Piston pin offset-QV | FerrariChat

Piston pin offset-QV

Discussion in 'Technical Q&A' started by fastradio, Dec 14, 2010.

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  1. fastradio

    fastradio F1 Rookie
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    David Feinberg
    #1 fastradio, Dec 14, 2010
    Last edited: Dec 14, 2010
    In reading over the WSM regarding piston/rod installation, it would appear that the wrist pin offset is different for the 1-4 bank, versus the 5-8 bank. In that the pin offset is typically opposite the direction of rotation, the WSM seems to be breaking the rules of conventional engine building.(On one bank, the pin offset is opposite the direction of rotation, on the other bank, it is in the same direction of rotation!) Anyone ever notice this...or am I mis-reading the manual?

    Is the Ferrari V8 different than your typical American V8 in terms of how the piston pin offset is done?
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Not according to my book.

    It says to place the mark towards direction of rotation. One bank will be on exhaust side and the other bank will be towards the intake side.



    Page B36 in the 308QV/328 WORKSHOP MANUAL.
     
  3. fastradio

    fastradio F1 Rookie
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    Well...I'm really beginning to feel stupid Brian, as I (wrongly) used an engine that I had torn down as my visual "reference" and tried (unsuccessfully) in my mind to make it agree with the WSM. It would appear that one of my virgin QVs in for an overhaul has been down before at some point in her life...and the pistons were installed backwards. This might just explain some of the internal problems I found.

    All is clear now. Thank you!

    Best,
    David
     
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Even the cast iron blueprint is not always to be trusted.
     
  5. thecarreaper

    thecarreaper F1 World Champ
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    Sep 30, 2003
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    have you had to rebuild many QV's? if so, why?

    do you feel the sodium filled valves in the older 2v cars are in fact a negative if they have not been changed by now? (I do).

    interesting.
     
  6. fastradio

    fastradio F1 Rookie
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    #6 fastradio, Dec 15, 2010
    Last edited: Dec 15, 2010
    A few in recent years...and more many years back. Basically, these are very tough engines that will go a long, long time between overhauls. Why are these engines being overhauled or why do they fail; I'll answer both.

    Overheating...and I'm not talking a little hot, either. If you constantly run them in the 230+ temperature range and you've done all of the "snake-oil" tricks such as (but not limited to) a trick water pump, new fans, racing radiator and she still runs hot; there's a real problem. Unfortunately by the time you figure this out, you've likely killed the liners.

    High miles: They only live so long.

    Lack of service/poor service: Low miles doesn't mean no service.

    "Major services" without removing those valve covers: Valves with not enough clearance run hot. Over time, this will lead to valve failure...

    Yes! On all of the 2-valve cars, I replace the sodium valves (with stainless) any time a head is off, or the engine is being rebuilt. The cost of the valves is chump change in comparison to the cost of a failure.
     
  7. dino clay

    dino clay Karting

    Oct 31, 2007
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    san mateo, cal
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    clay cavanaugh
    Piston pin offset is:

    short side towards thrust of piston
    the thrust side of the engine concerns the rock over of the piston when the spark plug fires. See an explanation of piston thrust on the net
    Most high performance engines do not have offset piston pins

    dino clay
     
  8. Rifledriver

    Rifledriver Three Time F1 World Champ

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    We understand




    Thanks
     
  9. Badman

    Badman Formula 3

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    Lol
     

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