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wdills
08-14-2017, 07:49 PM
So I am on to the next topic of investigation regarding the vibration in my Hawk that occurs around 73 mph. Tonight I measured the angles of all the drive line components. Engine / Transmission is about 6 degrees down. Drive shaft is flat, 0 degrees. Differential pinion is about 6 degrees down.

From what I have read, to get the ideal setup I would need a 12 degree wedge to rotate my differential around to 6 degrees up. This seems like a lot of wedge. Would I be better off putting a shim under the rear engine mount to flatten out the down angle of the engine / transmission a little and then picking a wedge for the differential?

64studeavanti
08-14-2017, 08:05 PM
I think 6 degrees is a bit much. IIRC, the target is around 3. Which transmission do you have? If manual, do you have the spacers under the rear mount?

wdills
08-15-2017, 08:24 AM
I do have a manual transmission (3spd / OD). No I don't have any spacer under the rear engine mount. Car didn't have any when I got it, and I never thought to look if any belonged there. Looking at the parts book, it appears that I need spacer P/N: 1548406. I have checked the major online vendors and nobody lists them. Anyone know how thick they are supposed to be? I saw an old post that suggested 1/2" but the poster did not seem sure this was the correct measurement.

WCP
08-15-2017, 12:34 PM
Wayne, I believe the general rule is for engine to be 3.5 degrees down toward the rear, a 0 driveshaft, and 4-5 degrees down toward the front for the axle. That may translate to something like 7, 3.5 & -0.5-(-1), or 8, 4.5 & 0, engine, driveshaft, axle, depending upon engine to frame angle.

DEEPNHOCK
08-15-2017, 12:45 PM
??
Whatever you put in at the front, you take out at the back.
If the crank centerline is down, then the pinion should be up.
Maybe remove a degree or two for spring wrap...
There are numerous spring and driveline shops that can help you out...

wdills
08-15-2017, 03:32 PM
I apparently have several things to deal with. First priority is new rear springs. I know mine are week and letting the back of the car sit lower than it should. Changing the height of the rear of the car will impact all the other angles so I need to take care of this first. Plan to get a new set of HD springs. Once they are installed and the correct ride height is restored, then I will get back to drive line angles.

Second, I need to level out the engine a little. I will have to check how much clearance I have in various places to determine the best way to change the angle. SI has thinner front mounts and I can add a spacer at the rear mount. Objective is to end up around 3 degrees down on the engine / trans while still maintaining fan to shroud clearance as well as all the other things that could hit when you start changing the mounting position of things.

Once the engine is at a better angle I will determine the correct wedge to change the pinion angle. I am hoping for 3 degrees down on engine and 3 degrees up on pinion. Fingers crossed.

Hawkowner
08-15-2017, 03:51 PM
Max angle between shaft and center line of the yokes should be 6 degree. The yokes should be parallel.which yours seem to be.
Hawkowner

Hawks have a critical wheel and tire vib at The 70 mph range. Are you sure it is drive line tires and wheels have a vib in the ten Hertz range.ls the vib a bounce or a drumming noise.
Hawkownhner

Treblig
08-15-2017, 03:52 PM
https://video.search.yahoo.com/yhs/search?fr=yhs-mozilla-004&hsimp=yhs-004&hspart=mozilla&p=how+to+set+drive+shaft+angle#id=6&vid=15a88240b99e4a78e9df9cc64042896d&action=view

And many more examples.

Treblig

alpayed
08-15-2017, 05:53 PM
Hawks run a brokenback arrangement. Transmission is down, shaft horizontal and the pinion points down. If you raise the rear transmission mounts to get 4.5deg to 5 deg down and leave the diff down 6deg it should solve the problem. They need to be equal within 1.5 deg. Not necessarily equal and opposite but equal.
What is happening is as the speed increases the diff angle changes (winds up) and your transmission is still 6 down but the diff has wound up to 2deg down.
You then get a large difference (4deg) which causes the vibration.
The angles will always change and on a broken back arrangement you need to have a happy medium so that under all driving conditions the angles remain not too far out.
On a more conventional arrangement the angles cancel when the suspension moves up and down because the transmission and pinion are parallel. However the diff will still wind up so the 1-1.5degperload should be there. This arrangement will not work on a hawk unless you alter the transmission tunnel at the rear. It is not deep enough to allow the driveshaft to be high at the diff.
Hope this helps.
Allan

wdills
08-15-2017, 07:52 PM
Hawkowner, I have heard about the 70mph Hawk vibration. I just don't understand where it comes from. Wheel and tire doesn't make sense for me because I have aftermarket wheels and new radial tires. They were spin balanced so I don't see them causing the vibration. Bad drive line angles are the most reasonable thing I have run across so far.

