440 Dart pinion angle?

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standup303

standup303

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I have a 8.8 cut and taking it to the welder Monday. I’ve read to properly get pinion angle I need everything installed for the 440 swap, set the car fully down on the tires with 8.8 under it, and measure output shaft then calculate the pinion angle and weld the perches on as pretty much the last step in the swap.

Is there a chart or anything that could give me a pinion angle now. I’d love to just get the perches welded on Monday and be done with it. I’ve seen a lot of threads saying 3-5* down.
 
I found it easier to weld the perches level with the pinion, install the rear on the vehicle and shim the pinion 3-5 degrees down. 65'
 
just me I would wait. that way you wouldn't have to deal later with undoing the ubolts & installing tapered shims if needed & on a side note there was a post on tacking a weld on one side of the perch & letting it cool then repeat on the other side & repeat till done
 
Ripped axle perches off my 440 powered rear axle welded by a friend. Took the housing and perches to a professional next time. I did set it with axle in car and marked it with a sharpie. The welder heated the tube before welding so that the weld would penetrate deeper. One side at a time to avoid twisting the ends.
 
standup303 said:
I have a 8.8 cut and taking it to the welder Monday. I’ve read to properly get pinion angle I need everything installed for the 440 swap, set the car fully down on the tires with 8.8 under it, and measure output shaft then calculate the pinion angle and weld the perches on as pretty much the last step in the swap.

Is there a chart or anything that could give me a pinion angle now. I’d love to just get the perches welded on Monday and be done with it. I’ve seen a lot of threads saying 3-5* down.
Click to expand...
The angle needs to be calculated relative to the crankshaft centerline angle. Opinions differ as to how much this should be. It should be front of pinion lower than parallel to the crankshaft centerline. If someone thinks this is wrong jump in.
 
The first thing is to decide on what angle you need. Then put the housing at the ride height . leave the perches unwelded u-bolt the rear in place loose but snug. Center the rear in the car . Now you can turn the housing . Have the out put shaft of the trans parallel with the pinion in the rear. After you find parallel . The turn the nose down the angle you decided on. I would stay at 3-5 for a race car with stiff front segments or calvert bars. Under hard acceleration the trans output and the pinion should run parallel.. If they are not parallel a constant velocity joint must be used
 
Everybody hollers "pinion angle" but the pinion angle is but ONE small piece to the puzzle. The u-joint working angles are what to pay attention to. See @Oldmanmopar's description above. That's really how simple it is.
 
Oldmanmopar said:
The first thing is to decide on what angle you need. Then put the housing at the ride height . leave the perches unwelded u-bolt the rear in place loose but snug. Center the rear in the car . Now you can turn the housing . Have the out put shaft of the trans parallel with the pinion in the rear. After you find parallel . The turn the nose down the angle you decided on. I would stay at 3-5 for a race car with stiff front segments or calvert bars. Under hard acceleration the trans output and the pinion should run parallel.. If they are not parallel a constant velocity joint must be used
Click to expand...
92b said:
The angle needs to be calculated relative to the crankshaft centerline angle. Opinions differ as to how much this should be. It should be front of pinion lower than parallel to the crankshaft centerline. If someone thinks this is wrong jump in.
Click to expand...
:thumbsup:
 
In my opinion what old man mopar said is right but he left out the math part.
After you have the pinion and crank shaft centerline parallel to each other measure the pinion angle relative to the ground.
For example: If the crankshaft centerline is angled down (from front to rear) 2 degrees relative to the ground. And the front of your pinion is angled up (from rear to front) 2 degrees relative to the ground then they are parallel to each other.
Here is an example if decide you want 4 degrees of pinion angle ( front of pinion lower than rear) relative to the crank shaft centerline.
Because the front of your pinion is pointing up 2 degrees relative to the ground you will need to rotate the front of your pinion down toward the ground until the gauge reads 1 then 0 then 1 then 2 degrees relative to the ground (see picture). Or 4 degrees front of pinion lower than the crank shaft centerline.
I'm not saying you must have the front of the pinion 4 degrees lower than the crankhaft centerline. I'm only using it as an example.
Hope this makes sense. If someone thinks this wrong please point it out. Wouldn't be the first time i was wrong.

16767536678871020083981748867773.jpg
 
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The ground has nothing to do with pinion angle unless your output shaft is level with the ground. You can stand the car on end you still make the trans output shaft parallel with the pinion shaft . Then tilt the pinion opposite of its travel during acceleration a certain degree depending on your calculated twist of the differential . That calculation changes with suspension which controls torque wrap of the rear.

It's pretty easy , Something a kindergartener can do. You all are making it into a geometry class.

Make the shafts parallel and tilt the nose down so they are parallel when you hit the throttle. Put 2 socket swivels on three extensions and play with them . Not that hard to see how it works. If the end 2 are not parallel you won't turn them without bind
 
Oldmanmopar said:
The ground has nothing to do with pinion angle unless your output shaft is level with the ground. You can stand the car on end you still make the trans output shaft parallel with the pinion shaft . Then tilt the pinion opposite of its travel during acceleration a certain degree depending on your calculated twist of the differential . That calculation changes with suspension which controls torque wrap of the rear.

