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225 Oddfire Pistons

Discussion in 'Early CJ5 and CJ6 Tech' started by EDDY ARNOLD, Apr 20, 2022.

  1. Apr 20, 2022
    EDDY ARNOLD

    EDDY ARNOLD Member

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    Is there a reason that oddfire have heavy full skirt pistons? I know the evenfire has one bank offset so thrust could be the reason? Any manufacture make lighter or forged pistons like later 231?
    Thanks
     
  2. Apr 20, 2022
    jeepdaddy2000

    jeepdaddy2000 Member

    Eagle Point oregon
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    Kenne Bell used to manufacture a complete line of Buick aftermarket items. Might contact them to see if they have anything gathering dust in the warehouse.
    I believe the Buick 350 pistons will work. Double check but there may be some options there.

    Remember, the 225 oddfire uses a massive flywheel that pretty much negates rapid spool up. You may be better off looking for a lighter aluminum flywheel.
     
  3. Apr 20, 2022
    Jw60

    Jw60 WRPD855 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    A lot of the engines of the time had the heavy skirt like the ladies of the day. Some of it acts as a bearing surface and also helps cool the piston.

    Most 4.3's have the heavier offering of the 350's piston lineup, until the balance shaft made them incompatible. The 4.3 was not the performance choice (omit the cyclone, typhoon, and performance boats) the normal automotive 4.3 was in full size trucks, cars, vans as a value option and got the heavy duty pistons since it would need to do more work per cubic inch all the time.
    Interestingly the 4.3 and 454 use the same heavy flywheel. (Or at least mine does)

    If you change the piston weight On a 90deg v6 It's going to be a mess at the balance shop since most of that skill has passed. I wouldn't jump from a stock flywheel to aluminum. Maybe a lighter steel one but not aluminum with an oddfire, it's massive for a few reasons.
     
  4. Apr 20, 2022
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor 2021 Sponsor

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    "You may be better off looking for a lighter aluminum flywheel."

    This depends on what you want out of a Jeep. I like the heavy flywheel on one of these engines, it dampens the roughness of the engine design, and works better for low end crawling power.
     
    fhoehle and Beach66Bum like this.
  5. Apr 21, 2022
    jeepdaddy2000

    jeepdaddy2000 Member

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    I agree.
    The question of lighter pistons begs the goal of a quicker reving engine, which is why I went with that suggestion.
     
  6. Apr 21, 2022
    Keys5a

    Keys5a Sponsor

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    I’ve built a 225 using standard 231 cast pistons, requiring the block to be bored to accept them. I think they also were slightly less dish, raising the compression a little.
    -Donny
     
  7. Apr 21, 2022
    EDDY ARNOLD

    EDDY ARNOLD Member

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    I guess you went 0.050 over and used oddfire 231 pistons? My understanding is evenfire pistons are offset. Just thinking about possible performance options of which are few and far between heavy flywheel and limited pistons. Not to mention stock oddfire heads.
    I have set turbo evenfire 231 heads but not sure effort to build 231 evenfire would be worth it.
    Thanks for all the advice.
     
  8. Apr 21, 2022
    jeepdaddy2000

    jeepdaddy2000 Member

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    There is an HP book "how to hot rod your V6". I lent mine out and never saw it again.
    It covered a number of V6's including the Buicks and featured a TON of performance parts offered at that time. If you are still thinking about working on your engine, you might try purchasing the book and perusing it to glean various parts and their manufactures. From there you may be able to contact them and see if there are any such parts collecting dust on a shelf somewhere.
     
  9. Apr 21, 2022
    zinertia2

    zinertia2 "and which part are you keeping?" 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    TA Performance in Scottsdale AZ may have some or be able to produce forged pistons
    Dennis
     
  10. Apr 21, 2022
    maurywhurt

    maurywhurt Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    My Dauntless likewise has 231 pistons. The only issue was that the 225 block had to be decked around 0.1" or so in order to use them.
     
  11. Apr 22, 2022
    duffer

    duffer Rodent Power

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    Only $$$, but any of the performance piston manufactures will make just about any piston you want for probably about $100-150 each. TA Performance would be the first place I would look for an off-the-shelf version.

    And yes, one should rebalance the engine but that is something I always do anyway. There are lots of machine shops that still balance engines. There is no way I would go with a lighter flywheel on the 225 if you still want some bottom end use and definitely not to aluminum. You can probably get a steel flywheel at less than half the weight of the stock version if you are going for rpms.
     
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  12. Apr 22, 2022
    Warloch

    Warloch Did you say Flattie??? Staff Member

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    I've got a 231 OF steel flywheel that is @ half the weight of the 225s. It was on a setup with a Saginaw car 4 speed and setup for RPMs. They are out there, but hard to find outside of the TA Performance now days.
     
  13. Apr 22, 2022
    EDDY ARNOLD

    EDDY ARNOLD Member

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    Maury decking for compression or proper squish?
     
  14. Apr 22, 2022
    maurywhurt

    maurywhurt Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    The block was decked because the new Sealed Power 231 pistons turned out to be approx. 0.1 inch lower, or "shorter", at TDC than the original 225 pistons were. The 231 crankshaft the Sealed Power pistons were intended for may have had a slightly longer stroke than the 225 crankshaft. I'm not sure if the pistons used were for an odd- or an even-fire 231 (or if the pistons between the two versions are different).

    The final compression ratio in my rebuilt engine was calculated as 9.18 : 1.
     
    Last edited: Apr 22, 2022
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