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Bihili
03-30-2016, 06:08 PM
A few facts first:
Completely stripped down 57
I have about 250 pounds in trunk to simulate a gas tank, bumpers & misc
The current pinion angle is between 2.5 and 3 degrees on the stock rear end.

While test fitting the LS 5.3 & 4L60E the angle at tail shaft is 5 degrees.

I cannot get less engine angle because the top of the tail shaft is hitting transmission tunnel.

http://i686.photobucket.com/albums/vv226/bihili57/four%20door%20hardtop/20160330_190454.jpg (http://s686.photobucket.com/user/bihili57/media/four%20door%20hardtop/20160330_190454.jpg.html)

I had not planned on modifying the tunnel for this project. Am I missing something?

NickP
03-30-2016, 07:46 PM
What engine mount are you using? Pics, brand, manufacturer etc.

chevynut
03-30-2016, 08:47 PM
Why not just leave the engine at 5 degrees and set the pinion appropriately? We typically set our engines at 5.5 degrees and the C4 IRS at 5 degrees. That's because of rack clearance. Is your engine sitting higher than stock?

Bihili
03-31-2016, 07:24 AM
Nick, the motors mounts were welded in place by the former owner who died.
Nick, years ago you posted the factory pinion angle was 4 degrees to match the engine angle of 4 degrees and it had something to do with the float on carburetors.
This car is stripped down but my pinion angle is only 2.5 to 3.0 degrees. Do you think it will change that much when at full body weight?

I don't think the engine is sitting higher.

I notched the crossmember to make room for the factory AC compressor and removed original motor mount humps from crossmember to give additional clearance to oil pan.

What is factory engine angle for a LS engine?
http://i686.photobucket.com/albums/vv226/bihili57/Mobile%20Uploads/2016-03/20160329_190940.jpg (http://s686.photobucket.com/user/bihili57/media/Mobile%20Uploads/2016-03/20160329_190940.jpg.html)

NickP
03-31-2016, 07:59 AM
3° , 4°, 5° or 5.4978345°; As Laszlow is alluding to, the main function to consider, for me is to keep the pinion center-line and the power-plant center-line parallel or as close as possible, say (arguments to ensue) +/-.25° We all strive for perfection for the most part but I feel as hot rodders in the new technological era, we tend to overthink and shy away from allowances and tolerances given. Sure, it's cool to converse to the highest degree about some exponentially wonderus feature of the front gizmo that's attached to the turbocharged thin-a-ma-jig but for me, the expense doesn't outweigh the aggravation of the train ride.

As to the question, angle for stock LS, I have never measured any of my present vehicles so am unable to give direct feedback/numbers on that but with an LS (fuel injected) the float level is no longer an issue really.

Not being an engineer, I know there are specifics relative to a minimum/maximum angle of operation on universal joints but I can't expound upon specifics, just generalities.

chevynut
03-31-2016, 10:41 AM
Like you said Nick, the EFI doesn't care what angle the engine is at and oil flowback isn't going to matter if it's different by a couple of degrees. The car probably has a slight rake anyhow. You want the crank and pinion centerlines to be parallel while under a constant load so the u-joint angles and their resulting acceleration cancel each other. I think they recommend to have them within 1 degree or less of each other. I set my pinion 1/2 degree below engine angle to account for any flexing of the mounts, etc. If you ever look at a leaf spring vehicle while driving, the pinion goes all over the place.

From what I've read the maximum recommended u-joint angle is usually around 3-4 degrees but I don't know where the limit really is. That's the angle between the driveshaft and crank, and between the driveshaft and pinion.

WagonCrazy
03-31-2016, 01:54 PM
5885

chevynut
03-31-2016, 02:29 PM
Paul, any idea what they mean by "strain"? Some of those diagrams and comments make no sense to me. Having shafts in perfect alignment is NOT good, as the u-joint bearings don't move and don't get lubed properly causing brinnelling. That's why the C4 IRS knuckles are set back from the differential yokes...to ensure the u-joints are always moving.

