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Changing from roller cam to flat tappet cam, have questions

Discussion in 'The Garage' started by jim burke, Apr 20, 2005.

  1. jim burke

    jim burke Registered Member

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    I'm swapping out the roller cam in my '89 Blazer and installing a flat tappet cam. The roller cam was installed by the previous owner and is (apparently) not compatible w/ the chip for the Edelbrock fuel injection. The front of the cams is different between flat tappet (on the left) and the roller cam on the right:
    [​IMG]

    I bought a new timing chain set, so no problem there. I can't use the plate that kept the roller cam in place:
    [​IMG]
    so what do I do now? What's going to keep the cam in place (not having too much movement forward and back)?

    Here's the old setup for keeping the (roller) lifters in place (sorry for the dark picture):
    [​IMG]

    Obviously, I don't need that setup anymore. I don't need to re-install anything in the lifter valley, correct? The three bolt holes (the ones in the middle) seem to be "blind" (they don't go into a water or oil passage) so I can just leave out the three bolts (that held the sheetmetal piece in place), right?
    [​IMG]

    I don't know if the block is the original or not. Would an '89 truck block have had a provision for installing a roller cam? I'm pretty sure the '89 Blazers had flat tappet cams. Were all the blocks (car or truck) the same (they all have the provision for installing the roller setup)?

    Would the block have been machined this way from the factory? (I'm referring to the flat part, not the lifter bores).:
    [​IMG]
    If not, does this cause a problem w/ installing the flat tappet lifters?

    Thanks in advance,

    Jim
     
    Last edited: Apr 21, 2005
  2. slimlynn1

    slimlynn1 1/2 ton status

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    Why not get a roller cam that is compatible with the computer or have a chip burned for the cam you have. I believe you can install the flat tappet cam in the block by just removing the retaining plate. Also the flat tappet cam is ground on an angle so the lifters keep the cab from comming out of the block.
     
  3. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    What are the specs on the roller cam, and how much for it and all the roller accessories?

    I wouldn't mind making my truck a roller, they produce a fair bit more power due to the decreased amount of friction with lifter vs cam :)
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Is there any reason you can't just get another factory roller cam? Pieces on ebay for used factory stuff are typically CHEAP, and there is no reason to not reuse a roller cam unless it is damaged...with people swapping cams all the time, a roller camaro cam, TBI, should be real easy and cheap to find.

    I see you bought a timing chain, I'd REALLY consider re-using a roller, but looks like you already bought a flat tappet cam too? :(
     
  5. smalltruckbigcid

    smalltruckbigcid 1/2 ton status

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    The second picture shows the retainer plate and front cam bearing. The bearing looks a little hacked in the picture, bad picture or is it really pitted like it looks like?
    George
     
  6. jim burke

    jim burke Registered Member

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    I don't think there is a roller cam that's compatible w/ the chip that's in there now. You can read all about my emissions problem(s) here: http://coloradok5.com/forums/showthread.php?t=131057 :)

    It seems like it's much cheaper to just install the flat-tappet cam and lifters (instead of having a new chip burned). The parts really weren't that expensive ($19 for the timing chain set, $23 for the cam, $4 a piece for the lifters, etc.). I'll probably sell the roller cam setup (cam, lifters, timing chain, pushrods, etc.) on eBay to recoup some of the cost of the stuff I'm installing.

    I'm not 100% sure the flat tappet cam will solve my emissions problem, but I'm going to try it. I also wanted to make sure there wasn't something wrong w/ the way the roller cam was installed or w/ the cam itself (there isn't).
     
  7. jim burke

    jim burke Registered Member

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    The bearing is slightly worn but nothing I'm worried about (it looks worse in the picture than it actually is).
     
  8. HarryH3

    HarryH3 1 ton status Author

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    You just leave the retainer plate off when you install the non-roller cam. It isn't required for a flat tappet cam. The cam lobes are ground so that the cam is always being slightly pushed to the rear of the block. Roller cams can't be ground like that, so some type of cam retainer is required.

    If you want a stock roller cam, I've got one that I'd let ya have pretty cheap. :cool1:
     

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