Tapping roller tip rockers (not header leak)

Discussion in 'Technical' started by scooper77515, Nov 2, 2007.

  1. scooper77515

    scooper77515 No current projects.

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    NAFORD302 just called me and reminded me that the GT40P heads are set up for a roller cam. I wonder if the spring pressures are such that they led to the premature failure of this lifter?
     
  2. Mavman72

    Mavman72 Gone backwards but lookin' forward

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    Its my understanding that those springs are good to .500 lift so its possible,but more likely something caused that lifter to stop rotating.Cam lobe probably started going and took out the lifter.Its possible that one valve was on the verge of coil bind at max lift also and just took its time mashing that lobe/lifter.(1.7:1 ratio lifters) are a bit much for those springs considering the lift figure on that cam and the increase with the taller rocker ratio.Lots of guys run em without any problems though so who knows??Either way it stinks.Good luck
     
  3. dkstuck

    dkstuck Member

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    Be a great time to ask Santa for a roller! Valve springs oughta be checked for any cam you put in now. I've had it up to here (hand held high) with non roller cams!

    Never use to have a problem,, got a cleveland on a third cam,, Followed directions an oil additive to the T,,,Bought more oil for this car than gas since this project started. On hold for now, gotta get race car done,,then the cleveland will be a roller cam!

    Lots of cams are making it,, I'm just fed up with close to 10 grand in cleveland and aint got 300 miles on it. I would really think about a roller! And yes, I would do a complete freshen up as all bearings got the metal flush. Good Luck
     
  4. Rick Book

    Rick Book Member

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    Scott, I have a 5.0 roller cam in storage. I went with a taller profile for track only. This one has very few miles on it.

    I'm headed there today. Let me know if you want it.

    .224/.232 @.05, .510/.534 w/1.6 on 110 deg


    You're welcome to try it if you want (of course you'll need to make other changes to make your block a "roller"; new springs, lifters - which I have 10-12 of, new push rods, the spider and retainer for the lifters - not sure what else ).

    [​IMG]



    Bah. It's easier (on you and your wallet) just to go back with a non-roller setup. Good luck.

     
  5. dkstuck

    dkstuck Member

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    Scott, I can check with my buddy, I think he has all the rollers.
     
  6. Rick Book

    Rick Book Member

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    additional info: the cam I mention is a Nitrous cam (fwiw).
     
  7. scooper77515

    scooper77515 No current projects.

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    Rick, I would love to go with the spider setup to allow a roller lifter to be used, but I am not sure if my springs can handle the .520, especially if you toss in the 1.7 ratio.

    If I could recycle some of those parts to get me half way there...:huh:

    Dk, anything that you might have that would fit and would get me half way there...wait, I already said that;)
     
  8. 71gold

    71gold Frank Cooper Supporting Member

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    i gave a guy $150 for my ...roller motor assy...:yup:
    i got the...
    block
    crank
    rods
    spyder
    dog bones
    lifters

    ...:outtahere:
     
    Last edited: Dec 10, 2007
  9. 71gold

    71gold Frank Cooper Supporting Member

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    ...after cleaning my rear end off...:whew:

    ...:outtahere:
     
    Last edited: Dec 10, 2007
  10. MNTony

    MNTony aka Godzirra

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    Keep in mind that if you have a pre-1985 302 that the lifter galley would have to be drilled and tapped for the spider and that you would have to use a small base circle cam to use the stock roller lifters. Otherwise the lifters stick up to far to work properly. You could also go with the Crane link-bar lifters skipping the small base circle cam, but these run almost $450 last time I checked. If it were me, I'd stick with either a solid or hydraulic flat tappet cam and call it good. It looks like you just had premature lifter failure due to it not rotating properly. I've seen cams chew up one lobe for no apparent reason and it usually turned out to be an oiling problem or just a bad part to start with. Good luck and let us know what you end up doing.
     
  11. scooper77515

    scooper77515 No current projects.

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    With the prices and amount of work, I will probably do what Tony says, but I am hoping that if I shop around, someone will suggest a way to swap to roller for somewhere in the $300-400 range (that is cam, lifters, and all other hardware to make it work).

    Probably won't happen, but I have a week or so to shop around so I may as well do a little research during that time.
     
  12. Rick Book

    Rick Book Member

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    I'll give YOU the cam and most of the lifters.

    The spider bar and retainers kit is $55 at Scummit. A set of Holley hardened push rods are around $50 (you'd have to determine the new length required).

    The lifters that you'd need (4-6) aren't that expensive ($6.25/ea).

    The other items are items that you'd have to replace anyway (gasket/seal set, etc).

    Strange though - a lot of racers want to go from hydraulic to solid. "Shoot yourself." ;)


    Lemme know.
     
  13. scooper77515

    scooper77515 No current projects.

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    Thanks rick, but like you said earlier, it would probably be easier to just stick with the flat tappet at the current time, even if it is a hundred bucks or so more expensive. Those parts are WAY over the limit of my heads/springs.

    I am currently looking at a Comp kit that comes with the cam, lifters (flat hydraulic), double roller chain and sprockets, NEW SPRINGS good for .600 lift, retainers, etc. All for around $325.

    I need to look to see what the P heads can take max at the valves in lift. Then likely shoot for something with .550 or so lift, hopefully.

    Then, no machining, drilling, or tapping. Just pop in the swap parts and back on the road in 2 weeks or so (not because of the labor, but saving, purchasing, and shipping of the parts).
     
  14. scooper77515

    scooper77515 No current projects.

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    I have changed my mind again. My new block has the mounting points for the spider, and I could convert to roller pretty easily now...
     
  15. Blown 5.0

    Blown 5.0 Hooked on BOOST MEMBER

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    Just thought id throw this in, A blower grind cam still works OK naturally aspirated. Be one less thing you will have to do when you install the IRON LUNG.
     

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