pinion angle help please

[shawn2002z28]

I had -2.5 on the driveshaft and +3 on the tork bar. so that made -.50 my ? is do we want the tork side + or in the - when subtracting from the driveshaft for our pinion angle any info on this would be a great deal of help

[mrr23]

that would be +.50* not -.50*. you want the pinion to be 2* less than the driveshaft angle. so, with a driveshaft angle of -2.5**, you subtract 2* and get -.5** on the angle finder.

the yoke on the pinion needs to be lower than the driveshaft. not higher.

[1QuikWS6]

DS angle doesn't mean shit for setting pinion angle. Proper way to measure pinion angle (from GM Engineer) is:

1) Remove DS
2) Measure angle of tranny at face of tailshaft and record number + whether 'Up' or 'Down'
3) Measure angle of rear pinion at face of yoke where U-joint straps attach and record number + whether 'Up' or 'Down'

U-joints are made to run with equal, but opposite angles (pinion angle is set at zero degrees from factory).

If you were to draw an imaginary centerline thru the crankshaft/tranny out put shaft, and another thru the pinion shaft in the rear, the lines need to be Parallel (not necessarily in-line).

So for example; if your tranny angle is 2 degrees pointing Down - then your rear angle should be 2 degrees pointing Up to yield a zero degree pinion angle. This will be the smoothest setting.

If you want to 'preload' your rear a slight bit & have a high HP car you can get away with a -1 or -2 degree pinion angle on the street.

[ninobrn99]

DS angle doesn't mean shit for setting pinion angle. Proper way to measure pinion angle (from GM Engineer) is:

1) Remove DS
2) Measure angle of tranny at face of tailshaft and record number + whether 'Up' or 'Down'
3) Measure angle of rear pinion at face of yoke where U-joint straps attach and record number + whether 'Up' or 'Down'

U-joints are made to run with equal, but opposite angles (pinion angle is set at zero degrees from factory).

If you were to draw an imaginary centerline thru the crankshaft/tranny out put shaft, and another thru the pinion shaft in the rear, the lines need to be Parallel (not necessarily in-line).

So for example; if your tranny angle is 2 degrees pointing Down - then your rear angle should be 2 degrees pointing Up to yield a zero degree pinion angle. This will be the smoothest setting.

If you want to 'preload' your rear a slight bit & have a high HP car you can get away with a -1 or -2 degree pinion angle on the street.

im sure this will stir you up the method that i got from MADMAN was to use the ground as a constant. basically, put the angle finder on the yoke and put it at -1 or -2 or whatever you want it at. Thats how you do it for the strip. for a daily driver he said he takes the driveline angle (what your measuring) into consideration and trys to keep it -1.5- -2 since the ujoints arent meant to work at 0*, they need the slight offset.

[1QuikWS6]

No I wasn't saying that there would be no angle when I referenced zero degrees (I did state not in-line) U-Joints do need an angle to perform correctly. But if you notice I stated that if the tranny angle is pointing Down by 2 degrees - the rear should be pointing UP by 2 degrees for a zero degree pinion angle.

The DS will still be on an angle between the U-joints - they will just be equal but opposite angles (the whole parallel thing).

[ninobrn99]

my bad, i didnt read your post i was just putting that out there... i know you've been going through hell figuring out the correct way to do it. just thought Id share. Im sure you posted the correct way to adjust the driveline angle.
Nino

[shawn2002z28]

Thanks to mrr23 i got it. It's set at -2 for now.

[mrr23]

http://bmrfabrication.com/instructions/ta001.htm and right off BMR's site is how i told shawn2002z28 how to do it.

9. Set pinion angle using the following method:

· Make sure the rear end is loaded by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle.


· Place angle finder on the driveshaft and record the angle. Now place the angle finder on the rear end torque arm mounting plate and record the angle.

· Subtracting one angle from the other results in your pinion angle.(Ex: -2 rear end angle subtracted from 0 driveshaft angle = -2 degrees)

· Turn adjuster to achieve the desired angle.

· As a starting point, most F-Bodies seem to like the following initial settings: Automatics: 1-2 degrees negative, Manuals: 2-3 degrees negative

so, driveshaft angle does mean shit.

