Slam Specialty(UPDATE: 7-21-08)

Oh, Seth.. I was actually asking about the dimensions of your x-members, lol...

I'm sure it all differs from one truck to another, so I guess I should ask what kind of clearance I should make for the driveshaft notch... BTW, what kind of spread do you have on the datsuns upper links at the x-member?

Haha, sorry speedster, I tend to do that alot. Its easier to convey it you were in person...

My tranny points down -5 degrees as well as the front portion of the first driveshaft. Which means their OA(operating angle) is 0.

I thought I was then supposed to figure how much the driveshaft was pointing down so I took the next measurement in degrees and worked it. Which would be the first driveshafts two angles. -5 and -5. So I get 0 degress.

So then I went on. -5 minus -2 =-3 degrees OA. And then -2 minus -1 = -1. So if that is so would I have to subtract the -1 from the -3 to figure pinion angle? Which would then be -2 or +2 for pinion angle?

LOL, does that make sense now speedster? But like you said and I said, I need to actually get the axle setup now... So I guess it was a little premature, eh?

Hey immortal! Nice to hear from ya! Where ya been hiding? I could use another smart guy around here! I'm not sure how to take that info, lol, but I'll take it. I think your referencing to the part whee I asked about 0 OA for the driveshafts being bad, right? OR are you just talking about that so to say that if my pinion is off a few degrees, it will be okay because of how they have the driveshaft oriented from a top view?

Thanks for the help guys, I dunno how many times I can say that before it starts getting over rated, haha! I'm gonna get out there today and get this all setup and see what comes out, lol... I'll even have a person to talk to.

I'm up friggin early this morning too! Alarm on my truck goes off and I get out there ready with my shotgun thinking someone is out there trying to steal my stuff! False alarm! f'in alarm! Funny cause I got the truck in the "garage" and I gott keep the doors open and all me tools are in there!

Thats a dimension you are going to need to find for yourself. Get the truck in the laid out position, and see how high the driveshaft goes. Add an inch to that and make your cross member kick up that high.

And the spread is like I have told you before, 8.565" at the axle, 7" at the frame, 20" bars.

Not a problem buddy! I need to make a trip over and see this in person!

Looking good though!


Dev <img src="{SMILIES_PATH}/icon_biggrin.gif" alt=":D" title="Very Happy" /><!-- s:D -->

Well, don't be a stranger immortal! Like to hear from ya! And how in the world would I figure out the angle from the top? Hmmm...

Seth, I used the wrong word, lol. I was talking about your upper links triangulation at the x-member. Cause I built my 4-link geometry at a 4&quot; triangulating spread at the x-member and if the height is all screwy, I will probably have to redo it to compensate for the driveshaft notch and all..

YEA! DEV! We also need to get together sometime when I'm done and make some DRAG VIDS! WOOO! I got big plans for some fun this summer!

UPDATE!

OKAY! Guys, let me know if I'm doing something wrong here...

So I spent a couple hours today making up a little cradle for the rear end. It turned out pretty nicely, and 'am a little proud of myself! Except lifting the rearend like it is and using my feet to kick this thing under is a pain!

I've got some outriggers on the bottom to keep the rearend from tipping it over and the legs are at a fixed height unless I put new ones in or cut them. I had to compensate for the floor and I did good I think!

This is'nt quit a jackstand and all and I only have 4 not 8 laying around, haha! I made another part of the cradle with an arm that comes out and holds the driveshaft. I can adjust the angle by rescrewing the wood in... It will be pretty sweet!

This is the only way I figured I could make it so nothing moves on me and all and keep it fixed when setting my 4-link up... So what do you guys think? As far as I can tell now, the only thing I need to now is just set the pinion angle and start on the 4-link!

But, I'd rather have some professional approval before I go ahead!



Took my handy dandy pumb bob I use for work and got it her set side to side!

My contraption to hold the rear end! Not bad for not being a carpenter, eh?!

Used my torpedo level and the angle finder to level it out so I get the most accurate reading. You can also see the arm that comes out to support the driveshaft to fix my pinion angle!

So I got a little jumbled on my numbers when I was making the legs for height and I guess Seth subconciously convinced me to have my ride height at 5&quot; instead! lol.. The tape actually shows that its 6 3/8&quot; which is only an 1/8 from actually being 5 inches, but we'll just say 5&quot;! This is also accounting for the 1 1/2 extra room that there is when laid out. If this don't seem to work out right in numbers let me know!

