Just joined? Please introduce yourself.
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 26

Thread: LS engine angle problems

  1. #11
    Registered Member
    Join Date
    Apr 2012

    Member #:571
    Posts
    4,671
    #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.

  2. #12
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    www.iedls.com/asp/admin/getFile.asp?RID=10&TID=28&FN=PDF

    http://www.iedls.com/asp/admin/getFi...&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/freq...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.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  3. #13
    Banned
    Join Date
    Nov 2015

    Member #:2775
    Posts
    1,426
    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.

  4. #14
    Registered Member
    Join Date
    Apr 2012

    Member #:571
    Posts
    4,671
    That's correct.

  5. #15
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    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.
    Last edited by chevynut; 04-01-2016 at 08:13 AM.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  6. #16
    Registered Member Bihili's Avatar
    Join Date
    Sep 2012

    Member #:896
    Location
    outside K. C.
    Posts
    267
    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.
    Bill 1957-427-177-6-410

  7. #17
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    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.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  8. #18
    Registered Member Bihili's Avatar
    Join Date
    Sep 2012

    Member #:896
    Location
    outside K. C.
    Posts
    267
    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.
    Last edited by Bihili; 04-01-2016 at 10:41 AM.
    Bill 1957-427-177-6-410

  9. #19
    Banned
    Join Date
    Nov 2015

    Member #:2775
    Posts
    1,426
    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.

  10. #20
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Quote Originally Posted by Bihili View Post
    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.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

Page 2 of 3 FirstFirst 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •