check my pinion angle before i start welding!! Please

[SatisTraction]

on tuesday i installed some DSE 3" drop leafs with their adjustable pads. i am about to weld the pads but i want to be sure everything is in the right place.

here are the numbers.
the tranny tail shaft is pointed down 4*
the rear pinion is 7* down
the driveshaft is .5" up (towards the front of the car)

how do those numbers sound?

UPDATED INFO BELOW

for me if the part point down then the angle is down :



The tranny tail shaft is 3* down


the Drive shaft is at 2* down in front


the rear pinion is 4* down

[darren@ridetech]

I am no expert, and I have heard many "opinions" on pinion angle, but from what I understand on a leaf spring setup like that you would want to bring your tail shaft up about 1 degree, and bring the pinion up about 4 degrees.

Second opinion???

[Twentyover]

My understanding ( and we all know how limited that is) is that the tailshaft and pinion angles should match...

If the tailshaft is pointed down 4°, the pinion shoild be pointed down 4° OR up 4°.

Unless I'm answering a question that wasn't asked

[hotrdblder]

pinion shoul dbe pointed down 3-4º , because under load the pinion will twist up.

[SatisTraction]

My understanding ( and we all know how limited that is) is that the tailshaft and pinion angles should match...

If the tailshaft is pointed down 4°, the pinion shoild be pointed down 4° OR up 4°.

Unless I'm answering a question that wasn't asked

that is my understanding also. however you have to take the axle wrap into account.

The tranny is where it has to be to clear the thransmission housing.

[SatisTraction]

pinion shoul dbe pointed down 3-4º , because under load the pinion will twist up.

is that 3-4 degrees more then the tranny or 3-4 total?

how to account for the axle wrap?

[darren@ridetech]

They need to be at the same angle when cruising down the highway, otherwise you will get a vibration. Since the tranny must stay 4 degrees down, set your pinion at 4 degrees down as well.

[Vegas69]

whoops

[Vegas69]

_______________

[Vegas69]

Done alot of research and it's been a nightmare of mine lately. It really depends on how low your car is at ride height. The whole driveline and pinion at the same degrees equal but opposite works great on stock ride height but most of us have slammed our cars.
I tried this on mine. The driveshaft pointed up towards the rear of the car over 1 degree. Meaning I had over a 5.5 degree working angle sincet the tranny points down and the shaft up. Ideally you don't want over a 3.5 degree working angle on your u joints. Meaning if your driveshafts slopes down 1 degree and your tranny points down 4 degrees your working angle is 3 degrees. When I talked to DSE about this they said 3-4 degrees on the driveline and 2-3 degrees pinion down is what they usually run. Worth a call to them to verify.

[SatisTraction]

hmm, i am now thinking about either putting the rear rear down 6 or up 1.

ether would should work but the 1 up would make a better drive shaft angle. however that is supposed to bad to traction.

[hotrdblder]

its this easy
if tranny is pointing down 4, then rear shoul dbe pointing down 4, or in most cases you can put rear at plus one of tranny, so 3 down on rear would work well. as stated above thats what most builders and dse use's.
once close you need to drive it at wot, if vibrating you need more inital angle, set it at 3 or 4 degrees down and call it a day

[1969CamaroRS]

Just took a suspension class so some of this is still fresh in my mind, but I am certainly no expert.

But what think I remember on U-Joints was that working angle was supposed to be between 1/2 to 3 degrees. The working angles of the two u-joints should be within 1/2 degree of each other to cancel out the speed differences.

Also if the working angles differ by more than 1/2 degree a vibration could occur that is torque sensitive.

[jaybee]

Like hotrdbldr said. The equal and opposite angles cancel out the twice per rotation speed variation that is inherent to a u-joint. If you ALWAYS drive the car at WOT then fine, the pinion needs to point down a little to account for axle wrap. At part throttle you don't get much pinion rise. On the other hand if you're off by 1-2* it's probably close enough you won't notice the difference.

[Bad Bowtie]

Satistraction,
Here is some very good reading on driveline angles. This explains a lot and should help clear up confusion
http://www.prostreetcamaro.com/dshaft.shtml

BB

[The WidowMaker]

ive always heard the equal and opposite, but its not always true. the angles of your actual parts mean nothing in terms of angles by themselves. its the relationship btwn the parts being connected that matters (ie. the working angle!!!!). this angle should be as close to 1* as possible, and not over 4 degrees. also, your front and rear working angles should not differ by more than .5*. this means if your front working is 2, your rear working needs to be 1.5-2.5*.

forget about matching the trans to pinon. work on the relationship btwn the trans and ds, and ds and pinion. currently my setup has the trans 3* up, ds 2* up and pinion 1* up. this puts 1* working angles front and back and since they are btwn 1 and 4 and within .5 of each other its perfect.

also remember that if it points up towards the front, its an up angle, or at least it is in my examples.

if im understanding you correct, your tailshaft points to the ground 4* (up in my terms), your ds is .5 up and your pinion points down 7*? if thats the case, you have a 3.5* front working angle and a 7.5* rear working angle. if you want the 3* for pinon "wind up" you still need to raise the pinion .5* to be within the .5 max difference or just raise it 1* so theyre the same.