[1QuikWS6]

Yeah, so that's how Spohn shows to do it also (and how I set mine originally - and incorrectly I might add - by blindly believing them) - doesn't make it right

I HIGHLY doubt that either of them know more on how to do this than a GM Engineer that designs the f****in suspension

So just keep on posting your method to set P/A - I'll do it my way - you do it yours...

From Inland Empire DS:

Here is what you need to know. The center line of the crankshaft and transmission output shaft must be parallel to the center line of the pinion shaft as shown in Figure 1. You will note that there is some distance between these parallel lines. The distance is caused by the angle of the components and their distance apart.

Planning these component angles is critical. 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.

From Rossler Transmission:

Pinion Angle

Tired of breaking cases and drive shafts? There are many books that misled you on setting the pinion angle. For Drag Racing this is simple. You are trying to set the pinion angle to be parallel with the centerline of the engine & transmission on hard acceleration. To achieve this you must first figure out the parallel setting of the rear end to correspond to the angle of the engine & transmission, then add the proper amount of pinion angle. Add 1 deg. for 4-Link vehicles, 2 to 3 deg. for ladder-bar vehicles. Place stands under suspension to duplicate vehicle at ride height. Caution do not remove drive shaft without securing vehicle first. Take measurement with drive shaft removed. (shown below)

From Mark Williams site:

Driveshaft Tech and FAQ

--------------------------------------------------------------------------------


Operating Angle

--------------------------------------------------------------------------------

Operating angles in a driveshaft are the angles between the pinion, driveshaft and transmission centerlines. The optimal angle for any driveshaft to run at is 0 degrees, where many vibrational and frictional problems are non-existent. In order to minimize power loss and vibration in an offset configuration, the pinion centerline and the transmission centerline need to be parallel. In general, the largest angle for racing applications should be 2 degrees and the centerlines should be parallel within 1/2 degree. If the centerlines are off too far, the u-joints travel at different speeds causing vibration (this is the same problem induced by poorly phased end yokes). This vibration is hard to distinguish from an unbalanced driveshaft.

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.

For every (1) article you can post to set P/A by using the DS - I can post (10) that state to do it the way I described - which is the method that was described to me in detail from GM.

[mrr23]

and what's amazing is how in this very pic you posted shows both the trans and yoke referencing off the driveshaft. thanks for the assistance. what they are trying to tell you is to make the pinion angle the same amount of degree angle as the trans to driveshaft angle is. but, in the opposite direction of each other. again, driveshaft angle is important.



again. referencing off the driveshaft.

[mrr23]

I HIGHLY doubt that either of them know more on how to do this than a GM Engineer that designs the f****in suspension

don't cuss im my forum. period. i didn't cuss at you. if you can't converse in a more civil matter, then don't. GM did a great job of designing the car. in a generic way. not all the smart people work at GM. usually, the smartest people don't work for a major corporation. they are usually hired in.

[02z28ls1]

and what's amazing is how in this very pic you posted shows both the trans and yoke referencing off the driveshaft. thanks for the assistance. what they are trying to tell you is to make the pinion angle the same amount of degree angle as the trans to driveshaft angle is. but, in the opposite direction of each other. again, driveshaft angle is important.



again. referencing off the driveshaft.

Disagree-they are not referencing driveshaft angle there at all. That illustration is showing a straight line there-not a driveshaft,and the other one is showing clearly the angles being measured off of the yoke and the seal area of the tail shaft. By using the driveshaft you are introducing the possibility of error in your measurements,the driveshaft is not the angle important here-the tailhousing/output shaft,and yoke/pinion shaft is the important angles. Remove the driveshaft and do it right. There is a possibility of the driveshaft having an error in it's construction that would throw your reading off. Any machinist would understand the importance of correctly referencing your readings to eliminate the possibility of stacking up errors. Sorry if people's feelings are involved here-but I'm are discussing mechanical issues here -let's stick to that. Most mechanics that I know curse as a matter of daily conversation,it may not be pretty but then neither is the bottom side of most cars on the road either.

