click. Tighten the nut slowly until the click just disappears, then turn the nut 3/4 of a turn more. This will cause the engine to stumble since the valve is being kept off the seat until the lifter can compensate.

Oil plug in place on one rocker arm (old junk engine used for example)

The problem with this method was that the oil pooled on the rocker arm and then was thrown off onto the hot exhaust manifold. Not a good thing! So I thought that I would cut up an old valve cover and it would prevent the oil from dripping (more like gushing) onto the exhaust manifold.


Cut up valve cover

This didn't work as well as I liked as the oil plugs would fall off and then the oil would squirt out about 2 feet in the air. It was like trying to adjust the valves with someone constantly squirting you with an oilcan. A better solution would be to drill or punch out holes that just fitted the socket rather than cut a long slit like I did. You wouldn't have to use the oil plugs either.

There's some caveats with this method:

The tappets must be reasonably adjusted to start with.
The engine must be reasonably quiet to hear the clicking
I found that the engine exhaust was loud, the noise from 8 rocker arms clicking and the air being sucked into the carb drowned out any hope of hearing a clicking noise. All in all, it was pretty much a waste of time.



--------------------------------------------------------------------------------


Measure freeplay


The last method was simple and worked the best. It requires you to measure 0 play by using a 0.0015" feeler gauge (that's pretty close to 0 play). Each tappet is adjusted in a specific order. The stud nut is adjusted so that the feeler gauge is a tight fit but can be removed. There is about 1/64 of a turn of the stud nut between a tight fit and a loose fit on a 0.0015" feeler gauge. then the feeler gauge is removed and the nut is turned an additional 3/4 turn. This works beautifully.

Just a quick note: There are two TDC on the crank. One is at Cylinder #1 and the other is 360 deg later at cylinder #6. This is due to the cam rotating at 1/2 the speed of the crank (4 stroke engine and all that stuff)

The order of adjusting the tappets for a SBC is:

Starting with the crankshaft at Cylinder #1 TDC
Cylinder #1 valves do not move when the crankshaft it rocked around TDC. Adjust the black valves as indicated on the following image.



Valve adjustment order - black are adjusted at Cylinder #1 TDC, Red are adjusted when Cylinder #6 is at TDC.


Starting with the crankshaft at Cylinder #6 TDC
Cylinder #6 valves do not move when the crankshaft it rocked around TDC. Adjust the red valves as indicated on the following image.

[67chevemall]

Adjustment with engine running.

Place newspapers between the heads and the fenders. Cover the fenders. With the engine at normal operating temperature, slow the idle to the slowest speed at which the engine will run. Remove one rocker cover and slowly loosen one adjusting nut until that rocker assembly begins to clatter noticeably louder. Oil may begin to spurt from the rocker arm. Slowly tighten the nut until the noise ceases (which is zero clearance) and then tighten 1/4 to 1/2 turn tighter. Note that when tightening the nut, the lifter has to compensate and it may hold the valve open slightly causing a miss if you adjust too quickly. The lock type nuts should stay at the final setting. If using polylocks, tighten the setscrew firmly. Set the remainder of the rockers in the same way. If several are making excessive noise when starting the adjustments, it may be necessary to temporarily tighten all nuts to eliminate the excess noise while you make final adjustments on each. Reset idle speed.


Sounds messy, but good for race days.

Readjust the lifters with the engine running and warmed up.

1. Remove rocker arm covers and gaskets.

2. Place oil deflector clips on rocker arms.

3. With engine running at idle, back off rocker arm nut until it starts to clatter.

4. Turn nut down until clatter stops; this is zero lash.

5. Tighten nut down one-quarter turn. Pause ten seconds. Repeat additional quarter turns and ten second pauses until nut has been tightened down one full turn from the zero lash position.

6. Repeat steps 3, 4, and 5 for all rocker arms.

[67chevemall]

Number 1 firing position:
Intake numbers 1, 2, 5, & 7 as well as exhaust numbers 1, 3, 4, & 8.