It's pretty easy , Something a kindergartener can do. You all are making it into a geometry class.

Make the shafts parallel and tilt the nose down so they are parallel when you hit the throttle. Put 2 socket swivels on three extensions and play with them . Not that hard to see how it works. If the end 2 are not parallel you won't turn them without bind
Click to expand...
Exactly! The only place the ground is used is when you weld perches on if you're doing it outside the vehicle. Then......the way I do it is weld them on so the pinion center line is 5 degrees nose down to the ground......although I do it with the rear end upside down so I can get to the perches to weld them, so it's 5 degrees up until in the car. It really is grammar school geometry.....probably kindergarten by now, you're right. lol
 
I think the problem is when when people don't understand the difference between 5 degrees relative to the ground and 5 degrees relative to the centerline of the crankshaft. The numbers we read on the protractor or angle finder are relative to the ground. You can say it doesn't matter and be right, but it's still the numbers that we read on the gauges. To somebody who has never done this before that can be confusing.
If somebody ask " What angle should I run my pinion at?" and the reply is "5 degrees down" then the person who is asking is likely to put a angle finder on the rear end, pull the pinion down until it reads 5 degrees and weld it.
The people on this forum are pretty smart. It's not that it is too hard but " 5 degrees down" is not enough information for someone who doesn't know how to do it or doesn't know that 5 degrees down relative to the ground and 5 degrees relative to the crankshaft centerline can be the same or it can be a long way off.
 
92b said:
I think the problem is when when people don't understand the difference between 5 degrees relative to the ground and 5 degrees relative to the centerline of the crankshaft. The numbers we read on the protractor or angle finder are relative to the ground. You can say it doesn't matter and be right, but it's still the numbers that we read on the gauges. To somebody who has never done this before that can be confusing.
If somebody ask " What angle should I run my pinion at?" and the reply is "5 degrees down" then the person who is asking is likely to put a angle finder on the rear end, pull the pinion down until it reads 5 degrees and weld it.
The people on this forum are pretty smart. It's not that it is too hard but " 5 degrees down" is not enough information for someone who doesn't know how to do it or doesn't know that 5 degrees down relative to the ground and 5 degrees relative to the crankshaft centerline can be the same or it can be a long way off.
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If people would only follow instructions and get the Mopar Suspension and Chassis manual, it would be clear as day. Step by step instructions with pictures. But it's like pulling teeth to get folks to find a simple book. They'd rather fuss, fight, argue and pull their hair out on a forum, than find the information themselves. It boggles my mind.
 
RustyRatRod said:
If people would only follow instructions and get the Mopar Suspension and Chassis manual, it would be clear as day. Step by step instructions with pictures. But it's like pulling teeth to get folks to find a simple book. They'd rather fuss, fight, argue and pull their hair out on a forum, than find the information themselves. It boggles my mind.
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True, but if we got rid of every thread that asked a question that could have been lookup or answered somewhere else there wouldn't be much of a forum left. Sometimes you hve to put up with stuff you don't like to enjoy the part you do.
 
92b said:
True, but if we got rid of every thread that asked a question that could have been lookup or answered somewhere else there wouldn't be much of a forum left. Sometimes you hve to put up with stuff you don't like to enjoy the part you do.
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...and I've been right here on every one of these threads askin the same **** over and over and over again trying to explain it, have I not?
 
Here is a link to a video of my circle track car (metric 4 link) on our dyno to see and measure pinion wrap. First let me say that the shock is not bent. The lens on the gopro makes it look that way.
The 3" mark is the at rest zero. I know I should have marked it differently. Anyway, the rod is 12" long from the centerline of the axle to the black mark on the rod. Math: .209 inches per degree. so .5 inches of travel = 2.39 degrees at the maximum amount of wrap up travel seen. At the end of the video I make the long measured and recorded pull by the dyno. If you watch closely you can see the pinion wrap to max travel then slowly unwrap as it goes past peak power.
Different cars , traction , suspension types, horsepower levels and etc. are going to affect what the correct pinion angle is for your application.

 
92b said:
Here is a link to a video of my circle track car (metric 4 link) on our dyno to see and measure pinion wrap. First let me say that the shock is not bent. The lens on the gopro makes it look that way.
The 3" mark is the at rest zero. I know I should have marked it differently. Anyway, the rod is 12" long from the centerline of the axle to the black mark on the rod. Math: .209 inches per degree. so .5 inches of travel = 2.39 degrees at the maximum amount of wrap up travel seen. At the end of the video I make the long measured and recorded pull by the dyno. If you watch closely you can see the pinion wrap to max travel then slowly unwrap as it goes past peak power.
Different cars , traction , suspension types, horsepower levels and etc. are going to affect what the correct pinion angle is for your application.

Click to expand...

Hey is that shock bent?
 
Thanks all. Get motor/trans installed, set rear pinion parallel with trans output shaft. Then set pinion down
3-5* from there, weld perches. Got it. Sounds easy.
 
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