I did some measuring on my driveline today and need to know if I am off and how far. The trans is pointing 3* upward and the rearend is pointing 5* degrees upward. Which direction do I need to turn the rearend to get the correct angle and how far?
Which way should I go with pinion angle ??????????????????????
- Thread starter duster360
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straightlinespeed
Sometimes I pretend to be normal
Ideally you want them pointing directly at each other. If you have a high horsepower car then you want the pinion pointing downwards slightly. When you get on the gas hard the rear end wants to rotate up (pinion rotating towards the bottom of the car). The less stress you have on the u-joints the better so depending on your application is where I would go from there.
67Dart273
Well-Known Member
Are you CERTAIN of your measurements? This does not seem reasonable.
What you want UNDER ACCELERATION is the two shafts, that is the transmission output shaft and the pinion shaft should be PARALLEL.
There is some argument as to how much "down" pitch you need in order to obtain parallel under hard load, but somewhere in the 2-3* range. This WILL DEPEND on how strong the springs are, how much HP you have, any traction devices used and so on
What you are saying is that the rear axle already points UP too far. I'm not sure I understand how this could be true.
Again, the drawing depicts UNDER LOAD/ ACCELERATION
[ing]http://www.4xshaft.com/images/2joint_angle.gif[/img]
I had this rearend built to fit an A body. I had to weld on new spring perches and it has 2800 lb super stock springs. The engine is a 340 with 350hp or less. This is just a street car.
67DART273. The link is no good.
67DART273. The link is no good.
straightlinespeed
Sometimes I pretend to be normal
As mentioned above, you want them inline. I do know they make shims to give you different angles on the pinion. There are a lot of good write ups on the internet about pinion angles. I had to do a lot of research when I built a off road jeep and did a axle swap.
straightlinespeed
Sometimes I pretend to be normal
Do you have the drive shaft installed? Its easier to get the correct angle with that installed. Also do you have the full weight on the car? You cant measure pinion angle with the axle hanging.
Hyper-Performance
Late Apexer
As a rule of thumb, I try to set up a driveline with the trans. output shaft 3 degrees downward and the rearend yoke 3 degrees upward.
The car is on 4 ramps that are the same height. No driveshaft yet, I am working on getting one. I also made sure the torsion bars are loaded so the car will sit at the correct height.
Don't know if I can lower the tail end of the trans.
Woods74
Broke Senior
Guys, stop bs'ing and please read this article:
http://www.carcraft.com/howto/91758/
"The average car crafter should strive for between 1 and 3 degrees between the tailshaft of the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite (see crude diagram)." - Driveline Gods
http://www.carcraft.com/howto/91758/photo_08.html
http://www.carcraft.com/howto/91758/
"The average car crafter should strive for between 1 and 3 degrees between the tailshaft of the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite (see crude diagram)." - Driveline Gods
http://www.carcraft.com/howto/91758/photo_08.html
67Dart273
Well-Known Member
I'm not B.S.ing as you put it
The first part of that statement is MISLEADING
"strive for between 1 and 3 degrees between the tailshaft of the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion"
IS MISLEADING
The driveshaft angle does not mean squat and is in fact a function of suspension, IE my old Landcruiser had ONE HELL of a lot more shaft angle than 1--3*
THE LAST SECTION of the statement is partially correct:
"the two angles should be nearly equal (------------------), but always opposite"
THE THING THAT IS IMPORTANT is that the TWO SHAFTS are PARALLEL under full load. JUST LIKE in the diagram I posted. PARALLEL
This is not some B.S. I dreamed up.
IMO, static, you never want the angle to be zero.
I run them from 2-4 down. Some cars need a bunch more.
Double check, unless the butt of your car is WAY up in the air, the trans output is almost always pointing down. In your current case if the trans is pointing up, your want the pinion pointing down the same number of degrees to get a zero angle. Then roll your pinion down 2-4 and that will set it right. If the trans is 3* up and pinion is at 5* down, you have a -2 angle. If it's up and up that's a +8 angle, not good
I run them from 2-4 down. Some cars need a bunch more.
