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Chevy guys: Is my distributor shaft messed up?

Discussion in 'The Hokey Ass Message Board' started by tylercrawford, May 29, 2013.

  1. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    Wasted two hours of my life last night trying to get a vertex mag into a generic 350 (howards solid roller cam, bronze gear) and ended up in the same place I started and cracked the cap :mad:

    Feel stupid for even bringing this up but I am at my wit's end and is literally the last thing on the car.

    Tried lining the oil pump driveshaft up with the priming tool, marking the top of the rotor, and stabbing it in to no avail. Spun the motor over with a wrench on the crankshaft bolt, zero luck. Tried tapping on the cap with a rubber mallet, nothing except cracking the cap.

    The design seems to be awful. The oil pump driveshaft O.D. has got to be ~3/8" smaller diameter than the hole/boss in the block and allows it to move off-center 20-30*. Every time I got the mag down all the way to where it should engage the oil pump driveshaft and pulled it back out, the driveshaft had rotated ~20* about the centerline. Does the gear O.D. fit with the hole in the block to act as the bearing surface? Got to think that or I am missing a bushing in there.

    So I'm left with (I think) 3 options:

    1. Try another distributor. As a side note, is the engagement flat on the shaft messed up? Looks a little wore out like someone was beating the crap out of this thing (looked like this BEFORE I used the rubber mallet :p )
    [​IMG]

    Take off the gear, lightly touch up the flat that engages the oil pump driveshaft on the bench grinder/buffing wheel? If a new dist fits than I would assume that would lead to my vertex's shaft being the culprit. I did test fit the oil pump driveshaft on the bottom of the mag before putting it together and it did feel snug initially going on.

    2. Drop the oil pan and line up the driveshaft from the bottom. Really don't like this idea. Should work but there's no way I am doing that everytime I have to take the mag out. Would have to pull the starter/oil filter and I don't even know if the oil pan will come off inbetween the frame rails as the baffling/pickup are a hard fit (milodon 7qt dragster pan)

    3. Seems to be about half and half online about bumping the starter motor to get the thing to engage. Some people say they would never try any other way again while others say it can mess up the gear.

    or bribe someone with food/beverages and sitting in the dragster on warmup for having the magic touch?

    I really don't know how you chevy guys do it. Maybe the motor knows I'm a ford guy? :D I wouldn't have believed how much better ford's hex driveshaft makes things but I've never spent longer than 2-3 minutes getting a SBF distributor where I want it.
     
  2. Put the mallet down.

    Compare the end of the "new distributor that fits" to the one that don't.
    You might need calipers and micrometers not a mallet.
     
  3. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 3,646

    2OLD2FAST
    Member
    from illinois

    That dist. shaft is seriously fucked up. On to plan B.... get a replacement !!!

    dave
     
  4. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    That was the plan for today. Go by generic auto parts store on the way home from work, grab a stock dist and see if it fits.


    Highly likely :D

    I could only take about an hour of finessing it before obscenities started to appear and then suddenly a rubber mallet found its way into my hand. After I cracked the cap I just had to walk away before something got thrown. :D
     

  5. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    excellent. I knew the "flat" didn't look "fresh" which is why I stuck on the driveshaft outside of the motor before assembling it. It did hang up on the flat on the mag side like it had a burr but didn't take too much effort to "push past" the "burr" and then it slid on fine.
     
  6. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    Well, I think I got screwed on ebay.

    Mag came from a guy on ebay that said it was pulled from a "running" bbc in a tractor pull deal. When I got it, I saw the flat looked a little messed up and the plug wires were taped together per side which I know is a big no-no with the solid cores.

    Flat is off roughly 20* from the pin hole. Not sure how I got the driveshaft on originally as it will absolutely not fall into the female end on the driveshaft in the motor . . .

    [​IMG]

    [​IMG]

    Haven't talked to spud miller yet but I guess the distributor shaft can be replaced?
    Use a stocker and its good to go or I need a vertex specific one?
     
  7. Cardot60
    Joined: May 29, 2013
    Posts: 12

    Cardot60
    Member
    from Illinois

    Ah the oil pump drive has got to be the worst part of putting in a sbc distributor. I've noticed if you're using a reasonably heavy oil or it's cold that the oil pump drive will turn back from where you initially turned it. Glad you figured out the culprit, wish I could help more.
    Fun fact, GM later started using a hex on the oil pump drive with engines like the 2.8, 3.1, ect.
     
  8. Atwater Mike
    Joined: May 31, 2002
    Posts: 10,728

    Atwater Mike
    ALLIANCE MEMBER

    Welll...Not sure about that Scintilla Vertex shaft, but something had to take hold inside the mag to twist that tang...
    Disassembly and inspection is definitely on the menu.

    Likely a small part (magnet, or a screw, etc.) fell off and got jammed between the armature and the case...

    Hopefully, the shaft is a lower replacement...

    Bubba on this site is extremely qualified, and honest. If it can be easily repaired, he will advise the most efficient path.
    (Guess that would be the 'path of least resistance'!)
    Sorry, couldn't resist!
     
  9. You needed a bigger hammer to get that twisted SoB in.
    Looks like the oil pump must have jammed up or something jammed the rotor.
    Any nicks inside ?
     
  10. Glad you got it figured out!
     
  11. BJR
    Joined: Mar 11, 2005
    Posts: 7,251

    BJR
    Member

    It would have to be the oil pump that stuck. If it was the top of the mag stuck, the gear or pin hole would be screwed up. The part that twisted only drives the oil pump.
     
