# push rods and rocker arms



## Topkat (Sep 9, 2010)

While rotating the motor trying to find my "click", 
I noticed that one of my pushrods has a point in its travel where there is no tension at all. and I am able to lift it up and down between lifter and rocker arm a good 1/16 of an inch or so.
Bad rocker arms?
(I have replaced as new just about everything in this motor)
thanks as always


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## dimitri (Feb 13, 2009)

I think you may have adjusted your rockers incorrectly. Who made your cam and lifters?


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## Topkat (Sep 9, 2010)

crower


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## dimitri (Feb 13, 2009)

I have never used Crower before in a car. Motorcyle yes, but car no. What I think you need to do is read the instructions for adjusting your rockers arms again. Start at the beginning and readjust all of your rockers as per instructions.


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## BearGFR (Aug 25, 2008)

Topkat said:


> While rotating the motor trying to find my "click",
> I noticed that one of my pushrods has a point in its travel where there is no tension at all. and I am able to lift it up and down between lifter and rocker arm a good 1/16 of an inch or so.
> Bad rocker arms?
> (I have replaced as new just about everything in this motor)
> thanks as always


Sounds like adjustment to me too, Top. The "best" way to do it is to follow a procedure Mr. P-Body espouses because that will result in a consistent preload across all 16 lifters. If perchance you've already filled/soaked the lifters in oil, then you'll probably want to use the alternate method. 
To do it right, you'll want both valve covers off and a way to turn the motor over with a wrench, using the crank bolt. Start with cylinder #1 (front, driver's side) and turn the motor until you see the *exhaust* valve just beginning to open. Adjust the *intake* valve for cylinder #1. The "old" way is to tighten the rocker nut just until you've taken all the slack out of the pushrod - i.e. - you can't move it up and down. Then tighten the rocker ball nut an additional 1/4 to 1/2 turn (the specific amount isn't as important as doing 16 exactly the same). Turn then engine over about 90 degrees until you see the exhaust valve for #8 just starting to open --- adjust #8 intake the same way. . The "new" way is to use a dial indicator and tighten the rocker nut to depress the piston inside the lifter a specific amount (I forget the distance, but maybe Mr. P will be along shortly.) Lather, rinse, repeat adjusting all the intake valves in firing-order sequence 1-8-4-3-6-5-7-2. You'r half done at this point. Now turn the motor over until you see #1 *intake* valve open all the way and just starting to close. Adjust the *exhaust* valve for that cylinder the same as you did the intake. Work your way ariound again, setting each cylinder's exhaust valve just after you see the intake beginning to close.

There's another sequence that lets you do two valves at once, but it can get you "off" especially if you've got a longer duration cam with a little attitude. Doing all 16, one at a time, through two complete engine revolutions is always better an more consistent.

What you're accomplishing by watching for the exhaust valve beginning to open, is making sure that the intake valve is fully closed and the lifter on the base circle of the cam. Likewise, when the intake is just beginning to close you know the exhaust is fully closed and the lifter on the exhaust lobe base circle.

Bear


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## Instg8ter (Sep 28, 2010)

thanks Bear was just getting ready to post about Mr.P-bodys procedure, will be getting the engine in and fired up in the next few weeks. Are you ready for paint? Man these 66-67 bodies are a chore to get straight, with their 7' long rear quarters. I have sanding blocks from 1-4'. i will be priming w/high build for my final blocking down to 180 and wet sanding as soon as our weather allows me to get the body temp up over 50 degrees. I am hoping to spray color in April, I have found a downdraft spray booth to rent for color/clear.....spring is looking good for a debut....arty:


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## Topkat (Sep 9, 2010)

I removed the drivers side rocker arms. rotated the motor and the pass.side was making a "click" .
removed them all and the noise stopped.


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## Topkat (Sep 9, 2010)

I did indeed pre soak the lifters.
The book says to torque the rocker arm nuts to 20lbs
is that out the door with the procedure you described?
thanks again


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## freethinker (Nov 14, 2009)

Topkat said:


> I did indeed pre soak the lifters.
> The book says to torque the rocker arm nuts to 20lbs
> is that out the door with the procedure you described?
> thanks again


it could be this. some aftermarket cams have a low cut heel that makes it impossible to adjust the valves with the stock nuts. if you have tightened the stock bottoming nuts correctly and you have slack in the pushrods you either need to use adjustable nuts or get custom pushrods to achieve the correct valve adjustment.


