Register now to get rid of these ads!

Featured Customs Do I offset the engine?

Discussion in 'The Hokey Ass Message Board' started by ahshoe, Jan 8, 2026 at 4:08 PM.

  1. ahshoe
    Joined: Sep 12, 2012
    Posts: 1,058

    ahshoe
    Member

    Building another frame, with a small block ford motor and an AOD trans for my 56 F100. The rear end I am using is offset 3” towards the right . A friend of mine said that I should also offset the motor that 3” to the right. Obviously the rear end at the U joint is lower than what the trans will be ….so he said you don’t want the driveshaft to both pitch down and because of the 3” side offset , also pitch to the right those 3”. I have not yet welded in any motor mounts yet and curious if I should do this?
     
    dana barlow and LOU WELLS like this.
  2. BJR
    Joined: Mar 11, 2005
    Posts: 11,383

    BJR
    Member

    Center the engine and you will be fine. The offset just makes the U joints work and not develop flat spots on the rollers.
     
  3. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,848

    Doublepumper
    Member
    from OR-WA, USA

    Not a problem. I've done several swaps with offset pinions and never moved anything. Important thing is to make sure the pinion angle is correct for the engine angle.
     
  4. Find another friend to get advice from
     
    MARKDTN, GuyW, slayer and 75 others like this.
  5. Hollywood-East
    Joined: Mar 13, 2008
    Posts: 2,167

    Hollywood-East
    Member

    For the Win $)
     
  6. proartguy
    Joined: Apr 13, 2009
    Posts: 832

    proartguy
    Member
    from Sparks, NV

    Probably as many ideas here as can be posted, but I bought a truck where there was that kind of off set and the first highway drive resulted in the rear seal in the trans giving out and the resulting trans fluid spill had major smoke from the heat. Granted, the truck was low geared with considerable driveshaft speed. With no way to move the engine over I elected to use a double carden front joint from a ‘60s Lincoln suggested by the driveline shop, which worked out well.

    Universals only like to accommodate one direction without problems. Adding another direction (sideways) only adds problems. I prefer to center the pinion to the output shaft by either offsetting the engine or modifying the rear axle.
     
  7. -Brent-
    Joined: Nov 20, 2006
    Posts: 7,867

    -Brent-
    Member

    Or just move him 3" away from the garage door... and then close it. Hahaha.
     
  8. DDDenny
    Joined: Feb 6, 2015
    Posts: 22,592

    DDDenny
    Member
    from oregon

  9. jimmy six
    Joined: Mar 21, 2006
    Posts: 17,172

    jimmy six
    ALLIANCE MEMBER

    You should fill the engine bay….. 5.0 Coyote, early Cammer Ford, Chrysler hemi….
     
    clem and seb fontana like this.
  10. twenty8
    Joined: Apr 8, 2021
    Posts: 3,753

    twenty8
    Member

    Millions....... no, wait......... probably BILLIONS of cars running around out there disagree with this statement.;)
     
    MARKDTN, slayer, 05snopro440 and 10 others like this.
  11. jaracer
    Joined: Oct 4, 2008
    Posts: 3,059

    jaracer
    ALLIANCE MEMBER

    As long as the engine is square in the ch***is and the rear end is also square, the angle at the rear end due to the offset pinion will be exactly the same as the angle at the back of the transmission. Since they are the same, they will cancel and not cause any vibration. Most rear wheel drive vehicle have the pinion off the center line of the vehicle. It does not cause any problem.
     
    Damon777, bschwoeble, KevKo and 3 others like this.
  12. tim troutman
    Joined: Aug 6, 2012
    Posts: 1,346

    tim troutman
    Member

    when I built my f1 pick up I used a 64 f100 9 inch which had 2 axles the same length setting it to the right. I set the engine to the right it made sense to clear the steering. When building the wife's 64 f100 I used a front frame section that had the motor centered with the same type 9 inch rear. from what I have read both work but you do not want to put the motor in at an angle to point it at the rear
     
    Tow Truck Tom likes this.
  13. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 14,432

    Johnny Gee
    Member
    from Downey, Ca

    Rotating 3D imaging will show only one angle, not two.
     
  14. 31 Coupe
    Joined: Feb 25, 2008
    Posts: 548

    31 Coupe
    Member

    Where were the original engine and transmission positioned. ????
    I'd ***ume that Ford had a good understanding of driveshaft geometry.
    All earlier F100 - 9" rear ends had offset pinions because they used equal length axles on both sides. That positioned the pinion ~2" off center.
     