Allan, I am concerned that I won't be able to get the ideal equal and opposite 3 degree angles due to clearance restrictions. I hope to at least achieve a broke back arrangement with 3 degrees on both ends. From what I have read the angle of a U-joint should never be more than 3 degrees.

64studeavanti
08-15-2017, 09:21 PM
Try the easy stuff first. My 4spd Avanti had vibration problems when it did not have the spacers installed under the rear mount
Adding them cured the problem. IIRC, they were about 1/2". You could use a stack of washers and vary the number to suit.

wittsend
08-15-2017, 11:35 PM
Please read post #9 - again. As alpayed has stated you have a 'broke back' configuration where the transmission AND the pinion shaft point downward. Some have mentioned the configuration for a standard set up (both parallel) but the driveshaft would probably have to pass through the shaft tunnel to achieve it. On my '64 Daytona I don't think I could get any less that 6 down at the trans. I don't recall what the pinion was at but I know it didn't match. I'll look tomorrow and see if I can find what it was. Remember you are comparing angles to each other and not necessarily that the shaft is at 0. In theory you could figure it out on a sloped driveway.

bensherb
08-16-2017, 12:54 AM
Allan, I am concerned that I won't be able to get the ideal equal and opposite 3 degree angles due to clearance restrictions. I hope to at least achieve a broke back arrangement with 3 degrees on both ends. From what I have read the angle of a U-joint should never be more than 3 degrees.

After setting ride height with new springs, tires , etc... When parked on a flat level surface, I would put my angle finder on the carb flange of the intake and raise or lower the engine/trans at the trans mount until it's level. Then, measure the trans output shaft angle and adjust the rear axle pinion angle so it is paralell. This is how I've done it many, many times and have never had any problems. I had no problem acheiving the correct arangement in my dads '53 coupe. It has a GM TH350 trans, a Ford 8" rear axle, a one piece drive shaft and sits and looks factory stock. Actually I set it up twice; I replaced the Dana 27 with a Dana 44, then later replaced the 44 with the 8".

Ideally, the operating angles at each end of the driveshaft should be within 1 degree of each other and at least 1/2 a degree of operating angle; not inline.

As for a max drive shaft angle; 3 degrees is incorrect. Perhaps you read 30 degrees. Take a look at the front drive shaft on a 4wd truck sometime. The more extreme the angle the more likely you'll bind the U joint and twist the driveshaft into a knot with the application of the needed power, plus, the U joints won't last long. U joint life decreases as the angle goes up and it is forced to work harder.

The max normal operating angle for a driveshaft that is expected to turn at 5000 rpm is 3.25 degrees. As the expected driveshaft rpm drops the max normal operating angle can increase, for example at 1500 rpm a 11.5 degree angle could be considered normal.

5brown1
08-16-2017, 06:38 AM
How do you set the angle with the two piece drive shafts?

wdills
08-16-2017, 07:24 AM
bensherb, I didn't mean a max drive shaft angle of 3 degrees. We have plenty of 4wd trucks around here with drive shafts that look to be 30 degrees or more. I was referring to the operating angle of the u-joint. According to the Spicer / Dana website the operating angle of their u-joints should be no more than 3 degrees.

Based on feedback received, I am just hoping to get my u-joint angles less than three degrees even if I can't get away from the broke back configuration that Studebaker designed.

Hawkowner
08-16-2017, 09:15 AM
I am working through the same problem after new American Racer wheels new radial tires. Hunter road force balanced tires and wheels. I have moved the vibiraton speed with different tires balances but not eliminated it . I have done extensive drive line and wheel vibiraton trouble shooting all over the country and drive line vib makes a difference noise and changes with speed.
I can see a slight bounce in the front end.
Just before storing the car for the summer. I found a bent rear hub and a out of round front brake drum. I suspect badly out of balance brake drums.
Disc brakes are coming.
Hawkowner

wittsend
08-16-2017, 12:08 PM
After setting ride height with new springs, tires , etc... When parked on a flat level surface, I would put my angle finder on the carb flange of the intake and raise or lower the engine/trans at the trans mount until it's level. ...

I can't account for a Studebaker engine because my '64 Daytona came with a 283 McKinnon when I bought it. However, on a lot of engines the surface of the carb mount is not parallel to the crank centerline (and thus the trans output). The manifold carb mount surface can have a designed in tilt to compensate for engine tilt. Therefore the possibility exists that wrong reading might occur. That aspect should be confirmed before using the stated surface. I say this as a caution only given my lack of familiarity with Studebaker engines.

