2000 Chevy Silverado project "Charlie Murphy"
04-19-2012, 01:03 AM
#32
Thats a good idea with the bumpstops, I think I may do that as well.
You generally want the axle to point down 3* so when you apply power the springs flex and the axle will rotate upwards...about 3*...so its perfectly level with the driveshaft.
Good job on the project!
You generally want the axle to point down 3* so when you apply power the springs flex and the axle will rotate upwards...about 3*...so its perfectly level with the driveshaft.
Good job on the project!
04-19-2012, 01:13 AM
#33
You removed 2" lift blocks, and since the diff is now closer to the chassis, your driveline angle straightened out, and you lost a couple of degrees. Then you added your lowering shackles and straightened it out even more. I'll say that it is true that the shackles also changed the angle of the leaf spring, and that also affects pinion angle, but only by half as much as the drop. Now you have almost a 0* pinion angle, +/- 1 degree. I know this is true because I've lowered several 4x4's over the years, and this is always the case.
In the end, you want to have around a 4* negative pinion angle when you're all done. That will help the u-joints live, and reduce driveline vibrations. Also, when you launch the truck, or accelerate hard, the pinion gear will try to climb the ring gear, which points the pinion up, and straightens out your pinion angle(so to speak). When you're WOT, and the driveline is exactly in-line with the pinion shaft, that is a perfect setup. It takes the least amount of hp to turn it.
04-19-2012, 02:01 PM
#34
Let me elaborate. *Your truck at stock height should have had a 3-4* negative pinion angle(driveshaft to pinion).
You removed 2" lift blocks, and since the diff is now closer to the chassis, your driveline angle straightened out, and you lost a couple of degrees. *Then you added your lowering shackles and straightened it out even more. *I'll say that it is true that the shackles also changed the angle of the leaf spring, and that also affects pinion angle, but only by half as much as the drop. *Now you have almost a 0* pinion angle, +/- 1 degree. *I know this is true because I've lowered several 4x4's over the years, and this is always the case.
In the end, you want to have around a 4* negative pinion angle when you're all done. *That will help the u-joints live, and reduce driveline vibrations. *Also, when you launch the truck, or accelerate hard, the pinion gear will try to climb the ring gear, which points the pinion up, and straightens out your pinion angle(so to speak). *When you're WOT, and the driveline is exactly in-line with the pinion shaft, that is a perfect setup. *It takes the least amount of hp to turn it.
You removed 2" lift blocks, and since the diff is now closer to the chassis, your driveline angle straightened out, and you lost a couple of degrees. *Then you added your lowering shackles and straightened it out even more. *I'll say that it is true that the shackles also changed the angle of the leaf spring, and that also affects pinion angle, but only by half as much as the drop. *Now you have almost a 0* pinion angle, +/- 1 degree. *I know this is true because I've lowered several 4x4's over the years, and this is always the case.
In the end, you want to have around a 4* negative pinion angle when you're all done. *That will help the u-joints live, and reduce driveline vibrations. *Also, when you launch the truck, or accelerate hard, the pinion gear will try to climb the ring gear, which points the pinion up, and straightens out your pinion angle(so to speak). *When you're WOT, and the driveline is exactly in-line with the pinion shaft, that is a perfect setup. *It takes the least amount of hp to turn it.
I can't see how the removal of the blocks would affect the pinion angle at all. What it would affect is the driveline angle.
Also, the degree change because of the shackles does not need to be divided by 2. I'm not sure why you think that.
The only thing I can figure is you're confusing lowering the vehicle with shackles and only getting half of the difference in lowering verses the length of the shackle. This is because you're only changing half of the leaf spring.
The picture is correct. The only way you would put the fat end facing forward would be if the springs went under the axle instead of over.
It's best to have some angle between the pinion and driveline (not zero degrees) because engineers want the u-joint to lubricate via some movement. If it turns out that I have zero degrees, oh well. I don't think it's that big of a deal. Although, 3° or so negative pinion angle would be ideal for the reasons you listed above.
The best thing will be for me to measure the angles and see what I have. I won't be able to do that for a few days though. I'll be working 12 hour shifts for a while.
Any guesses on what my pinion angle is?
Oh, if removing the blocks affected pinion angle, then why aren't the blocks wedge shaped?
04-19-2012, 04:34 PM
#36
I was talking specifically about my factory 2 inch block. I could see the larger blocks being tapered because it lifts the truck so high that the driveline angle is pushed beyond what the pinion angle is capable of. So in essence, a tapered block would affect both the driveline angle and the pinion angle.
Like I said earlier, I'll just measure it myself when I'm done and see what it is. Well, I'll try. I don't have a 4 post lift so I'm not sure if I can get under there.
It's funny, I researched a lot about pinion and driveline angles when I was building my 4Runner. Everybody wants to set them up a bit differently. Some suggest 0-3°, others up to 6°. It all depends in what kind of rear end setup you have. 3-Link? 4-Link? Leaf or coil? I read where one gout recommended different angles depending on how much horsepower you're planning on making.
Thanks for bringing it up though. I love discussing stuff like this!
Like I said earlier, I'll just measure it myself when I'm done and see what it is. Well, I'll try. I don't have a 4 post lift so I'm not sure if I can get under there.
