Far easier to machine new shafts from alloy steel and then gas nitride than all this monkeying around. Jim Carter sell a set of new shafts for $60... I won't even power up a machine for that. Some folks are much further along in the development of stovebolt roller rocker arms.
Maybe there’s a different way to skin the Torrington bearing idea…..
Sounds like turning down the original hardened shafts is a PITA. Who says we need to use them at all?
If 3/4 OD is a good number for sourcing common roller bearings….just buy some sort of hollow round stock (perhaps it’s even sold in specific hardness).
Drill the holes in the right size and the places with your drill press and V blocks. Bush the shaft supports with an off-the-shelf bushing and drill accordingly. Drill a weep hole in the bearings and fit them in their rockers. Assemble and done.
Could it be that easy? What am I missing?
(Side note: the rocker shaft I measured came up way closer to an inch that the 0.79 you quoted earlier. Highly possible I screwed up. Will have to re-check mine this evening)
Jerry thanks much for the update and the work on this! Interesting that shaft is harder/softer in places.
Okay, since I first mentioned the Torrington bearings, I've had another thought. What about reducing the diameter of the shafts but only where the rockers run, hone each rocker as needed and just use loose needle bearings? For example: 1.5mm diameter loose needles not quite as long as the rockers. Machine the shaft .75mm where the rockers run and hone each rocker the same amount. Use grease to hold the roller bearings for assembly, slide the rockers on and use the spring loaded washers to reduce the oil flow. If that would work, replacing rollers as they wore would be simple ("everyman" could do this easily) and depending on the cost it might be less $$. The friction would be reduced in the same fashion.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
The rocker shafts and rocker arms have been pretty consistently the same size- - - -216 through 261. The oil grooves in the rockers changed location in the late 1950s when the shaft oiling system got reworked. Somebody is selling replica shafts on Ebay, but the supply is somewhat intermittent, and I wonder if they are getting the same kind of heat treat as the OEM shafts? Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jerry thanks much for the update and the work on this! Interesting that shaft is harder/softer in places.
Okay, since I first mentioned the Torrington bearings, I've had another thought. What about reducing the diameter of the shafts but only where the rockers run, hone each rocker as needed and just use loose needle bearings? For example: 1.5mm diameter loose needles not quite as long as the rockers. Machine the shaft .75mm where the rockers run and hone each rocker the same amount. Use grease to hold the roller bearings for assembly, slide the rockers on and use the spring loaded washers to reduce the oil flow. If that would work, replacing rollers as they wore would be simple ("everyman" could do this easily) and depending on the cost it might be less $$. The friction would be reduced in the same fashion.
Several of us posted all about the same time. Why not just skip the whole machining exercise and just start with new hollow round stock of the preferred diameter? Something like this…..
"Welded", not seamless "Annealed"- - - - -"soft" "Stainless"- - - - -no idea if it can be heat treated to the proper hardness.
Few poeple I know of, except maybe a particularly obnoxious machinist, have the right type of heat treat facilities to harden a fabricated shaft properly to work with needle bearings running on them.
Other than that- - - - -good idea! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
"Welded", not seamless "Annealed"- - - - -"soft" "Stainless"- - - - -no idea if it can be heat treated to the proper hardness.
Few poeple I know of, except maybe a particularly obnoxious machinist, have the right type of heat treat facilities to harden a fabricated shaft properly to work with needle bearings running on them.
Other than that- - - - -good idea! Jerry
Let’s pretend a guy could source something similar of suitable hardness. Would it work then? How hard would it need to be to prevent wear with the needle bearings and a good oil supply? Im learning here.
Since the shafts seem to only be hardened in specific locations, I don't know if something with uniform hardness would be suitable. Probably so, but we're getting into territory that's way beyond the average back yard tinkerer's capability. Normally, machining of precision located holes is done on "soft' (annealed) metal of the proper alloy, and then it's hardened afterwards, with a final grinding operation to achieve the proper dimensions and surface finish. That's professional shop territory, not a "Harbor Freight drill press" operation. Just my opinion- - - -that, plus five bucks or so will get you a cup of fancy coffee where the man bun wearing, bike riding, spandex shorts crowd hangs out! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Think about a tapered roller wheel bearing- - - -precision ground hard steel rollers, running against glass-hard inner and outer races with grease as a lubricant. There are a few instances where a hardened part is runnig against a somewhat softer one, but I don't think that would be correct in this situation. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
It is that easy but not with a roadkill raccoon resurrection approach. I see no improvement or benefit with this exercise but if I was a farmer with only a Harbor freight drill press, no parts availability and had to make something work I would do the following:
!. Buy some precision ground ¾” 4140 alloy steel shaft. See here:
My purchaser has sourced precision ground 4140 heavy wall tube so I know it’s out there but drilling lengthwise may be more economical/timely.