Vibration can be caused by out-of-balance, or by the acceleration of the shaft as the u-joints turn. If the ends are at the correct angles (same u-joint angles), the acceleration is cancelled out, eliminating vibration. You can get the same u-joint angles if you do #2 AND #4. I see no reason for #4 to have, "rediculous vibe" any more than #1 or #2. Pinion lubrication might be a problem depending on how the case is designed. I don't see why a Dana 44 would have any lubrication issues as there's a passage for oil thrown from the ring gear to the front pinion bearing. I imagine most cases are designed that way.

55 Rescue Dog
03-31-2016, 03:15 PM
So does 5.5 degrees work or not, if 3-4 degrees is considered max? Or is kinda close good enough at 100mph?

chevynut
03-31-2016, 04:28 PM
So does 5.5 degrees work or not, if 3-4 degrees is considered max?

Re-read what's been posted.

Rick_L
03-31-2016, 06:11 PM
#4 is OK as long as the angles are equal. That would be an unusual situation for what we usually have to deal with, it usually doesn't come up.

I don't think "perfectly in line" is ever really achievable, particularly if there's suspension motion or any elasticity in the mounts, so what happens there is mostly an internet debate.

The actual u-joint angle does matter, should be equal within reason on both ends, but there is a vibration vs. speed relationship that Spicer has published (available on the internet somewhere). I don't recall the exact recommendation, but staying under 3-4 degrees should be ok for most of what we do. Again this shouldn't be a problem for most of us - where it comes in is with 4x4 trucks with lift modifications.

chevynut
03-31-2016, 07:21 PM
www.iedls.com/asp/admin/getFile.asp?RID=10&TID=28&FN=PDF (http://www.iedls.com/asp/admin/getFile.asp?RID=10&TID=28&FN=PDF)

http://www.iedls.com/asp/admin/getFile.asp?RID=10&TID=28&FN=PDF

"Your task is to set the components up so their center lines are parallel and so that the angle made THROUGH the U-joints is 3-degrees or less as shown in Figure 2. While it is possible to run at zero degrees through the U-joints, something more than actual zero and less than three degrees seems to run smoothest."

"Drive shafts explode at an RPM called Critical Speed. In theory Critical Speed depends on shaft length, weight, diameter and RPM. In the real world Critical Speed is lowered by u-joint angles, shaft mounts and even the engine’s firing. Keeping safely away from critical speeds affects decisions about drive shaft tube diameter and the decision to move to two-piece shaft sets to add support when bridging long spans.

U-joint angles affect critical speed. If you look at a dinner plate it’ll look round. If you pick it up and tilt it, it’ll look elliptical. This ellipse is the way the drive shaft “sees” the universal joint. For the joint to rotate through the ellipse it must speed up and slow down twice per revolution. As the angle of operation increases the abruptness of the speed change also increases."

Critical Speed Calculator: http://www2.dana.com/expert/wc.dll?hvtss~decrits~warn1

http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

"RULE 1: UNIVERSAL JOINT OPERATING ANGLES AT EACH END OF A DRIVESHAFT SHOULD ALWAYS BE AT LEAST 1 DEGREE.

RULE 2: UNIVERSAL JOINT OPERATING ANGLES ON EACH END OF A DRIVESHAFT SHOULD ALWAYS BE EQUAL WITHIN 1 DEGREE OF EACH OTHER (ONE HALF DEGREE FOR MOTOR HOMES AND SHAFTS IN FRONT OF TRANSFER CASE OR AUXILIARYDEVICE).