It's funny, I researched a lot about pinion and driveline angles when I was building my 4Runner. Everybody wants to set them up a bit differently. Some suggest 0-3°, others up to 6°. It all depends in what kind of rear end setup you have. 3-Link? 4-Link? Leaf or coil? I read where one gout recommended different angles depending on how much horsepower you're planning on making.
Thanks for bringing it up though. I love discussing stuff like this!
04-20-2012, 10:32 AM
#37
The bolts that come with the shims are longer because you need to put in spacers between the head of the bolt and the leaf spring so it protrudes all the way through the shim and into the spring perch. They keep the axle centered with the leaf spring. I didn't use spacers with my 2* shims and the bolt heads weren't long enough. I'd double-check your install. Belltech is stupid and doesn't provide spacers with their bolts though.
Get a angle finder and measure your rear end angles, that's the only way to be sure. I went with 6* shims, fat end forward, to give me a -1* pinion angle (pinion is pointing towards the ground at 1*). But mine is 2wd, 2" hangers and shackles.
Get a angle finder and measure your rear end angles, that's the only way to be sure. I went with 6* shims, fat end forward, to give me a -1* pinion angle (pinion is pointing towards the ground at 1*). But mine is 2wd, 2" hangers and shackles.
04-20-2012, 11:02 AM
#38
So you're saying that the bolts that came with the shims are meant to be installed with the threaded part facing downward? Then you screw on the nut and the nut locates the spring pack in the axle housing?
That seems like a lot of work getting the bolts cut to exactly the right length so they can be installed upside down.
I assumed that the bolts included with the shims would have a taller head than the factory ones, but when I had it all apart, the heads were the same height. That's why I don't bother changing out the bolts.
There may have not been as much of the bolt head protruding into the axle mount as there was before, but it was aligned with the mounts. I kept pressure on the axle until I heard (and felt) the spring pack click into place.
The only way to get the spring pack's bolt to sit deeper in the axle mount's hole, would be to install it upside down like you said and that would be very difficult to do. If even possible at all since the nuts that came with the kit are so long.
It's probably not the best shim design. A kit that had bolts with extra tall heads, and shims with holes in them, rather than slots, would be a better design.
That seems like a lot of work getting the bolts cut to exactly the right length so they can be installed upside down.
I assumed that the bolts included with the shims would have a taller head than the factory ones, but when I had it all apart, the heads were the same height. That's why I don't bother changing out the bolts.
There may have not been as much of the bolt head protruding into the axle mount as there was before, but it was aligned with the mounts. I kept pressure on the axle until I heard (and felt) the spring pack click into place.
The only way to get the spring pack's bolt to sit deeper in the axle mount's hole, would be to install it upside down like you said and that would be very difficult to do. If even possible at all since the nuts that came with the kit are so long.
It's probably not the best shim design. A kit that had bolts with extra tall heads, and shims with holes in them, rather than slots, would be a better design.
04-21-2012, 12:23 PM
#39
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So you're saying that the bolts that came with the shims are meant to be installed with the threaded part facing downward? Then you screw on the nut and the nut locates the spring pack in the axle housing?
That seems like a lot of work getting the bolts cut to exactly the right length so they can be installed upside down.
I assumed that the bolts included with the shims would have a taller head than the factory ones, but when I had it all apart, the heads were the same height. That's why I don't bother changing out the bolts.
There may have not been as much of the bolt head protruding into the axle mount as there was before, but it was aligned with the mounts. I kept pressure on the axle until I heard (and felt) the spring pack click into place.
The only way to get the spring pack's bolt to sit deeper in the axle mount's hole, would be to install it upside down like you said and that would be very difficult to do. If even possible at all since the nuts that came with the kit are so long.
It's probably not the best shim design. A kit that had bolts with extra tall heads, and shims with holes in them, rather than slots, would be a better design.
That seems like a lot of work getting the bolts cut to exactly the right length so they can be installed upside down.
I assumed that the bolts included with the shims would have a taller head than the factory ones, but when I had it all apart, the heads were the same height. That's why I don't bother changing out the bolts.
There may have not been as much of the bolt head protruding into the axle mount as there was before, but it was aligned with the mounts. I kept pressure on the axle until I heard (and felt) the spring pack click into place.
The only way to get the spring pack's bolt to sit deeper in the axle mount's hole, would be to install it upside down like you said and that would be very difficult to do. If even possible at all since the nuts that came with the kit are so long.
It's probably not the best shim design. A kit that had bolts with extra tall heads, and shims with holes in them, rather than slots, would be a better design.
04-21-2012, 01:51 PM
#40
If you are certain the head of the bolt is long enough to stick through the shim and securely center the spring on the perch then fine. Maybe my 2* shims with thicker than yours.
The bolts they supply are really long because they are universal so they can go through much thicker leaf spring packs. If they are too long then you just cut off some of the threaded end. Mine stick out about 1" but they don't hit anything. Here are the ones I got. You can see in the pic that they come with spacers to "extend" the head of the bolt so it's long enough to go through the shim.
You can probably find spacers that will work at the hardware store, and some actual lock nuts, not the stupid coupling nuts Belltech gave you.
The bolts they supply are really long because they are universal so they can go through much thicker leaf spring packs. If they are too long then you just cut off some of the threaded end. Mine stick out about 1" but they don't hit anything. Here are the ones I got. You can see in the pic that they come with spacers to "extend" the head of the bolt so it's long enough to go through the shim.
You can probably find spacers that will work at the hardware store, and some actual lock nuts, not the stupid coupling nuts Belltech gave you.