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Technical Flat tappet cam failures

Discussion in 'The Hokey Ass Message Board' started by mustangmike6996, Oct 15, 2014.

  1. tubman
    Joined: May 16, 2007
    Posts: 6,321


    I don't know about SBF's, but I had a ton of trouble when some genius engine builder put a HV pump in the 327 in my Corvette. Smoke on startup, pegged oil gage, fouled plugs, excessive oil consumption, etc. I finally solved the problem by installing a stock replacement pump. Seems all of the oil being pumped to the top of the engine was overwhelming the drainback system. The guys who designed these engines knew what they were doing and provided the optimum pump fotr the application. Use of a HV pump in anything but a racing engine with opened up clearances is folly. If you check the suppliers (Jeg's Summit, etc.), you will see that the HV pumps (for a SBC anyway) are half the price of a quality standard pump. It seems some of these engine builders can't resist "upgrading the build" while saving a few bucks.
  2. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,911

    dirty old man
    Member Emeritus

    I have no experience with a high volume pump on a sbf, and the only reason I used a high volume pump in my sbc was because of the extra oil bleed off from the flat tappets with .012" oil hole in the face.
    But unless you had low oil pressure without a high volume pump with stock type flat tappets, I wouldn't use a high volume pump. In fact some builders restrict oil flow to lifter galleys on some engines when using roller lifters.
  3. Flatheadguy
    Joined: Dec 2, 2008
    Posts: 2,037


    1973. IMSA 500 race at Pocono. My Camaro had a small block with a rather unusual, but legal, engine.
    The camshaft was a prototype from Smokey Yunick. He was a friend. The car ran about three hours
    before the engine just shut off. Pulling off the track, opening the hood, flames from the staggered dual four barrel carbs. Oh, yeah, a Smokey intake prototype. Hit it with an extinguisher. When we got it back to the shop the tear down started. When the cam was removed it looked like a broomstick. No lobes!!
    Called Smokey and he said, "Return it and we'll throw it out for you". Lots of laughter, but it did lead to a DNF. Smokey was a GREAT guy in every auto endeavor and one helluva interesting guy. RIP.
    mustangmike6996 likes this.
  4. yellow dog
    Joined: Oct 15, 2011
    Posts: 501

    yellow dog
    from san diego

    I guess oil pumps are related to thread.....anyway I run 2 SBF's w/ high volume and one
    w/ standard. I would not run a high volume pump unless you are spraying the valve springs even with race clearances. Moving more oil puts more strain on the drive and a bit more HP.
    Unless the cylinder head is modified, the extra oil is also a concern being in limited by the relatively small opening at each end plus being counter current to crankcase breathing.
  5. mustangmike6996
    Joined: Apr 7, 2013
    Posts: 147

    from the D

    I chose to run a standard volume/standard pressure Ford Racing pump.

    Do you guys recommend any mods to the block, oil passages or anything else to add any needed security?
  6. lcfman
    Joined: Sep 1, 2009
    Posts: 359

    from tn

    I think engine man is correct. Lack of quality control for heat treating is a big factor. I had a comp cams go down about 10 years ago. I checked the hardness of the camshaft and it was below the comp cams specs. If I had to use a flat tappet cam i would do the following. Have the cam tuff coated, check the hardness, use Gibbs break in oil, start up with low psi springs and follow the break in procedure.
  7. seb fontana
    Joined: Sep 1, 2005
    Posts: 7,819

    seb fontana
    from ct

    Pretty sure there are hydraulic lifters with the face oil hole, can check on brand....Now if one thinks that all the lifter bores are in the right place from the start that ain't so...If they are with in .020 of true location it would be surpriseing and not much need for break in if they were dead nuts..For that matter what makes one think that the lobe radius or the lifter face radius are right on perfect? Bore off some, lifter face off some, cam lobe off some and you have the need for break in time..if all were to basic dimension there would be no necessity for any mating ritual...
  8. Futura63
    Joined: Dec 3, 2011
    Posts: 146

    from N/W ohio

    If you read the propaganda from from your new cam supplier "who ever you choose " they ussually offer an additional treatment you can pay for , not sure what it is but it should nt be an option ! They should just provide the best product they can in the 1st place . bad promo lasts a very long time .
    The engine break in , is the scariest time at the shop , I run in everything I build befor joe public gets his hands on it.. its just easier to get some sleep
    T.L. likes this.
  9. models916
    Joined: Apr 19, 2012
    Posts: 380


    Lifters wear to the cam. The cam will not wear in, it will only wear out. Surface is hardened. That's why you can put new lifter on an old cam, but not a new cam with old lifters.
  10. 61falcon
    Joined: Jan 1, 2009
    Posts: 772


    never had a cam fail, old or new. I use whatever oil is required by the cam manufacture and follow the break in guide lines and then run the crap out of it. some times cams fail for other reasons than improper break in. to much valve spring pressure, insufficient oiling, and poor castings lead to premature failures.
  11. mustangmike6996
    Joined: Apr 7, 2013
    Posts: 147

    from the D

    picked the block and rotating assy up today. Drilled and tapped the cam retaining bracket holes. Cleaned up some casting areas that were rough, painted the block. Tomorrow I will begin re-reassembling the bottom end. I have the new valve springs but the crappy compressor that I loaned from Orielys doesn't want to sit securely on the spring retainer so I will need to find or make something else that works better.

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