TFX 92 max bore

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by WIDEOPEN231, Jun 7, 2018.

  1. WIDEOPEN231

    WIDEOPEN231 Member

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    Ok have cpl way out dated TFX92 blocks,one repaired and one brand new. Thinking about boring both to max and building two Identical bracket motors.Yes a waste,but at what most want to pay for them I can't get anything near as strong even if they are overkill.

    Whats max bore size on TFX92. One is 4.310 and other is 4.250 now. Can they handle 4.375? Or is that getting too big?
     
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  2. WIDEOPEN231

    WIDEOPEN231 Member

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    Oh yea they are solid blocks,but not billet's.
     
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  3. REEHL EQUIPMENT

    REEHL EQUIPMENT Active Member

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    If the sleeves are 4.550 O.D. at the bottom, you can open those 4.250 and 4.310 sleeves to 4.375.

    The sleeve blanks are the same for all 3 bores.

    Hope this helps!
     
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  4. WIDEOPEN231

    WIDEOPEN231 Member

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    Thanks. I di not think it would be problem. As for blanks. I have found with a little machining on lower half outer part of sleeve on KB and JP1 sleeve can be used.Just takes real slow speed on lather and good carbide cutting tool to cut the required step.Well a little time too.
     
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  5. REEHL EQUIPMENT

    REEHL EQUIPMENT Active Member

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    They are great blocks, I ran 4.59 with one in my T/F car 19 years ago.

    3.88 to 1000 ft.

    Most think they were better than the TFX 96 blocks.

    Let me know if you need gear drive parts, I stock most all of the parts.
     
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  6. Nitro Madness

    Nitro Madness Super Comp

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    You might wanna consider the piston skirt thickness when deciding on the bore....years ago I chose 4.310" bore and had issues collapsing the piston skirts....the pistons went in at 4.300" measurement just below the oil ring and 4.304" at the bottom of the skirt....after a dozen runs some were collapsed to 4.300' at the bottom....I changed them when they measured negative taper....
    Tried several piston forgings at Venolia and could not find one with thicker skirts (more the .130" thick) that would fit 4.310....
    Pretty sure if I had any other size bore a beefier forging would have been available....
     
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  7. WIDEOPEN231

    WIDEOPEN231 Member

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    Never had problem with 4.310 bore. Ran it for years,was in top alcohol cars.Heck was kind of standard issue back then 4.310 x 4.500 .
     
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  8. Nitro Madness

    Nitro Madness Super Comp

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    Yeah.....that's why I picked that bore and stroke combo - very popular with TAFC....I was running 20% Nitro and that might have been the cause of the skirt collapsing issue....
     
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