When I set my angles I used the trans output shaft's vertical face. On the rear end I used a short piece of pipe that fit the joint saddles and positioned it vertically using the pipe surface for the reading. In my case the trans was a 700R4 and perhaps not all trans output shafts extend that far out so I understand the limitation. My recollection was I had no more that 1 degree adjustability before the trans hit the tunnel or dropped onto the mount(no shims).

As to understanding the broke back driveshaft (I can't bend the lines but hopefully this helps):

Conventional: Trans output--/ -- shaft --/ -- rear end

Broke Back: Trans output--/ -- shaft -- \ -- rear end

oilnsteel
08-16-2017, 01:42 PM
A Studebaker V8's carb mounting surface is not parallel to the crankshaft centerline.

Jim

bensherb
08-16-2017, 03:32 PM
I haven't seen an engine yet that did have the carb on a paralell plane as the crank centerline. You don't seem to understand what I said.

Almost all carbs are meant to operate when sitting level, paralell to the ground. Get that right first. THEN, measure the angle of the trans output shaft. That will then give you the angle you need to match the rear axle to.

Neither my GT nor my dads '53 have any vibration at any speed. But I haven't run either over 90 mph. Typical freeway speed here is around 75. My '54 wagon is good to over 100, but it has a big block ford, c6 and 9". I've done many others the same way. I don't know if they vibrate at a given speed or not, if so it's not a lot, it's hard to tell when it only runs 8 seconds at a time but they were good for 140+. It's always worked for me.

wittsend
08-16-2017, 04:48 PM
Thank you I better understand now. My focus was on the trans, shaft, rear end angles and I missed the aspect of getting the carb level - first. (note to self, eat breakfast first, read twice, then reply).

I will say with my '64 Daytona using a 350 Chevy (Edelbrock Intake) and a 700R4 trans I could in no way get the carb level even with the built in compensation of the intake manifold. I have the trans yoke about as close as I dare to the rather shallow shaft tunnel. I don't see dropping the engine as an option (as a means of reducing that angle) because the oil pan is already rather close to the center steering bellcrank. I just checked and the carb itself tilts back 3 degrees from level and the engine is in the 6-7 degree range from notes I have. That is the best I can get without significant trans and driveshaft tunnel modifications.

Jerry Forrester
08-16-2017, 07:39 PM
Almost all carbs are meant to operate when sitting level, paralell to the ground.


I agree with all that and have almost always been able to get carb. level fore and aft and side to side when doing an engine swap.
BUT, I have often wondered how I was going to keep the carb. level when going up and down hills and keep the gas level in the carb. while making those sharp left turns on the 3/8 mile banked dirt track. (Tongue planted firmly in cheek.)

bensherb
08-17-2017, 02:22 AM
Wittsend: Wow, that Lark must have a tiny tunnel. I didn't pay too much attention to it when I had my '61 Lark. The last C/K I put a 350 into, the damper was just high enough above the bellcrank to get a fan belt between them, but I could get the carb level. They must have a larger tunnel than the Lark; surprising.

wittsend
08-17-2017, 03:19 PM
Here are several images:

First is a '66 Lark Type that came with a McKinnon engine originally. As one can see the engine tilts rearward significantly. I chose this over my engine to illustrate that it is a factory configuration though it is nearly identical to my '64 transplant using 65-66 mounts with a 350.

The second is the trans/driveshaft tunnel in my car. Note especially how shallow the driveshaft tunnel gets at about the point where the trans tunnel theoretically ends (and the yoke would be).

The third is the bottom side of my tailshaft/yoke/driveshaft tunnel. I have no more than 1/2" to 3/4" clearance from the outermost swing of the yoke to the tunnel underside. And, as the rear springs might compress they move the shaft closer to the tunnel.

How does this compare to the C/K?

bensherb
08-17-2017, 03:39 PM
In the pic of the engine the angle doesn't look that bad, I wonder if the factory original Stude manifold might have had a different carb angle than the Chevy or maybe a wedge of some sort to compensate? I know with the Ford "FE" engines, there were different manifolds for different model cars in order to make things fit and keep the carb level.