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## BearGFR (Aug 25, 2008)

Topkat said:


> I did indeed pre soak the lifters.
> The book says to torque the rocker arm nuts to 20lbs
> is that out the door with the procedure you described?
> thanks again


Hey Top,
That "torque to 20" proceedure will work only with all factory parts in 'like new' condition. If anything in the valve train is non-factory, or if the rocker-ball nuts (or studs) are worn a little, it's not reliable. It helps to understand what you're trying to do --- and that is to remove all the "slack" from the lifter to the push rod to the rocker arm to the valve stem *when the lifter is on the cam 'base circle' --- at minimum lift in other words*, then take out "just a little more" in order to depress the internal spring inside the lifter that supports the pushrod cup "just a little bit". If the lifters haven't been pre-filled, then you can get them all "dead on" using a dial indicator and Mr. P-Body's proceedure. If they have been pre-filled, then you can get them very close using the proceedure I described -- take out all the slack, then tighten the rocker ball nut (or poly-lock, if that's what you have) an additional 1/4 to 1/2 turn (and lock it down, if it's a poly-lock). *Very important to make sure each lifter is on the cam base circle when you adjust it.* That's why you follow the proceedure I described earlier - doing all the intakes first, in firing order sequence, then the exhausts in firing order sequence. You'll rotate the engine through 4 complete revolutions, 90 degrees at a time --- 2 rev's for the intakes, 2 rev's for the exhausts.

Side note: If you're using the factory rocker ball nuts, and after following the procedure they don't "hold" their adjustment, then either the nuts, the studs, or both are worn and need to be replaced. If that happens, just go to poly-locks and be done with it.

Bear


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## geeteeohguy (Feb 2, 2008)

I agree with Bear on the hardware.l I've seen the stock nuts go after one use. They are a slight interference fit, and after they're removed/replaced one time, they won't hold an adjustment. Poly locks are a great solution.


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## freethinker (Nov 14, 2009)

there seems to be a missunderstanding. with stock valve train parts(ex ra4)there is no adjustment. they are non adjustable. you just torque them down to specs and the adjustment is built in. the pontiac factory nuts do not wear out. they are reuseable. they are torqued onto a tapered shoulder on the stud so they do not lose their ability to hold their position.
the problem comes from using aftermarket parts. that can cause the factory preset adjustment to be incorrect. then you need to come up with a way to compensate. the common methods are adjustable nuts or custom length pushrods. if you are using adjustable nuts then you need to do the adjustment method described above.


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## Rukee (Feb 8, 2007)

I might disagree with the factory nuts being reusable. They achieved the 'lock' by rolling over the top edge of the nut. Once they are installed that edge can be straightened out just by torquing the nut, thus making the next torquing inaccurate.
I do agree with Bear's adjusting method of the valve adjustment, however I do it 1 cyl at a time as to know I'm not missing any valves, but I fail to see why the adjust made should be any different if the lifters have been soaked or not. If you tighten 1/2 turn after slack is taken up, how is 1/2 turn any differnt between the lifter being soaked or not? Maybe he can exlain.


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## freethinker (Nov 14, 2009)

Rukee said:


> I might disagree with the factory nuts being reusable. They achieved the 'lock' by rolling over the top edge of the nut. Once they are installed that edge can be straightened out just by torquing the nut, thus making the next torquing inaccurate.
> I do agree with Bear's adjusting method of the valve adjustment, however I do it 1 cyl at a time as to know I'm not missing any valves, but I fail to see why the adjust made should be any different if the lifters have been soaked or not. If you tighten 1/2 turn after slack is taken up, how is 1/2 turn any differnt between the lifter being soaked or not? Maybe he can exlain.


you are confusing chevy nuts with pontiac nuts. chevy nuts use a thread locking method. factory pontiacs use a bottoming on a shoulder method.


