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Re: Pinion Angle - One More Time - Please
[Re: Junky]
#1187782
03/01/12 01:52 PM
03/01/12 01:52 PM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
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Joined: Mar 2010
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Out in Left Field, NY
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Quote:
383man, you're forgiven. 
To all. I'm gonna follow Bob's advise and go with 2° nose up (positive) or as close to that as I can.
Thanks again, Bob. 
Just to be clear, you want to make sure the pinion is at the SAME angle as the output shaft. It isn't necessarily nose up or down. That depends on whether the trans is higher in the car than the rear, which most are. The 2 degree angle is measured compared to the DRIVE SHAFT. If that's the case then the pinion will be nose DOWN in relation to the drive shaft. In any case as long as you keep both at the same angle and there's a 2 degree or so angle where the u-joints are, you should be good to go.
FOLLOW THE TUTORIAL IN THIS LINK. It explains it better than I can.
http://www.hurst-drivelines.com/files/Universal_Joint_Alignment_Proc_111606.pdf
Read through it so you understand it.
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Re: Pinion Angle - One More Time - Please
[Re: bobs66440]
#1187783
03/01/12 02:09 PM
03/01/12 02:09 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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Grand Haven, MI
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Cass (Dr Diff has it right)....pinion angle is in relation to the tranny output shaft. for a street car, measure the output shaft of the tranny. then measure the pinion. make them parallel, then roll the pinion down about 2 degrees, so they're parallel when the car is under power. driveshaft angle is incidental, as long as it's not in line with the tranny output or pinion.
so if the tranny is say, 3 degrees nose down to the world, the pinion needs to be 3 degrees nose up to the world to be parallel. Then it needs to be rolled down about 2 degrees, so the pinion is 1 degree nose up to the world, so it's 2 degrees nose down to the tranny.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Pinion Angle - One More Time - Please
[Re: DoctorDiff]
#1187785
03/01/12 02:42 PM
03/01/12 02:42 PM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
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Posts: 1,880
Out in Left Field, NY
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Quote:
Yes. Static pinion angle on most stock, original cars is around 2 degrees negative. In other words, the pinion centerline points 2 degrees downward relative to the transmission centerline at rest.
This allows the pinion to run parallel with the transmission as the pinion winds up a tad under cruise.
If this is the case, then why does every tech article and diagram including all the ones posted here state to make the (static) center lines parallel (excluding drag car setups)? I can understand why you would want to do it on a drag car because it's always under acceleration. But a street car isn't always accelerating. Sometimes it's coasting or cruising with little or no load, in which case the nose down setup would cause a vibration. Sometimes it's braking which would make it even worse.
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Re: Pinion Angle - One More Time - Please
[Re: DoctorDiff]
#1187788
03/01/12 03:51 PM
03/01/12 03:51 PM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
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Ideally, you want the pinion and transmission parallel under cruise, because that is where a street cars spends most of its driving time.
The pinion is not static under cruise. Torque rotates it upward a couple degrees.
Ok, I wasn't aware that it rotated and held there during cruise. I assumed that the springs or radius rods (or whatever is holding the rear in place) would counteract that motion after the initial torque from accelerating had dissipated. Of course, we're only talking a couple of degrees which isn't much. You learn something new every day.
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Re: Pinion Angle - One More Time - Please
[Re: 67Satty]
#1187789
03/01/12 04:30 PM
03/01/12 04:30 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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Quote:
Not to hijack, but I measured my pinion angle. I found that I am 2 degrees up on the pinion and 2 degrees up on the driveshaft/trans for a total of 4 degrees positive.
The Mopar Performance Chassis book says the pinion angle should be 5 to 7 degrees negative. But that's for a drag-only car I guess.
I've got a street/strip car with Superstock springs. I ordered a pair of 4 degree shims. By my calculations that should get me down to 4 degrees negative (a 2 degree shim would get me to 0, so another 2 degrees would get the pinion down 2 degress plus the driveshaft down 2 degrees for 4 degrees down total). Is that a good compromise for a street/strip car? I've been researching this online and have been coming up with the recommendation of 4 degrees negative a lot. Some will even recommend various amounts of negative pinion angle for various amounts of horsepower. Like 4 degrees down for cars in the 400 HP range and more towards the 7 degrees down end for higher HP like 700 HP and up. Is my math correct? Thanks!