From the pic of the trans tunnel it does appear the tunnel is very small. Even the tunnel in the early C/K is much larger and the later C/K tunnel is a bit bigger than it. I'm not sure, it may be an illusion due to the shape, but the fire wall may be a bit further forward on the lark too, forcing the engine a bit further forward and consequently higher too.

alpayed
08-17-2017, 07:05 PM
You cannot achieve a normal configuration. I have tried with a 62GT and with my 60 Hawk. The 60 Hawk has a 2 piece shaft and even the short rear shaft hits the tunnel at the rear. So it runs broken back.
The alignment and phasing of a 2 piece shaft is even more critical as I have found with the 60 Hawk. The Ford302 and BTR transmission are so much shorter that a 1 piece shaft would need to be 4" diameter.
Keep in mind that the tunnel is offset 1" to the right hand side. Dana 44 has a 1"pinion offset to keep the axles the the same. LHD engines are offset 1/2" to the right so you have a 1/2" offset in the drive shaft also.
RHD engines are offset 1/2" to the left so you have a 1-1/2" offset in the drive shaft.
So it gets even more complicated. I plan view the shaft is conventional arrangement, transmission and pinion are parallel, in side view the arrangement is broken back.
Imagine looking along the driveshaft from the rear. The pinion points upward to the left and the transmission points upward to the right.
If the transmission and pinion were in the same line they would both point vertical when looking along the shaft.
This is why Studebaker put an offset in the yolks on the tailshaft. They are twisted to bring the universals back into phase.
Australian built Hawks were set up engine down 5 Deg and diff down 6 Deg. This allowed 1 Deg windup to run equal at operating speed.
If they are set up as designed they run well.
66303
This shows what i am describing.
66304
Here is a 60 Hawk floor pan.
I think they are all roughly the same.
Allan

JoeHall
08-17-2017, 07:45 PM
You cannot achieve a normal configuration. I have tried with a 62GT and with my 60 Hawk. The 60 Hawk has a 2 piece shaft and even the short rear shaft hits the tunnel at the rear. So it runs broken back.
The alignment and phasing of a 2 piece shaft is even more critical as I have found with the 60 Hawk. The Ford302 and BTR transmission are so much shorter that a 1 piece shaft would need to be 4" diameter.
Keep in mind that the tunnel is offset 1" to the right hand side. Dana 44 has a 1"pinion offset to keep the axles the the same. LHD engines are offset 1/2" to the right so you have a 1/2" offset in the drive shaft also.
RHD engines are offset 1/2" to the left so you have a 1-1/2" offset in the drive shaft.
So it gets even more complicated. I plan view the shaft is conventional arrangement, transmission and pinion are parallel, in side view the arrangement is broken back.
Imagine looking along the driveshaft from the rear. The pinion points upward to the left and the transmission points upward to the right.
If the transmission and pinion were in the same line they would both point vertical when looking along the shaft.
This is why Studebaker put an offset in the yolks on the tailshaft. They are twisted to bring the universals back into phase.
Australian built Hawks were set up engine down 5 Deg and diff down 6 Deg. This allowed 1 Deg windup to run equal at operating speed.
If they are set up as designed they run well.
66303
This shows what i am describing.
66304
Here is a 60 Hawk floor pan.
I think they are all roughly the same.
Allan

If you 60 Hawk has a 2-piece driveshaft, it must have been converted, using parts from a 57 or earlier C/K. The 1-piece shaft started in 58, unless they are different Down Under.

bensherb
08-17-2017, 08:52 PM
Both my '62 GT hawk, and my dads '53 Coupe currently have one piece drive shafts. I know dads car has a level carb and correct drive shaft angles since I did it, the floor and firewall is factory un-altered. My GT is stock (for now) as far as I know. Since the trans (3 spd OD) came apart, It's making ungodly noises now, I'm going to change it to a GM OD auto and add disk brakes.

The biggest problem with using a Ford engine is that the oil pump is in the front (they're also longer). Even with the Mustang shallow pan and extended pickup that moves the bulk of the sump to the rear, it still has to sit at least a couple inches higher in front than a Chevy or Stude engine in order to clear the steering bellcrank.

alpayed
08-17-2017, 09:27 PM
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.
6630666307663086630966310

bensherb
08-18-2017, 01:45 AM
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.

alpayed
08-18-2017, 06:02 PM
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

wdills
08-18-2017, 06:50 PM
No problem. You fellas have at it. I am currently just waiting to get my new rear springs.

jrlemke
08-18-2017, 07:26 PM
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

64studeavanti
08-18-2017, 07:36 PM
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.

Jerry Forrester
08-18-2017, 09:04 PM
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.
6630666307663086630966310

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.

Flat Ernie
08-18-2017, 10:43 PM
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

bensherb
08-19-2017, 02:26 AM
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.

Flat Ernie
08-19-2017, 08:57 AM
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

JoeHall
08-19-2017, 09:38 AM
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 :)

bensherb
08-19-2017, 12:48 PM
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.

wittsend
08-19-2017, 02:42 PM
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/frequently_asked_questions.html#faq_id25

64studeavanti
08-19-2017, 03:08 PM
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.

alpayed
08-19-2017, 06:35 PM
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.
66349

Allan

Flat Ernie
08-19-2017, 09:25 PM
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...


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.



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.
66349

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. ;)