[1QuikWS6]

BTW, 02z28ls1 is correct in his assessment.

[ninobrn99]

This needs to be handled by PM's, not in someone elses threads!
18. Moderator or Administrator bashing

Posting a thread or reply to question or criticize moderator or administrator actions is not appropriate in a public forum. Please utilize the board's Private Message function, or e-mail, if you wish to discuss these issues. As long as you bring up your concerns maturely and civilly to the moderator or administrator in question, we will do our best to address your concerns fairly and promptly.

Dont like pulling out the rule book, but this is the tech section. Bicker amongst yourselves. Im not taking sides, but it stops here. Either edit your posts to reflect your answers to the thread startes question and that only or lock it!
Nino

[1QuikWS6]

Took care of mine - and this will be the last post for me on this board

You may now all wallow in your own ignorance

(not referring to you Nino )

[mrr23]

Took care of mine - and this will be the last post for me on this board

You may now all wallow in your own ignorance

(not referring to you Nino )

don't go away just because you aren't getting your way. just do a better job of typing what you say. i'm all for having an intelligent conversation. not one of slinging words.

[mrr23]

ok let's get into this a little more in depth intelligently. we are both right in figuring pinion angle out. there are two things to consider when setting pinion angle.

1). having the pinion angle parrallel to the trans output shaft.
2). making wure the u-joints are within 3* as specified by the diagrams as 1QuikWS6 put up.

my mistake was confusing setting of the pinion angle with the operating angle of the u-joints. to set pinion angle correctly, you must also make sure the u-joint operating angle is within the specifications or you may end up with a vibration. so, after you set pinion angle, you must go and check the operating angle of the u-joints. if you cannot get into the operating angle of the u-joints, then you have to shim the trans up/down to get the operating angle of the u-joint at the trans side within specs. then you go and match the pinion angle to the trans output angle. so again, the driveshaft angle is important. just not in setting the pinion angle. which is where the confusion lies in this post.

now see, that's not so hard to do is it? i'm not above having something taught to me. i have problems with how people want to convey it.

now, maybe spohn and bmr use the operating angle as a way to set pinion angle as not to have complaints about vibration issues. IMO, honestly, with the average joe's car where he hasn't basically altered the design of the suspension (IE change from stock to a four link suspension), you won't be wrong with using the directions that bmr and spohn give you.

[mrr23]

Disagree-they are not referencing driveshaft angle there at all. That illustration is showing a straight line there-not a driveshaft,and the other one is showing clearly the angles being measured off of the yoke and the seal area of the tail shaft. By using the driveshaft you are introducing the possibility of error in your measurements,the driveshaft is not the angle important here-the tailhousing/output shaft,and yoke/pinion shaft is the important angles. Remove the driveshaft and do it right. There is a possibility of the driveshaft having an error in it's construction that would throw your reading off. Any machinist would understand the importance of correctly referencing your readings to eliminate the possibility of stacking up errors. Sorry if people's feelings are involved here-but I'm are discussing mechanical issues here -let's stick to that. Most mechanics that I know curse as a matter of daily conversation,it may not be pretty but then neither is the bottom side of most cars on the road either.

the pics i put up refer to setting proper u-joint operating angle. hence, the
A= front universal joint operating angle
B= rear universal joint operating angle

this is what is confusing some. along with me. and yes, driveshafts can be warped/bent which can throw off the measurement. but, if your driveshaft is bent/warped by more than 1/4*, you could be having a huge vibration issue.

[mrr23]

i've made a sticky on this important subject. if anything needs to be added/removed, let me know. this will keep the inaccuracies to a minimum.

http://www.ls1.com/forums/showthread...808#post224808 this one isn't a sticky yet.

http://www.ls1.com/forums/showthread...813#post224813 this one is stickied in my section.

[mrr23]

don't cuss im my forum. period. i didn't cuss at you. if you can't converse in a more civil matter, then don't. GM did a great job of designing the car. in a generic way. not all the smart people work at GM. usually, the smartest people don't work for a major corporation. they are usually hired in.

i have to apologize for this as this section isn't my part of the forum. it's keliente's section to maintain.