Double check, unless the butt of your car is WAY up in the air, the trans output is almost always pointing down. In your current case if the trans is pointing up, your want the pinion pointing down the same number of degrees to get a zero angle. Then roll your pinion down 2-4 and that will set it right. If the trans is 3* up and pinion is at 5* down, you have a -2 angle. If it's up and up that's a +8 angle, not good
pishta
I know I'm right....
You want them just short of parallel at drive load, ie..5 UP at trans+ 5 DOWN at pinion, but you want to start at like 8 down at trans so when pinion wraps UP it gets closer to parallel (ie total is 0, +5 at trans, and -5 at pinion. A neutral (0) driveshaft angle at drive is not recommended, but at WOT power it is....last post is correct.
Woods74
Broke Senior
67Dart273 relax, your wound up way to tight. Did you read the article? 404 not found on your diagram.
younggun2.0
Well-Known Member
ok, i just did this with my car. I spoke with the guys at cal-trac on the phone and had them dummy it down for me so i could understand.
you dont need a drive line in the car to to do this. it is actually easier without it. it just makes you over think it.
the factory set the engines with roughly 2 degrees of downward slope at the tail shaft of the trans. engine is higher than the trans.
so depending on your rear suspension you will have between 3-5 degrees of axel wrap in an upward motion at the pinion snout.
here is what i did. my engine and trans was pointing down 3 degrees.
so under full acceleration the snout of the pinion should be pointing up 3 degrees. that way both units are on parallel planes.
so you take the 3 degree upward degrees on the pinion and subtract the 3-5 degree of axel wrap. so you would be at between down 1 degree and 0 degrees.
you have it right to have the car up in the air but on the tires. get the car as level as possible but doesnt have to be perfect. measure your engine and trans angle and then use that to set the rear,
you dont need a drive line in the car to to do this. it is actually easier without it. it just makes you over think it.
the factory set the engines with roughly 2 degrees of downward slope at the tail shaft of the trans. engine is higher than the trans.
so depending on your rear suspension you will have between 3-5 degrees of axel wrap in an upward motion at the pinion snout.
here is what i did. my engine and trans was pointing down 3 degrees.
so under full acceleration the snout of the pinion should be pointing up 3 degrees. that way both units are on parallel planes.
so you take the 3 degree upward degrees on the pinion and subtract the 3-5 degree of axel wrap. so you would be at between down 1 degree and 0 degrees.
you have it right to have the car up in the air but on the tires. get the car as level as possible but doesnt have to be perfect. measure your engine and trans angle and then use that to set the rear,
Supershafts
Well-Known Member
None of this is right, this is ALL DEPENDENT on use, for a DD back and forth to work do as you are..
adriver
Blazing Apostle
Well, I got here. I took a detour.
Does this help?
Putting an answer into words makes my head hurt.
Does this help?
Putting an answer into words makes my head hurt.
With the output shaft on the trans at 0 the the pinion shaft on the rear should be 7 down. so if the trans is 3 down the rear should be 10 down using a bubble angle finder. If the trans is 3 up the rear should be 4 down. Another words the rear should have a 7 degree difference down verses the trans. This is with stock strong springs. This is to compensate for rear lift on acceleration. The two shafts on the trans and rear should be on the same plenum on acceleration. another words. if the trans is at zero the rear should be at zero on hard acceleration . This prevents the u-joints from fighting one another and binding. this is reason for setting the pinion angle in the first place. every spring wraps different. But 7 is the general number. A snubber forces the rear into the street for traction help and also helps control wrap. The rear should be left to rise the amount needed to get them on the same plenum. This is what I do and never have u-joint problems. Unless a constant velocity joint is used as seen on this lifted short bed diesel truck the rear faces up.
adriver
Blazing Apostle
It's not just me then.
And I even managed to find mine.
Two accomplishments in a row.
I must be having a good day.
Everything is starting to make more sense now.
I was sitting here thinking about the comments made here and it came to me that I totally screwed up when taking the degree measurements. I was ready to go in for the day and thought I would take those measurements quicly and go in and post here for info. Well, first off I put the angle finder on the bottom of the tailshaft housing instead of on the end of the output shaft itself. Second, I put the anglefinder on the bottom of the pinion yoke instead of on the front where the ujoint goes in. What in the he!! was I thinking last night.
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