273 rocker losing adjustment
- Thread starter Uncle Bob
- Start date
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Horse water. You know all that? lol
Correct! Which is what you DO when you convert to adjusters with lock nuts. I've done a lot o the 273 style and the set o slant 6 rockers on the unicorn head motor, since I have the adjusters with lock nuts on there.
Spotface with lock nuts is the best way to go. Interference fit works ok for stock engines and probably outlasted factory warranty. There's a reason why Isky and Crane made theirs to use a lock nut. Ya, just glue them in. While that may stop the one in question from loosening up, it's not the right way to fix the problem. Or do what I suggested in post #26.
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jimjimjimmy
lobsterman
This is what i have done for years not saying it's right but it works for me i take the adjuster out of the rocker and bung the threads up on the adjuster wind it back in , set the lash i never had one back off . it don't take much to get the interference back . Now everyone tell me how wrong i am .
If you get to that point, I would use blue. Red is more or less a permanent install. Very difficult to break the bond after cure. Blue should allow you to adjust later after cure.
A little heat on the locktite and it breaks free.
Actually, anything that gets the interference back in the threads is ok. There's nothing about any of these "back yard" fixes in the book, so technically, they're all wrong. The book would probably say replace the rocker and adjuster.
gzig5
Well-Known Member
The thread fit of the adjuster to the rocker body has a mechanical interference. This is a design feature so the adjuster doesn't back out. Over time the interference fit can wear, either on the male or female part, and it needs to be corrected. The simplest way to do it is to upset the female thread in the rocker by squeezing it to make it slightly oblong or pinch the bottom end. You could use a domed punch next to the hole to upset some material, but the vise or anvil method is sufficient. No need for a sharp punch poking divots all over the place and making sharp edges. No need for Loctite for sure. Flattening the rocker tang with a file and using a thin nut would be better than using glue. I'm all about being creative to fix stuff, but in this case there is simply no need to go outside the box. Do it right. These parts are under some pretty good stress and were designed the way they were for a reason.
jimjimjimmy
lobsterman
i don't understand why anyone would bend beat squeez or steak the rocker when the adjuster can be manipulated very easily to get the interference back but each of there own ..
I can. Because the adjusters were not "manipulated" from the factory. The rockers were. But I completely agree with either way.
Plenty of ways to skin this. Pick a method and go with it.
I prefer to put interference back into the rocker if not going the lock nut route. Press, Punch, Hammer.
I prefer to put interference back into the rocker if not going the lock nut route. Press, Punch, Hammer.
Uncle Bob
Shiny paint causes stress.
I was not too confident on my hammer fix, and I noticed there are other adjusters that seem to fit loose to me too. So I cleaned the threads on both parts and used orange locktite on them all. I'm hoping to not have to adjust the valves again unless I'm upgrading something.
I've never heard of orange, but it says it's 3x stronger than blue and doesn't require heat to remove so there you go.
I'm taking my time putting it all together because the locktite called for 24 hours setup time.
I've never heard of orange, but it says it's 3x stronger than blue and doesn't require heat to remove so there you go.
I'm taking my time putting it all together because the locktite called for 24 hours setup time.
PRH
Well-Known Member
I like it!!
Someone should try it for future reference…….. might as well be you
Someone should try it for future reference…….. might as well be you
Good move Bob. That is what I would have done. Locktite is a thread locker and not a glue. It does what it says. Good luck.
abdywgn
dismantler
All Poly 318s came with solid camshafts, so there was no need to search for rare adjustable rocker arms. The small 5/16-inch adjusters are sometimes known to back out when worn. The remedy, says Buck: "I rap the outside of the arm with a dead blow hammer to close-up the threaded hole and restore the grip of the imperfect threads, then they're just fine." The COMP conical valve springs and moly retainers shed a few ounces. Spring pressure is 160/350 pounds (closed/full lift). The rocker-arm ratio is 1.5:1, and spring installed height is 1.800 inches.
found this while looking at Poly engine builds.
found this while looking at Poly engine builds.
MOPAROFFICIAL
If it has tits, it's a liabilititty.
If we're going to do things the wrong way, how about we just cross thread that adjuster through there for a one time lash setting...
Like set it and never forget it , cuz it'll always wake you up at night n youll be saying " what have i done???!!"
I never paid attention that closely because I went with a set of mopar performance bushed rockers that have nut adjusters on them, but I always thought is was the original adjusters on the 273 rockers that were tapered, or the 'interference'. Lernt sumtin new tahday.
Maybe ta op can juss vice gwip his adjusser thrads and instull dems wiff a pipe wench
The bottom line was, this was another way for Mopar to save money by not using a jam nut to lock the adjuster. Think about the pounding the adjuster
takes, especially on a solid lifter cam, it's no wonder they start to fail.
takes, especially on a solid lifter cam, it's no wonder they start to fail.
Yup. That's why Locktite will fail. Locktite is made to resist the force of twist, a lateral force. It's not made to take the vertical pounding you just described. Without physically restoring the interference fit, that adjuster will eventually work loose again.
Cuda416
Well-Known Member
I get the op want's to avoid getting new pushrods etc, but the best solution is "fix" the rockers with jam nuts or replace the rocker or adjuster and move on. Anything else really seems like a hack to me. If this were a valve train geometry question, people would be all over doing things the "right" way.
No matter how hard you try, you just cannot get through to some folks. This is a five minute fix and back on the road for another fifty years. I just don't get it.
Uncle Bob
Shiny paint causes stress.
The adjuster is either being turned by the pushrod, or the threads are worn to where the up and down rocks the adjuster up the threads until it's loose. Both are hard to imagine but there's no doubt it's happening.
I expect to continue to have problems with these things, honestly. I could've and should've cut my losses when I found that 273 rockers won't work without grinding on OOTB Edelbrock valve springs. I could've had a set of Mancini HS rockers but instead here I am.
I wonder if the Mancini adjusters impact the pushrod length - they might work fine since it's the same rocker body and the spot facing doesn't affect that at all.
Uncle Bob
Shiny paint causes stress.
Not in a rush to install them, but they're here when I need them.
Now the question is, is it worth trying to rig something up to spot face the rockers with drill press, or is a file good enough and quick enough?
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