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Hodgepodge V6 - Question

Discussion in 'Early CJ5 and CJ6 Tech' started by Oldpappy, Apr 19, 2021.

  1. Apr 19, 2021
    Oldpappy

    Oldpappy Member 2021 Sponsor

    East Tennessee
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    What I seem to have is a 225 block, heads, and single bore intake with a later model 231 crankshaft, and a Delco Remy points distributor. I want to use something other than the Rochester BC, preferably a 2G or maybe a Holly/Motorcraft 2100 series carburetor, so need to find a manifold that will work for that.

    I have already spent $750 on machine work having the block bored, the crankshaft turned, the heads and rods reconditioned. So, I want to build it right.

    Should I go ahead and use the 231 crankshaft that was in it, or look for an odd fire crankshaft?

    It was running with that crankshaft which I have already invested in having it turned, so I am thinking it will work okay, but before I have the heavy Jeep flywheel balanced for the even fire crank I would appreciate any advice as I am a bit green on these Buick engines.
     
  2. Apr 19, 2021
    oldtime

    oldtime oldtime

    St. Charles,...
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    Besides the early single bore Jeep used a couple slightly different dual bore Dauntless manifolds.
    I prefer the various taps and fittings on this one:
    [​IMG]
     
  3. Apr 19, 2021
    Fireball

    Fireball Well-Known Member 2021 Sponsor 2020 Sponsor

    Pullman, WA
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    It's probably possible to use the even fire crank in a 225. At the very least, you'll have to use an even fire camshaft and an even fire distributor (only HEI from the factory). Otherwise your valve events and spark timing won't match the crankshaft for half the cylinders. You may also need to use even fire 231 connecting rods as they're probably narrower at the big end to make room for the crank pin offsets.

    It seems better to find a 225 crankshaft or a complete even fire 231 so you know it all works together.

    For more explanation, an even fire crankshaft brings a piston to top dead center every 120 degrees of crankshaft location. The odd-fire 225 and 231 bring pistons to top dead center on 150, 90, 150, 90, 150, 90 degree intervals. The valves have to open and the spark needs to fire on these intervals. Hence needing the matching cam and distributor. The engine will probably run with the wrong parts match, but one cylinder bank will have the timing way off and cause issues. Folks on this list have problems with this fairly often when installing a distributor and getting the orientation wrong so it's firing on the opposite intervals. One cylinder bank runs great and the other is way retarded and runs really hot. Of course power is way down.

    To verify you have an even fire crank, look at the rod journals. An even fire crank will have offset journals like this:
    [​IMG]

    While an odd-fire will have mated journals like a V8:
    [​IMG]

    It's also good you have the 225 heads to go with the 225 block. The oiling of the valvetrain changed between the 225 and the 231(both odd and even fire). 225s have a pressurized oil passage that supplies oil to the inside of the rocker shaft. The shaft has orifices to bleed oil out to the rocker pivots. 231s supplies oil through the lifters, up through hollow pushrods, and through an orifice at the top of the rocker. You can most likely put 231 heads on a 225 if you also do the change the lifters and pushrods but you can't put 225 heads on a 231 because there is no oil passage in the block to feed the heads.
     
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  4. Apr 19, 2021
    oldtime

    oldtime oldtime

    St. Charles,...
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    Yeah and beyond an hei I have no idea what DR points distributor would work on an even fire Buick v-6 because neither Buick nor Jeep ever used one.
     
    Fireball likes this.
  5. Apr 19, 2021
    Oldpappy

    Oldpappy Member 2021 Sponsor

    East Tennessee
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    Aha! As is often said "a picture is worth a thousand words".

    My crankshaft is like the one in your second picture which you labeled as being for the odd-fire.

    When I took the engine to the machine shop I thought it was an odd fire V6. My confusion comes from the machinist telling me the crankshaft was not the odd-fire. He described the one for the odd-fire as being like your first picture with the offset pairs of journals. So, apparently he had the two confused, and passed that confusion on to me. Now I will have to take a closer look at the distributor I have, which should also be for an odd-fire. It was missing the cap or I would have spotted that right away.

    I know the history of the Jeep going back to 1977 which made it seem very unlikely the engine had been built the way I was led to believe by what the machinist told me.

