348 power quest... head rebiuld | Page 2 | FerrariChat

348 power quest... head rebiuld

Discussion in '348/355' started by TheItalianJob, Feb 26, 2010.

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  1. Rifledriver

    Rifledriver Three Time F1 World Champ

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    I am not so sure about that. I have never CC'd one but the cranking compression does lend creedence to the 10.4 claimed and there was only one piston part number until very late in production when some variants had 10.8.
     
    Rifledriver, Jan 24, 2011
    #26
  2. TheItalianJob

    TheItalianJob Karting

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    why pistons? They look like a good design... they have narrow side skirts, narrow 1st and 2nd rings with 3mm oil ring, narrow pins. They are similar to SRP pro JE Pistons and 20 years old. Is it that the new ones are lighter and stronger? factory ones not forged?
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    Last edited by a moderator: Sep 7, 2017
    TheItalianJob, Jan 24, 2011
    #27
  3. Ferraripilot

    Ferraripilot F1 World Champ Owner Project Master

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    The piston in the above pic is scuffed at the skirt and needs to be replaced. Stock pistons are fine, but JE are also very good and much more reasonable @ around $1200 a set with rings and pins
     
    Ferraripilot, Jan 24, 2011
    #28
  4. Mitch Alsup

    Mitch Alsup F1 Veteran

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    BTW the 355 rods are only 390 gr.
     
    Mitch Alsup, Jan 24, 2011
    #29
  5. TheItalianJob

    TheItalianJob Karting

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    wow. that is 100g lighter!
    anyone have a set for sale? ...may be worth upgrading.
     
    TheItalianJob, Jan 25, 2011
    #30
  6. TheItalianJob

    TheItalianJob Karting

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    very interesting ernie... Now i have a project to test. I will make up a spacer and check if it improves the flow with the lid on.
     
    TheItalianJob, Jan 25, 2011
    #31
  7. TheItalianJob

    TheItalianJob Karting

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    Last edited by a moderator: Sep 7, 2017
    TheItalianJob, Jan 25, 2011
    #32
  8. TheItalianJob

    TheItalianJob Karting

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    TheItalianJob, Jan 25, 2011
    #33
  9. TheItalianJob

    TheItalianJob Karting

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    TheItalianJob, Jan 25, 2011
    #34
  10. davehelms

    davehelms F1 Rookie

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    davehelms, Jan 25, 2011
    #35
  11. davehelms

    davehelms F1 Rookie

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    davehelms, Jan 25, 2011
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  12. vvassallo

    vvassallo F1 Veteran

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    Spacers fabricated by gothspeed engineering using plate aluminum and waterjet cutter. Don't ask me if it does anything by itself. It's part of a package of mods we made that do work, but who's to say if it's one thing, all of them or something else?

    Note: You will have to work up something to elongate the shaft for the balancing butterfly in the center of the upper plenum. With gaskets it's about .375" taller. Also note spacers at throttle bodies to free room for the throttle linkage to function without binding.
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    Last edited by a moderator: Sep 7, 2017
    vvassallo, Jan 25, 2011
    #37
  13. TheItalianJob

    TheItalianJob Karting

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    Nice pic Dave.
    It is easy to see how they bumped the OEM CR from 10.4 to 10.8

    Also, all the pistons look the same height... so i guess they all maximize piston quench height this way.

    The Cosworth piston has huge valve reliefs... what size valve will it accommodate? Looks like 34mm Intake and 28mm Ex.
     
    TheItalianJob, Jan 25, 2011
    #38
  14. TheItalianJob

    TheItalianJob Karting

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    thanks, i'm going to see if i can get any improved numbers on the flowbench with a spacer while the head is being tested. Now i just have to make a spacer. :(

    Notes are a help too... if i do follow through with the mod. The H lid looks about 1" taller then normal.

