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Post by mongoose on Aug 16, 2011 6:35:06 GMT -5
Periodically I'll see a post from one of you, or somewhere else that talks about the importance of driveline angles, and how that can affect traction related issues... wheel hop, etc.
What method do you use to determine these angles, and what angle should I be in search of?
I figured while I'm putting things back together, I might as well check that. My frame has the multiple rear upper control arm mounting points, so those may come in handy. Worse case is I would have to get adjustable upper arms.
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Post by shane on Aug 16, 2011 7:09:02 GMT -5
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Post by mongoose on Aug 16, 2011 13:38:19 GMT -5
Ah yes... I remember that post... a couple good pieces of advise and insight, mired with a whole lot of irrelevant BS.
Postcar and Andy had some good input... but failed to provide the method they use to actually measure the pinion angle.
Yes my car sits about 2" lower in the rear (which appears to be a good thing), but I've got my motor mounted with solid mounts which holds it approximately 3/4" higher than stock. So I don't know if any slight difference in the motor/transmission angle also needs to be taken into account when determining an appropriate range for setting the pinion angle.
Is the angle measured compared to the drive shaft? Or compared to the ground? What tools do you use to measure it? A magnetic angle locator?
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Post by Deleted on Aug 16, 2011 16:38:04 GMT -5
Pinion angle is in direct relationship to the crankshaft centerline, always was, always will be. There`s no magic involved, that`s why it was never addressed. If you changed your output angle you have altered your angle, changed your instant center.  I know this is leaf spring, but you get the idea After giving this some thought, the best advise I can give you is, if your REALLY wanting those solid mounts, get a set fabricated to set your drive angle where it belongs. Your headed for nothing but problems, and unless your putting out some serious power numbers you don`t need them. Or are you using them for header clearance? Whatever the reason it isn`t worth what your headed for. |
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Post by Deleted on Aug 16, 2011 17:18:45 GMT -5
Ah yes... I remember that post... a couple good pieces of advise and insight, mired with a whole lot of irrelevant BS. Postcar and Andy had some good input... but failed to provide the method they use to actually measure the pinion angle. Yes my car sits about 2" lower in the rear (which appears to be a good thing), but I've got my motor mounted with solid mounts which holds it approximately 3/4" higher than stock. So I don't know if any slight difference in the motor/transmission angle also needs to be taken into account when determining an appropriate range for setting the pinion angle. Is the angle measured compared to the drive shaft? Or compared to the ground? What tools do you use to measure it? A magnetic angle locator? One thing you should realize, in most all discussions there enters in the mix what some may feel is irrelevant content, in ALL my discussions, it seems to always go to pissin on someones shoes. So I guess with that being said, if anyone feels I get a little too pissy with people in my posts, my suggestion would be, if you see postcar as the poster, skip over it, save yourself the aggravation. |
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Post by shane on Aug 16, 2011 18:33:28 GMT -5
Pinion angle is in direct relationship to the crankshaft centerline, always was, always will be. There`s no magic involved, that`s why it was never addressed. If you changed your output angle you have altered your angle, changed your instant center. I know this is leaf spring, but you get the idea After giving this some thought, the best advise I can give you is, if your REALLY wanting those solid mounts, get a set fabricated to set your drive angle where it belongs. Your headed for nothing but problems, and unless your putting out some serious power numbers you don`t need them. Or are you using them for header clearance? Whatever the reason it isn`t worth what your headed for. Very good advise postcar you couldn't have said it any better. |
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Post by bubbasz1 on Aug 16, 2011 21:11:53 GMT -5
Pinion angle is in direct relationship to the crankshaft centerline, always was, always will be. There`s no magic involved, that`s why it was never addressed. If you changed your output angle you have altered your angle, changed your instant center. I know this is leaf spring, but you get the idea After giving this some thought, the best advise I can give you is, if your REALLY wanting those solid mounts, get a set fabricated to set your drive angle where it belongs. Your headed for nothing but problems, and unless your putting out some serious power numbers you don`t need them. Or are you using them for header clearance? Whatever the reason it isn`t worth what your headed for. Very good advise postcar you couldn't have said it any better. One thing I have noticed is the people who actually do know what they are talking about tend to get a little wrinkled when their opinion is offered but gets questioned or is maybe not what the poster wanted to hear. Saying that Dave and I get along quite well, must be his skin has gotten a little thicker when it comes to me, he only gets pissy with me every couple of years.  Oh lets just stick around, maybe we'll all learn a thing or two from these discussions whether it be mechanical or not. I better bookmark this post, if my 5 speed ever comes in I'll need to check it and this tidbit of information will come in handy. |
