Rocker Arm Adjustment

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jmorgan_68
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Rocker Arm Adjustment

Post by jmorgan_68 »

I got the newly rebuilt 302 put into my 68 swb but something doesn't sound quite right. I tightened the rocker arms until they were tight against the valves and then 1/2 turn more. Any ideas or tricks to adjusting them?
cdeal28078
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Re: Rocker Arm Adjustment

Post by cdeal28078 »

Are you sure you have adjustable rocker arms? What year 302 is it? Tight against the valves and a 1/2 turn more? I don't understand what you did yet. What year 302 did you get rebuilt? Can you post a picture of your rocker arms? That would help a lot
clint
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Re: Rocker Arm Adjustment

Post by 70_F100 »

cdeal28078 wrote:Are you sure you have adjustable rocker arms? What year 302 is it? Tight against the valves and a 1/2 turn more? I don't understand what you did yet. What year 302 did you get rebuilt? Can you post a picture of your rocker arms? That would help a lot
clint
:yt:

If you DO have adjustable rockers, did you make sure the lifters were pumped up fully? Did you rotate the engine so that each of the lifters was on the bottom side of the cam lobe before adjusting?

If you have adjustable rockers, the "zero lash plus 1/2 turn" will work. I've always just tightened them an extra 1/4 turn on SBF engines.

Back in '74, I was working for a GMC dealer, and we had a TON of top-end failures on 454's. Through some research, we found that the rockers on those required a full turn past zero lash to center the plunger in the bore to provide the proper lubrication through the push rod and rocker arms.
Wise men talk because they have something to say; fools talk because they have to say something.--Plato
Why is it that there's seldom time to fix it right the first time, but there's always time to fix it right the second time???

That's not an oil leak :nono: That's SWEAT from all that HORSEPOWER!! :thup:
jmorgan_68
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Re: Rocker Arm Adjustment

Post by jmorgan_68 »

The heads are pre-70 289 on a 77 302 block. The rocker arms aren't adjustable
cdeal28078
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Re: Rocker Arm Adjustment

Post by cdeal28078 »

Some 289's did have adjustable rockers. Does it have slotted holes where the pushrods inter the heads?
clint
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Re: Rocker Arm Adjustment

Post by cdeal28078 »

jmorgan_68 wrote:The heads are pre-70 289 on a 77 302 block. The rocker arms aren't adjustable
I am confused just a bit. YOu know they are not adjustable right? Did you torque them down or try and adjust them. The positive stop type heads all you do is torque them down to about 25ft lbs. There is supposedly a way in the books that has you turn the engine with the cam timing to keep the valves on the back of the cam lobe while you tighten them but I have never done that
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Re: Rocker Arm Adjustment

Post by 70_F100 »

jmorgan_68 wrote:The heads are pre-70 289 on a 77 302 block. The rocker arms aren't adjustable
But what you did is essentially "adjusting" them. :doh:

And if they aren't adjustable, why are you asking about adjusting them? :hmm: :hmm:
Wise men talk because they have something to say; fools talk because they have to say something.--Plato
Why is it that there's seldom time to fix it right the first time, but there's always time to fix it right the second time???

That's not an oil leak :nono: That's SWEAT from all that HORSEPOWER!! :thup:
jmorgan_68
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Re: Rocker Arm Adjustment

Post by jmorgan_68 »

Maybe i should reword my question since the rocker arms are not "adjustable". "Installation" may be more appropriate, when i installed the rocker arms i tightened them down against the valves and then went 1/2 turn more. I have ran the engine but not for very long maybe 5 to 10 minutes and there seems to be some rattle in the rocker arms so i don't think something is right.
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Re: Rocker Arm Adjustment

Post by cdeal28078 »

jmorgan_68 wrote:Maybe i should reword my question since the rocker arms are not "adjustable". "Installation" may be more appropriate, when i installed the rocker arms i tightened them down against the valves and then went 1/2 turn more. I have ran the engine but not for very long maybe 5 to 10 minutes and there seems to be some rattle in the rocker arms so i don't think something is right.
That is pretty much adjusting them to a point. I bet you have had chevies most of your life. No insult intended.
On a Ford Positive stop rocker stud all you do is tighten them down and torque them to about 25 FT Ft. Forget about them touching the valve or tightening them down until they touch the valve. Just torque them down to 25 FTLBS.
The rocker arm studs have a large area that you tighten the rocker arms down to. The valves never come into the equation at all. Just torque the rocker arm nuts down to and I THINK it is 25ftlbs. Can somebody else verify that?
Bet honest money your valves are too loose.
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Re: Rocker Arm Adjustment

Post by 70_F100 »

cdeal28078 wrote:
jmorgan_68 wrote:Maybe i should reword my question since the rocker arms are not "adjustable". "Installation" may be more appropriate, when i installed the rocker arms i tightened them down against the valves and then went 1/2 turn more. I have ran the engine but not for very long maybe 5 to 10 minutes and there seems to be some rattle in the rocker arms so i don't think something is right.
That is pretty much adjusting them to a point. I bet you have had chevies most of your life. No insult intended.
On a Ford Positive stop rocker stud all you do is tighten them down and torque them to about 25 FT Ft. Forget about them touching the valve or tightening them down until they touch the valve. Just torque them down to 25 FTLBS.
The rocker arm studs have a large area that you tighten the rocker arms down to. The valves never come into the equation at all. Just torque the rocker arm nuts down to and I THINK it is 25ftlbs. Can somebody else verify that?
Bet honest money your valves are too loose.
clint
:yt:

Since you've had it running and the lifters are pumped up, just make sure to turn the engine over so that the valves are fully closed.

That way, there's no chance of a valve hitting a piston or the valve spring retainers hitting the valve guides.
Wise men talk because they have something to say; fools talk because they have to say something.--Plato
Why is it that there's seldom time to fix it right the first time, but there's always time to fix it right the second time???

That's not an oil leak :nono: That's SWEAT from all that HORSEPOWER!! :thup:
JMcTurnan

Re: Rocker Arm Adjustment

Post by JMcTurnan »

Most 302 you just torque down, in fact every single one i've seen with stock heads you torqued down. 35 ft/lbs i believe is what it was.
jmorgan_68
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Re: Rocker Arm Adjustment

Post by jmorgan_68 »

Clint- I have never owned a chevy, we bleed ford blue at my house between me and my dad we own 10 fords. Im 19 years old this is the first truck i have completely rebuilt, I have torn down sanded,painted, and disassembled and reassembled the engine by myself. I wasn't sure if the rocker arms should be torqued down or set some other way, I couldn't find torque specs for them in any of the books i have. I appreciate your advice that is exactly the information that i was needing. Thank you
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