one last 273 rocker question

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j par

j par

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if it's not one thing it's another with this damn motor at the machine shop. It's in quality control and its boiled down to the 273 adjusters won't hold adjustment ? supposedly there wore out? has anybody ever heard of this and is there any kind of cure? Like lock tight or something? Thank you . ...:banghead:
 
This s a common problem. They should be modified as follows for ANY type of performance above stock, IMO.

Remove all the stock adjusters. Open the nearest trash can and throw them in. Buy new Crane adjusters and lock nuts. Take a tap and make sure the rockers have all of the self locking ability cut out of the threads so the new adjusters will turn freely.

Have the rockers spot faced on the top side of the threaded hole where the adjusters screw through. This provides a flat, true surface for the lock nut to tighten against.

That's all there is to it. Don't skimp on this, because nothing short of it will keep tem tight in a performance engine. Once modified like that, they are VERY dependable.
 
RustyRatRod said:
This s a common problem. They should be modified as follows for ANY type of performance above stock, IMO.

Remove all the stock adjusters. Open the nearest trash can and throw them in. Buy new Crane adjusters and lock nuts. Take a tap and make sure the rockers have all of the self locking ability cut out of the threads so the new adjusters will turn freely.

Have the rockers spot faced on the top side of the threaded hole where the adjusters screw through. This provides a flat, true surface for the lock nut to tighten against.

That's all there is to it. Don't skimp on this, because nothing short of it will keep tem tight in a performance engine. Once modified like that, they are VERY dependable.
Click to expand...
Thank You Triple R is this something that I can just order from Summit or something?
 
RustyRatRod said:
This s a common problem. They should be modified as follows for ANY type of performance above stock, IMO.

Remove all the stock adjusters. Open the nearest trash can and throw them in. Buy new Crane adjusters and lock nuts. Take a tap and make sure the rockers have all of the self locking ability cut out of the threads so the new adjusters will turn freely.

Have the rockers spot faced on the top side of the threaded hole where the adjusters screw through. This provides a flat, true surface for the lock nut to tighten against.

That's all there is to it. Don't skimp on this, because nothing short of it will keep tem tight in a performance engine. Once modified like that, they are VERY dependable.
Click to expand...

Great advice Rusty!
 
Yes. Summit has them. I think they are 5/16 fine thread if I remember right.
 
RustyRatRod said:
Yes. Summit has them. I think they are 5/16 fine thread if I remember right.
Click to expand...

only one flaw in your plan Triple R, I collect scrap metal for a living and I will can't throw away my money! Lol thank you for the great advice and I will probably roll with it!
 
Yeah. That's them. ^^^^^ 3/8 not 5/16. Sorry bout that. I just couldn't remember
 
yep just checked back into the thread here and got the same thing. lol thank you everyone and expecially you Triple R.
on a side note I've only been on this forum for less than a year and I know this is the internet so you never really know who's on the other line. I've got this image of Triple R being a 11 year old girl with a big stack of her dads Mopar action Mopar muscle magazines and a bunch of his old Mopar shop manuals. Lol :D
 
I wish I was 11. I'd do the girl thing too. Already ridden the ride as a dude. I'd be a *****. That way I could sell it and keep it. I would much rather work layin down.
 
Very good reply reply Rusty ! nearly choked on the scotch !
 
my 1967 dart factory manual shows a hole in the rocker pointing up, do check that its open. the rocker shaft bracket bolt torque is 15 ft lbs..5/16-18. intake manifold 35 ft lbs. 3/8-16 cyl head cover 36 in lbs, 1/4-20 con rod nut 45 ft lbs 3/8-24
 
Why is the Crane considered an upgrade? I replaced a factory one in Dads 273, with a used factory one. So far so good.(other than hard to find)
Im not being a smartass, this is something I may look at doing in the future.
 
well I'm glad you took that in the way it was meant ! like I said you just really don't know who's on the other line so sometimes you just gotta make up your own scenario
again thank you and I did push the little think you button
 
4spdragtop said:
Why is the Crane considered an upgrade? I replaced a factory one in Dads 273, with a used factory one. So far so good.(other than hard to find)
Im not being a smartass, this is something I may look at doing in the future.
Click to expand...

Steve, the factory adjusters do not have a lock nut. They are an interference self locking fit and that interference loosens up over time causing the adjusters to back off. Since the top of the rocker at the adjuster hole is "as cast" it is rough and not flat. That's why it has to be spot faced to provide a positive flat surface for the lock nuts to tighten against.
 
j par said:
well I'm glad you took that in the way it was meant ! like I said you just really don't know who's on the other line so sometimes you just gotta make up your own scenario
again thank you and I did push the little think you button
Click to expand...

Glad I could help. Any number of guys could have told you the same thing. I just happened to be first.
 
RustyRatRod said:
Steve, the factory adjusters do not have a lock nut. They are an interference self locking fit and that interference loosens up over time causing the adjusters to back off. Since the top of the rocker at the adjuster hole is "as cast" it is rough and not flat. That's why it has to be spot faced to provide a positive flat surface for the lock nuts to tighten against.
Click to expand...

Thanks Rob, my memory sucks. Christ it was only last spring I set the valve lash on it....you'd think I would remember no lock nut. Now it makes sense.
Pretty damned cheap upgrade really.
 
4spdragtop said:
Thanks Rob, my memory sucks. Christ it was only last spring I set the valve lash on it....you'd think I would remember no lock nut. Now it makes sense.
Pretty damned cheap upgrade really.
Click to expand...

It is. And if you have a decent drill press, you can do it yourself. All you need is a decent end mill bit.
 
Matter of fact, I actually HAVE a set I need to do. I may write up a how to on it.
 
RustyRatRod said:
It is. And if you have a decent drill press, you can do it yourself. All you need is a decent end mill bit.
Click to expand...

I do actually, got one that was Dads. Never used it since I got it.

RustyRatRod said:
Matter of fact, I actually HAVE a set I need to do. I may write up a how to on it.
Click to expand...

Ill keep my eye out for it.
Mill bit? For the spot facing?
Thanks
 
Well the motor is still at the machine shop, so $50 for the parts plus machine work the tops of rockers ? $100? Plus labor to install ? Now I'm thinking - " forget it" just add another $100 and spend $250 and get the cheap #66869 rockers from Summit !! :banghead:
 
Do the machining, labor and install yourself. Works out to just the cost of screws. Machining the rocker tops shouldnt be too hard??
 
4spdragtop said:
Do the machining, labor and install yourself. Works out to just the cost of screws. Machining the rocker tops shouldnt be too hard??
Click to expand...

So get the stroker back from the machine shop 98% finished, after 5k spent? I'm past the dime, and in for the dollar ! I'm not going to get it back this close to being finished and have them able to say it was something that I did .
 
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