no, driveshaft really has nothing to do with pinion angle. it's the relationship of the tranny output shaft to the pinion that's important. as Dr. Diff said, for a street car, 2 degrees nose down relative to the tranny output shaft is good for a street car
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Pinion Angle - One More Time - Please
[Re: patrick]
#1187793
03/01/12 05:52 PM
03/01/12 05:52 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Posts: 27,421
Balt. Md
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Its no wonder so many get confused about pinion angle when you read some of the article's about it. Some talk about the driveshaft angle and has many thinking the pinion should be 2 less then the driveshaft angle. The one article posted says to leave the trans and pinion the same as he states that where he prefers street cars to be. But really as Dr Diff says its very simple. Dont worry about the driveshaft angle just check the eng,trans angle which you could measure at the trans output shaft yoke and then measure the pinion angle which can be checked at the pinion yoke. Just make sure you are on the yokes and not the driveshaft. So you check the trans and pinion angle then just set the pinion 2 degrees down from the trans and you are done. Ron
Last edited by 383man; 03/01/12 05:54 PM.
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Re: Pinion Angle - One More Time - Please
[Re: 383man]
#1187794
03/01/12 05:57 PM
03/01/12 05:57 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Posts: 36,040
Lincoln Nebraska
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Quote:
So you check the trans and pinion angle then just set the pinion 2 degrees down from the trans and you are done. Ron
Ron if my trans is 2 deg down and the pinion is 4 deg down I'm good? EDIT & forget about the parallel in diff planes info
Last edited by RapidRobert; 03/01/12 06:05 PM.
live every 24 hour block of time like it's your last day on earth
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Re: Pinion Angle - One More Time - Please
[Re: Kern Dog]
#1187795
03/01/12 06:58 PM
03/01/12 06:58 PM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
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Quote:
Could I get this explained again?
Second or third time around it's not "explained" anymore,...it becomes "splain it agin plez".... 
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Re: Pinion Angle - One More Time - Please
[Re: RapidRobert]
#1187796
03/01/12 07:01 PM
03/01/12 07:01 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Posts: 27,421
Balt. Md
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Quote:
Quote:
So you check the trans and pinion angle then just set the pinion 2 degrees down from the trans and you are done. Ron
Ron if my trans is 2 deg down and the pinion is 4 deg down I'm good? EDIT & forget about the parallel in diff planes info
No actually if the trans is 2 down the pinion would be 2 up to have the same level centerline as the trans and then go 2 down on the pinion from there which would be 0. Ron
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Re: Pinion Angle - One More Time - Please
[Re: 383man]
#1187797
03/01/12 09:45 PM
03/01/12 09:45 PM
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Joined: Jan 2003
Posts: 5,186
Wherever I am.
Junky
OP
master
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OP
master
Joined: Jan 2003
Posts: 5,186
Wherever I am.
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Quote:
Quote:
Quote:
So you check the trans and pinion angle then just set the pinion 2 degrees down from the trans and you are done. Ron
Ron if my trans is 2 deg down and the pinion is 4 deg down I'm good? EDIT & forget about the parallel in diff planes info
No actually if the trans is 2 down the pinion would be 2 up to have the same level centerline as the trans and then go 2 down on the pinion from there which would be 0. Ron
Far out. I don't have to shoot me.
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Re: Pinion Angle - One More Time - Please
[Re: RapidRobert]
#1187799
03/02/12 09:26 AM
03/02/12 09:26 AM
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
bobs66440
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Joined: Mar 2010
Posts: 1,880
Out in Left Field, NY
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Quote:
Quote:
No actually if the trans is 2 down the pinion would be 2 up to have the same level centerline as the trans and then go 2 down on the pinion from there which would be 0. Ron
Thank you Ron, I'm grasping it now. It amazes me that something this simple can be that confusing 
I think a lot of the confusion comes in because a lot of this is based on theory. I would imagine that many of cars like ours that have been modified so many times over the years by God knows who, are running around with screwed up configurations without the driver even knowing it. When you are talking 1 or 2 degrees, it probably goes unnoticed because of natural vibrations from an old car, monster motors, etc. If someone sets a suspension up slightly wrong, drives it and it feels ok, then it becomes gospel in his mind. My opinion is that if you get the setup within a degree or two plus or minus, most people will not notice a difference.
Apparently, you have half of the guys setting it up perfectly parellel, and the other half setting it up 2 degrees down, and they're all happy with it...it must not make much difference. Everybody's correct.
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