Engine 1st Gen 81 mm bore

Discussion in 'Tuning and Performance' started by Whine not Walnuts, Sep 17, 2020.

  1. Whine not Walnuts

    Whine not Walnuts Active Member

    Mar 14, 2017
    waitin for my check
    Fuquay Varina, NC
    +287 / 0 / -0
    I have never chased the most horsepower but rather have been interested in alternative methods to get a little better performance. A long time ago this was called hot rodding. In this pursuit I came across an old thread about a 1.7 sleeveless piston kit. There were issues as due to core shift the coolant passages were not centered between the cylinder walls. The wall cracked on one of the kit engines and that was the end of it. There were attempts at larger bores with wet sleeves that also had issues so the alternative has been the 1.8 Stroker.

    I have a Thumper TPR2 head and I know he has built some Tritec engines over the years including a 1.8 sleeved engine where the owner supplied the pistons. With Gainesville and Daytona being in northern Florida there are some high performance engine shops. Thumper knows one of them that happened to build some Swamp Rat engines for Don Garlits. I asked Thumper to build me a 1.8 sleeved engine and he used 81 mm JE Pistons, K1 rods and high strength ductile iron, some call them steel, not cast iron sleeves. The cylinders were sonic tested and the final piston size was determined. Calculations were performed and I was told 23 to 24 psi of boost would not be an issue.

    I now have 350 miles on this TP-1,8 engine and still tweaking the tune. I have a M62 supercharger and with the increased displacement the boost dropped from 18 to 15.5 PSI. The cost of the engine with a core is $4250.

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  2. Thumper460

    Thumper460 Active Member

    May 26, 2009
    United States Navy ..Retired
    +97 / 0 / -0
    #2 Thumper460, Sep 17, 2020
    Last edited: Sep 17, 2020
    We ( Thumper Performance) just did what was needed for the 81 mm Big Bore Tritec engine. We decided to go to the Thin wall, super strong High Strength Ductile Iron Sleeves (While there is no large difference when it comes to tensile strength, ductile iron has the greater yield strength (40 ksi). Cast steel, on the other hand, can only reach 36 ksi yield strength. As the strength of ductile iron increases ductility decreases. Ductile iron has superior shock absorption to steel. ) .
    High Boost was one of the criteria ( whether used or not) We kept the stock steel Crank stroke and added in the H-beam K1 Connecting rods.
    JE made the custom Pistons, Pins and locks. They also provided the ring set for the 81 mm Forged Pistons.
    King Bearings with their Silicon-aluminum Performance Rod and Main Bearings.
    The engine was then blueprinted ( end gaps/piston clearance/bearing clearance/ Decked and trued the deck). We didn't do anything Trick, just good Performance Engine Building.

    Attached Files:

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