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Technical SBC Rocker Arm ID

Discussion in 'The Hokey Ass Message Board' started by Mitchell Rish, Oct 8, 2021.

  1. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    I traded for a batch of parts a good while back and you know how sometimes what looks like a duck turns out to be a chicken.
    I have what I thought was a set ofSBC roller rockers like any other one of the 50 sets I’ve had in my life time. Today I pulled this set out and noticed 4 things.
    Number one. They are none adjustable like they are.
    Number two. They are on a common shaft per pair like a Jessel.
    Number three. They fit any stock sbc head as far as the rocker studs. ( slide down over them perfectly )
    Number four. They have 1.52 ratio -which is the normal SBC ratio for stock.
    Now. What do I have. There isn’t a label or part number on the box anywhere. Ok Squirrel you have impressed me often. Your up again
     

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  2. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    I have a lathe and I will/can cut two new grooves for the retainer clips and then cut the shaft in to two separate pieces. I just want to know what they are I have not ever seen this set up
     
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 49,876

    squirrel
    Member

  4. indyjps
    Joined: Feb 21, 2007
    Posts: 4,406

    indyjps
    Member

    On a shaft mount the rockers are all tied together by the shaft. With a common shaft, shim the rocker stand for valve tip adjustment. Set lash at each rocker. Here's Crower's instructions.

    https://www.crower.com › pdfPDF
    shaft mounted rocker installation instructions - Crower Cams
     
    Last edited: Oct 8, 2021
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  5. gary macdonald
    Joined: Jan 18, 2021
    Posts: 142

    gary macdonald
    Member

    If you cut them apart , wont that diminish the advantage of having the rigidity that was built into them by having them connected ?
    Maybe an updated version I found on ebay , adjustable.
     

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  6. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 3,527

    2OLD2FAST
    Member
    from illinois

  7. Tickety Boo
    Joined: Feb 2, 2015
    Posts: 1,404

    Tickety Boo
    Member
    from Wisconsin

    Is the inner diameter of the rocker shaft holes a tight fit on the rocker studs, they may be loose enough to get
    a little adjustment individually.
    If all the valve stems are equal length "not mixed brands ect" why wouldn't they work as designed :confused:
     
    Last edited: Oct 9, 2021
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  8. indyjps
    Joined: Feb 21, 2007
    Posts: 4,406

    indyjps
    Member

    Big block chevy use individual shafts due to valvetrain geometry, still more stable than not running shaft.
    Agree. Separating SBC makes no sense.
     
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  9. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    If these were used with a solid flat tappet / or a solid roller there would be no adjustment at all. ( which is just about all I use- period).Normally the adjustment( for shaft mount rockers) would be push rod side of the rocker( like my Donovan/early Chrysler stuff was) or use adjustable push rods.
    If I cut two new retainer grooves / then separate them - all in the lathe- YES I would loose some of the inherent strength- but I would be essentially converting them to adjustable stud mount.
    (I just got a message stating it maybe a LT4 ???? rocker set up?) It useless to me until its adjustable. The polly locks look like any other so that gives no clue either.
    I would simply like to know - never seen this before- I have used T and D/ donovan/ and Jessel. and they were all adjustable on the push rod side.
    Keep the info coming and no you wont hurt my feelings - I don't have a lot invested - but for us they are usless if not adjustable.
    Thanks for the other pics and info - I figured some of you would have some insight.
     
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  10. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    And for the record -Squirrel- that box / and rocker set looks almost identical.
    I just don't understand their thought process on it with out push rod side adjustment if its shaft mounted. oh well no worries.
     
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  11. Pete Eastwood
    Joined: Jul 27, 2011
    Posts: 1,042

    Pete Eastwood
    Member
    from california

    maybe they require adjustable push rods . . .
     
  12. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    Thats an option for sure. I used them more than once with 455 olds we ran on the street with a pretty good size hyd. cam.
     
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  13. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 9,484

    Johnny Gee
    Member
    from Downey, Ca

    Maybe think Ford.

    upload_2021-10-8_21-15-12.jpeg
    upload_2021-10-8_21-15-38.jpeg
     
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  14. Ericnova72
    Joined: May 1, 2007
    Posts: 477

    Ericnova72
    Member

    Those are a cheap china copy of the style rocker YellaTerra used to sell, an paired shaft rocker, but with one difference.
    The YellaTerras had individual pedestals that dropped on first, each stud fit through a pedestal, sort of patterned after the LS engines rockers. Only adjustment is pedestal shimming

    I never could figure out how the cheapo's were just supposed to float there in place, with no pedestal at each stud?

    You will have a hard time grooving that shaft, and cutting it...it is hardened, 68-70 rockwell C as it is the bearing race for the rocker needle bearings. Carbide groove tool probably won't get it?

    They were all over Ebay a few years back.

    Like a reverse of the stock Ford sled pedestal Johnny Gee just posted above me.

    If it was me, I'd just pitch em, bearings probably won't last long anyway.
     
  15. Ericnova72
    Joined: May 1, 2007
    Posts: 477

    Ericnova72
    Member

  16. SS327
    Joined: Sep 11, 2017
    Posts: 417

    SS327

    What about them fitting a Pontiac or Oldsmobile engine?
     
  17. indyjps
    Joined: Feb 21, 2007
    Posts: 4,406

    indyjps
    Member

    Interesting stuff. I haven't set up or adjusted shaft rockers in years. Only high end brands were out then.

    Mitchell Rish, how much cam are you running and what kind of heads?
     
