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Buick 225 And 231 V6 Parts Interchangeability. Frankenstein V6 Build

Discussion in 'Early CJ5 and CJ6 Tech' started by AyWoSch Motors, Mar 17, 2023.

  1. Mar 17, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

    Las Vegas, New...
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    So i recently i bought a package deal of a 52 willys wagon, a mystery CJ5 chassis, 4 buick 231ci V6s, a dauntless 225, 2 superhurricane 226, and a F134 Hurricane, 5 transmissions, 3 transfer cases, set of axles, rims, and a ton of parts. Traded my 75 C30 chevy for it.

    Anyway....
    Out of those 5 V6s, i picked the best one as my base for a rebuild. The one i picked is a 1979 -231 block out of a Regal.
    Block is healthy. I deep cleaned it, honed the cylinders and lifter bores, polished the bearing journals, and painted the block. Its ready to assemble. Now out of all the extra parts I have, ive picked the best of each. Now im down to picking a crank and cam.
    I have one good oddfire crank, and one good even fire crank, and about 3 good cams, but i don't know which one goes to which engine.

    My biggest issue that determines what parts i use is which cam is for even fire and which cam is for oddfire.
    That will determine what crank i use, and what bearing kit i have to by.
    Is there any way to tell them apart, by style or part number?

    No i know the 225 have a different size journal bore, so inlimintates that one. So really i just need to know if the remaining cams i have are 75 to 77 oddfire 231, or the 77 to 87 even fire 231.
    Someone told me that the cam with the removable fuel pump lobe and distributor gear are the older 75 to 77 ones, but i cant seem to corroborate that anywhere.

    I dont really care which crank/cam i use. Im more used to the evenfire, but a friend told me, for just putting around the ranch low RPM that the oddfire might be better.

    Also, it being a 79, it would have been an even fire engine. Will a oddfire fit and work with no issue if i go that way?

    Anyone have any insight on which might be better?
    Anyone have anyway to tell cams apart? Parts numbers i can check?

    I was shown to this site, specifically about this question. Was told there were many members here more suited to answering this.
    Have done some searching first, this site included, and found some good thoughts and ideas, but nothing specifically that helps my situation.

    Thank you..
     
  2. Mar 17, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

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    One thing i wanted to add that I found funny, is that all those blocks had mix matched parts. The 1967 225 and the 1977 231 both had evenfire cranks, and the 2 1979 blocks and the 1987 block had oddfire cranks in them. They all looked like they ran at some point like that.
    Seemed completely backwards from what they should've been oringally, as far as my research could tell.
    So that means there is some interchangeability between different the years, weather it be a good thing or not.
     
  3. Mar 17, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

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    A few pics of my build so far... Resized_Resized_20220821_130620(1).jpeg Screenshot_20230317-000244_Gallery.jpg Screenshot_20230317-000239_Gallery.jpg Screenshot_20230317-000226_Gallery.jpg Screenshot_20230317-000257_Gallery.jpg Screenshot_20230317-000305_Gallery.jpg
     
  4. Mar 17, 2023
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

    USA
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    from my POV you have 2 directions. Odd fire 225 has a bunch of weirdness thats cool and generally makes more HP than the even fire stuff or even fire stuff that is a lot easier to FI. As far as interchange between them, these guys can fill you in. I did a direct interchange between a 225 odd fire and a 4.3 FI chevy. Direct swap.. not.
     
  5. Mar 17, 2023
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    It seems odd that potentially all four blocks would have the wrong crankshafts. Are you sure?

    The 225s and odd-fire 231s though early 1977 would have crankshafts that look like this with connecting rod journals sharing a common pin:
    [​IMG]

    Late '77 and up even fire cranks will have offset pins like this:
    [​IMG]

    From stuff I've read in the past, the change to a one-piece camshaft happened mid-production in 1977 with the very last of the odd-fire cams having the cast on distributor gear. Any cams with removable gears should be odd fire. 99.9 percent of cams with a cast in gear will be even fire.

    Also note when you are swapping parts the engines are balanced differently. You need to use an odd-fire damper and flywheel along with the crankshaft. Same with even fire. An odd fire flywheel will bolt on to an even fire but you'll need to take it to a shop get it balanced to match the even fire crankshaft.
     
    Last edited: Mar 17, 2023
  6. Mar 17, 2023
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    The even and odd fire rods do not interchange. It is feasible to build an odd fire 231 in an even fire 231 block using the odd fire rotsting assembly.
    Personally I would use either the 225 or even fire 231. The 75-77 231 oddfires are getting expensive/ hard to source heads, rotating assemblies and cams for.
    The even fire is the easiest to fuel inject if that may be in your future.
     