    Last edited: Jan 8, 2026 at 5:55 PM
  15. I put a zillion miles on drive shafts with more than one angle
     
  16. Jeff34
    Joined: Jun 2, 2015
    Posts: 1,282

    Jeff34
    Member

  17. Lots of rods built with the center section “centered” for a uniform visual look.

    Dang crooked drive shafts
     
    gimpyshotrods and BJR like this.
  18. lostone
    Joined: Oct 13, 2013
    Posts: 3,638

    lostone
    Member
    from kansas

    There are millions of fords, car and trucks, that have been driven, used, abused, raced etc with offset pinions (9" uhm...) with no problems what so ever.

    U-joints don't see up, down, right, left, level plane, 90° degree plane etc. They only see 1 angle, doesn't matter where the housing sets, its still 1 plane to the u-joint....

    To you the housing nose may be 5° down, and offset 1" inch to the right, you see 2 planes, up/down-left/right but the u-joint doesn't. All it sees is 1 and that where the u-joint connects to the housing...


    ....
     
  19. oldiron 440
    Joined: Dec 12, 2018
    Posts: 4,089

    oldiron 440
    Member

    How to offset the engine?
    Try installing it centered, it will be off one way or the other.
     
  20. twenty8
    Joined: Apr 8, 2021
    Posts: 3,753

    twenty8
    Member

    Universal joints only ever have one angle applied to them at any given time. The pinion might be horizontally offset and vertically offset from the transmission output shaft, but in reality it is only ever a single constantly varying angle that the joint operates at. It is called a "compound angle", and as long as it is within the maximum recommended operating parameters, all will be ok.......:)
     
    Last edited: Jan 8, 2026 at 7:19 PM
  21. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 3,638

    Kerrynzl
    Member

    You need to think 2 dimensionally.
    The universals in what you describe are only accommodating one direction.

    If it was pointing down [eg: 3" ] AND pointing sideways [eg: 3"] It is technically only one angle at 45° from vertical
    [4.24" at 45°]

    I've done more than that! I've done a "****load" of miles :D
     
  22. 57Fury440
    Joined: Nov 2, 2020
    Posts: 570

    57Fury440
    Member

    A lot of Chrysler Corp. cars had their motors offset in the sixties and later.
     
    bschwoeble likes this.
  23. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 3,638

    Kerrynzl
    Member

    C3 Corvettes as well
    When they did RHD conversions on these, the firewall and tunnel was cut and shifted with the whole drivetrain to the left.

    @ahshoe I have just done a swap of a Ford Explorer 8.8 rear end into a 55 Chevy
    The 8.8 has the pinion offset 3.75" to the RH side [p***enger side] and there is Zero driveshaft issues.
     
  24. Toms Dogs
    Joined: Dec 16, 2005
    Posts: 1,144

    Toms Dogs
    Member
    from NJ

  25. willys36
    Joined: May 6, 2006
    Posts: 3,216

    willys36
    Member

    You could move the frame over 3". Or better yet, move the frame 1 1/2" and the engine 1 1/2".
    happy1.jpg
     
    TwistedMetal, clem and Kerrynzl like this.
  26. 69fury
    Joined: Feb 24, 2009
    Posts: 1,738

    69fury
    Member
    from Topeka

    Just tilt your head 45 degrees to the side and you'll see the same thing the ujoint sees. Since it rotates, there is only one angle and it's measured in "X" degrees from straight.

    Another way to visualize is to get 2 laser pointers, put one on the trans yoke and one on the pinion yoke, blow some baby powder or smoke in between to show the lines and observe the physical distance between the beams. That distance is where the angle comes from, not which line is left/right/higher/lower.

    -rick
     
  27. The offset will cause the ride to track crooked if you don’t change the thrust angle of the rear to compensate the offset. :)

    dog leg like an old ford truck with frame damage.


    (Sarcasm. This is BS)
     
    Last edited: Jan 9, 2026 at 9:42 AM
    05snopro440 and 427 sleeper like this.
  28. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,777

    theHIGHLANDER
    Member

    Pinion offset, isn't the actual measure considered as ½ for offset purposes? I bought a lot of axles and narrowed a **** ton (a bit less than a **** load) of housings, and a distant echo is telling me this truck offset is actually referred to a 1½". Feel free to correct my recollection. GMs were ½, Mopars were ¾, Fords were either/or, some ½ and some ¾. Be gentle with me, that was more than 30yrs ago:oops:
     
    427 sleeper likes this.
  29. whiteknuckle
    Joined: Feb 6, 2007
    Posts: 161

    whiteknuckle
    Member
    from Dryden, NY

    As a mechanical engineer retired from the auto industry I just love these posts. If you're going to be wrong, be aggressively wrong. Kudos to people that can view things in 3D.
     
  30. twenty8
    Joined: Apr 8, 2021
    Posts: 3,753

    twenty8
    Member

    Is it this one? If it is, it has nothing to do with engine/pinion offset.

     
    theHIGHLANDER and 69fury like this.

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.