OK ..See if I have this right before I tack weld the spring perches on my rearend. I have a 348/200 4R in a 34 Ford chassis with a 57 Ford 9" rearend on parallell leaf springs. My carburetor mount is at 1° pointing down at the rear. I intend to keep it at this instead of perfectly level so it will clear other stuff at the trans crossmember. My slip yoke is at 4° pointing down at the transmission output shaft. My pinion on the 9 inch is pointing up at 4°.The driveshaft is at 1°going down to the pinion. Does this sound like it will be right? This will never see a drag strip so I am not interested in spring wrap up,it is just a cruiser.Its been many years since I did this so I need to see if my research is correct.
Hard to tell from what you posted, but 4 down and 4 up is fine. I try for 3 degrees, but sometimes you have to go differently to make things work. I have had them all over the place, especially in engine swaps, and they seem to be fine most times. I put a 5.0 Ford engine into a Jeep pickup where the engine had to go very steep to clear stuff, and I drove it that way for 5 years with no shakes or u joint wear. Don
"Hard to tell from what you posted," I don't know what else I could have said. What information did I leave out? My ex always said I didn't communicate well so I need to know.
According to Pro Stock chassis builder Jerry Bickel, the goal is to create a straight line from the back of the crankshaft through the transmission, driveshaft, and the pinion of the differential under load. Due to the tendency of the pinion to rise under load, some angle must be present at rest. How well the rear suspension controls the position of the rearend is the most critical issue that determines how much pinion angle will be needed. Some types of rear suspensions offer more control than others and require different angles. According to Bickel, a ladder-bar suspension normally requires ½ degree of pinion angle, a four-link requires 1-2½ degrees, and a leaf-spring suspension requires up to 6 to 7 degrees. In all examples, we’re talking about negative pinion angle, i.e., the pinion is nose-down in relation to the driveshaft. Bickel says a straight driveline delivers the most power to the rear wheels. Currie says nose down also at rest. Read more: http://www.carcraft.com/howto/91758/index.html#ixzz1VtJ2IBPI
If you're at 4 up/ 4down that's O.K. ,but w/ the driveshaft at 1, that means your working angle is 3 , that's still O.K. but I'd rather see 1 to 2 working angle. My .02 dave
Some may disagree, but Ive always used what jdj9410 posted above, except for using 3-4 degrees down on a street car with leaf springs. No problems so far.
<table class="contentpaneopen"><tbody><tr><td class="contentheading" width="100%">Driveline Angles & Phasing Problems </td> <td class="buttonheading" id="tweetmeme" width="100%" align="right"> </td> <td class="buttonheading" width="100%" align="right"> </td> <td class="buttonheading" width="100%" align="right"> </td> </tr> </tbody></table> <table style="width: 96%;" width="96%" border="0"> <tbody> <tr> <td style="width: 35%;">The u-joint operating angle is the angle formed by two yokes connected by a cross and bearing kit. There are two kinds of u-joint angles. The simple one plane angle found in most installations has all driveline slope confined to one plane, usually the vertical plane. The other type of driveline angle is compound angle in two planes. This is found in driveline designs where offset exists in both the vertical and horizontal planes. </td> <td style="width: 35%;"> </td> </tr> </tbody> </table> <table width="80%" border="0" height="256"> <tbody> <tr> <td width="50%"> </td> <td width="50%"> </td> </tr> <tr> <td width="50%"> One Plane Angle Driveshaft's, Side & Top View </td> <td width="50%"> Two Plane Angle Driveshaft, Side & Top View </td> </tr> </tbody> </table> High angles combined with high RPM is the worst combination, resulting in reduced u-joint life. Too large and unequal u-joint angles can cause vibrations and contribute to u-joint, transmission and differential problems. The improper u-joint angles must be corrected. Ideally, the operating angles on each end of the driveshaft should be equal to or within 1 degree of each other, have a 3 degree maximum operating angle and have at least 1/2 of a degree continuous operating angle. RPM is the main factor though in determining maximum allowable operating angles. As a guide to maximum normal operating angles, refer to the following chart: <table width="61%" border="0" height="176"> <tbody> <tr> <td width="50%"> DRIVESHAFT RPM </td> <td width="50%"> MAX. NORMAL OPERATING ANGLE </td> </tr> <tr> <td width="50%"> 5000 </td> <td width="50%"> 3.25º </td> </tr> <tr> <td width="50%"> 4500 </td> <td width="50%"> 3.67º </td> </tr> <tr> <td width="50%"> 4000 </td> <td width="50%"> 4.25º </td> </tr> <tr> <td width="50%"> 3500 </td> <td width="50%"> 5.00º </td> </tr> <tr> <td width="50%"> 3000 </td> <td width="50%"> 5.83º </td> </tr> <tr> <td width="50%"> 2500 </td> <td width="50%"> 7.00º </td> </tr> <tr> <td width="50%"> 2000 </td> <td width="50%"> 8.67º </td> </tr> <tr> <td width="50%"> 1500 </td> <td width="50%"> 11.5º </td> </tr> </tbody> </table> When the transmission output shaft centerline and axle input shaft centerline are parallel, the u-joint operating angle permissible is length of driveshaft divided by five. Example: A short coupled driveshaft with a 15" length would be limited to 3 degrees maximum operating angle. A 30" shaft would be limited to 6 degrees.