Turn adjusting nut until all lash is removed. When all play has been removed, turn adjusting nut one more turn. This will place the lifter plunger in the center of its travel. When above valves have been adjusted, rotate crankshaft until cylinder #6 is in firing position.

Number 6 firing position:
Intake numbers 3, 4, 6, & 8 as well as exhaust numbers 2, 5, 6, & 7.

Repeat adjustment.

[67chevemall]

Well I think I answered my own ?. Going to give it a try tonight.
Hope this helps out others too.

cheers

[mrein3]

I always follow the procedure in the Chevrolet Service Manual. I figure if I always follow the book I don't have to remember anything and I'll always get it right.
FWIW, my faulty memory is telling me the procedure sounds alot like your first post.

[67chevemall]

Well to make a long story short I found my manual!! It says the procedure in my first post is for 6 bangers....now it says to get TDC and tighten the intake and exhaust valves the same way buy twisting the rod till snug...then one full turn tight.

Then turn the crank 90 deg and tighten # 8 valves....then turn 90 deg and go down the firing order...4...3....6...5...7...2.....

Seems like more work if the other way works too.....way better to just turn the motor once around....

Anybody a pro at this subject???????????

[OhOneWS6]

There is no single correct answer. There are multiple ways to do it. Any of the procedures mentioned above will work. Just pick one and go with it. If your rockers are not staying adjusted you should invest in new lock nuts. They are cheap and you should be able to get them at any parts house.

[chevybuldr]

The first post is the way I do it to a point. Never had one come back or sombody complain. There are a few things though. First that video is with poly-locks, do you have those or do you have stock? Second, I like to get the up and down movment out of the push rod and then give it 3/4 turn. Now you will notice that the valves will open a little till the pressure backs off of them, no biggie it will in a few minutes.
Everybody has a different way to do it. This works on a stock or close to stock cam. i hope that helps. Thats the way I do it in the machine shop.

[67chevemall]

No poly locks, just the stock nut.

Well if the first method works, I'm going with that then. Seems the easiest way.

I have the heater hoses and wires out the way, covers off and plugs out, so I have to try something.

Valves are loose because I played around with them before I looked into how to do it.
lol

[RRR18]

You are on the right track man. Once you do it you'll see it's actually a pretty simple adjustment and will become fairly common. You could do it everyway that you stated above. It's just which way you want to do it that's all.

[67chevemall]

Thanks guys...lots of small enigne expirence but never had to work on the Chevy yet. And it has been 18 years since the motor was built.....

[Frkypunk70]

I personally get them to where they are suppose to be, like described in first post, then I do it by sound with the engine running. It has never let me down. I bought mr gasket clips to stop oil from shooting out of the pushrods, they are pretty cheap. Good luck whatever method you use.
Posted via Mobile Device

[bigsnookmaster]

I run a mechanical roller with a .900 base circle. Valve adjustment is critical with this setup. I use the EOIC method. Exhaust Opening , Intake Closing. If you start with #1, rotate the engine until the exhaust valve starts to open, then adjust #1 intake. I use feeler guages for mechanical roller lifters, but with a hydraulic cam, you spin the push rod until it just gets tight, this zero lash, then tighten the additional 1/2-3/4 turn. Then rotate the engine until the intake just goes over the top of the lobe, and starts to close, then again spin the exhaust pushrod and tighten to zero lash, then your additional 1/2-3/4 turn. Go through each cylinder in this manner and I promise your valves will be dead on! Also, you will have no oil to clean up! .02 Good luck!

[67chevemall]

oh man I sweated all over it for a few hours and gave up.....just sat back to think it over and noticed it is not E I E I E I E I it is E I I E E I I E

OH MAN! I got it now ... I hope.....

[bigsnookmaster]

Now you got it! Just look and see if there is an exhaust port, or intake port under the valve you're working on.

[67chevemall]

Well it has been two weeks and mission is a success... All you need is this picture and turn them all 1/2 turn...3/4 was too much in my case anyway.
After adjusting I started the motor and all was perfect.
Put the new gaskets on with the covers and away I went.
Hope this helps others too.
I did break my heater core in the process of taking the hoses off. Always something else with this hobby...lol