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Drive Line Angles

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  • Flat Ernie
    replied
    Originally posted by bensherb View Post
    Why not? If everything is assembled properly, the engine/trans should be perpendicular to the pinion shaft. As long as the rear end alignment doesn't get messed up in an accident or something it should remain that way. A horizontal adjustment can be made, it just not as easy to do. .
    Parallel is the key. If the axis of the centerline from the crankshaft through the tailshaft is parallel to the centerline axis of the pinion, horizontally, offset does not matter. I probably wasn't clear - I wasn't referring to offset, I was referring to angles where the centerline of the crank is not parallel to the pinion horizontally. Vertically is simpler to address via shims...

    Originally posted by wittsend View Post
    Hummm..., lots of differences being stated here. From my studying on the subject I've found that:

    3. I'd be curious to know the reason the offsets only work in the vertical plane??? On my Sunbeam Tiger the drive shaft has an obvious offset horizontally. I'd think there is some logic that any horizontal offset should match and vertical offset angle.
    I wasn't clear - I'm not referring to offset horizontally, I'm talking about off-axis where the centerline of the output shaft is not parallel to the pinion.


    Originally posted by alpayed View Post
    Read my post #29 again and look at the pdf.
    Aussie Hawks ran broken back when looking from the side. they have 1-1/2" engine/transmission offset from the diff looking down. LHD cars had 1/2" offset.
    They were set up 5 deg down on the transmission and 6 deg down at the diff static. (sitting on 4 wheels, no passengers)
    With leaf sprung rear the angles will be all over the place. The diff pinion angle could vary +_3 deg from full power to backing of in low gear.
    At 70mph the diff would probably wind up 1 to 2 deg easily. The springs are long and offer little resistance to twisting.
    As a universal rotates the driven yolks will speed up and slow down twice every rotation. If you look at the graph on the RHS you will see amplitude or height of the sine wave represents the speed (angle A) of the uni joint. the greater the angle the higher the speed variation will be.
    In that diagram there is a blue trace representing the first yolk travel. The green trace representing the second yolk. The amplitude is the same height so the angles are the same and should cancel each other out.
    The problem here is that engine and transmission are offset which angularly shifts the blue and green trace apart by angle "B" and "C".
    To compensate for this Studebaker rotated the yolks on one end of the driveshaft by B+C deg.
    This puts the blue and green trace back on top of each other and the cancel. The amount of engine offset determines the amount of angular shift.
    Had they ran broken back in both planes they would have cancelled each other out. IE put the engine on an angle, front offset and transmission output central.
    In theory it would work but practically it is extremely difficult to align the angles exactly. I know because I tried it with the 60 Hawk.
    So if you ever wondered why there is a twist in the driveshaft yolks that is the explanation.
    [ATTACH]66349[/ATTACH]

    Allan
    That's why we match them with static loaded weight...

    With my engine mounts tight, and my 'transmission' mount (bellhousing) tight - I can move the tailshaft of the T5 a fair amount laterally/horizontally. This phenomenon existed with the stock 3 speed, but the additional length of the T5 exaggerates this movement. So if the 3-spd output shaft moved 1/4" (random number for illustration purposes), then the T5 output shaft would move 1/2" (another random number). This, coupled with the shorter overall length of the driveshaft means the angles are more severe and doubles the angles experienced - this is not horizontal offset, this is horizontal angular error.

    I'll just put the H joint in and see what happens when I swap the 8.8" in and let you all know.

    Leave a comment:


  • alpayed
    replied
    Read my post #29 again and look at the pdf.
    Aussie Hawks ran broken back when looking from the side. they have 1-1/2" engine/transmission offset from the diff looking down. LHD cars had 1/2" offset.
    They were set up 5 deg down on the transmission and 6 deg down at the diff static. (sitting on 4 wheels, no passengers)
    With leaf sprung rear the angles will be all over the place. The diff pinion angle could vary +_3 deg from full power to backing of in low gear.
    At 70mph the diff would probably wind up 1 to 2 deg easily. The springs are long and offer little resistance to twisting.
    As a universal rotates the driven yolks will speed up and slow down twice every rotation. If you look at the graph on the RHS you will see amplitude or height of the sine wave represents the speed (angle A) of the uni joint. the greater the angle the higher the speed variation will be.
    In that diagram there is a blue trace representing the first yolk travel. The green trace representing the second yolk. The amplitude is the same height so the angles are the same and should cancel each other out.
    The problem here is that engine and transmission are offset which angularly shifts the blue and green trace apart by angle "B" and "C".
    To compensate for this Studebaker rotated the yolks on one end of the driveshaft by B+C deg.
    This puts the blue and green trace back on top of each other and the cancel. The amount of engine offset determines the amount of angular shift.
    Had they ran broken back in both planes they would have cancelled each other out. IE put the engine on an angle, front offset and transmission output central.
    In theory it would work but practically it is extremely difficult to align the angles exactly. I know because I tried it with the 60 Hawk.
    So if you ever wondered why there is a twist in the driveshaft yolks that is the explanation.
    Drive shaft_fig3..pdf