Look at this..... http://www.vibratesoftware.com/html_help/2011/Diagnosis/Propshaft/Propshaft_Angles.htm
If the drive shaft were straight out of trans, then add 3 degs more down,That would be max angle,now bring rearend to meet, The rearend should be down not up.
This remains one of the most controversial subjects on the HAMB and yet, it really is stone simple, especially for a street cruiser such as you intend yours to be. I think you included all relevant information in your post and I believe you are good to go with what you have. Bickel is a racer and his recommendations are for racers. Just as many other specifications on a race car differ front normal street use, so does this subject. And, the pinion does NOT need to be 'down'...........it CAN be, depending on other factors, but it does not have to be. MY $.02 Ray
Yes, it's fine. You answered the main question in your OP. You're not worried about spring wrap.... Match the angles and forget everything else.
Thanks for the replies. No, its not a racer, I drive like an old woman, just want it to run smooth. Looks like most think its ok.I guess I am ready to weld it up.
The angle between the trans or pinion to the ground doesn't matter one bit. measure the angle from the trans yoke to the drive shaft. measure the angle from the pinion yoke to the drive shaft. make sure they are in opposite directions (a shallow zigzag) you can add an extra degree or two (if needed) at the rear to account for leaf spring wrap so that the angles are even at highway speed/accel. -rick
First guy to get it. It's not that the up and down match, but the working angle. Need some, but not too much. 3* sounds OK to me.
It sounds good where you are, they make wedges for the spring pads to fine tune it if there is a vibration problem.
It is important to have the angles // to each other with the car on the ground. Matching four degree angles is standard on most 60's muscle cars with leaf springs. The carb mount should be level = zero degrees with the weight of the car on the ground. Most intake manifolds have a carb mount 4 degrees sloped down towards the front of the engine to compensate for the four degree decline angle of the engine and trans to match the opposite matching angle of the pinion yoke. The car in my avatar has matching three degree angles because of the four link rearend. Matching angles help keep vibrations at a minimum at freeway speeds.
My concern is with a pinion higher than the tranny as extra weight goes onto the rear end the angles become greater whereas in previous posts it was explained the the angle in the normal situation smooth out!
Ok if we are now discussing LOAD, we need to look at specific suspension designs. Some will cause the pinion to climb, others will cause it to drop under load. That wasn't part of the original question, and my comments applied to steady state conditions.
In street driven applications remember that universal joints don't run perfectly straight, they are designed to work in order to keep lubricant working through the needle rollers, hence the slight angle. As the rear axle moves the joint compensates for the movement. Keeping angles low (Shallow) makes the joint work less, last longer and use less power. No room for error. Angling the tail shaft slightly makes the universal joints actually work and rollers don't suffer from brinelling.The steeper the angle, the less longevity (Life span) the joint has. I try to follow the KISS principle.
The info does,nt seem right.This must be one low car.If the driveshaft is 1 deg down to rearend,the trans must be maxed out at 3 degs and rearend to. What is must look like is the trans say is 13inches off ground and rearend is 12 inches.with a 30inch tire is 15 minus york say 12"
Your numbers sound good, about 3 degrees u-joint working angle with almost level carb. You can never get it perfect and keep it there, each bump on the road changes its along with the amount of fuel in the tank or the weight in the seats. As long as you are with in range of the u-joints (1-3 degrees) it will last a long time. As a side note, u-joints do not care if the drive line is pointing up or down or one of each, as long as the angles are very close. Look at a long wheel base delivery truck next time one passes you, those drivelines go all kinds of angles and directions.
For a triangulated 4-link, the trans should be 0 to 1 degree down, the pinion 0 to 1 degree up? Is that what you mean?
I guess not... The trans shaft and pinion shaft should be parallel to cancel out rotational motion of the u-joints. We are talking about a typical one-piece, slides in the trans driveshaft here... One u-joint is pulling, the other is pushing at the same time. Time to get the 3/8 universals and extension out and get a feel for it...
Those numbers apply primarily to drag racing. The idea is that under load (pinion climbing), the trans and pinion shafts end up parallel. That's why the leaf spring runs more lead angle on the pinion...the springs wrap more. For normal street driving, just set the trans and pinion parallel and forget about it.
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