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Do I need to use guide plates

Discussion in 'The Hokey Ass Message Board' started by danritz, Mar 13, 2014.

  1. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    I'm building a Summit short block 350 for my '63 Nova. I'm in the process of installing the valve gear on the heads. I thought that I had a handle on heads, rockers, and pushrod guidance; my understanding:

    There are 3 types of pushrod guide systems:

    1. The stock heads are slotted where the pushrods pass thru and the slot is the guide.
    2. When adding guide plates the slot in the head is opened up and the guide plate does the job. This would involve machining the slots much wider to prevent interference between the slot and the guide plates.
    3. The self aligning rocker, which requires the slot in the head to be opened up just like when using guide plates. If your heads still have the slot type guide system then you'll use standard style rockers.

    Here’s what my heads look like: http://www548.pair.com/danritz/head02.jpg

    I was under the impression that my setup – with the slotted pushrod holes in the heads – fall into category number ONE above.

    Specific parts info:
    - SBC 350 (HPE-SP01 Engine Assembly)
    - Cast iron heads (SUM-152123 Cylinder Heads)
    - SUM-1103 cam (214/224 @ .050, 0.444 int./0.466 exh. lift)
    - 1.5 roller rockers (Harland Sharp Roller Rockers S1001) Not self aligning
    - Hydraulic lifters (Summit Racing® Hydraulic Lifters SUM-HT817)
    - COMP Cams High Energy Pushrods 7812-16

    The pushrods just fit through the slots from side to side. I was under the impression that the narrow slots would basically act as guide plates. If guide plates were to be added to these heads, I’m quite sure the existing slots would need to me machined much larger to prevent interference with the guide plates, which would destroy the pushrods.

    Additionally... if these heads work as-is with the ball-fulcrum type of stock rocker arms, which can slop side to side, why wouldn’t they work with my Harland Sharp non-self-aligning roller rockers?

    I posted this earlier today; unfortunately I posted it on the wrong board and the complete dialog was deleted, so I just re-entered this.

    Two responses to the earlier post stated that I do not need guide plates, due to the low-lift cam that I'm using. One response stated that, since these are Vortec-style heads, I need self-aligning roller rockers (I'm a rookie, don't understand that). So... am I good as is, with non-self-aligning roller rockers and no guide plates, or...? I don't want to take any short cuts, want to do it right.

    Thanks a lot for any help that you can give me. Dan
     
  2. Russco
    Joined: Nov 27, 2005
    Posts: 4,132

    Russco
    Member
    from Central IL

    Why don't you assemble one head with all the valve train and see how the rocker tips align to the valves. Then go from there.
     
  3. saltflats
    Joined: Aug 14, 2007
    Posts: 10,252

    saltflats
    Member
    from Missouri

    ^^^ what Russco said plus make sure you have harden push rods.
     
  4. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    The roller rockers are still new in the box, was going to wait for opinions on whether I need to trade them in for self-aligning ones before trial fitting them.
     

  5. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    I was under the impression that hardened pushrods are only required when using guide plates, not if the slots in the heads are guiding them. Not true?
     
  6. So, If your question is "what do I need to do to use my roller rockers?"

    You need something to take the place of the self aligning rocker and that's going to be guide plates. Ok now follow standard guide plate procedure. A guy running roller rockers shouldn't be worried or thinking about cutting corners on other valve train parts either.
     
  7. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    I believe that these are old-school non-Vortec heads (even though they are cast with the center valve cover mounts in addition to the perimeter ones), which would have used the factory stamped-steel rockers, which I believe were kept aligned by the slots cast into the heads. I'm not really replacing self-aligning rockers, am I? Rather, replacing stamped-steel non-self-aligning? What would have kept them aligned, the pushrod slots in the heads, true? Not trying to be argumentative, just trying to understand...
     
  8. Well that's my bad, I was thinking that they were vortec heads.
    I went to summit http://m.summitracing.com/parts/sum-152123
    And checked them out better. Ill have some more coffee and come back :p
     
  9. saltflats
    Joined: Aug 14, 2007
    Posts: 10,252

    saltflats
    Member
    from Missouri

    I think the guide plates give you better control of the rocker arms.
     
  10. RichFox
    Joined: Dec 3, 2006
    Posts: 9,948

    RichFox
    ALLIANCE MEMBER

    I personally, do not see any reason for putting guide plates on heads with the slots already doing the pushrod alignment. Now if you were to install the rockers and they were not centered over the valve stem, you might want to go to guide plates. In that case you would need to machine the slots wider to allow the pushrods to align with the plates/rockers. In that case you may also find you would need to modify the plates to allow the pushrods to move over to where you want them. I believe you will find the slots are right where you want them and everything will be fine as is. Yes, you will still need hardened pushrods.
     
  11. 1971BB427
    Joined: Mar 6, 2010
    Posts: 5,799

    1971BB427
    Member
    from Oregon

    The slots have too much room for movement vs. guide plates. Since you've chosen the roller rockers that require guide plates, you now have to either run guide plates to keep them aligned, or swap to self aligning rockers to use with the stock head setup. You'll also need hardened pushrods with guide plates, but don't need them with the stock head holes. They don't hurt to have either way, but are only necessary with guide plates.
     
