***Hydraulic cam recommend for my 273....

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65Val said:
Rob...No prep on the rockers...I just installed the Crane adjusters and nuts...I didn't realize the rockers needed maching for these adjusters.
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Yup. There's your problem. The factory rockers are GREAT pieces, but to use the good locking adjusters, two things need to be done. First, you need to run a tap through all of the threaded holes in the rockers. This removes any self locking qualities the rockers may have left. They usually do not have any left, but I always do it anyway.

Secondly, and this is where your problem is, you must, must, MUST spot face the top side of each rocker adjuster hole. This assures that the area around where the lock nut seats is good and flat. Since they do not come with lock nuts from the factory, this area is not critical. When you make the conversion to the good lock nut type adjusters, it becomes critical for that area to be flat in regards to the adjuster hole. This is why yours keep backing off. There's not enough contact surface between the rocker nut and rocker to keep them tight. It is a very simple procedure and not costly for a machine shop to do it. I recommend letting the shop do it, because they can get it 100% perpendicular to the center line of the adjuster holes.
 
RustyRatRod said:
Yup. There's your problem. The factory rockers are GREAT pieces, but to use the good locking adjusters, two things need to be done. First, you need to run a tap through all of the threaded holes in the rockers. This removes any self locking qualities the rockers may have left. They usually do not have any left, but I always do it anyway.

Secondly, and this is where your problem is, you must, must, MUST spot face the top side of each rocker adjuster hole. This assures that the area around where the lock nut seats is good and flat. Since they do not come with lock nuts from the factory, this area is not critical. When you make the conversion to the good lock nut type adjusters, it becomes critical for that area to be flat in regards to the adjuster hole. This is why yours keep backing off. There's not enough contact surface between the rocker nut and rocker to keep them tight. It is a very simple procedure and not costly for a machine shop to do it. I recommend letting the shop do it, because they can get it 100% perpendicular to the center line of the adjuster holes.
Click to expand...

Oh, mmaaaannn...NOW ya tell me!!!...LOL...I bought these adjusters and locknuts used, and they came with no information sheet, so I did not know I had to do this. I'll inquire as to cost to do this and if it's feasible, I'll try it first.

Thanks for chiming in, Rob!!

I also appreciate everyone who has chimed in with hyd. cam recommends...I'll file these away in case the rocker machining process doesn't do the trick.

Thanks all!
 
i have my factory 1967 dart, coronet, charger, service manual, right here. it shows the 273 with the 2 bbl 240 degrees cam, .395 lift. the 4 bbl ver, 248 degrees cam .415 lift. IMHO, a 268 degree .430 lift will still be very street able. if it was mine i would do hydraulic cam.
 
It would be easier and cheaper to adjust your rockers correctly. Rusty has a good point about machining a flat on the rocker arm for the locknut to hold the adjusting screw. What specs are you using, and are you moving the cam and readjusting if any are out? Did you add .002 to the specs if you are adjusting them cold? I assume you are not adjusting the valve lash hot and running, since you are not using the factory interference adjusting screws.
 

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