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Post by mongoose on Aug 16, 2011 21:37:16 GMT -5
save yourself the aggravation. And I typically do... not singling you out... but to the group in general when the topics change from a legitimate discussion into people who think they swing the biggest dick. Once I see that start, I typically just close out that thread. But that's the beauty of a forum... you don't have to put up with it. Your information here is helpful... thanks for your input. |
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Post by mongoose on Aug 16, 2011 21:45:38 GMT -5
Pinion angle is in direct relationship to the crankshaft centerline So a zero degree pinion angle is one where the center line of the crankshaft and the center line of the pinion gear run parallel to each other. So then which way would the pinion gear have to be rotated to be considered a negative pinion angle? Up? |
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Post by shane on Aug 16, 2011 22:09:32 GMT -5
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Post by chadman on Aug 17, 2011 7:06:23 GMT -5
Pinion angle is in direct relationship to the crankshaft centerline So a zero degree pinion angle is one where the center line of the crankshaft and the center line of the pinion gear run parallel to each other. So then which way would the pinion gear have to be rotated to be considered a negative pinion angle? Up? Pinion angle is the relationship of the driveshaft centerline to the pinion centerline. Negative would be with the pinion pointing toward the ground in relation to the driveshaft. I measure mine with the same tool that's in the link Shane posted. Adjustable length upper control arms will let you set this angle to your desired number. |
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Post by mongoose on Aug 17, 2011 8:25:15 GMT -5
Pinion angle is the relationship of the driveshaft centerline to the pinion centerline. Ok. So ideally you want there to be a straight line (under load) from the crankshaft to the pinion gear. But the pinion angle that is referred to is the relationship you mention above between the driveshaft and the pinion gear. But short of being able to create the perfect straight line, and to prevent undo stress on the u-joint at the transmission yoke, or also want to avoid an angle in excess of 3-4 degrees there as well? |
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Post by Deleted on Aug 17, 2011 10:07:38 GMT -5
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Post by shane on Aug 17, 2011 21:54:47 GMT -5
Here is a link to MJ performance they make solid mounts for our olds in case you were thinking of changing them. www.mjproformance.com/products/mounts.php They also have an agreement with ARH to have headers manufactured for our Oldsmobiles. I was talking to a gentleman who has a set of there stainless steel headers on his 65 he said they fit great. Just food for thought. |
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Post by 442scotty on Aug 17, 2011 22:15:15 GMT -5
Great info...thanks all !
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Post by chadman on Aug 19, 2011 9:58:59 GMT -5
Here is a link to MJ performance they make solid mounts for our olds in case you were thinking of changing them. www.mjproformance.com/products/mounts.php They also have an agreement with ARH to have headers manufactured for our Oldsmobiles. I was talking to a gentleman who has a set of there stainless steel headers on his 65 he said they fit great. Just food for thought. I run one of those M&J mounts on my drivers side and a stock style on the passengers side. |
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Post by mongoose on Sept 16, 2011 13:42:52 GMT -5
Ok... so here are the measurements of my driveline.  My pinion has a +1 o angle (nose up) and my transmission shaft has a -5 o angle (nose down), and both my frame and my driveshaft run parallel to the ground (0 o). So if I understand this right, my net "driveline angle" is -4%, which appears to be a good angle for a car with urethane bushings. Yes? Or is the fact that the pinion is pointed "above" the driveshaft (ie already rotated past the centerline of the driveshaft) not a good thing? |
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Post by Deleted on Sept 17, 2011 8:34:54 GMT -5
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Post by Deleted on Sept 17, 2011 9:25:53 GMT -5
Made a phone call to a local chassis builder. Granted, these people make suspension components for nascar, indy and formula one cars, they understand the geometry involved. Gave them the scenario of a trans/engine with a -5 rake, pinion of +1, shaft length of approx 60", he asked for the plane differential between the trans and the pinion, of course without rolling around on the floor under my car I couldn`t give the dimension, so I just said typical A body mid 60`s GM four link. Quick answer , "typical 400 hp range, -3 max on the trans, -2 to -3 on the pinion, -5 is too drastic on the trans to make up in a 60" span considering the close plane a A body has. He went on about how this is all dependant on frame height for and aft, engine alignment, but you get the idea. So this is just another opinion, I`m sure there`s many more.
I hope I relayed the info correctly, I know what he`s saying, but sometimes what`s in my mind doesn`t come out the tip of my finger
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Post by mongoose on Sept 17, 2011 12:57:54 GMT -5
Thanks Postcar... as you suggest, let me study this a half-dozen times, and see if I can get my head around 1) where the set-up is currently at, and 2) what changes I'll need to make to get it where is should be.
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