RULE 3: FOR VIRTUAL VIBRATION FREE PERFORMANCE, UNIVERSAL JOINT OPERATING ANGLES SHOULD NOT BE LARGER THAN 3 DEGREES. IF THEY ARE, MAKE SURE THEY DO NOT EXCEED THE MAXIMUM RECOMMENDED ANGLES.


http://www.dennysdriveshaft.com/frequently_asked_questions.html

"How much driveline angle is right for my application? Thats a loaded question. The best answer is....the least amount of driveline or u-joint angle is the best amount of angle. Try to achieve the least amount of u-joint angle but don't make it less than 1 degree. A little known fact about u-joints is that they require about 1 degree of operating angle to get the needle bearings rotating. If they do not rotate they will fail. Too much angle will also cause them to fail. "


http://www.markwilliams.com/driveshafttech.aspx

Critical Speed - Critical speed is the speed at which a spinning shaft will become unstable. This is one of the single largest factors in driveshaft selection. When the whirling frequency and the natural frequency coincide, any vibrations will be multiplied. So much that the shaft may self destruct. Another way to think of this is that if a shaft naturally vibrates at 130 times a second, and one point on the shaft passes through 0 degrees 130 times a second (7800 RPM) then the shaft has hit a critical speed. There are several ways to raise the critical speed of a driveshaft. You can make it lighter, stiffer, or increase diameter without increasing weight. This is the reason carbon fiber makes a good driveshaft, it is stiff and light and can be made to any diameter or wall thickness. Aluminum, while it has a very good critical speed is not quite as strong as steel. Steel, with good strength characteristics will have a lower critical speed.

55 Rescue Dog
04-01-2016, 06:49 AM
Okay, so 5.5 degrees will work, but it could knock the max driveshaft speed down to almost 3000 rpm, which with a 3.70 gear would be only around 70 mph.

Rick_L
04-01-2016, 07:45 AM
That's correct.

chevynut
04-01-2016, 07:55 AM
5.5 degrees is too much angle on the u-joints at high speeds. As stated, you should stay around 3 degrees maximum and 1 degree minimum. Notice the critical speed calculator on the Dana site doesn't factor in u-joint angle at all. The critical speed isn't only limited by the u-joint angle, but by the length, diameter and material of the driveshaft. This is why a lot of overdrive vehicles use lightweight aluminum driveshafts. I went to a 3.5" diameter aluminum shaft with 1350 u-joints for torque reasons, but it will help with critical speed too.

Bihili
04-01-2016, 09:47 AM
Well, I guess my problem will be solved when I replace the cabin floor.
Already replaced trunk floor so this summer when I replace cabin floor I will either raise body or probably just massage the new floor to allow more clearance for the 4l60E.
I wanted about 3 degrees engine angle to match pinion angle.

Of all the LS swaps I have read about there was only one other guy that complained about the same problem.

chevynut
04-01-2016, 10:13 AM
Bill, I guess I don't understand why you're even having the issue if you haven't raised the engine. I put an LS1 and 4L60E in Wade's blue 57 Nomad and all he had to do is cut the flange off of the firewall to floor seam. That's with the engine raised higher than stock but at a 5.5 degree angle. He didn't have to do anything else to make it fit.

Is your engine moved forward to clear the stock firewall? Are you measuring the engine angle with the frame rails level? Are you measuring it on the tranny pan? I would measure it on the engine oilpan rail or somewhere on the top of the engine to be sure it's correct. It just seems to me that you shouldn't be having this problem.

For what it's worth, here's my recommendation if your engine angle measurement is correct. I'd place the engine angle where it needs to be for the tranny to clear the floor. Then I'd build the tranny mount and put it there. If it needs to be at 5 degrees, I'd use that angle. Then I'd shim the rearend up to where you want it with tapered shims that are used to adjust pinion angle. If you're using stock springs and don't have any traction control device, it might be fine at 3 degrees depending on how much axle rotation you get under load. To me, that's a lot easier and cleaner solution than cutting the tranny tunnel out or raising the body. And your new floor probably won't fix the problem.

Bihili
04-01-2016, 10:33 AM
I am confused why I am having this problem too.