2. Drill/tap shafting as required for needle bearings/stands, etc. 3. Mock up parts to insure no further machining on shafts is required. 4. Uniformly heat shaft until at least dull red approaching bright red being careful not to scorch the surface. 5. Toss the shaft in a pail ( metal) of used oil and leave it there until cool. 6. Polish the surface with emery cloth. 7. Confirm with your metallurgist that they’re similar in hardness to Superman’s kneecaps.
I think I junked them, but wish I had a picture to share. The rocker shafts on my truck when I got it, were scarred and grooved VERY deeply. Now that someone has investigated the hardness, it’s remarkable to me they could get so bad.
I ended up replacing with some shafts off a spare engine that were in much better shape. And got the proper connector and rockers to make the late, pressurized shaft design work as intended. The rockers on the engine were a hodge podge of early and late design.
I just ordered a single Torrington bearing with a .750" inside diameter, a 1" OD, and 1" wide. (J-1216) I'm going to see if I can drill and ream a stovebolt rocker arm for that bearing without severely weakening the rocker. If so, grinding and polishing the shaft down to a 3/4" OD would allow the original rockers to be rollerized.That's about a 1MM reduction in shaft diameter. (.040") I'm using a follower rest on the lathe, across from the grinder stone to minimize shaft flex, sort of like using a steady rest while regrinding a crankshaft journal. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'm also looking at a design that will allow the rocker shafts to rotate inside the standoffs on the cylinder head, resulting in evenly distributing the wear all the way around the shaft. That design uses short sections of thick wall high pressure seamless tubing, needle bearings in the rocker arms, and bushings fitted to the shaft standoffs so the pivot shafts can rotate at random. Short sections of pivot shaft can be surface hardened pretty easily with Kasenit powder and an acetylene torch if necessary. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Once I get a few standoffs modified, I'll post some pictures. It would take several thousand words, most likely, to describe what is bouncing around in that big empty echo chamber between my ears! I'm not quite sure of the final design yet, and it will probably involve some "cut and try" experimentation before I have a working prototype on a running engine. LOL! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The original shafts had a machined hard chrome overlay on them which is why the replacement shafts are at first glance expensive. There is some time, machine work and expense involved in producing them over and above what you might think.
I know, no one really wants to spend a couple of hundred on rocker arms. But the rocker system is really important to a good running motor. New rocker assemblies are near impossible to find now. Yes, you can maybe try to cobble, mix and match arms with new shafts, might work. But if you have a set of rockers that has done its job and is now in need of a little proper servicing, a real rebuild by someone who knows what they are doing is a pretty good option.
There is now only one USA based rebuilder left. Rocker Arms Unlimited in California. They have done a couple of sets for me. Not cheap I know, but correctly rebuilt the first time out. No crappy chinesium, bad machining, sloppy work.
Make that two rebuilders. There's one that makes roller rockers for stovebolts. I brush his teeth a couple of times a day! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Hotrod Lincoln- Have to somehow bolt the standoff below the hole for the shaft? Maybe drill out for an Allen cap screw or some such thing?
That is a great idea- - - -one that I'm planning on incorporating into the design. There's an Ebay ad for "explosion proof" thick wall seamless steel tubing that looks like it would make excellent material for a rocker arm shaft. The 16mm (5/8 inch) version of that, with an 8MM (5/16 inch) center hole would be plenty strong for a rocker shaft, the alloy is most likely to be able to be case hardened, and there's a 16MM ID X 12MM wide needle bearing that could be fitted to stovebolt rocker arms (two of them with an oil groove in between) . The pivot shaft can be made to free float in the standoffs in bronze bushings so the bottom of the shaft doesn't wear excessively. Yes, it's a lot of work, but the finished product ought to last about 3 days past forever, and have a tiny fraction of the parasitic drag of an OEM rocker assembly. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Given any thought to which style center shaft connector/ oiling setup you might use? I’m kinda partial to the late design that has the closed off connector that pressurizes the inside of the shaft, and then the offset rocker groove that keeps oil from spurting everywhere. But it probably doesn’t matter much. I think you could make either work with this roller concept thing.
I'll be machining my own custom oil connector and plumbing the oil supply to it with copper/nickel brake line tubing, most likely. I'll also be putting brass orfices into the rocker arms to control the oil flow- - - -probably pointing towards the tip instead of just an open hole squirting straight up. I'm also kicking an idea around for fabricating my own standoffs from 3/4" X 1 1/2" square steel bars instead of making reducer bushings for the original standoffs. I'll probably try it both ways to see which one works best. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Boy- - - -talk about thread drift! This whole 7 page odyssey started out talking about salvaging a worn set of rocker shafts by turning them upside down! Wait until I start talking about running roller lifters on the camshaft! LOL! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