Where the pinion angle currently sits until I go through again and work the angles... Not too bad at all for just sticking on the arm for the shaft!

Well if I get the okay from you guys, I'll start on my 4-link!

Okay guys, just went outside and took another look at the driveshaft angles! I need a little help clarifying this... and to see if I'm right?

I used this source to figure out my pinion angle needed:


So angles are as follows!

Tranny output shaft angle: -6 degrees
1st driveshaft angle: -5 degrees
2nd driveshaft angle: -1
Pinion angle: -3

I use the - to state that the angles point down. In the link above it says not use this in the equations.

So with that said I will try and explain how I got my numbers as best as I can! As well, I also apologize for previous posts with different numbers but this time I stared at each measurement for a good while to determine what it was at. It is dang hard to read that little needle!

Okay so here is what I got:

-I took the tranny output shaft angle and subtracted the 1st driveshafts angle from it. 6-5= 1 degree operating angle.

Operating angle between tranny output shaft and 1st driveshaft is 1 degree.

- Then I took the first driveshaft angle and subtracted the second driveshaft angle from it. 5-1=4.

Operating angle between 1st and 2nd driveshaft is 4 degrees.

- So then it says to subtract the 1st and 2nd operating angles from each other. That means 1-4=-3 but its not a - so it would be 3 degrees operating angle between the 2nd driveshaft and pinion that I need.

- From all that then, I would need to point my pinion up 4 degrees for a 3 degree operating angle since the 2nd shaft points down 1 degree. -1+4=3.
OR
- I can point it down 2 degrees for a 3 degree operating angle. Cause -1-2=-3 operating angle.

I'm thinking though that I should point the pinion up 4 degrees instead of down. Which would be better? Cause I've seen articles say to have them same angles but opposite...

If someone could confirm this for me, I would appreciate it! I'd like to get on this 4-link!

EDIT: BTW, this makes no sense to me either! If I point the pinion at whatever angle then wont the second driveshaft also change cause it pivots at the u-joint? If I set the pinion will that mean that the 2nd driveshaft angle is okay or do I need to remove it from the yoke and adjust the pinion that way and the reattach the driveshaft? Although, I think that even doing it this way, that would still change the 2nd driveshaft angle, right?

After reviewing the link and your info, i would go with the 2 degrees DOWN. But as you said, as you rotate the pinion up or down, the second driveshaft angle changes which changes the calculations. BUT given the numbers you posted I would go with the 2 down. Also for what its worth you could add some shims between the axel and your support until you get your 2 down on the pinion without changing your 1 down on the second driveshaft. This would give you the right angles and only change your ride height a 1/4&quot; or so.

As stated in earlier posts, it's nice to see someone going thru the effort to learn how to do it right. Good luck with the rest of your build and I will do my best to help out when I can.

Haha, you know how retarded I'am? So retarded that I went outside today to look at my pinion and play with it. but before I did any adjustments I check the pinions angle and it was at -3 degrees!

So I got on here and I noticed my numbers said that too! WOW!

Haha, someone tell me, how retarded is that? Which means now, I don't even need to touch my pinion! I can set my 4-link up!

I just gotta adjust my driveshaft plunge and I'll be good to go!

daumn you talk alot..LOL....trucks looking good...hope to see you and your truck at lowdown

Can you blame me though? This is some intense stuff man! There is alot to it! Glad I can understand most of it, lol!

Unfortunately, you won't find me at lowdown... You could find me at the Visions show this year though! I could give you your shock kit too! lol, when are you gonna get that from me too?

A little update!

So I went ahead and got my driveshaft adjusted and all for the slip yoke in the tranny. It looks alot better now and I moved it about an inch out! The only thing that concerns me is that the way the carrier bearing sits! It does'nt sit straight like it did before I adjusted and wonder if thats going to make a difference? I'm thinking about going back under and tapping it straight with a hammer. Although, I took my plumb bob and the axle sits the way it needs to now, just an inch back more...

Check it out, let me know what you guys think!

BEFORE:


AFTER:

Immortal, thats what you were talking about, right?


Should I straighten here out?