[The WidowMaker]

also, if you shimmed your tranny up, you would decrease its angle and increase the angle of the ds. this would lower that working angle. since you can set you pinion anywhere you want, i would try and get the working angles closer to 1*. just use some trig and realize that moving the pinion up also moves the rear of the ds up which changes its angle and changes its relationship to the tranny.

[SatisTraction]

first let me say thanks for all the advice :cool: that is what makes this place great!!!

i did talk to DSE and i plan to send them a link to this post. The tech i spoke with said to use the rockers as a base line. set them at 0*. did so and here are the numbers.

for me if the part point down then the angle is down :

The tranny tail shaft is 3* down

the Drive shaft is at 2* down in front

the rear pinion is 4* down

[jonnyc]

i've never set up a pinion angle yet but i'm getting ready to.the couple of people i've talked both said to just make sure the car is setting with all the weight as it would be on the ground.find your angle on the output shaft(should be the same as the harmonic balancer) then set the pinion at the same anlge or slightly down.
so in your case,if your tailshaft reads 3* down,set the pinion between
2-3 degrees up.
on gm cars the pinion is set slightly to the drivers side which is what keeps the ujoints from freezing up when the driveshaft is in a straight line.

[The WidowMaker]

if thats the case, then you have a 5* (3 - (-2) working angle in the front and a 2* (-2 - (-4) in the rear. not only will that cause a HUGE vibration issue, but it will also lead to excessive wear.

one thing to remember, the axle centerline to the front of the pinion is at ~12". this means that for every inch it moves up or down with shims, the pinion will change 5*. this is not true for the ds since its MUCH longer. meaning, if you move your pinion up 4*, you will only move your ds 1*.

with the numbers you gave, there is only one real solution if you want to keep it at this ride height; you must move your tranny up. doing so will decrease its angle and increase the angle of the ds to a less negative or even a positive *. this will therefore decrease the working angle at the front. but, by raising the front of the ds, youre changing your rear WA, so you may need to raise your pinion 1 or 2*.

Tim

[Vegas69]

Ride height is by far the biggest factor here. Stock angles just don't work on these slammed pro touring cars. I don't have the time or drive to figure out what ^ he is saying

[SatisTraction]

i understand what he is saying but i dont like it :) LOL.

to raise the tranny would be a HUGE undertaking at this point. the tunnel would have to be cut out and re fabbed.

[darren@ridetech]

There is always the old school method.....obviously many reason not to rely solely on this method. Drive it. If you get a vibration on acceleration then the pinion angle is too high. If the vibration occur under deceleration then it is too low.

I know that you haven't welded your brackets on yet and want to get it right before, but this may help for finished cars. Also on some suspensions you will get more spring wrap than others.

[SatisTraction]

that may be the best advice.

just spoke with mark at DSE and he confirmed the numbers with Kyle. They said forget the 5* front angle and run it like i have it. They said real world experience says it will work just fine.

[hotrdblder]

yes, if an issue ocurs you can buy pinion angle shims to correct the problem easily

[SatisTraction]

yes, if an issue ocurs you can buy pinion angle shims to correct the problem easily

well i am about to go weld it in. i will admit that my heart is not in it at this point. i have a naggin feeling that i will be doing it all again.

i actually think i should swap the 3" drop leafs out for some 2" drop leafs.

[darren@ridetech]

Ironic how the words "opinion" and "pinion" are strikingly similar.... ;)

[Never Enough]

well i am about to go weld it in. i will admit that my heart is not in it at this point. i have a naggin feeling that i will be doing it all again.

i actually think i should swap the 3" drop leafs out for some 2" drop leafs.
I don't understand how this would help you figure out the angles?

[Never Enough]

Ironic how the words "opinion" and "pinion" are strikingly similar.... ;)
As clear as mud.

[SatisTraction]

I don't understand how this would help you figure out the angles?

that would lower the rear which is the same as rasing the tranny. both would still be at 3* but the driver shaft would be lower in the rear and that would change the driveshaft angle.

