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Technical Chevy 327 crankshaft question can not find a flywheel that fits! HELP!!!!

Discussion in 'Traditional Hot Rods' started by Bryan Andrews, Jun 13, 2021.

  1. Bryan Andrews
    Joined: Jun 13, 2021
    Posts: 7

    Bryan Andrews

    So I bought a shortblock. Everything was going well. Built everything put her together and then go to put the flywheel on... doesn't fit. Tried other flywheels they don't fit either. It's like the bolt holes are just ever so slightly off a 16th to an 8th of an inch. The from my little knowledge and research the crank I have in it currently is a small journal 327 crank. Gm 4577 based on the 2 notch flange it assume it was a 65-67 forged crank. (I'm no guru so I could be wrong.) To my understanding any early sbc flywheel should fit, yet here we are. Even tried a later model truck flywheel. Nothing will work. I am lost and no one I know can seem to give me any help, so I'm hoping for some old knowledge here. Wtf is going on? I just want my car to run again.
     
    Deuces likes this.
  2. Roothawg
    Joined: Mar 14, 2001
    Posts: 21,617

    Roothawg
    Member

    The are all the same, to my knowledge. That’s odd. I’ll be following this to see the conclusion.

    @squirrel, front desk please.
     
    Last edited: Jun 13, 2021
    1949*john, 31hotrodguy and Deuces like this.
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 49,263

    squirrel
    Member

    pictures? Of the crank and the flywheel.
     
  4. Bryan Andrews
    Joined: Jun 13, 2021
    Posts: 7

    Bryan Andrews

    Can do... gimme 2 mins
     
    31hotrodguy and Deuces like this.

  5. Bryan Andrews
    Joined: Jun 13, 2021
    Posts: 7

    Bryan Andrews

    20210613_095821.jpg 20210613_095836.jpg
     

    Attached Files:

    loudbang and 31hotrodguy like this.
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 49,263

    squirrel
    Member

    you don't have any old Chevy flywheels or flexplates laying around to try on the crank, do you?

    I'd suspect that imported new flywheel....
     
  7. SS327
    Joined: Sep 11, 2017
    Posts: 292

    SS327

    It may sound stupid,but have you tried rotating the flywheel to the next spot to see if that helps bolt alignment.
     
    probird, Joe Travers, Deuces and 3 others like this.
  8. Bryan Andrews
    Joined: Jun 13, 2021
    Posts: 7

    Bryan Andrews

    I have the one off the 68' 350 that was in it. Had the same issue. And yes I agree that flywheel is shit but I've been just playing guess and check.
     
  9. Bryan Andrews
    Joined: Jun 13, 2021
    Posts: 7

    Bryan Andrews

    Yeah, no such luck
     
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 49,263

    squirrel
    Member

    Huh. I don't know what could be wrong.
     
    31hotrodguy and 1Nimrod like this.
  11. Oilguy
    Joined: Jun 28, 2011
    Posts: 533

    Oilguy
    Member

    Do you have a buddy who could drop by another flywheel or flexplate and see if that will fit? The crank flange and casting number all look good and correct. Weird!
     
    Deuces likes this.
  12. OK we got photo's thanks to Jim asking. Can you supply us with measurements of both crank flange and flywheel?
     
    1Nimrod likes this.
  13. landseaandair
    Joined: Feb 23, 2009
    Posts: 4,470

    landseaandair
    Member
    from phoenix

    Bizarre, I've had a bunch of small journal motors and any two piece seal flywheel should bolt up to it. Is it the diameter or an odd spacing on the pattern?
     
  14. "Determine the flywheel-flange bolt pattern. These are the bolt holes found around the center of the flywheel. According to GM Parts Direct, 1955 to 1985 small-block Chevrolet flywheels have a 3.58-inch bolt pattern, whereas 1986 and later flywheels have a 3-inch bolt pattern. Determine the bolt pattern by measuring the distance between the bolt holes. Some 350 cubic-inch and smaller engine-flywheels have bolt holes to accommodate both patterns"
     
    1Nimrod likes this.
  15. B.A.KING
    Joined: Apr 6, 2005
    Posts: 3,756

    B.A.KING
    Member

    Could someone broke or stripped hole in crank and weld up and drilled it wrong? I've never heard this one before??
     
