Banana grooves..

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Here’s our pictures from our Banana-Rama.

We also popped out the end caps and ran a wire bottle brush through them.

So far they seem to be working fine.




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I dismantled a small block once that had 273 adjustables on it, the shafts were just hydraulic ones by the look of them. The rockers and shafts looked OK but the pushrod cups were smoked, so yeah I'd break out the Dremel !
 
I’m currently having a set of these rockers bushed and spot faced for the locknut adjusters at Rocker Arms Unlimited. He’s also hard chroming the shafts and highly recommended Banana grooved shafts, which my set already had.
 
So, first pic shows 2 sets of 273 rocker shafts. The shaft on the right has one oiling hole, and was used for a short time on a 340 hydraulic set up. The single round hole in the first pic would would be oriented so that it would line up with the oiling hole in the rocker during it's cycle. These holes are the same size and location on both shafts, and would provide ball/cup oiling and a little on the shaft in that area.

Pic 2 is where they differ......As you can see on the right shaft, there is definitely wear on the loaded side of the shaft. Since they were used for a very short time, I believe that they would inevitably score due to insufficient oiling. The shaft on the left has addressed this issue. A second hole with a banana groove cut right across the loaded part of the shaft spreading out the oil where it is needed.

I believe that both holes are needed to address ball/cup lubrication, and shaft lubrication when using adjustable 273 rockers with hydraulic pre-loaded lifters. From what I understand (info obtained here), with mechanical lifters, because of the designed lash, one hole is adequate because at certain points of the rocker cycle there is absolutely no pre-load on the rocker/shaft. This allows the oil to move around in the rocker arm/shaft fit clearance.........Just my thoughts!

BTW....Both shafts are OEM 273 shafts.

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CFD244 said:
So, first pic shows 2 sets of 273 rocker shafts. The shaft on the right has one oiling hole, and was used for a short time on a 340 hydraulic set up. The single round hole in the first pic would would be oriented so that it would line up with the oiling hole in the rocker during it's cycle. These holes are the same size and location on both shafts, and would provide ball/cup oiling and a little on the shaft in that area.

Pic 2 is where they differ......As you can see on the right shaft, there is definitely wear on the loaded side of the shaft. Since they were used for a very short time, I believe that they would inevitably score due to insufficient oiling. The shaft on the left has addressed this issue. A second hole with a banana groove cut right across the loaded part of the shaft spreading out the oil where it is needed.

I believe that both holes are needed to address ball/cup lubrication, and shaft lubrication when using adjustable 273 rockers with hydraulic pre-loaded lifters. From what I understand (info obtained here), with mechanical lifters, because of the designed lash, one hole is adequate because at certain points of the rocker cycle there is absolutely no pre-load on the rocker/shaft. This allows the oil to move around in the rocker arm/shaft fit clearance.........Just my thoughts!

BTW....Both shafts are OEM 273 shafts.

View attachment 1715712604

View attachment 1715712608
Click to expand...

Good observation and probably accurate.
 
mopardude318 said:
I’m currently having a set of these rockers bushed and spot faced for the locknut adjusters at Rocker Arms Unlimited. He’s also hard chroming the shafts and highly recommended Banana grooved shafts, which my set already had.
Click to expand...
If I can ask, what did they quote you for this work?
 
Moms68 said:
If I can ask, what did they quote you for this work?
Click to expand...
It was $508 shipped back to me, billet steel hold downs, shim/spacer kit ready to go. Might be high for some, but I was happy with the work and happy to support a local business. :)
 
Some eye candy right there! I went all out on a scrap pair of hydro shafts: thrust side oil hole, banana grooved, went full cam lift and marked em and added another smaller hole that lined up with a rockers valve stem oiler hole that was extended through to the pushrod oiler hole. and another that lined up when on the cam base. So 3 small strategic holes per rocker arm. If they dont work, I got 3 more sets of hydro shafts to play with. If oil was blood, this is gonna look like a stuck pig when running.
 
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