[paul67]

The faces must run pararell, // so if your gearbox is facing down 4 deg's \ then the axle flange face must face up 4 deg's \, but if you are going to drag race the car then you have to factor in the wind up of the axle when thrashing it up the strip, as the axle is under load up the strip and that would be down to how strong or weak the spring are and if slappers are fitted to restrict the movement of wind up.

[paul67]

ps the 4 deg is to do with the angle of the intake manifold on the engine as most after market manifold carb faces are set at 4 deg , so if like me running an injection engine then it sits flat and so does the axle. A friend of mine builds and recons axles for a living ie his own company been going for 25 + yrs.

[The WidowMaker]

again, the parallel trans to pinion is NOT always true. it works for a stock height car with a stock length trans and a gm rear, but it changes when any of the above change. when lowering a car you can still have equal WA's, but those WA's may be way out of spec. considering a 48" DS, your adding 3.75* to your ds when you move the rear of it up 3" (his 3" drop). that alone is at the far end of the spec. you cant just move the rear, match the pinion and trans and "call it good". ~4* is huge...

how much can you move your tranny up? .25, .5+??? any will help in this instance. just stick something under it and see where your angles fall. i wouldnt just weld it in. you will be vibration free up to a certain speed and then it will get UGLY.....

[SatisTraction]

whats done is done. i hope it works out. if not i will swap to some 2" drop springs. anyone want to trade some 2" for 3" drops?

https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

[paul67]

Not being funny but I bought a 57 chevy truck a few weeks ago that had a vibration problem so bad after 6 miles I got a headache ie you could not drive it, it runs 78 camaro running gear engine a box lower in the weeds,its got 3" dropped spindles front lowered springs and at least 3 leaves removed out back., the axle was so far out of correct angle the bolts holding the ujs were hitting the the prop, now I have corrected the axle to run pararell .with 6 deg wedges so its runs as i said to do and the truck runs vibration free over 100 mph, ie I now use it as my daily driver and have done over 200 miles in 2wks, and its being drag raced this weekend .

[SatisTraction]

i will give a ride report soon. it is ready to go but it has a gas leak at the fuel pump. a new sending unit is on the way!!! :)

[SatisTraction]

well i took it on 1/2 mile 30mph ride and the rear end did not fall out :)

once i get the fuel leak (at the rear of the car) fixed i will beat on it some more.

that was the 1st ride since october!!!!!!!!!!!!!

[jaybee]

"again, the parallel trans to pinion is NOT always true. it works for a stock height car with a stock length trans and a gm rear, but it changes when any of the above change." I maintain that you're partly wrong, partly right. If the trans output shaft and pinion shaft don't run parallel to each other the result WILL be an oscillation in pinion speed. On the other hand a change in ride height will often change the pinion angle and could cause the included angles of the individual u-joints to be excessive. Therefore you can't just put in drop springs (or a lift kit for the 4x4 types) and call it good.

[SatisTraction]

i did some trading for some 2" DSE drop springs so i hope that will help some. i will know next week or so.

[The WidowMaker]

jaybee - putting the two parts parallel guarantees that your WA's will be the same, therefore limiting vibrations. but just because your WA's are the same, does not mean that they are within spec, and that in itself may lead to vibrations. all im saying is that there are other ways to make the WA's the same and still maintain your joints within specs. ill use my current setup as an example; trans up 3, ds up 2, pinion up 1. that leaves 1* at each WA and is the perfect setup because they are as close to 1 as possible without being under, and they are within .5 of each other. but my trans and pinion are still not parallel.

Tim

[The WidowMaker]

check out vibratesoftware.com. its a good site and should solve some questions. it shows that you can even run the trans up and the pinion down; ie. trans 2 up, ds level, pinion 2 down. this is a good configuration when you pinion is higher than or equal to the trans output.

tim

[jaybee]

OK WidowMaker, I think we're thinking pretty close to the same thing but expressing it differently. I said elsewhere if they're close you probably wont notice the difference and you've expressed why...very well. Thanks for clarifying.

[John S]

I know I'm coning in to this thread pretty late but I can help but wonder id things are being made more difficult then they need to be.
Going back to my modified 4X4 days when i was working on lifted trucks there was one general rule of thumb when setting up axles, both front and rear. That was that the pinion U joint needed to be as close to the same plane as the slip joint angle and that the ujoints needed to be in sync.
This would mean that if the slip shaft yoke was 3* down (front to rear) then the pinion yoke would need to be 3*up (front to rear).
Wouldn't the same be true for a lowered car?
Here is a page with useful information
http://www.pirate4x4.com/tech/billavista/PR-shaft/index2.html

Here is an image showing proper setuphttps://static1.pt-content.com/images/noimg.gif