  12. Guide plates work well with high lift and high spring pressures and So do roller rockers. Sort of a package where everything compliments each other.

    Can you run rollers with stock stuff, sure but there's no need or real benefit from it.
    Same goes for hardened pushrods, sure wont hurt anything.

    Upgrading a cam is whats causes the need and chain reaction to the valve train. First its the Springs, then rockers, plates and pushrods. The plates give more control closer to the spring force, that's a good thing.

    I see those heads require extra machine work for plates and will handle just over 500 on the lift. So there you go, no need for plates in your application, your cam is less than 450
     
  13. Am I mistaken? Or, Does using guide plates on those heads cause binding and bent pushrods?
     
  14. old.hot.rodder
    Joined: Oct 13, 2012
    Posts: 173

    old.hot.rodder
    Member

    What I have found to be the biggest concern is sometimes the heads wear on the sides of the slots requiring guides to keep the pushrods true. If the slots are excellent with NO wear on the sides this is a pretty stable system. GM used this on 60's corvettes with 375 HP and solid lifter motors with out problems. Not sure if you want to run those rockers though. my 2 cents.
     
  15. Russco
    Joined: Nov 27, 2005
    Posts: 4,132

    Russco
    Member
    from Central IL

    Don't assume that this stuff is going to be correct because it's supposed to be. I would still mock it Ll up and check for alignment and pushrod length as well, also don't skimp on the rocker studs. My AFR heads came with non ARP studs and I found I had a couple alignment issues due to the studs themselves.
     
  16. davedriveschevy
    Joined: Mar 16, 2011
    Posts: 37

    davedriveschevy
    Member

    Head on left requires guidance either plates or s/a rockers.
    Head on right does not.
    pusrdslt.jpg
     
  17. I too was guilty of not noticing that they had both sets of valve cover holes when I posted in the deleted post earlier.
     
  18. 1971BB427
    Joined: Mar 6, 2010
    Posts: 5,799

    1971BB427
    Member
    from Oregon

    If he's using the full roller non self aligning rockers, he needs guide plates with either head. But you're right as far as stock rockers go.
     
  19. 1971BB427
    Joined: Mar 6, 2010
    Posts: 5,799

    1971BB427
    Member
    from Oregon

    Not if the guide plates and screw in studs are properly installed. The bosses have to be machined down a little so that after assembly with new plates and studs the overall height is back to what it was previously.
     
  20. RichFox
    Joined: Dec 3, 2006
    Posts: 9,948

    RichFox
    ALLIANCE MEMBER

    This is where i don't get it. If the slots align the pushrods, what purpose do the guide plates serve? And if the guide plates are not near perfectly aligned with the slots, it seems binding is practically assured. When the SBC first came out, as I remember, they all had slots and that was what aligned the pushrods and the rockers. If you went with a really high lift cam the slots weren't long enough to accommodate the pushrod swing through the rocker movement. So guys took a die grinder and elongated the slots. Not that easy to do right. So somebody invented guide plates and you could just drill out the slot. But they both did the same thing, the plate just allowed more cam lift. Am I wrong?
     
    Last edited: Mar 15, 2014
  21. No, not as far as I'm concerned.
    I go with guide plates when high lifts and stiff springs get involved, That's usually accompanied with high rpms- at that point roller rockers start to make good sense along with hardened pushrods . Lookie there! A complete high performance valve train.

    The plates move the support closer to the load and closer to the greatest amount of movement in the arc. That's where you need with the above circumstances.
     
  22. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    I think you're dead on. I've done a lot of research the last couple of days, and your statements are a good summary of my findings thus far.
     
  23. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    The slots in my head appear to be the same width as those in the guide plates, no wider.
     
  24. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    Don't see how that would be the case; the slots in my head are about the same width as those in guide plates, no wider.
     
  25. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    I'm must be missing something... how can this be true? The stock stamped steel ball-fulcrum rockers would offer no more built-in guidance than the non-self-aligning roller rockers.
     
  26. saltflats
    Joined: Aug 14, 2007
    Posts: 10,252

    saltflats
    Member
    from Missouri

    The guide plates are supporting the push rod closer to the rocker arm where the higher load is.
     
  27. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    Gotcha. I can see how that would be beneficial, esp. for high-lift cams.
     
  28. saltflats
    Joined: Aug 14, 2007
    Posts: 10,252

    saltflats
    Member
    from Missouri

    It looks like for your combination you wont need to go though the expense of the guide plates if the heads that you have are the ones with the slot and not the large hole. But a trial fit would be a good idea if it is going together with after market parts.
    Then you can check alignment and for proper rocker tip contact on the valve for push rod length and coil bind.
     
  29. danritz
    Joined: Oct 10, 2011
    Posts: 21

    danritz
    Member
    from Wisconsin

    Well... I installed the studs and lifters today. Ran out of time, was able to also test-install one rocker and its pushrod, and spin the motor over a couple of times. Everything's looking really good thus far. Again, my cam has ~.450 lift, so nothing dramatic going on. Hope to get the other rockers/pushrods installed over the next few days, and will report back.
     
  30. saltflats
    Joined: Aug 14, 2007
    Posts: 10,252

    saltflats
    Member
    from Missouri

    Sounds like you got things under control. Now get out there and burn a tire.
     

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