ill get right to the point.

rockers that originally came on my motor, had jam nuts on all the adjusters.
i tried the trick of squeezing the rocker a bit to keep them tight, (atleast long enough to adjust all valves one after another, then jam the nut after engine shutoff.) one of the rockers cracked, so i decided to go to junk yard and pick my self up another assembly.

new rocker setup, adjusters all seem tightish, but the adjuster it self, is very different from my original set. they are "hollow" (one is actually cracked in half) and shorter then my original set.

i tried using the (new) shorter adjuster in my original rockers, and they are same, tightish, and use the longer jam nutted adjuster on new rockers, and are loose. so i think the threads on adjuster are what make it tight, not a pinched rocker.

my question is what should i do, id like to keep the adjusters tight by them selves, but also use a jam nut to prevent future problems.

the long adjusters are always lose, and the shorts are always tight (but seem too short for a jam nut, unless i can find super thin ones. any ideas?

(ps, shorter adjusters seem to have a 'missing thread' towards ball end)

"new" rocker on left, original rocker on right

The "short" adjusters are slant-6 adjustors. No idea what the "long" ones were originally meant for, but they probably aren't quite the correct thread which is probably what caused the cracked arm. I don't use jam nuts. Never needed to. I make sure all the adjustors are tight enough to require some muscle and a "snap" to move, and adjust the valves as needed, every 10 or 20 thousand miles.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The rocker snapped, because I squeezed it in the vice. Read on here that's a "fix", what do you do Dan. To make sure they are tight enough, these things don't "snap" they are just harder to turn, I don't feel like its up to par

80 views and only 1 dood replies? you damn lookie loos!

how common is it to have an adjuster crack in half? one side is split about 1/4 inch, the otherside, doesnt look to be broke, but can see a fiiiiine line, ill post a picture in a bit.

also what can i do to ensure proper tightness of adjuster, with out squeezing in a vice, i find that method not so good. (yes i was very very carefull to not over torque it) it just popped before i could get it to budge at all.

I have a set of rockers up in the garage just like yours with the lock nuts on them. Not sure where they came from, but all the other dozens of sets I have seen did not have them. Someone likely added them.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

It's not.
Rockers and adjustors in excellent, clean condition and perhaps a bit of Loctite 242 (blue) if you feel it's necessary.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

so when you have a rocker or adjuster become loose, you toss it, and put in a new one?