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Crankshaft oil gallery plugs

Discussion in 'Technical Q&A' started by fly, Jul 4, 2006.

  1. fly

    fly Karting

    Nov 20, 2003
    124
    Sydney, Australia
    Full Name:
    Steve
    Has anybody experienced a loss of oil pressure due to one of the Crankshaft oil gallery plugs falling out? A friend of mine has experienced this with an Alfa and suspects this may be the case with my '87 TR, due to large fluctuations of the dash oil pressure gauge. If anyone has experienced anything like this, i.e.. large fluctuations of the dash oil pressure gauge, please post any info. which may help, or is this just normal on a TR? Thanks Steve
     
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  3. ProCoach

    ProCoach F1 Veteran
    Owner

    Sep 15, 2004
    5,439
    VIR Raceway
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    Peter
    More likely problem is the oil pressure sending unit on the TR.

    The Alfa problem has to do with the aluminum "plugs" driven in and not well peened into the crankshaft oilways in the Alfa crank. That said, in twenty-five years of building over a hundred Alfa Romeo engines, mostly for competition, I've not seen one come out... We do drill, tap and plug the oilways with threaded NPT plugs in every one of our crankshaft preparations, however...
     
  4. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
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    Paul

    Had a simular plug come out of crank on a Continental engine in a Bonanza. Plane flew wonderfully for an hour. Then later when ran up on the ground at full power, less than a minute and its squeaked to a dead stop. I think Ferrari are screwed in plugs as well.
     
  5. Watry

    Watry Karting

    Aug 8, 2005
    78
    Berkeley, CA
    Full Name:
    Andrew Watry
    I just pulled a 2000 out of a 73 Alfa Spider that had one plug lying in the bottom of the pan. Engine still had good pressure, and original standard bearings looked fine. Alfa 2000 cranks are nitrided; not sure about Continentals or Ferrari V8s.

    Andrew
     
  6. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
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    Paul
    Aircraft engine cranks are probably equal with Ferrari as to whatever kind of metal they are made from. Most aircraft cranks are several thousand $$$$ to replace, many are hollow, and most of the opposed six cylinders have floating dynamic balancers on the flyweights.

    Ferrari cuts thier crankshafts from solid billits of super high grade alloy steel. There used to be a display at the Smithsonian Institute of Technology of a set of Ferrari crankshafts in various stages of machining from solid billit, the display commenting Ferrari being the only production car in the world so made. After its machined, I understand its deeply nitrided.
     
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  8. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
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    Just to comment on the Alfa 2000. My 72 GTV oil guage read to 175 psi. It would bury the needle when idling cold, and warm would settle around 100 at idle, and climb to 175 when revved. With pressure like that I can see one plug out not wrecking the engine.
     
  9. Kingpin328

    Kingpin328 Formula Junior

    Nov 7, 2003
    433
    #7 Kingpin328, Jul 8, 2006
    Last edited by a moderator: Sep 7, 2017
    In the old days, I think. This picture was posted here recently, forged crank-'roughlings' waiting for machining ...
    Image Unavailable, Please Login
     
  10. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
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    Wow, thats interesting, wonder when they started doing that. I know there has been an ongoing argument between billit and forged and which is stronger. I honestly dont know how aircraft cranks are made, but seeing them hollowed out sure raises your eyebrows. Anything to lose a pound here or there.
     
  11. JCR

    JCR F1 Veteran
    Silver Subscribed

    Mar 14, 2005
    7,418
    H-Town, Tejas
    There is no arguement. Forged cranks are stronger than billet.
     
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