    Allan

    Leave a comment:


  • 64studeavanti
    replied
    Back to Wayne's original post, according to the 62-64 shop manual. The front angle should be 4-5 degrees. The rear should be 1/2 degree higher. I assume this would be the same for all single shaft C/K. The procedure for checking front angle is to place gauge on driveshaft and set to 90 degees. Then measure from bottom of starter. The angle is number of degrees from 90. The rear is similar except that it is measured from the forward edge of the diff. In this case, the angle is the number of degrees from 180. Before measuring, the car should have the weight supported by all four wheels with the frame level.

    From this description, it would appear that both the engine and diff are pointing down.

    Leave a comment:


  • wittsend
    replied
    Hummm..., lots of differences being stated here. From my studying on the subject I've found that:

    1. Angles are necessary to cause the needle bearing in the U-joint to rotate. Otherwise the stresses are constantly in the same position and the needle bearings or surface they rotate on will soon flatten. It is likely why the needle bearings are so small to facilitate as much rotation as possible. Note too that the transmission shaft and pinion can be parallel but this doesn't mean they are 'in line" with each other.

    2. The trans, pinion angles need to match so the forces offset each other. As Joe Hall stated in post #38 those aspects are not static. My understanding is that under the broad term of "normal driving" - that would include spring wrap-up, you want equal, offsetting angles that are minimal to lessen shaft speed changes and sufficient to cause the needle bearing rotation. To achieve that the angles would not match in a static state. My guess would be that there are a lot of 'we'll just have to live with it' points in the suspension travel when the engineers deal with this.

    3. I'd be curious to know the reason the offsets only work in the vertical plane??? On my Sunbeam Tiger the drive shaft has an obvious offset horizontally. I'd think there is some logic that any horizontal offset should match and vertical offset angle.

    4. At nearly 40 posts I haven't gone back and read each, but my '64 Daytona came with a drive shaft where the shaft yokes were not indexed at equal angles. I don't think this has been mentioned yet. I've heard it was to deal with shaft vibrations. While my car rides and sounds like an old truck I have not noticed any (obvious) vibration using a standard 90 degree offset driveshaft that was pirated from a '78 Buick when I went to a 700R4 trans.

    I found this site very helpful when I was studying the "Diveshaftology." http://www.dennysdriveshaft.com/freq....html#faq_id25

    Leave a comment:


  • bensherb
    replied
    Originally posted by Flat Ernie View Post
    You are correct, if and only if, you can cancel the other end out by matching the angle at the driven end - that's the only way to keep the U-joint turning the driven side at a constant speed. We can do this in the vertical by shimming the rear to set pinion angle parallel to the transmission yoke. You cannot do this in the horizontal plane,
    Why not? If everything is assembled properly, the engine/trans should be perpendicular to the pinion shaft. As long as the rear end alignment doesn't get messed up in an accident or something it should remain that way. A horizontal adjustment can be made, it just not as easy to do.

    GM eliminated a driveline vibration in their Camero by running the driveshaft yokes out of phase, forcing the U joints to remain loaded.

    Leave a comment:


  • JoeHall
    replied
    Drive line angles are not static, but operate within a range. That range is limited by spring jounces, front and rear. The specific range of operation on any given day is influenced by several factors: amount of gas in tank, number of folks in car and their weight, cargo in trunk, HD or regular springs, type of shocks, etc..

    In light of the above, I do not believe there is a specific, must-have angle, when setting a car up with an alternate drive train. Matter of fact, what is optimal for one car may not be for another, mainly due to HD or regular springs, and condition of springs. Maybe that is why there are several sets of holes in the frame cross member to choose from, for mounting the carrier bearing in a 2-piece drive shaft equipped Stude

    Leave a comment:


  • Flat Ernie
    replied
    Originally posted by bensherb View Post
    A single drive shaft will work in both directions at the same time, that's not at all unusual. Just don't get crazy with the offsets. The same rules apply for horizontal as for vertical.
    You are correct, if and only if, you can cancel the other end out by matching the angle at the driven end - that's the only way to keep the U-joint turning the driven side at a constant speed. We can do this in the vertical by shimming the rear to set pinion angle parallel to the transmission yoke. You cannot do this in the horizontal plane, consequently, you will have varying speed at the driven end...and vibration, wear, and strain on the u-joint - it's the same effect as having improper phasing of the U-joints themselves. I believe a double U-joint with an H-yoke will cancel this and allow a constant driven speed and consequently, no vibration.

