Thread: driveshaft angle from trans to rear

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It's funny that you should mention that Kitz. I've thought about mounting a video camera under there to see what's happening.

Please read this in a positive manner -

General specs are +/- a degree but the preferred angles by most "experts" in the field is 3* as I noted above. In cruise mode, my guess is that the road's surface makes any laser/machinists angle finder a moot point. But if anyone really feels that universal joint wear will be minimized by taking it to a small part of an angle, I'd like to see the final results.

Obviously, to run these tests, among many variables, you would need to take assembly tolerences(bolting, welding, etc), tire pressure and diameter differences, spring/shock assembly compression and rebound rates, differential weight patterns for other drivers and passengers plus the fuel in the tank into consideration.

As the price of a U joint is so very inexpensive ($15 - $20), and the fact that they will tolerate a lot of abuse, going to extremes, IMHO, is fun to consider as an engineering problem but really not worth my time .
(Though I would like to see a video of what is happening under there)

you do not want the pinion up you want it down .it will climb up and if it runs up bad things will happen on leaf spring cars . the leafs springs whined up pinion climbs up

Pat,

I'll agree if we're talking aabout high horsepower cars with a lot of bite and leaf springs. However, the car in question here is a street rod with ladder bars. Not much - if any - wrap on the rear axle under power with this setup.

Also, if you have the pinion down and the trans down and are not under power, just cruising, I don't think that's a good thing.

Just my opinion.

OK boys, it' all gonna be OK.

I think the parameters have been set here for a successful adventiure.

Peeace out, Kitz

It's all good . . . discussin without cussin

sorry i only work on hi HP cars? i will now pickup my marbles and go home the street ligths are on

Originally Posted by pat mccarthy

sorry i only work on hi HP cars? i will now pickup my marbles and go home the street ligths are on

Pat,

No, I think you're one of the most knowledgable folks on this board. I said it was just my opinion, and based on my knowledge and experience about the particular type of car he asked about.

i have been thru this i think its a very intersting post .i have seen stuff you would think ? no way in hell will that work and it will how long??the 4 wheel drive guys have proved it to me. i was just having some fun. now Henry please put the rifle down

he guys , thanks for the posts . to keep on track as henry said the car in question has ladder bars , 4 spd . 500 hp engine and a 3/4 quick change . the pic henry posted is dead nuts on what im dealing with . will that angle work is the question . to add im also using lakewood non greaseable u joints for strenth . if we can get this resolved peacfully that would be cool ...thanks so much for the efforts and input this is my first street rod build so i do have questions . all my other experience is with muscle cars ...

i hear crickets........henry putthe rifle away i need more info ....

A rule of thumb that I have been told is to get them close to parallel, then test drive. If you get a vibration under acceleration then tilt the pnion down a couple degrees and retry. If you get vibration on deceleration then tilt the pinion up a couple degrees and retry. Repeat until vibrations are gone. With a ladder bar or 3-4 link suspension you should be able to make adjustments pretty easily. With leaf springs you can use wedges between the housing mount pads and the springs. If with the leaf springs you can't eliminate the vibration under both of the conditions, something to control the axle wrap must be installed. Please correct me if I'm wrong.

Pat

Damn it guys-----this gets argued about once every 2 months. For a street driven car, tilt the pinion angle up 3 degrees to match the down angle of the tranny tailstock. No, they don't have to be in the same plane, just close to parallel at normal ride height. If it is a drag car that will mostly see constant acceleration while going down the 1320, then set it up with the pinion pointing down 3 degrees. The wrap up in the springs, and frame torsion, will bring it up into line with the tranny tailstock while under acceleration. If you do much street driving with a dragstrip set-up, the universal life will be shortened, and you could have vibration issues.---Brian

Yep, short and sweet, what he said. I've had them close to ideal, and sometimes way off, and never encountered a problem. My Jeep with the 302 is a perfect example, I had to wedge it in there on a pretty steep angle to get the engine to clear the front suspension........no vibrations whatsoever.

Main thing is get a quality driveshaft built, with new components, and you will be fine.



Don

Brian,

Exactly.