  18. onetrickpony
    Joined: Sep 21, 2010
    Posts: 529

    onetrickpony
    Member
    from Texas

    Maybe they would use different thickness lash caps over the valve stems for adjustment.
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 49,876

    squirrel
    Member

    It looks to me like they would be adjustable, just like any normal single stud mounted roller rocker arm. There's nothing keeping the shaft perfectly horizontal, is there? It just "floats", like the shorter shaft in a normal roller rocker arm. It just can't float as much, since it's held in place by two studs, instead of only one.

    Yup, if the cam is relatively mild, I'd probably just use stock rockers on it....like on my 9 second Chevy II.... :)
     
  20. TA DAD
    Joined: Mar 2, 2014
    Posts: 503

    TA DAD
    Member
    from NC

    They look like 350 Olds to me. Get a rocker bridge for a Olds and check the distance between the holes.
     
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  21. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 9,484

    Johnny Gee
    Member
    from Downey, Ca

    I was also thinking that but... Then there's if one isn't up on his game setting preload one could get things all caddywompus. This is why I brought up Ford on #13.
     
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  22. MCjim
    Joined: Jun 4, 2006
    Posts: 330

    MCjim
    Member
    from soCal

    This...like Later Harleys when changing cams.
    From Crower catalog:
    ADJUSTABLE PUSHRODS When going from hydraulic to solid lifters, adjustable pushrods are often required if there is no adjustment provision at the rocker arm. The overall length of Crower adjustable pushrods is listed with adjustable end in the middle of the adjustment range.
     
  23. lippy
    Joined: Sep 27, 2006
    Posts: 5,688

    lippy
    Member
    from Ks

    Be better to run some crower rockers and a stud girdle maybe? Lippy
     
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  24. Ericnova72
    Joined: May 1, 2007
    Posts: 477

    Ericnova72
    Member

    Problem is with them calling those "shaft rockers", because they really aren't......since there is no shaft bed or pedestal the rocker shafts are bolted down to.

    They are just two stud mounted rockers on a common shaft.

    I don't know how you'd get the adjustemnt set exactly parallel to the stud in each poly lock, be near impossible to keep adjustment EXACTLY the same for two studs. One stud is always going to end up holding more load, and it will be very hard to keep the roller tip parallel and flat on the stem tips.

    Here is the LS version they are patterned after, note they state "NON adjustable".
    See the tubular pedestals and shims...
    YELLA TERRA GM LS3 Ultralite R/A Kit - 1.7 Ratio Non-Adj YT6667 | eBay

    If you decide to work with what you've got, maybe you would be farther ahead to make up your own pedestals, with some careful measurements. Just need to get the height within range of hydraulic plunger adjustability for the pushrod length that fits the geometry and you would be fine in a hydro valvetrain....solids would be a bit trickier..

    Here is the SBC Yella Terra's, they were adjustable..
    Chevrolet V8 Small Block Platinum 7/16" Rockers, Ratio 1.6 YT 6696 - yellaterra

    The actual Yella Terra's with the support pedestals were a fine design, just not much cost savings over a true bedded shaft set-up so they never really caught on here(they are Australian). Big name Down Under.
     
    Last edited: Oct 9, 2021
  25. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    I typically run 600 or less lift. And will turn them 7k or less. I am not known for running huge valve spring pressure unless there is no other way.I use a lot of older grinds /Herbert /Engle /Isky and some stuff that uncle Marion used to cut for us from trade ins etc.
    I have a set of worn out comp cams steel roller rockers somewhere. Might just steal the trionion / pivot if I can find them and combine them And that’s a big if.I just had never seen any set up like this. My intent is to make them usable by what ever means /with out spending much or let em go. Make a spare set.
     
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  26. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    Typically I run a solid lifter or a solid roller. These are also 1.52 ratio. Wes and Mick are willing to spend the money at times I’ll choke over. I usually have run pretty well on everyone else’s cast offs for years.
    They are brand new and the idea is that I would use them on a spare grenade if we needed them.
     
    Last edited: Oct 9, 2021
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  27. seb fontana
    Joined: Sep 1, 2005
    Posts: 7,155

    seb fontana
    Member
    from ct

    I would separate and cut new snap ring grooves with a die grinder/cut off wheel clamped to tool post in lathe if too hard for C'bide.
     
  28. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    Yep / have even thought of a way to mount the Die grinder to the tool post.
     
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  29. Ericnova72
    Joined: May 1, 2007
    Posts: 477

    Ericnova72
    Member

    If you've got a lathe, seems like just makes the correct size pedestals during final engine mock-up and make them just like the LS version of the Yella Terra's.
    Get all the advantages and no drawbacks.
    The Yella Terra pedestal is just a tubular spacer, with a radius cut on the upper end to cradle the rocker shaft....all you have to do is make them the correct length to match your other parts and produce good geometry, then shorten that dimension by whatever amount of lifter preload you want to run.
    Rock solid stable. Use something like die button shims under the pedestal if you desire more adjustability.

    Die grinder internal end play is not good enough for a precision slot....scrap that idea.
    Maybe if you could work up a wheel mandrel to fit a router motor, maybe.

    Make you own pedestals seems a lot smarter to me.
     
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  30. Mitchell Rish
    Joined: Jun 10, 2007
    Posts: 1,370

    Mitchell Rish
    Member
    from Houston MS

    If you look at any aftermarket roller for a conventional sbc set up its pretty simple- which also so explains why they have been around for ever. Considering the cams that I run- ill cut the grooves and then cut the shaft in half and install as per traditional rollers rocker. Or that's the plan. I have no desire to keep the shaft set up-the way it is. Its just not adjustable enough to for what we are doing. If the shaft gives a lot of trouble to groove and cut- Ill shelve them or trade . I am not a fan of no adjustment / and I 've owned enough early hemis to tell you adjustable push rods work - but I don't care for them when spring pressures go up- take some getting used to to set correctly also.
     
    Last edited: Oct 14, 2021
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