Welcome to Our Community

Wanting to join the T-Bucket Forums discussions? Then sign up for a free forum account, today!

Sign Up

Ron Pope Motorsports                California Custom Roadsters               


Dismiss Notice
Thank you for visiting the T-Bucket Forums! This site was created in 2006, to provide enthusiasts with a place to discuss T-Buckets. Over the years, there have been many imitators, but this is the T-Bucket resource you have been looking to find. We encourage you to register a FREE account and join in on the discussions.

Drivetrain Angles... too much for the street?

Discussion in 'Engines and Drivelines' started by AltBantam, Oct 26, 2022.

  1. AltBantam

    AltBantam
    Expand Collapse
    Member

    Joined:
    Aug 12, 2022
    Messages:
    77
    Likes Received:
    63
    Gender:
    Male
    When I set the engine and transmission in place, I set the angle at 3 degrees. Did the same with the pinion. The u-joint angles came out to 1.8 degrees. So, I sat the body on the chassis this afternoon to make some measurements on the rear frame. When I walked around to the front, I realized the cowling was higher than the engine, a lot higher than I thought it would be. From the top of the intake manifold to the cowl is nearly 9 inches. And that is with a 1 inch spacer. I started to think I might need to raise the motor and transmission up 3 inches. It would look better and give me 3 extra inches between the frame rails and the headers, once I build them. But, if I raise the engine and transmission and keep the same 3 degrees, the u-joint angles will be over 9 degrees. My question, what is too much drivetrain angle to use on the street? The new angle of the driveshaft will increase from 4.8 degrees to approximately 12.8 degrees. That would mean I would need to set up a 10 degree drivetrain/pinion angle to end up with 2.8 degrees at the u-joints. At 5000 RPMs, the max angle for u-joints is around 3.25 degrees. Now, I measured the engine angles of several side view photos of actual alter dragsters from the 60's. The engines were angled from about 6 to 10 degrees, but they were not street cars. I feel 10 degrees would be pushing it. I know many inboard boats have engine angled close to 10 degrees when moving. I can replace the stock mid-sump oil pan with the rear sump oil pan to take care of the oiling pooling at the rear of the engine. Not sure about the manual trans. Another option is to lower the body over the frame 3 inches, but that causes problems with the fuel tank, rear tire clearance and seats. Or, just live with it. To bad no one makes a tunnel ram for BB Buicks. Any thoughts would be appreciated.
     
  2. 409T

    409T
    Expand Collapse
    Moderator
    Staff Member

    Joined:
    Jan 16, 2009
    Messages:
    1,800
    Likes Received:
    557
    Gender:
    Male
    Occupation:
    Retired
    I'm not going to go out and measure, but I'll bet the drive shaft angle of my lifted 4 x 4 truck is a whole lot more than 10 degrees, and it has been my daily driver for 19 years.
     
  3. AusBucket

    AusBucket
    Expand Collapse
    Active Member

    Joined:
    May 23, 2008
    Messages:
    417
    Likes Received:
    237
    Gender:
    Male
    Occupation:
    Photocopier Tech-Retired
    Out of phase U/J's contribute more to drive line vibrations than an extra couple of degrees ever did.
     
    lincolnuT and choppedtop like this.
  4. T-Test

    T-Test
    Expand Collapse
    Supporting Member
    Supporting Member

    Joined:
    Feb 6, 2009
    Messages:
    1,722
    Likes Received:
    932
    Gender:
    Male
    Occupation:
    Machinist/Welder/Mechanic
    Look up drive line post by me on this forum
    A u- joint has to have an angle for to work properly. Measure the angle that the input yoke to the driveshaft is when fully bent and won't move anymore. Any angle will work as long as the yoke doesn't hit the driveshaft.

    With your engine and transmission combo, you will have to make decisions as to looks, ride, drivability.
    Can't wait to see it finnished. Good luck.
     
    rbsWELDER likes this.
  5. T-Test

    T-Test
    Expand Collapse
    Supporting Member
    Supporting Member

    Joined:
    Feb 6, 2009
    Messages:
    1,722
    Likes Received:
    932
    Gender:
    Male
    Occupation:
    Machinist/Welder/Mechanic
     
    rbsWELDER likes this.
  6. AltBantam

    AltBantam
    Expand Collapse
    Member

    Joined:
    Aug 12, 2022
    Messages:
    77
    Likes Received:
    63
    Gender:
    Male
    Thanks for the posting, T-Test. I have read hundreds of posts over many different forums and it is surprising how much counter intuitive information is out there. Even among the 'professionals' there is not consistent terminology. I knew about the max RPM angles for u-joints as well as phasing. My first setup was just over 1 degree, to keep the u-joints working. The new setup will keep both angles at or below 1.56 degrees, on paper. Funny enough, I used two jack stands and 2x4 to simulate the driveshaft and the measured angles were close to the calculated angles. I may shim or adjust as needed once I actually mount the driveshaft. As for the difference in position, below is an image of the engine before, left side, and approximately the engine angle to the right. The right is more what I wanted so...

    Engine plus 3.png
     
  7. PotvinGuy

    PotvinGuy
    Expand Collapse
    Well-Known Member
    Staff Member

    Joined:
    Feb 22, 2008
    Messages:
    1,864
    Likes Received:
    781
    Gender:
    Male
    Occupation:
    Quantum Mechanic (semi-retired)
    I raised my motor and tranny 6 years ago after banging pans for years. And it looks better too. Here's some pics of the work: Big redo of the old bucket I made spacers of hardwood and then eventually found a metal tranny mount. The engine mounts still have the wood spacers and work fine. I didn't bother checking driveline angles, but with the engine/tranny and the rear end both still parallel to the frame the angles should be the same.
     

Share This Page







Advertise with Us! Advertise with Us! Advertise with Us!

SSL Certificate