    Mystery solved, this explains a lot.

    I am actually pleased to find out I was wrong about this being an even fire, which didn't make good sense to me. I like the rumble of the old odd fire, and now I don't have to have the flywheel re-balanced.

    Thanks guys.

    I have built many engines, mainly Chevy and Ford small block V8s, VW air-cooled (built dozens of those), and a few other engines but this is my first time with one of these so I am sure I will need some guidance.
     
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  6. Apr 19, 2021
    Fireball

    Fireball Well-Known Member 2021 Sponsor 2020 Sponsor

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    Sounds like the shop is confused and you have a vanilla even fire 225. Which is a great thing to have! The points distributor makes sense in that case.
     
  7. Apr 19, 2021
    Oldpappy

    Oldpappy Member 2021 Sponsor

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    Yes, I am convinced now about that.

    I had a M38 30 years ago which had been converted to the V6 (225 odd-fire) and I sure did like that little engine. It had plenty of torque and was great on the mild trails I drove the Jeep on. I liked the way it sounded too. I remember having a time figuring out how to get the timing set right on it, which is why I said I would have recognized the distributor on this one had it still had a cap on it.

    Do they make an electronic distributor for the 225 ?
     
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  8. Apr 19, 2021
    Fireball

    Fireball Well-Known Member 2021 Sponsor 2020 Sponsor

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    There are several options:
    • If you have a Delco points distributor, you can do a Pertronix conversion and keep the stock look. They don't make a kit for the Prestolite distributors though: PerTronix 1165 Ignitor Delco 6 cyl Odd Fire
    • You can get a remanufactured HEI distributor for a 75-76 Buick 231 odd fire like this: More Information for ACDELCO 88864758. You'll need a cap/rotor, coil, and wires to go with it. Due to the larger diameter base you need to grind down the front left corner of the intake manifold and use a button head bolt in that position.
    • You can buy a newly manufactured HEI distributor. Cheap Chinese ones are best avoided. DUI make quality ones, but they aren't cheap: Buick DUI Distributors – Performance Distributors. They even make a 1" extended one so you don't need to grind the intake manifold but that comes at a silly $120 premium over their already expensive standard unit.
     
  9. Apr 19, 2021
    Oldpappy

    Oldpappy Member 2021 Sponsor

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    It is the Delco distributor. I don't have any problems maintaining a points distributor but it seems getting quality parts is becoming more difficult. I tried 3 sets of new points and condensers on the F134 in one of my Jeeps before I got a good condenser and I am not overly confident in that one. Doing the electronic conversion using the Pertronix Ignitor sounds like a good option to me.
     
  10. Apr 19, 2021
    timgr

    timgr Eppur si muove. 2021 Sponsor 2020 Sponsor

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    I would point out - this all happens because the 225 is a 45 degree V engine. If the banks were 60 degrees apart, it would be even fire.

    I guess it's easier to make a crank with the paired journals separated by 15 degrees, than to design a block at 60 degree separation. Perhaps the V6s are slaves to the tooling of the V8 engine production line, which dictates the 45 degree separation of the V8 blocks. Supposedly the 231 displacement came about because Buick unified the 231 bore with the 350 to conserve tooling, with the 350 bore being 0.050" larger than the 225.
     
    Last edited: Apr 19, 2021
  11. Apr 19, 2021
    Fireball

    Fireball Well-Known Member 2021 Sponsor 2020 Sponsor

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    You mean 90 degree bank angle. I'm sure you're right the original 198 V6 was 90 degrees to use the same tooling as the 215 V8 when they were initially put into production (also front accessories).

    Most production V6s have a 60 degree bank angle unless they were derived from an exiting V8. The Ford 3.8, Chevy 4.3, and Buick V6 being V8 derived examples. The European PRV engine is the only 90 degree V6 I can think of that didn't start from an existing V8. Lord only knows why that did that. Maybe for lower hood heights?

    ...Then there is weird stuff like the VW 15 degree bank angle VR6 with a single cylinder head over both banks.....
     
  12. Apr 19, 2021
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

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    They sound soooo good
     
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  13. Apr 19, 2021
    timgr

    timgr Eppur si muove. 2021 Sponsor 2020 Sponsor

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    Yes, 90 degrees. Doh.
     

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