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Tech: Cheap and Easy 4-speed to Flathead V8

Discussion in 'The Hokey Ass Message Board' started by Artiki, Mar 6, 2010.

  1. Artiki
    Joined: Feb 17, 2004
    Posts: 2,013

    Artiki
    Member
    from Brum...

    Few years ago, I was looking for a decent 4-speed trans to go behind my banger. I owned an old Volvo Amazon at the time and had a spare gearbox, so using an AA bellhousing, me and a pal grafted one to the other with great success. The tech for that is here... The Volvo transmission is a great little unit, with 3.13 1st, 1.99 2nd, 1.33 3rd and 1-1 top, and synchro on all four speeds. It really livened my 90hp banger up, managing 17.3 @ 77mph on the quarter through 4.11 gears, and having the synchro is great.

    Well, I've recently gone over to the dark side and bought a flathead V8 to go in my T Touring, but I didn't want to go back to using a three-speed trans, and as I just happened to have another Volvo 'box lying around, it seemed the obvious thing to do. The method is almost identical to the banger, but we approached it slightly differently...

    First up, here's a pic of the trans...

    [​IMG]

    Then I needed to locate the right bellhousing, I believe from a '40s truck. (Are these the bellhousings that you guys are using to fit T5s? It's about 3" deep.)

    [​IMG]

    Part of what makes locating the Volvo trans easier than some is the round snout at the front.

    [​IMG]

    All that's needed to centre the round snout of the trans in the larger hole in the bellhousing is a ring spun up on a lathe. This is where I take a step back and shove my pal Spock into the spotlight. It's bloody handy to have a guy just down the road who can think out of the box. We spent a while looking through Spock's shed and stores for a piece of ali stock that we could spin up, but everything was too small. So, thinking on his feet, he drilled and sawed the end off a spare ali Volvo B/H...

    [​IMG]

    [​IMG]

    [​IMG]

    This was then tidied up a little with a hacksaw before going in the lathe. Before long, voila!...one locating ring and one centred gearbox.

    [​IMG]

    [​IMG]

    All that was left to do was drill and tap the bellhousing so that the trans would bolt to it using the original lug holes, then we could bolt it up to the V8 for a look.

    [​IMG]

    [​IMG]

    When I ran this trans on the banger, I redrilled the flywheel to take the Volvo clutch assembly, so I'll do the same here as there isn't enough room to run a V8 pressure plate. The V8 clutch fork will need modding to take the Volvo release bearing, but other than that, this doesn't need much else to make it work. The tip of the input shaft needs 10mm removing, and then a small bronze bush to take up the difference between the OD of the shaft and the ID of the pilot bearing. Since the last pic was taken, I've offered the block and trans into place, and it all lines up just as it did with the banger. Even the old driveshaft will bolt up!

    This particular transmission is known as the M40 unit, which is a four-speed. There was also an M41 which is essentially the same, but with a Laycock overdrive on the back. I've seen the M40 go for £5 (less than $10) on eBay, though the M41 go for a bit more. Like I say, cheap and easy.

    Just need to build the engine now...
     
    55willys likes this.
  2. Great stuff. Now to adapt it to a torque tube :)
    What year Volvo is that from?
     
  3. Artiki
    Joined: Feb 17, 2004
    Posts: 2,013

    Artiki
    Member
    from Brum...

    The Amazons were from the mid 60s, I believe. Mine was a '66. There was some debate as to whether it could be done, retrofitting a torque tube. We thought it possible, but my axle is open drive anyway (quick-change) so we didn't follow it up.
     
  4. Jimmy Tee
    Joined: May 29, 2009
    Posts: 582

    Jimmy Tee
    Member

    Great idea & Good work... Those 3 speed Box's were terrible on the Highway. You need all the help you can get out there these days.