    47v6, Stakebed and vtxtasy like this.
  7. Mar 17, 2023
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    What Fireball and RichM said. The 225 is cool but I always liked how my 231 with an RV style cam performed.
     
    Lockman likes this.
  8. Mar 17, 2023
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    It should also be noted that 231s and 225s oil the rocker arms differently.

    225s have a pressurized oil passages that feed oil up through the head into the rocker shafts. There are holes in the rocker shafts that oil the rocker pivots. It's critical that the rocker shafts are installed correctly to allow oil flow.

    All 231s, even or odd-fire, use the more standard method of hollow pushrods feeding oil up to the rocker arm. A hole in the tip of the rocker allows oil from the pushrod to run down to the pivot.

    You can use 231 heads on a 225 block as long as you also use the matching pushrods/lifters. Since there are no matching oil passages in the block, you can't use 225 heads on a 231 block.

    Following is 225 rocker shaft orientation information from this older thread: Dauntless Rocker Arm Oiling

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
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  9. Mar 18, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

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    Okay, so at first what you just said was really confusing, then i realized im having a stupid moment.
    See I've never messed with a V6 before, this is new territory. Ive rebuilt big block and small block V8s, straight 6, and 4 cylinder engines before, which are all naturally balanced engines and v8s share a commom rod pin. Im very used to seeing v8 crankshafts.
    I saw the odd offset looking crank, and assumed that meant oddfire, and saw my of so familiar shared pin crank, and assumed that was even.
    You taught me something new, i was being stupid. Explains why all my research seemed very confusing, and it Explains why all tye engines are set up the way they are.
    That actually answers all my questions, and makes for an easy decision.

    Thank you very much. Pictures are worth a thousand words somedays... especially when they come from someone who knows what they're talking about.
     
    Fireball likes this.
  10. Mar 18, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

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    So that means that all the parts put of my complete turbo 87 block, can go right in my 79 block no issues, and i cam buy a bearing kit for my proper year block. That works. Thanks.

    Also all the front accessory drive, balancer, and flywheel off my other 79 block will work perfectly too. Nice.
    Im happy.

    And the reason why im not using that 87 block, is that all though all the internals are healthy, and it was running, the block is cracked. 2 big splits up either side. Same with my complete 79 block, split up both sides. This 79 block im building, although it looked the worse, is actually really nice, and isnt cracked.
     
  11. Mar 18, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

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    And dont worry, i never planned on using anything out of that 225. Everything about it, looked horrible, its junk.

    If anyone wants it, let me know. Its a 67 jeep block. All there and complete. I have all the 225 specific parts. Water jacket is in good shape, not cracked. Has cracked cylinder. Would need to ne be machined amd sleeved, but still buildable, just not to me.
     
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  12. Mar 19, 2023
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Another small item of note. The water pumps are different length. The length difference may matter depending on your application. I had to swap a 225 water pump onto the 231 in my '69 to clear a thicker Champion radiator.

    The 231 water pump is about 3/4" longer than the 225 water pump. 231 left, 225 right:
    [​IMG]

    If you use the pulley that matches the water pump, the belts will line up with the crank pulley. 231 left, 225 right:
    [​IMG]
     
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  13. Mar 19, 2023
    AyWoSch Motors

    AyWoSch Motors New Member

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    Did not know that, thanks. Will keep in mind. I have 4 or 5 to pick from, so ill look for the right one.
    Its probably going to have a stock style cj2/L134 radiator in my 48 engine bay, but on a cj5 frame
     
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  14. Mar 29, 2023
    Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I'm Sending this along ..... so you can take a look for reference. The 231's were both known as the109 Block.... long & Short. The 231 even fires have a soft plug in the front of the DS head.
    I 've also got some various 231 even fire SFI turbo parts such as aluminum valve covers , fans, P.S pumps, pulleys, & other's that I'm willin' to let go , if interested.
     

    Attached Files:

  15. Mar 29, 2023
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I'll add here what I put in another thread:

    If your learning and possibly mix-matching these motors, get Pat Ganahl's V6 Book. It will point you in the right direction and clear all the little things up for you we may forget. Folks think the 231 and 225 are the same, but they are not. Can swap them out for each other, but internals and lots of little parts different - even the water pump cover changes how and where your timing goes.
     
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