    1949*john likes this.
  16. 97
    Joined: May 18, 2005
    Posts: 1,909

    97
    Member

  17. Are you sure the 350 is a '68? Any chance it is a later one-piece seal block IN a 1968 vehicle?

    If the "68 350" isn't actually an earlier engine and you matched that pattern to the new flywheel ....

    Got a part number off the new flywheel? (which may mean nothing if they packaged it wrong).
     
    Johnny Gee likes this.
  18. Well,,,,,it’s obvious from looking at the flange,,,,,it has had a flywheel bolted on before.
    So,,,,it can’t be the crank.
    Yes,,,it looks like a small journal crank flange,,,,,so,,,,that means any old model two piece rear main seal flywheel should fit .

    Are you trying to bolt it on with the engine still mounted to the engine stand ?

    The crank has the hole for the alignment dowel,,,,so it is pretty obvious where to mount the pattern on the flywheel.
    Have you tried starting the bolts without the flywheel,,,,,it wouldn’t be the first time the incorrect bolts had been tried ?
    Believe me,,,,it’s easy to get mixed up on starting a bolt pattern .

    Let us know what happens please .

    Tommy
     
    Deuces likes this.
  19. Bob Lowry
    Joined: Jan 19, 2020
    Posts: 611

    Bob Lowry

  20. Budget36
    Joined: Nov 29, 2014
    Posts: 6,711

    Budget36
    Member

    From my view it appears the dowel in the crank is not there.
     
  21. Double and triple check this ^
     
  22. gary macdonald
    Joined: Jan 18, 2021
    Posts: 108

    gary macdonald
    Member

    Have you fixed it yet ? Ill go out and take a pic of the same forging crank.
    Ive never had an issue, nor do I think the crank has been messed with .
    Your engine looks typical small journal sbc . Small rod nuts , oil filter adapter etc .
    Let me know if you want a pic of the crank end .
    Gary MacDonald
     
    Deuces likes this.
  23. I'd be interested to know if he's trying to install it on the engine stand ... I don't think there is enough room for flywheel install.

    I'd say the flywheel is wrong yet he claims one from a '68 350 won't fit either so .... sumpin' ain't right here.
     
    Last edited: Jun 13, 2021
    Deuces and Desoto291Hemi like this.
  24. 31Apickup
    Joined: Nov 8, 2005
    Posts: 2,693

    31Apickup
    ALLIANCE MEMBER

    As ss327 stated you need to rotate it around until it lines up. Here’s my small journal 327, the end of crank, where only one or so bolts line up then rotated around until all line up.
     

    Attached Files:

  25. squirrel
    Joined: Sep 23, 2004
    Posts: 49,263

    squirrel
    Member

    It never occurred to me that someone would try to install the flywheel without aligning the dowel hole...I always do...but then I guess I'm weird.
     
    mctim64, 19Eddy30, alanp561 and 9 others like this.
  26. jimmy six
    Joined: Mar 21, 2006
    Posts: 9,452

    jimmy six
    Member

    GMC 6’s are the same with no dowels. One way but I have a crank where the assembler got 5 in right and 1 with a big impact. I’m sure there are thousands of stories others here on the HAMB can tell.
     
    Wanderlust likes this.
  27. chasracer
    Joined: Dec 18, 2015
    Posts: 12

    chasracer

    You have to align the dowel hole to get any of them lined up correctly. You don't have to have a dowel pin.
     
    Mr48chev, '34 Ratrod and Deuces like this.
  28. Roothawg
    Joined: Mar 14, 2001
    Posts: 21,617

    Roothawg
    Member

    So what happened?
     
  29. 1971BB427
    Joined: Mar 6, 2010
    Posts: 6,899

    1971BB427
    Member
    from Oregon

    Early two piece main seals didn't use the dowel. Which makes me wonder about the flywheel shown, as it's got the extra hole for a dowel that it shouldn't have? But maybe it's just the way they're made?
    Since the one piece main seals engines had an externally balanced flywheel, they needed a dowel pin to clock them correctly. The two piece main flywheel can go on any direction and work.
     
    Budget36 likes this.
  30. 26Troadster
    Joined: Nov 20, 2010
    Posts: 627

    26Troadster
    Member
    from Texas

    i know i'm late to the party, but i don't believe i have ever seen a flywheel that looks like that one. all of mine the face covers the whole side then all you can see are the teeth on the starter ring.. i that one for something like a chevy II?
     

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