Pinion angle help please. In the middle of setup
07-05-2009, 10:21 PM
#21
If you have an all heim joint suspension I wouldn't go more the 1.5 degrees of pinion angle.
You always have to watch what information you get off the internet. Everytime I see someone tell somebody else to run the pinion angle pointed down 2 degrees no matter what, I always cringe as thats the type of information that gets somebody hurt.
You always have to watch what information you get off the internet. Everytime I see someone tell somebody else to run the pinion angle pointed down 2 degrees no matter what, I always cringe as thats the type of information that gets somebody hurt.
07-05-2009, 11:43 PM
#22
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We are talking about f-bodys not lifted trucks... -2* to the ground isn't going to hurt anybody in this situation. You for sure don't want your pinion pointed straight at the tail shaft or above it, and you would be hard pressed to do that in a f-body with -2* pinion.
07-05-2009, 11:56 PM
#23
you don't want the tailshaft pointed straight at the pinion? realy? think about that statement.
Thats the primary goal you try to achieve. In street cars its hard to accomplish due to the trans tunnel getting in the way, but every professional chassis builder builds there cars with everything dead strait from the front of the crank to the pinion so the u-joint has to do no work what so ever. This also frees up any horsepower it takes to pivot a u-joint.
A pinion pointed up to far is just as dangerous as one pointed down to far. If your trans is pointed down 3 degress and your pinion is pointed down two, thats 5 degrees the u-joints are seeing. You dont think that will break a u joint?
It would be hard pressed to do? Its happened. And its caused a lot of injuries, its nothing to take lightly. I take it you have never seen the after math of a driveshaft coming through a floor?
Thats the primary goal you try to achieve. In street cars its hard to accomplish due to the trans tunnel getting in the way, but every professional chassis builder builds there cars with everything dead strait from the front of the crank to the pinion so the u-joint has to do no work what so ever. This also frees up any horsepower it takes to pivot a u-joint.
A pinion pointed up to far is just as dangerous as one pointed down to far. If your trans is pointed down 3 degress and your pinion is pointed down two, thats 5 degrees the u-joints are seeing. You dont think that will break a u joint?
It would be hard pressed to do? Its happened. And its caused a lot of injuries, its nothing to take lightly. I take it you have never seen the after math of a driveshaft coming through a floor?
07-06-2009, 06:47 AM
#24
All heim joints. I will drive it at the 1.5* neg it currently sits at and see how she drives before doing any hard launches with it. I most likely will not go any more than the -1.5* if there is no reason to. Thanks again for the time promod1955. Finally someone that actually has made this make sense.
07-06-2009, 07:33 AM
#25
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Having the pinion pointed straight at the tail shaft will cause excessive wear to the needle bearings because they will not roll in that type configuration and they will get beat flat. Pro mods must be running bushings to be able to run that type configuration (no needle bearings).
5* may cost you a few horses, but a u-joint will be just fine at that angle.
5* may cost you a few horses, but a u-joint will be just fine at that angle.
Last edited by SPEEDYws6; 07-06-2009 at 07:52 AM.
07-06-2009, 08:47 AM
#27
speedy, your way off on the u joint thing. We run needle bearings in the u joint. Its not the angle that causes the failure, its the two opposing forces that creates vibration that causes the failure. See the last diagram on the right, as this is what your implying needs to be done. Not the case.
I hope this diagram helps everyone. I drew it up in paint right quick and put it on photobucket so I hope it comes out clear.
I hope this diagram helps everyone. I drew it up in paint right quick and put it on photobucket so I hope it comes out clear.
07-06-2009, 08:58 AM
#29
speedy, I hope you understand the reason you even put some pinion angle in the rear to start with is so that under acceleration, the pinion comes up slighty and makes it point the same angle as the transmission tail shaft. Or in a tube chassis car, it's pointed dead smack in the center of the tailshaft under acceleration.
07-06-2009, 11:05 AM
#31
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Most misunderstood deal on the internet. If your transmission tailshaft is pointing down toward the ground 3 degrees (and most fbods are close to that), you better point the pinion yoke UP 1 degree to get proper u joint phase under load.
If you point the pinion yoke down 2 degrees it will come back to 0 under load and the trans tailshaft will still be down 3 degrees...and be out of phase....ujoint killer...
If you point the pinion yoke down 2 degrees it will come back to 0 under load and the trans tailshaft will still be down 3 degrees...and be out of phase....ujoint killer...
07-06-2009, 12:48 PM
#32
The tailshaft and crank should be the same correct? So taking the reading off of either would work? Out of all the searches I have done on this subject though out this forum this has by far been the clearest of them all. Thanks again for the help.
07-06-2009, 01:56 PM
#34
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Thanks promod, looks like I need to get under the car again. I think mine is jumping rope as you put it. I'm not quite sure, but definately think it needs to be looked at.
07-06-2009, 06:52 PM
#39
yall are making this way more difficult then it is. This is the simplest thing to do on your suspension. Look at the chart I did. Its pretty straight forward. Like onfire said, the tailshaft and the pinion yoke is all you need to be worried about. Make them the same, then run the pinion down 1.5 degrees from there. Set it and forget it.
07-06-2009, 09:11 PM
#40
I got my setup figured out. I was however on the wrong side of 0. With a tq arm diagram from Eric @ Midwest I was able to see I was too much positive. I have re adjusted and I am finished for the night. It wound up with -1.0 as of right now. I will finish tomorrow and let you know the actual pinion angle. I can already tell you it won't be close to 2* pinion down toward the ground. Promod is correct tailshaft and pinion. Set to 0 and go down from the zero point. Once I used the smart level and tried to simulate the pinion turning up under load is when I realized I was on the wrong side of 0 as that 1.5* number got larger. Now I am at 1.0 but when I simulate the pinion turning up that number goes to 0 then to the positive side.
