roller rockers
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jtfairlane
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You need to provide more information.
Are they pedestal mount or stud-mount.
They have totally different installation procedures.
Are they pedestal mount or stud-mount.
They have totally different installation procedures.
With the cylinder at TDC, loosen the rocker arm, and then slowly tighten until you can no longer move the pushrod up and down. Then tighten 3/4 of a turn and lock in place.
jtfairlane
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NO NO NO NO NO!
1982 Matthew to answer your question about pedestal mount rockers, they are "adjustable" in the sense that you can adjust/correct their valvetrain geometry via changing pushrod length, or by placing shims underneath the pedestal rails.
With adjustable stud mount rockers, you DO NOT adjust with the cylinder at top dead center. It is with pedestal mount rockers that you torque both rockers to spec for a given cylinder when that cylinder is at TDC.
With stud mount rockers it is a little more complex.
I don't feel like typing out the instructions for this, so please visit this link:
http://compcams.com/Technical/Instructions/Files/151.pdf
Skip to Steps 7 and 8, that's what you need to do.
the easiest way is to roll the engine over by hand. until a cyl starts on it compression stroke, both lifters will be at the bottom of their bores and on their base circle of the came. its VERY important that you adjust and set preload with the lifters on the base cirlce of the cam and not on the lobe. adjusting your rockers with the lifter on the lobe of the cam will result in LESS lift and slack in the valve train once it comes back down past where it was adjusted.
it had nothing to do with TDC BDC etc etc.
assuming you have already measure for the correct length pushrod. run your rocker down by hand and find zero lash with all slack taken up and then set your preload on the lifter plunger.
on a 3/8-24 fine threaded stud, a 1/4 turn will be .010". i set mine to .020" (half turn) and they seem pretty quiet so far.
as for the pedestals they can be adjusted. they ARE NOT just a "bolt down and go" deal. i think it was jtfairlane who tried to tell me this a long time ago and i didnt take his advice and it came back to bite me in the butt.
the pedestal rockers are HARDER to adjust than studs. you have to shim/mill pedestals to get the roller tip of the rocker in the correct spot and THEN you measure for your pushrod. more work involved and has an extra step to it.
but IMO a properly set up pedestal style is very similar to a shaft style rocker and is very stable, only thing i would change is maybe get rid of the 5/16 hold down bolt and get a 3/8 bolt.
someone may need to chime in, but i dont see why someone couldnt use a 3/8 stud rocker as a pedestal style. just get your heads drilled to 3/8 and find a bolt for them, this is assuming the trunion pin is the same size as the pedestal style. you would also have to drill the pedestals bigger. also some rockers wouldnt work. the roller rockers i just bought have dual trunion flats so they wouldnt work. but it would be interesting to see if it could be easily and efficiently done with other styles.
stud rockers especially smaller studs like 3/8 can flex with stiff valves pressure and high rpm. nothing a bigger stud or a stud girdle cant fix
it had nothing to do with TDC BDC etc etc.
assuming you have already measure for the correct length pushrod. run your rocker down by hand and find zero lash with all slack taken up and then set your preload on the lifter plunger.
on a 3/8-24 fine threaded stud, a 1/4 turn will be .010". i set mine to .020" (half turn) and they seem pretty quiet so far.
as for the pedestals they can be adjusted. they ARE NOT just a "bolt down and go" deal. i think it was jtfairlane who tried to tell me this a long time ago and i didnt take his advice and it came back to bite me in the butt.
the pedestal rockers are HARDER to adjust than studs. you have to shim/mill pedestals to get the roller tip of the rocker in the correct spot and THEN you measure for your pushrod. more work involved and has an extra step to it.
but IMO a properly set up pedestal style is very similar to a shaft style rocker and is very stable, only thing i would change is maybe get rid of the 5/16 hold down bolt and get a 3/8 bolt.
someone may need to chime in, but i dont see why someone couldnt use a 3/8 stud rocker as a pedestal style. just get your heads drilled to 3/8 and find a bolt for them, this is assuming the trunion pin is the same size as the pedestal style. you would also have to drill the pedestals bigger. also some rockers wouldnt work. the roller rockers i just bought have dual trunion flats so they wouldnt work. but it would be interesting to see if it could be easily and efficiently done with other styles.
stud rockers especially smaller studs like 3/8 can flex with stiff valves pressure and high rpm. nothing a bigger stud or a stud girdle cant fix
jtfairlane
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You're flat out wrong.
You do not adjust stud mount rockers with the piston at top dead center. With stud mount rockers, you must adjust the intake valve when the exhaust valve is just beginning to open, and you adjust the exhaust valve when the intake valve has reached max lift and is approximately half way back down to seated. In neither of those instances is the cylinder at top dead center.
Seriously, read the link I provided. Do people even click on these things?
Wow, and to think that for the last 28 years I have been doing it WRONG!, and all those engines I have built and assembled were never put together right! I should quit and retire now! It is amazing that those damn things spun to 8,000 rpm and lived!
You're a freaking idiot dude, telling people how wrong they are when you have no clue how the thing works. You can adjust them at any point in the cycle as long as the valve is fully closed. Your problem is you take instructions way too literal, and all you know is one set of instructions. There are multiple ways to do it.
What I have found to be the easiest method is to start with cylinder #1. Bring it to TDC on the compression stroke, cause at that point, both valves are fully closed. Adjust those two rockers. Rotate the engine clockwise 1/4 of a turn (mark your balancer in 4ths to make this easier.) Each 1/4 of a turn of the engine brings the next cylinder in the firing order to TDC on its compression stroke. So start with 1, rotate the engine 1/4 turn, then do both valves on #3, rotate 1/4 turn again, do #7, etc. Just make sure you are on the compression stroke.
That method talks half the time that the comp cams website recommends because they want you to do one valve at a time. The method I use does two at once. Comp cams just gives those directions because it is probably the easiest for a noobie to figure out. In all actuality, you can adjust all 16 valves using only 3 points of the engine rotation, I just don't know which ones they are, but you can find that stuff online. One of them is starting with #1 at TDC on its compression stroke, then you can do the intake valves on some cylinders and the exhaust valves on others without rotating the engine.
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