    -daniel
     
    Last edited: Jan 25, 2011
    TheItalianJob, Jan 25, 2011
    #39
  15. plugzit

    plugzit F1 Veteran Silver Subscribed

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    Wouldn't it be cool if somebody had a few of those cast?
    Could probably be done in some of today's plastics.
     
    plugzit, Jan 26, 2011
    #40
  16. vvassallo

    vvassallo F1 Veteran

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    It would have to be a package because of all the other stuff involved: throttle bodies moved outboard; longer Allen head bolts; extra gaskets; butterfly valve shaft extension. I suppose goth could come up with something. The risk to me is that we could not tell you if these mods alone yield any benefit. Add ported and polished runners along with completely smoothed upper plenum surfaces and bored throttle bodies, and yes, you will get more performance.
     
    vvassallo, Jan 26, 2011
    #41
  17. ernie

    ernie Two Time F1 World Champ Lifetime Rossa Owner

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    I still need to get my coffee straws ported, er..... I mean, the throttle bodies.

    On second thought, scratch that. I need to get this pile of crap running right........if that will ever happen???????
     
    ernie, Jan 26, 2011
    #42
  18. davehelms

    davehelms F1 Rookie

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    The reliefs are cut with 35/30 cutters. I had to pocket them a bit deeper for the Sprint engine cams. Its a heavy slug but made to live at very high CR's and abuse levels. Sy's LM and my IMSA are both running the same Cosworth pistons but he is running sans head gasket with a fully Cooper Ringed head thus giving even higher CR figures.

    I am in full agreement with you regarding the OEM pistons. A wonderful blend of longevity and high performance that is quite hard to improve upon. Ferrari chose to stick with the identical design through the F50, 355, 360... only changing the crown design for the 5 valves.

    Somewhere in the stacks of parts I have an unaltered H manifold I can flow to get some base numbers for your research if that helps. If I can find my old files from years ago I flowed a good many of the intakes. On one of the H manifolds I installed stacks inside much like the 550/360 design but never had time to flow it or study it further. I believe that showed a good deal of promise to be built upon.
     
    Last edited: Jan 26, 2011
    davehelms, Jan 26, 2011
    #43
  19. TheItalianJob

    TheItalianJob Karting

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    i made up a .75" spacer and flow test yesterday. It flowed exactly the same numbers as without the spacer. I think the only way to see what difference it makes is on the dyno so i will save it and hopefully get a chance to dyno test it later.
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    Last edited by a moderator: Sep 7, 2017
    TheItalianJob, Feb 1, 2011
    #44
  20. TheItalianJob

    TheItalianJob Karting

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    TheItalianJob, Feb 1, 2011
    #45
  21. AceMaster

    AceMaster Three Time F1 World Champ

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    Excellent work, Daniel.
     
    AceMaster, Feb 1, 2011
    #46
  22. TheItalianJob

    TheItalianJob Karting

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    can the lighter 355/360 rods work in the 348? I have specs on the 348 rods in the workshop manual. Need to compare with 355/360 rod specs.

    -daniel
     
    TheItalianJob, Feb 1, 2011
    #47
  23. NeuroBeaker

    NeuroBeaker Advising Moderator Moderator

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    Hey, cool thread - I can't believe I've not noticed it before! :eek:


    Forgive me if this comes out sounding confused, but is that a timing chain to replace the timing belts and so improve longevity between majors or is that timing chain completely separate from the famous timing belt? :)

    All the best,
    Andrew.
     
    NeuroBeaker, Feb 1, 2011
    #48
  24. marcov

    marcov Karting

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    Good job Daniel,
    Did you keep the hour glass shape runner whan you ported them, or did you make them more cylindrical? Also, what size are you planning to port the Throttle body?
     
    marcov, Feb 1, 2011
    #49
  25. AceMaster

    AceMaster Three Time F1 World Champ

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    Andrew, this is something completely different than the timing belt that run the four cams on the 348 - this timing chain is for the oil pump inside the gearbox.
     
    AceMaster, Feb 1, 2011
    #50
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