The measuring of engine angle has been done by putting the angle finder vertical on the tail shaft of transmission and the yoke of the rear end with car sitting on the ground.

I have dealt with shims under the leaf springs before and am not a fan of the shims, so that's out.
The engine is moved forward 1 3/4 inches and that is another reason I should not have this situation.

On my first project with the T56 the tunnel was modified so my comfort level with tunnel mods will probably be my solution.

Just did not expect this situation.

55 Rescue Dog
04-01-2016, 11:12 AM
I'm seeing where I got confused, with 5 degree engine/rear angles. That doesn't determine the u-joint angle. The u-joint angle is determined by the relative distance in height between the tail shaft, and pinion on the same parallel plane. The trans/rear could be at a 45 degree angle, and still have zero u-joint angle.

chevynut
04-01-2016, 12:45 PM
The measuring of engine angle has been done by putting the angle finder vertical on the tail shaft of transmission and the yoke of the rear end with car sitting on the ground.

The engine is moved forward 1 3/4 inches and that is another reason I should not have this situation.

On my first project with the T56 the tunnel was modified so my comfort level with tunnel mods will probably be my solution.

Just did not expect this situation.

Bill, from what you're saying I think you might be measuring the angles wrong. First you have to get the frame level or correct for it not being level. The 4 degrees usually specified is relative to the frame, not the ground, unless the frame is level with the ground. It's not even level at stock ride height. If you look in the GM drawings you'll see the radiator support tilted back the 4 degrees to be parallel with the engine cooling fan. That's relative to the datum, which is parallel to the bottom of the frame rails.

I move the LS engines forward 2 1/4" to clear the firewall. But you still shouldn't be having the problem with a 4L60 at normal height. The T56 is a lot taller in front so it does interfere, and I haven't seen anyone install one yet without having to cut the tunnel....at least with a reasonable engine angle. I think a lot of guys have installed 4L60Es without cutting the tunnel.

rockytopper R.I.P 5-13-2017
04-01-2016, 03:07 PM
You should not have to mod the tunnel for a 4l60 they are the same as a 700r case and thousands reside in trifives.

I Also might add you guys running these OD trans behind even a stock LS1 be careful with a stock 3.5 drive shaft. I twisted a brand new one off at 135 mph about a foot behind the trans. I'm lucky to be here. In my case my front angle on the trans was a bit much which probably contributed to the failure I raised the tail an inch. I went back with a 4 inch and thicker wall basically nascar truck specs drive shaft. There have been many failures on the dyno with ls swaps in these older cars. Especially when they start making big horse power. The dyno has to run the car up to top of 3rd gear. I was just below the top of 3rd pulling strong when mine let go....

Rick_L
04-01-2016, 04:17 PM
bihili, in addition to Cnut's comments, you probably should pick a bigger flat area to use for your measurement. Also, I've seen the output shaft droop a bit when the yoke is removed, especially on automatics. Not sure the best spot on an LS/4L60 but there has to be a better one.

rockytopper R.I.P 5-13-2017
04-01-2016, 05:03 PM
The oil pan flange or trans flange are good areas even the bottom of the trans pan is flat good place for angle indicater.

For height reference I set my LS holley pan on a 2x4 so it is 1.5 inches higher than the center dropped area on the crossmember. I built my engine mounts with engine setting on the board. Hope that helps.


S&P oil pan.
http://i96.photobucket.com/albums/l179/rockytoppers/SPoilpan.jpg


Pan being installed.
http://i96.photobucket.com/albums/l179/rockytoppers/paninstall.jpg

Bihili
04-18-2016, 07:48 AM
Found the problem.
The engine angle at the tail shaft was giving me a false reading.
I put the angle finder on the bottom of the head and got a correct reading.
Now the engine is installed at 3 degrees and transmission clears the tunnel.

NickP
04-18-2016, 10:09 AM
Yahoo!

Rick_L
04-18-2016, 02:58 PM
Glad to hear that worked out.