rocker arm tightening
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Joined: Nov 2007
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From: windsor, ontario
Car: 87 mustang gt 89 camaro
Engine: 302 355 tpi
Transmission: manual
Axle/Gears: 3.55 and 3.42 posi
rocker arm tightening
do i tighten the rocker arm nuts till the pushrod just gets some resistance when the lifter is at tdc or at the bottom?
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Re: rocker arm tightening
You tighten it until the push rod just barely no longer can be jiggled up and down between the lifter when it's at the bottom of its travel, and the rocker arm. DO NOT try to use "resistance", it's much too hard to gauge accurately. Then add ½ turn to the nut.
Making sure the lifter is at the bottom of its travel is sometimes a challenge. If you have a stock or near-stock cam, you can use the Chilton's type method, where you put the engine in one place and adjust 8; then turn the crank one revolution and adjust the other 8. This is VERY imprecise, but it will get the engine to where it will at least run, and then you can adjust them running. The "EOIC" method is much better: you turn the engine to where one cyl's exhaust is just opening ("exhaust opening", "EO") and adjust the intake; and you turn the engine to where one cyl's intake is just closing ("IC") and adjust the exhaust. It's easiest to do all 8 of one kind, then all 8 of the other kind. That's FAR more precise. The MOST precise method is to observe a valve on one cyl, and when that valve reaches peak opening, adjust the same valve on the cyl 4 cyls away in the firing order which will then obviously be at the EXACT opposite point on its cam lobe. That method is accurate enough for a solid lifter cam, to get easily within .001" accuracy; but it takes the longest.
Then, no matter which method you use for roughing them in, adjust them running, as I've described often. Do a search for my userID and "adjust running".
Making sure the lifter is at the bottom of its travel is sometimes a challenge. If you have a stock or near-stock cam, you can use the Chilton's type method, where you put the engine in one place and adjust 8; then turn the crank one revolution and adjust the other 8. This is VERY imprecise, but it will get the engine to where it will at least run, and then you can adjust them running. The "EOIC" method is much better: you turn the engine to where one cyl's exhaust is just opening ("exhaust opening", "EO") and adjust the intake; and you turn the engine to where one cyl's intake is just closing ("IC") and adjust the exhaust. It's easiest to do all 8 of one kind, then all 8 of the other kind. That's FAR more precise. The MOST precise method is to observe a valve on one cyl, and when that valve reaches peak opening, adjust the same valve on the cyl 4 cyls away in the firing order which will then obviously be at the EXACT opposite point on its cam lobe. That method is accurate enough for a solid lifter cam, to get easily within .001" accuracy; but it takes the longest.
Then, no matter which method you use for roughing them in, adjust them running, as I've described often. Do a search for my userID and "adjust running".
Re: rocker arm tightening
I gave out pretty much the same advice on another post not too long ago. I usually "ballpark" them in by using the resistance or the Chilton's method to get the motor to run. With a hydraulic cam, doing the final adjustment with the motor running seems to be the best/easiest way IMHO. 
Thread Starter
Junior Member
Joined: Nov 2007
Posts: 47
Likes: 0
From: windsor, ontario
Car: 87 mustang gt 89 camaro
Engine: 302 355 tpi
Transmission: manual
Axle/Gears: 3.55 and 3.42 posi
Re: rocker arm tightening
cant find the thing on adjust running.can u get me a link? thnx
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