How come everytime some magazine (new R&C here) does a pinion angle thing they show a picture like this to suggest you get your angle from the surface below? If your frame's Z'd 14 inches, WTF's your u-joint angle like? Seems like vibrations an issue a lot sooner than the proposed angle in that situation. I don't know about the m***es, as i'm no fabricator, but i measure u-joint angle DIFFERENCE from trans yoke to driveshaft tube, and pinion yoke to tube and shoot for 1 1/2- 2 degrees difference. How about you?
Surely it doesn't matter where you measure it from, as long as it's the same datum for front and rear. As you said, you're just measuring the difference between the two.
Of course that is the optimum way to do it. But if you match the angle of pinion up and make it the same as the engine you are pretty much spot on. Dealing with parallel leaf or "soft" suspesion linkages you have to counteract pinion climb, blah blah blah and so forth. They do it this way because the real explanation is outside the grasp of the "average" hot rodder.
Very misleading. It leaves the "average" guy LESS informed. Actually providing a mis-service. Anyway i think the R&C article reccomended 4-7 degress(?) "IF" this is to the surface below, and you Z your frame 14 inches, your joints are at about TWENTY(?)degrees!!! Yeah, THAT'S where i want it. Look at most bigger vehicles going down the road where the driveshaft is in view. It's dam near straight from one section to another (multi piece tubes), or from tube to pinion yoke. Can't see the necessary angle for proper joint movement w/the naked eye. Just an observation on how USELESS some of these magazines/TV shows are. A lot more credibility here. BLa bla bla
What you want is for both the joints to be working THRU the same angle. If the front joint has an angle thru it of 4 degrees then the back joint should work thru the same angle. That way they cancell. If they are different and the working angles are large, the joints will wear out fast. I point the pinion down because it usually results in smaller angles and the angle change between the joints is less as the rear end moves. Draw it out on paper or make cut outs and put tacks in the pieces to see how it works.
you think this is bad, attempt to explain to someone how nose diving the pinion angle will make the car hook harder, and not wheelie as bad at the same time. Driveshaft and pinion angles, carbueration modification,Clutch base and converter stall speed are ALL under the "black magic" portion of auto work,Groucho. I have seen Jerry Haas built Race cars that needed M***IVE rear end tweaking to make them go fast and not shake the stupid thing apart. I guess my point is I agree. there is alot of "do what works for you" in cars as well. now I am going to go tell a guy the cam he has picked out is way too ****ing big for his cylinder heads, his carb is too big and needs the metering plates re worked to better emulsify the fuel, and the the 3 inch exhaust is too much for the car. wish me luck-same to you.
Yup, right on. If I had a dollar for every racer I know that ****s with the pinion angle using true zero to start vs differences as expressed above... I guess a little studying never hurt anyone, but some of em need detention! My take is to get zero under load. Some suspensions require more than others to achieve this as in the diagrams from lux. Good lookin out guys.
after i read it ...i thought ...they are nuts.....but i think they are figuring on setting it up with the frame level and not at ride height....possibly on a jig ...or level surface....3 up at ride height for me....brandon
Lux, That's a good table you have there. Now I just want to check something on my set up. I am using a banjo rear converted to open drive and mounted using an unsplit wishbone setup, pivotting on a ball as per unsplit front wishbones. That is obviously solid and is not going to be subject to spring wrap. I was setting it up with the pinion matching my gearbox output shaft i.e 4 deg down on the shaft / 4 deg up on the pinion. Should I be using the guide in your table for the ladder bar set up instead? Pete
Also, a lot of published info relies on a ch***is where the trans/rearend are a LOT closer to the same plane than some of the extreme Hot Rods we deal with here. Major "Z" for example. Anyway, my point is to AVOID a LOT of what you read. It's written sometimes by people who don't know ****. It's great opprtunity for a young guy to get off to a bad start
Yeah, I have always noticed they don't mention anything about driveshaft inclination, U'joint loading (or tht it has to have some angle to work properly) or even WHAT they did to correct a problem. Just deleted 3 paragraphs of ranting. to the point... these guys like to bolt in whatever trick of the week part is up for grabs. (my favorite being the adjustable upper control arms formustang and g.m. a-bodies) and never tell you WHY the car required them to begin with. every time I have had to deal with them, I end up pulling them out, setting them at stock lenght, and trying that first. so far,out of 6 cars, NOT ONE has required them. sure look "racy" though. on the more extremely built cars I have noticed an alarming trend of guys not knowing what the heck they are putting together just throwing parts on-my favorite being coil overs AND a leaf spring (You planning on towing a dump truck buddy?) or coil springs cut away to nothing...followed by a shock angle of about 65 degrees- and watching that car beat the **** out of the driver on the road because there is no shock travel at all. If you had any idea how many guys have no idea that sever shock angles= little or no efficiency from the shock itself= bounce your skull off the roof=broken parts on a regular basis, you would probably cry a little. that and the "I have really bad bump steer" thing. it might be because the front shocks are laying down, noodles...but I digress. I have tried to tell alot of guys (with both split and solid driveshafts) that if thier angles are really severe, they need to track down an old caddilac C.V. joint- not what is hanging off the front of your honda-but basically a collar with 2 u-joints back to back at the end of the shaft- and I can't beat into thier head that the shaft angle is too severe even though the yolk and pinion angles jive. whod'a thunk keeping needle bearings moving in a circle would be such a pain in the ***?
Just finished? my open drive phasing today. (I hope) Heated and bent the bones up til I got 1 degree neg. at the pinion and shimmed my trans to 1 degree pos. Looks fine to me . Before I had 8 degrees of driveshaft angle.
Just look at the front drive shaft angle on a mid 90's chevy fullsize 4x4 they got the same joint! They have a good angle on 'em so it must be worth somthin!
thanks for this post guys. i have a triangulor 4 link in my shoebox. i have a vibration at the ride height i like to drive at. i will need to check out my angles at that height. thanks, brandon
OK, subject within a subject. My 2 piece driveshaft has a severe angle on my 60 Pontiac because of it's shortness and severe lowering of the rearend. I tried to raise the center bearing to compensate, but it'll only go up about a half inch. Tell me more about this Caddy CV or 90's Chevy 4X4 front shaft.
Not easily at this stage. Sorry you gotta keep beating your head with this stuff. Just when I thought I had it all clear someone throws in another variation. The fact that there have been so many threads on this subject shows the lack of understanding a**** us. Even when you read "The ultimate driveline phasing" thread, it'll only be one guy's opinion. Thanks for your advice Pete
Pls. see post #6. I did this for a living and had a floor of engineers to direct. Been there and done that.
2 piece shaft with a CV joint in the middle. Not sure what years/models had what, but see what you can find.
Explain CV joint. Dual normal joints?? Or literally a CV. I've never seen the latter in 60's GM cars i don't think
Anyway, do i need a "double" joint at both ends of the rear driveshaft?? One at the center support, and one at the pinion on my 2 piece shaft? Obviously, the front shaft isn't affected forward of the center bearing, advise?
probably depends on how you set it up...if the center support is close to where the rearend pivots about, then you should be ok with just the one double joint, because the rear joint won't have much angle change on it. But be prepared to move stuff around as needed....there's some black magic involved with 2 piece driveshafts
Cool, i was thinking of bagging my car to eliminate a slight driveline vibration. This'll make more sense/cheaper. Thanks
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