offset vs centered pinion

Stewart Way · 11-21-2007, 12:56 AM

Putting a SS car together for my son, and maybe me, to play with. Its a Mopar and they come with the drive line offset to the pass side around .875 inch. I have access to a new 9" ready to go with fourlink, shock and wheelie bar mounts already mounted and 40 spline drilled axles but it is zero offset. My question is, with a 44" drive shaft that gives me around a 1 degree angle in the drive shaft to the side, will that be a problem? I don't see that that is anymore adverse than a 1 degree dowm angle. Plus, as I look at it, a 1 degree down pinion is no different than a 1 degree to the side and down. Still no more angle in the joint. Don't have the motor and mid plates mounted yet so I could take some of the offset out but it crowds the steering and adds more weight to the drivers side, although not much with 1/2" to 1" change.
As I said, I don't think its a big deal but was wondering what others thought and if anyone has ever played with this type of setup.
I realize that pinion angle eats power, Think I remember something like 1% for every 3 degrees.
Thanks

will prater · 11-21-2007, 07:48 PM

I am no chassis man but I am thinking now the drive shaft would be out in two directions instead of one.

Stewart Way · 11-22-2007, 12:41 AM

Will
Don't think so. Think of the trans tailshaft as the center of a circle and the pinion being the circle. If the circle is a 2" circle the pinion is 1" out. It can be out that 1" anywhere on the c1rcle but the joints only have to make the slightly over 1 degree correction every revolution. Doesn't matter where on the circle the pinion is. We are just used to thinking of the pinion directly below, in line or above thr centerline. I think.

will prater · 11-23-2007, 03:09 AM

Yep I see what you are saying and it sounds right to me. After thinking about it I doubt if very many are exactly centered anyway. Most seem to have a little side to side movement.

Jeremy · 11-24-2007, 11:21 AM

Years ago a friend built a C/G Angela and used a Jeep rear end which had a large off set to one side, I forget which way. We really didn't like doing it but did it anyway and never had a problem with it. I'll bet it's still sitting in his garage.
Thanks

Bryan Broaddus · 11-27-2007, 03:48 AM

My Super Stock car has had an offset pinion in it for 13 years and it has never caused any trouble.

If I were building a new car, I would center the pinion but if it is set up that way now I would not worry about it.

Stewart Way · 11-27-2007, 06:52 PM

Thanks Bryan
I'm sure your Monte hits the pinion harder than this car will. Think I'll go with it.

CPOlesen · 12-16-2007, 11:56 PM

All factory cars have offset to make the u-joints roll. Otherwise they will burn up. That is the reason for the offset.

Tailchaser · 12-24-2007, 11:15 AM

Quote:

Originally Posted by CPOlesen

All factory cars have offset to make the u-joints roll. Otherwise they will burn up. That is the reason for the offset.

True and false.....Chrysler offsets the engine for more floorpan clearance at drivers feet. (other manuf. Also may do the same)The working angle differences from the trans output shaft to pinion shaft is sufficient for rolling the U-joint needles even if both angles are the same, it doent mean each axis will be on the same plane......this creates the angle differential needed to "roll" the needles. I truly dont believe this is much of an issue on a drag car anyway.

11-21-2007, 12:56 AM	#1
Stewart Way Member Join Date: Aug 2003 Location: Atlanta Posts: 476 Likes: 20 Liked 70 Times in 22 Posts	offset vs centered pinion Putting a SS car together for my son, and maybe me, to play with. Its a Mopar and they come with the drive line offset to the pass side around .875 inch. I have access to a new 9" ready to go with fourlink, shock and wheelie bar mounts already mounted and 40 spline drilled axles but it is zero offset. My question is, with a 44" drive shaft that gives me around a 1 degree angle in the drive shaft to the side, will that be a problem? I don't see that that is anymore adverse than a 1 degree dowm angle. Plus, as I look at it, a 1 degree down pinion is no different than a 1 degree to the side and down. Still no more angle in the joint. Don't have the motor and mid plates mounted yet so I could take some of the offset out but it crowds the steering and adds more weight to the drivers side, although not much with 1/2" to 1" change. As I said, I don't think its a big deal but was wondering what others thought and if anyone has ever played with this type of setup. I realize that pinion angle eats power, Think I remember something like 1% for every 3 degrees. Thanks

11-21-2007, 07:48 PM	#2
will prater Member Join Date: Sep 2002 Location: Carthage, MO Posts: 108 Likes: 2 Liked 7 Times in 4 Posts	Re: offset vs centered pinion I am no chassis man but I am thinking now the drive shaft would be out in two directions instead of one.

11-22-2007, 12:41 AM	#3
Stewart Way Member Join Date: Aug 2003 Location: Atlanta Posts: 476 Likes: 20 Liked 70 Times in 22 Posts	Re: offset vs centered pinion Will Don't think so. Think of the trans tailshaft as the center of a circle and the pinion being the circle. If the circle is a 2" circle the pinion is 1" out. It can be out that 1" anywhere on the c1rcle but the joints only have to make the slightly over 1 degree correction every revolution. Doesn't matter where on the circle the pinion is. We are just used to thinking of the pinion directly below, in line or above thr centerline. I think.

11-23-2007, 03:09 AM	#4
will prater Member Join Date: Sep 2002 Location: Carthage, MO Posts: 108 Likes: 2 Liked 7 Times in 4 Posts	Re: offset vs centered pinion Yep I see what you are saying and it sounds right to me. After thinking about it I doubt if very many are exactly centered anyway. Most seem to have a little side to side movement.

11-24-2007, 11:21 AM	#5
Jeremy Junior Member Join Date: Dec 2002 Posts: 95 Likes: 0 Liked 1 Time in 1 Post	Re: offset vs centered pinion Years ago a friend built a C/G Angela and used a Jeep rear end which had a large off set to one side, I forget which way. We really didn't like doing it but did it anyway and never had a problem with it. I'll bet it's still sitting in his garage. Thanks

11-27-2007, 03:48 AM	#6
Bryan Broaddus Member Join Date: Jun 2002 Posts: 104 Likes: 2 Liked 18 Times in 4 Posts	Re: offset vs centered pinion My Super Stock car has had an offset pinion in it for 13 years and it has never caused any trouble. If I were building a new car, I would center the pinion but if it is set up that way now I would not worry about it. __________________ Bryan Broaddus 7568 STK ,SS

11-27-2007, 06:52 PM	#7
Stewart Way Member Join Date: Aug 2003 Location: Atlanta Posts: 476 Likes: 20 Liked 70 Times in 22 Posts	Re: offset vs centered pinion Thanks Bryan I'm sure your Monte hits the pinion harder than this car will. Think I'll go with it.

12-16-2007, 11:56 PM	#8
CPOlesen Junior Member Join Date: Dec 2007 Location: Chandler, Oklahoma Posts: 23 Likes: 0 Liked 0 Times in 0 Posts	Re: offset vs centered pinion All factory cars have offset to make the u-joints roll. Otherwise they will burn up. That is the reason for the offset.