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## Topkat (Sep 9, 2010)

How can I tell where minimum lift is?
When the rocker arm end over the valve is at its highest?
Still confused
thanks


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## likethat (Oct 5, 2007)

I have, on factory type rebuild for chevy's, set it to zero lash + 3/4 turn. Then run in cam, time and adjust carb, then loosen one valve at a time with engine running until I here lifter clatter. Tighten till quit then 3/4 turn more on each rocker.

On Pontiac I base circle cam and torque to 20 ft lbs. On Stock builds I have reused the nuts and balls on many Pontiac and driven years with out any trouble. Maybe I have just been lucky. As for a performance build it would be full rollers and poly locks. How much more is that really over the total build and how much is peace of mind worth?

TopKat minimum lift is the point at which the lifter is at the lowest point on the cam shaft or you can say at the most round point. This is when the lifter should not be pushing the valve.

On the cam there is an egg shape so maximum lift would be the smallest point on the cam lobe or the farthest point from the center of the cam. In this diagram, where it is pointing to intake lobe is the minimum lift, and where it says lift at the top, would be maximum lift. If you spin the crank around after the timing chain had been installed. Then you set the timing marks to point at each other. This is where you start on number one cylinder. If you have every thing buttoned up all ready and only have the timing marker and harmonic balancer. You need to have the balancer pointing at 0 deg's on the compression stroke. There will be 2 times the mark will hit 0 . If, when you tighten down the rocker over the #1 intake runner, and then turn the crank, and if the push rod gets to loose, or any slack in the push rod. Then you need to go to 0 again and re-tighten. turn the crank a bit. There should be no slack or up and down movement on the push rod. Once you have that on #1 intake you then follow the tightening sequence for the rest.


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## Mr. P-Body (Jan 20, 2011)

Agreed, "stock" Pontiac nuts are for non-adjustable valve train and are COMPLETELY "re-usable". 

As for the "preload" we put on lifters when using an "adjustable" valve train, assure the cam is on the "heel" of the lobe. That is, the cylinder is "up" on compression, and both valves are closed. Tighten slowly until there's resistance against turning the pushrod "by hand" (not TIGHT, just a little "harder"). Add 1/4 turn. This leaves the ball and plunger fairly near the "top". While still offering the advantage of the hydraulic lifter, it will be less apt to "pump up" if nearer the top.

"Minimum lift" is ZERO and this is not a term used by engine builders.

Jim


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## BearGFR (Aug 25, 2008)

Topkat said:


> How can I tell where minimum lift is?
> When the rocker arm end over the valve is at its highest?
> Still confused
> thanks


Best way requires you to turn the engine by hand (socket wrench on the big bolt in the center of the harmonic balancer) through a total of four (4) complete revolutions.

With the valve covers off, turn the engine with the wrench until you see the EXHAUST rocker/valve on #1 cylinder (drivers side front) just beginning to open. At that point you know that the INTAKE for #1 is on the cam base circle/("minimum" lift point). Adjust #1 INTAKE only. Rotate the crank until you see #8 EXHAUST just beginning to OPEN (ought to be real close to 90 degrees of rotation), then do #8 INTAKE. Continue working your way through the firing order (1 8 4 3 6 5 7 2) until you've done all the intake valves - at this point you will have completed two (2) complete crank revolutions. You're halfway done. Now start over on #1, turning the engine over until you see #1 intake valve just beginning to CLOSE. At this point you know that #1 INTAKE is on the cam base circle. Adjust #1 EXHAUST. Repeat for all the exhaust valves in the same sequence (1 8 4 3 6 5 7 2).

There's another pattern you might find or hear about that lets you do two valves at once and doesn't require as many engine rotations to complete, but it's not as accurate - especially if you're running a cam with more aggessive duration than stock.

In case you're not sure which valve is which, just look at the exhaust ports on your heads. The valve that's closest to the exhaust port on each cylinder is the exhaust valve. On a D-port Pontiac, working front to back the sequence is Exh-Int-Int-Exh-Exh-Int-Int-Exh

Bear


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