    I've done a similar thing adapting a 5 Speed Toyota Box behind my 8BA Flathead. I'm now waiting to get the Locating Ring Machined before I drill out the Bellhousing for the Mounting Bolts. See my post below for further details
     

  5. fitzee
    Joined: Feb 26, 2003
    Posts: 2,862

    fitzee
    Member

    What a neat way of doing it.I say there is a lot of cool ideas from using non American car parts in hot rodding.cool post
     
  6. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    That's almost cheating, that is! ;)
     
  7. daddylama
    Joined: Feb 20, 2002
    Posts: 930

    daddylama
    Member

    bitchin'.... i've got a spare from a '69 volvo 142 sitting here in my garage.
    i've also got one in my O/T 60s volvo daily driver: abuse the shit out of that thing every day, behind a hot 4cyl with narry a complaint. stout transmissions...

    don't forget there's an overdrive available to stick on the back of that thing, too...


    edit:
    might mention that there are absolutely no metric parts in the trans... M40s were all good ol' SAE.
     
    Last edited: Mar 7, 2010
  8. Stefan T
    Joined: Sep 15, 2008
    Posts: 2,165

    Stefan T
    Member
    from Sweden

    I have a bmw box to my flathead that i have rewelded the bellhausing

    [​IMG]

    I think of use a volvo box but i the bmw is stronger and the new volvos boxes a diffrent spilinced than ford or chevy.

    The Volvo box M40/41 fits on a flathead clutch disc and the bmw (getrag 260) fit on a 10 spline chevy clutch disc

    The M40/41 are used to 1976 and last gear only M40 the late boxes have the sick moved backwards from aprox. 1972.
    The first M45/46 have same splince as M40/41
    There is Volvo boxes from P1800 called M400/410 that are stronger with same splice
    They are even used on 164 but they have maybe another splice to the cluthdisc (maybe chevy 10 splice)
    If the volvo box break the housing will crack and the oil will drain out

    /Stefan
     
  9. HotRodMicky
    Joined: Oct 14, 2001
    Posts: 1,783

    HotRodMicky
    Member

    Where are the pics?

    Now i see them
     
    Last edited: Mar 7, 2010
  10. gas pumper
    Joined: Aug 13, 2007
    Posts: 2,957

    gas pumper
    Member

    Great job. And it looks vintage, well, it really is vintage now.

    I use plumbing pipe flanges to machine large diameter rings. cheap source of large, sort of flat rounds.
     
  11. has a great vintage look
     
  12. lionsgarage
    Joined: Dec 18, 2005
    Posts: 111

    lionsgarage
    Member
    from Washington

    Stefan, can yuo put the early top on a later 4 speed? I was thinking of using a later unit with the laycock overdrive behing my flathead but want the shifter forward.
     
  13. daddylama
    Joined: Feb 20, 2002
    Posts: 930

    daddylama
    Member

    ^ the later 4spds have the extended/remote shifter... can put the early shifter on 'em... or the other way around.
    can also put an OD from a late trans on the early trans.

    the 4spd in my car is an early / forward shift, with the later rear shift top on it.

    put 30W synthetic motor oil in it, and it shifts smooooth...
     
  14. johnny bondo
    Joined: Aug 20, 2005
    Posts: 1,547

    johnny bondo
    Member
    from illinois

    the price of those transmissions just went from $20 to $200 lol!!
     
  15. They aren't that bad! Run a 31" tall tyre with 2:7's and they go fine on the open road. Just a bit sluggish to get going down low.

    As much as I like the idea of overdrive boxes, it's the shifter position I have trouble with.
     
  16. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    They actually did...no kidding.
     
  17. daddylama
    Joined: Feb 20, 2002
    Posts: 930

    daddylama
    Member

    just find a junked 140, particularly a 4 door (144) since they're less valuable... gets you the trans and a perfect steering box... then part it out to recoup your expenses. just the headlight surrounds bring ~$100 on ebay, pre '70 grill ~$200.

    the price has been creeping up the past few years on old volvo parts, in general.
     
  18. Stefan T
    Joined: Sep 15, 2008
    Posts: 2,165

    Stefan T
    Member
    from Sweden


    You can put a early top on a late box and a M40 top on a M41 box.

    /Stefan
     
  19. Ilari
    Joined: Oct 30, 2009
    Posts: 188

    Ilari
    Member

    Cool tip, I have 10 of these volvo boxes lying around. Anyway, did not see a 3-speed volvo box tip if someone wants to stick with with 3-speed. It's called m30 and it fits on place of 4-speed m40.
     
  20. WillemVelde
    Joined: Feb 1, 2018
    Posts: 25

    WillemVelde

    I know this is an old post but I can't see the pictures in the original post. Is this possible to recreate??
     
    johndee138 likes this.

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