    A double U-joint will also correct improper angles, or extreme angles. Some offroad guys use this approach when doing extreme lifting of the chassis and end up with crazy driveshaft angles.

    Good video on angles:
    https://www.youtube.com/watch?v=DDmz0tibVGM

    I couldn't find a similar video on a double U-joint, but did find this animation:
    https://www.youtube.com/watch?v=m-RPmlcVIac
    Last edited by Flat Ernie; 08-19-2017, 07:03 AM.

    Leave a comment:


  • bensherb
    replied
    A single drive shaft will work in both directions at the same time, that's not at all unusual. Just don't get crazy with the offsets. The same rules apply for horizontal as for vertical.

    Leave a comment:


  • Flat Ernie
    replied
    When I did the T5 swap in my '53 C/K, I couldn't keep the two-piece drive shaft because the front part was too short and the angles ended up too severe and I had a LOT of vibration at low speeds. I converted to a one-piece drive shaft and now have the 70-75 vibe and it just gets worse.

    I think part of it is the engine mount setup (front mounts and bellhousing mount) and now longer transmission means the angles are a little exaggerated. I loosened all mounts and could move the tailshaft of the transmission back and forth in the tunnel a fair bit - I tried to get it perfectly centered (I have horizontal/lateral angle challenges in addition to vertical ones). I'm considering using a double U-joint with an H-yoke at the rear - has anyone considered this approach? It should cancel out the double angle speed-up/slow-down problem posed by a straight drive line or single drive shaft where you can't correct both angular errors with mounting...

    Was planning a '92 Ranger 8.8 axle swap in the future - thinking of doing it then, but was hoping to hear opinions

    Leave a comment:


  • Jerry Forrester
    replied
    Originally posted by alpayed View Post
    Here is a Ford bronco 5.0 in my 60 hawk. It would have been real easy with a carby. Look at the height of the intake manifold. It clears the hood by 3/4". No problem with bell crank clearance. Oil filter is in the original position no problems. starter is on the right side. Easy as pie.
    Yes I did convert it to a 2 piece shaft, even kept the footwells.
    I did shorten the sump as seen in the last pic. The Bronco sumps are at the rear with a long pickup and are bigger than a car. Still takes 7ltr. There is about 1" clear above nuts on top of bell crank. Oil filter can be seen on LHS.
    [ATTACH=CONFIG]66306[/ATTACH][ATTACH=CONFIG]66307[/ATTACH][ATTACH=CONFIG]66308[/ATTACH][ATTACH=CONFIG]66309[/ATTACH][ATTACH=CONFIG]66310[/ATTACH]
    Nice work Allen, super neat.
    The first pic looks like the engine is offset to the right much more than the 1/2" Stude engines were.
    I'm not saying there's anything wrong with that. I've offset engines as much two inches myself.
    In 1963 I built a '53 Champion Cp. with a Buick nailhead. The starter and pitman arm wanted to occupy the same space and I solved that problem by moving the engine to the right, About 2 inches if I remember correctly.

    Leave a comment:


  • 64studeavanti
    replied
    The 3/8" spacer is for automatic trans to clear the steering box. Manual trans have two 1/2" spacers on the studs under the rear mount so that they are between the cross member and the mount.

    Leave a comment:


  • jrlemke
    replied
    Isn't the spacer you are talking about in #30 used only on auto trans cars? The manual trans only has a single mount under the center of the bellhousing. Should there be one under it and if so, how thick?- Jim

    Leave a comment:


  • wdills
    replied
    No problem. You fellas have at it. I am currently just waiting to get my new rear springs.

    Leave a comment:


  • alpayed
    replied
    Sorry Wayne I didn't mean to hijack your thread.
    Also there is a spacer about 3/8" thick which goes under the rear engine mount on the LHS of a LHD car.
    On a RHC car it goes on the RHS. This is to make sure the engine is parallel as it is offset to the opposite side to the steering wheel.
    If it is missing the engine will point downwards more than it should and will put the engine on an angle.
    Allan

    Leave a comment:


  • bensherb
    replied
    Yeah, I have a 4" filter and a 1" carb spacer on my hawk and it clears the hood too. The '53 hood is quite a bit lower though, with only about 2.5" from carb to hood with a V8 and 4 barrel carb.

    Leave a comment:

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