Mojack
Well-Known Member
Is there any rhyme or reason why some shafts had the "banana groove" with oil hole and some didn't? It's not a stamped hyd. rocker shaft, they have a larger single hole on the bottom of the shaft.
Small block adj. rockers
- Thread starter Mojack
- Start date
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Mojack
Well-Known Member
Hyd. shaft
TrailBeast
AKA Mopars4us on Youtube
It' just a redesign where the banana cut spreads oil arcross the high pressure area of the shaft and the bigger hole is about being able to flow more volume the the inside of the shaft.
Of course the volume of the flow is all dependent upon the supply to the top in the first place.
I agree with the banana cut but the bigger hole really can't hurt anything even if it doesn't help anything.
Just my opinion obviously.
Of course the volume of the flow is all dependent upon the supply to the top in the first place.
I agree with the banana cut but the bigger hole really can't hurt anything even if it doesn't help anything.
Just my opinion obviously.
yellow rose
Overnight Sensation
The shaft on the left has the hole to oil the rocker. As in oil the adjuster.
nm9stheham
Well-Known Member
I suspect the bigger hole is the cheap way to spread the oil, akin to the banana groove but cheaper to make.
Mojack
Well-Known Member
Sorry guys, I think I did a poor job of asking the question and just caused confusion. In the first pic, both shafts came from separate cars with adj. rocker set ups . The one on the left has the grooves with two holes and the one to the right just has the one offset hole. I only included the second pic. with a shaft from a standard hyd. rocker shaft, which has a single larger hole, to qualify my claim that the top shaft on the right isn't just a swapped out hyd. shaft. I was just wondering if the different adj. rocker shafts were from different years or vendors or if anyone knew why the difference?
nm9stheham
Well-Known Member
I've seen both but sure don't know why....
perfacar
Well-Known Member
the banana grooves are original from mopar for the 273 adjustable rocker arms. without them , they gall the shaft and rocker arm. hyd rockers have only a hole , because, the rocker doesn't sit tight on shaft, also has a trough built into it. other shaft, must be from other vendor??
My 2 cents.............
I do not believe that banana grove shafts cam on any 273's from the factory.......I've torn down 64-5-6 273's that were unmolested originals and never found a banana grove shaft.
I believe, they may have come from the factory on the 340 T/A engines, can't say with certainty, never torn down an unmolested T/A engine; the bare shafts were/are available over the parts counter at the dealership.
The shafts are hard (in comparison to non banana shafts) and the groove are for better oil distribution and better wear characteristics when working with higher spring pressures.
There may be differing opinions..................
I do not believe that banana grove shafts cam on any 273's from the factory.......I've torn down 64-5-6 273's that were unmolested originals and never found a banana grove shaft.
I believe, they may have come from the factory on the 340 T/A engines, can't say with certainty, never torn down an unmolested T/A engine; the bare shafts were/are available over the parts counter at the dealership.
The shafts are hard (in comparison to non banana shafts) and the groove are for better oil distribution and better wear characteristics when working with higher spring pressures.
There may be differing opinions..................
Can't tell you why some of them, but I can tell you it's easy enough to make your own.
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