Hello all... So, call me crazy. This is just a thought, something I thought of, and probably someone else as thought the same, not even sure if it's viable or if there would be problems doing so, therefore why this post. for a bit of a discussion on this... Tearing into my 69 350, with all the help of you guys, and learning so so much on this Buick engine, I found quite surprising that there is no adjustment at all on pushrods. I'm used to old harleys, all of them have adjustable pushrods, either with solid or hydraulic lifters... or inline 4 jap sport bikes, with shims that can be put under the valve cups and you have to work out all the shims sizes in order to achieve the desired clearance.... So, yes, very surprised when I found there was no way of adjusting the 350 - except if you buy the $200 set of adjustable pushrods. So... I was thinking. has anyone tried taping the rocker arm end, say half of it, in order to fit a bolt in there so you can adjust the tip and achieve desired clearance? I'm not going to do it, but it's more of a mental exercise, to learn a bit more.... is there anything on this idea that will deem it ridiculous and would not work? and let's not go into the money side of things as in "yes you can do that, but it's easier to buy the $200 adjustable rods" I would like to think of this imagining there was no adjustable pushrods, would this idea be feasible? would the tapping not work and the valve movement end up stripping the threads with the constant push on the tip to the bolt? I have done a little drawing about what I mean, probably easier to visualise.
Very cool idea! I believe the rocker tips are radiused with respect to the rocker shaft and they should be fixed to not rotate. If you could maintain their alignment, I think a small amount of adjustment would be possible. However, I think the greater question is whether adjustment is even needed on a hydraulic lifter application. If the valve train geometry is modified to the extent that the lifter travel range can't compensate, it's probably a good idea to install push rods of the correct length to maintain original geometry. Keep thinking! It only takes one idea to change the world.
Oliver Colteryahn had a bunch of adjustable rockers somewhat like that for the BBB. They came out of the Buick engineering dept.
Hydraulic lifters have almost 1/4" of travel in the internal piston. If your pushrods are somewhere in the middle of that range, adjusters just add weight. Jim
Interesting! thanks for the replies.. I did think there would be some reasons why my crazy idea wouldn't work!
Don't give up on ideas, find a way to make things work. Adjusters are commonly put on the pushrod end both to simplify some things (described above) along with there being less of a weight penalty on 'that' side of the rocker fulcrum. The adjusters found on roller rockers usually are a simple 7/16-20 set screw (with a jam nut) that's hollowed out with a ball mill matching the diameter of the pushrod ball. These are things you could do on your lathe, but not as likely with the stock rocker. For that matter, some 7 or 2 series aluminum rocker bodies could be almost entirely made on your lathe, incorporating adjusters and/or roller tips. The issue mentioned with geometry is important because the wrong geometry won't "roll" the radius tip against the valve tip during it's lift arc cycle....it will "scrub" it and wear things rapidly. The main reason for roller tips is that it's an easy way to solve the scrub and most producers have a tough time doing the hardening properly.
I've often wondered if anyone ever took a set of roller small block chevy rockers and tried to run them on a single shaft of a Buick?
It might need some grooves machined so you could snap ring them in place. Not sure what size the shaft is on roller rockers. Might need a different sized shaft than Buicks normally run but not insurmountable.