  12. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    Member
    from Wisconsin

    Did the seller at least send some rectal lube with it?
     
  13. Lobucrod
    Joined: Mar 22, 2006
    Posts: 4,122

    Lobucrod
    Alliance Vendor
    from Texas

    I had a BBC twist off like that. Wire keeper that holds the plunger in the lifter broke. Piece of wire made it way through the pickup screen into the oil pump locking it up.
     
  14. Story of my life.
     
  15. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,401

    GMC BUBBA
    Member

    I have a box of used vertex shafts in good condition.
    Could just send you one , however there is a couple issues.
    One is the vertex uses some special nuts that requires a special tool to take the bottom.
    Two if the unit has advance plates in the lower in it takes some special skills (practice) to install the replacement shaft....

    I agree that the ebayer probably had a oil pump failure to twist the shaft..........

    Glad to help in any way I can.......
     
  16. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    Oil pump/driveshaft are new.

    I bought the mag about a year and a half ago, opened the box when I got it, visually looked under the cap and noticed the funky marks on the flat and put it back in the box. About 3 months ago I sent it to FIE/spud to have him rebuild it with rare earth magnets/high output coil. Brand new engine otherwise.

    Nope, and the auction is too old for it to be listed in my feedback . . . I have 3 sellers who I think it is but none of them have been active in a couple of months. :mad: Not only the flat and the wires deal were junk but when spud got it it barely spit out anything and the capacitor (I think?) bolts or something was broke off down in the body.

    Unless its super easy to take apart, I'd just as soon have someone else do it. Never taken a distributor apart and would rather not have the first one be on something I've put a lot of time and money into. Also, I'm tired of getting zapped by the thing :D It's gotten me 3 times even with the ground wire on.
     
  17. harpo1313
    Joined: Jan 4, 2008
    Posts: 2,338

    harpo1313
    Member
    from wareham,ma

    I think tractor pull should of scared you away.send it out to get it squared away.
     
  18. Not your oil pump- the tractor pull oil pump or whatever the hell it was in before you got it.
     
  19. indyjps
    Joined: Feb 21, 2007
    Posts: 4,545

    indyjps
    Member

    Good thing it didn't drop in, you would have chased timing issues for a long damn time before checking the distributor shaft for twist
     
  20. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,401

    GMC BUBBA
    Member

    Its always cool to be a part of a happy ending.
    Tyler shipped the mag to use to change out the shaft etc on the mag lower end.
    Somedays its just that simple , this one wasnt ! The lower end not only had a bend drive tang for the oil pump but showed bushing and shaft wear on the lower bushing as well.
    Not usually a problem but when i dug out another chevrolet housing it was quite a bit shorter than the unit we had on the bench. OOPS looks like the big block mag came from a high deck engine !!
    A call to the customer and we agreed the easy way to fix cheaply was to use the good used chevrolet housing i had based on his engine being a small block chevrolet. Dont have the tach drive but a tach purchase can fix that part.
    Note the lower end off shows no advance plates for centrifigual advance will need to static time the engine and roll the engine with mag grounded and then turn on to start up.
    This seems to work ok even on the street.
     

    Attached Files:


  21. Yep looks like the oil pump drive doesn't mesh with the distributer shaft. Maybe a little time the the dremmel is in order.
     
  22. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    Thanks again Jim.

    Glad we got it sorted out!

    Really don't think the guy that listed it ran it. Or he was intentionally trying to deceive someone out there on ebay? No mention of a tall block in the listing not to mention "overlooking" the drive tab down there on the bottom.

    Oh well, another to add to the "ebay" thread I guess :D

    Thanks for the pictures as well . . . I've never taken one apart
     
  23. inliner2318
    Joined: May 9, 2008
    Posts: 335

    inliner2318
    Member

    I see...

    Your shaft bend to the right and it is too long.

    She must be particular. mine never complains. ;)
     
  24. Good gravy they will complain about almost anything !!!
    Anything except a guy who can lick his eyebrows.
     
  25. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    :eek:

    Wait, we're still talking mags right? :D
     
  26. black 62
    Joined: Jul 12, 2012
    Posts: 1,895

    black 62
    Member
    from arkansas

    happy ending...
     
  27. dickster27
    Joined: Feb 28, 2004
    Posts: 3,200

    dickster27
    Member
    from Texas

    Always a happy ending when Bubba comes to the rescue.
     
  28. On a side note.....Small Block Chevy news.
    Lotsa guys don't realize they should fit a bare distributor =all the way in= temporarily into the intake when installing a new intake manifold to insure it[manifold] has not slid one way or the other and gotten missaligned, therefore making the later install of your distributor very difficult at best....
     
  29. drptop70ss
    Joined: May 31, 2010
    Posts: 1,186

    drptop70ss
    Member
    from NY

    Well, maybe in this case, but not if you are in jail. ;)
     
  30. Rick Beil
    Joined: Oct 18, 2010
    Posts: 15

    Rick Beil
    Member

    Just a note about chevy's. You can drop the dist in the correct spot for timing the engine. If the dist does not drop all the way down you just hold down on the dist and have someone bump the starter. The dist will stay in time and drop into the oil pump shaft as it spins around. This work for sure I've done it. Keep clear of all moving parts and don't get shocked either.
     

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