Rocker Arm Shaft Set 216

[chevyky]

My mechanic suggested i replace the rocker arm shafts in my 216 engine because there is some visible wear to the shafts. I got a set from Bowtie Bits.

The issue is that my mechanic pointed out that the bottom of the shaft is slightly ground along the length of the shaft( http://www.flickr.com/photos/union44...7623358552886/). Our old set of shafts does not have the underneath grinded. Does anyone happen to know why? My mechanic thought that perhaps this was an improvement... that GM or someone determined that the oil will flow better with that area grinded down a little.

We're concerned that with the grinded area, the oil wont spread around as its intended to do.

I appreciate your input as always.
http://www.flickr.com/photos/union44...7623358552886/

[dwcsr]

Oiling was always an issue with the 216 and early 235, Even the improved 235 in 58 and later still had issues with the rockershafts freezing up from lack of oil or rather the abundance of air that was passed throught the system. No matter what they tried at GM it still sucked air into the oil system and of course passed it through so they did have places that were made to allow the air out. The shaft was one, flat spotting the side if the lifters was another attempt. An oil line from the lower end to the rocker shaft was another attempt. In 58 they drilled the blocks to allow for better flow and the use of hydraulic lifters. Prior to 58 all blocks were solid lifter and can not be converted except by drilling the block oil passages to match the 58 system.

[chevyky]

Originally Posted by dwcsr

Oiling was always an issue with the 216 and early 235, Even the improved 235 in 58 and later still had issues with the rockershafts freezing up from lack of oil or rather the abundance of air that was passed throught the system. No matter what they tried at GM it still sucked air into the oil system and of course passed it through so they did have places that were made to allow the air out. The shaft was one, flat spotting the side if the lifters was another attempt. An oil line from the lower end to the rocker shaft was another attempt. In 58 they drilled the blocks to allow for better flow and the use of hydraulic lifters. Prior to 58 all blocks were solid lifter and can not be converted except by drilling the block oil passages to match the 58 system.

Great info! So are you telling me that the shafts i bought for my 216, which are flattened underneath, are OK for me to use? My mechanic is afraid that the flattening will reduce the amount of pressure normally there to shoot the oil up the holes onto the rockers. Thanks

[dwcsr]

The flats are a design change and they go on the bottom facing the head.