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Old May 29, 2018 | 09:54 PM
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Default Valve adjustment

I changed out some head gaskets now I must set the lash on the valves I watched a few video's and once you have taken the slack out of the push rods some go 1/4 round 1/2 one even goes a full round. Which method is right?
Old May 29, 2018 | 10:14 PM
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All 3. Go 1/4 turn.
Old May 29, 2018 | 11:26 PM
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1/4 is what I remember. My engine is still in a partially disassemble state. My rockers have a roller on them and I noticed a cam button on my sprocket. Would this still make it 1/4?
Old May 29, 2018 | 11:56 PM
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You just BARELY take the up and down slack out of them. You want the cup in the lifter to be at the top with no preload. THEN turn the additional amount. The 1/4 turn was always the plan for something you wanted to try and RPM pretty high. But you have to be careful if the lifters just have little wire clips in them as they can come out if they get pushed against too hard by plunger during a valve float instance or something. Some higher end Morel lifters seem to like almost a full turn to keep them quiet. For normal street stuff that isn't going to be flogged too hard I'd use 1/2-3/4 turn to keep them quiet.

JIM
Old May 30, 2018 | 06:23 AM
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Thanks for the replies guys.
Old May 30, 2018 | 01:41 PM
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Originally Posted by 427Hotrod
For normal street stuff that isn't going to be flogged too hard I'd use 1/2-3/4 turn to keep them quiet.
Old May 30, 2018 | 08:59 PM
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Originally Posted by 427Hotrod
For normal street stuff that isn't going to be flogged too hard I'd use 1/2-3/4 turn to keep them quiet. JIM
Yup, that's the ticket.
Lars
Old May 30, 2018 | 11:29 PM
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Go for 1 full turn like the book/maintenance manual says.
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Old May 31, 2018 | 12:37 AM
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Always went 3/4 to 1 full. Never had a problem.
Old May 31, 2018 | 02:14 PM
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I have always gone 1/2 turn with no issues.
Old May 31, 2018 | 02:31 PM
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one thing for sure,
over tightening ain't good.
read too many "my engine don't run"
threads from too tight valves.

takes a good technique to set hydro lifters
when engine is not running.

constant feeling of pushrod while slowly tightening rocker nut
until you can't spin the p rod.
can't is relative in that a non pumped up lifter can collapse.

so, do your best to get the lifters full of oil, take small turns on the nuts,
take care to "feel" when slack is out of p rod and then turn
the amount you want to use as the final setting.
Old May 31, 2018 | 05:45 PM
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Food for thought:

If we are dealing with a street engine that is not going to be driven like it was stolen and high RPM's all the time.

Back in the day. I was told by the old timers that setting the valve adjustment at one full turn will make it so when wear begins on the rocker arms and lifters. This will make it so the rocker arms will not need to be readjusted as quickly if they were adjusted at 1/2 of a turn.

Kinda made sense when I thought about it. But I do not get all hung up over this adjustment unless it is on an engine that is super high performance.

On an engine with 100K on it. I just get them to what I mentioned earlier and as long as they are quiet..I am good with it.

DUB
Old May 31, 2018 | 07:49 PM
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To get zero play (before doing your 3/4 additional turn) wiggle the short end of the rocker up and down while slowly tightening the adjuster. Spinning the pushrod makes it easy to over tighten.
Old May 31, 2018 | 08:55 PM
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Good tips!👍
Old May 31, 2018 | 09:47 PM
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Originally Posted by 427Hotrod
You just BARELY take the up and down slack out of them. You want the cup in the lifter to be at the top with no preload. THEN turn the additional amount. The 1/4 turn was always the plan for something you wanted to try and RPM pretty high. But you have to be careful if the lifters just have little wire clips in them as they can come out if they get pushed against too hard by plunger during a valve float instance or something. Some higher end Morel lifters seem to like almost a full turn to keep them quiet. For normal street stuff that isn't going to be flogged too hard I'd use 1/2-3/4 turn to keep them quiet.

JIM
I have Morel roller lifters and they recommend 1 full turn after zero lash and also recommend 10w 40 oil. I would think that a stock GM lifter will be fine at either 1/2 or 3/4 turn.

Last edited by Buccaneer; May 31, 2018 at 09:47 PM.
Old Jun 2, 2018 | 08:55 AM
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Originally Posted by zwede
To get zero play (before doing your 3/4 additional turn) wiggle the short end of the rocker up and down while slowly tightening the adjuster. Spinning the pushrod makes it easy to over tighten.
This is the best advice you can give. Up and down motion is easy for a novice to feel where spinning a pushrod is very imprecise. Too tight is defiantly possible if you do not ALREADY know how to do this! If someone is asking this question, they clearly need the best method that can be accomplished by a novice. Eliminate the slack with an up and down movement and then go a fraction of a turn more. The exact amount of the extra partial turn is just not critical.

Need to follow the book on which valves to set and which crank position to be at when you set them.

There are other methods to do this.... if you already know how.
Old Jun 2, 2018 | 10:45 AM
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The easiest and most precise method of finding "0" lash is to use a .001" feeler gauge between the valve stem and rocker arm. With the valve completely closed loosen the rocker adjustment until there is some slop in the arm. at this point slide the .001" feeler between the valve stem and rocker, it should slide back and forth easily. Start to tighten the adjuster until you feel a slight drag on the gauge. Now you have zero lash +.001" When I did my valves 2 years ago I used the opposing cylinder method to adjust the intake then the exhaust second. The opposing cylinders are 1<>6, 8<>5, 4<>7, 3<>2. With #1 fully open #6 will be fully closed and can be adjusted. I adjusted all my intakes first and then all the exhaust. The amount of pre-load will vary with each application. I first set my L48, with flat top pistons, RV cam and ported and polished heads to 1/4 turn and my car didn't like it very well, I then added another 1/4 turn to each rocker and it was much happier at 1/2 turn pre-load. More detailed description of the opposing valve method can be found by a quick Google search. There are easier methods but none are more accurate and this method allows for more hands on time with your engine.
Good luck, Jerry

Last edited by shenango; Jun 2, 2018 at 10:47 AM.

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Old Jun 2, 2018 | 06:56 PM
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funny xhit
you can't get "leverage" with moving around, up/sown, spin, feel
fart on.
i found pushing rockers sucks,
leverage on iffy lifter pump up condition.
Old Sep 24, 2021 | 08:24 PM
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Scares me to read all these replies.
Old Sep 24, 2021 | 08:54 PM
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Originally Posted by Tim H
Scares me to read all these replies.
yes, me too, they are over 3 years old!



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