Pinion angle?

[redss86]

Ok, I have read Inland Empires write up about setting driveline angle. My output shaft is currently around 3.5-4* down, and the carb surface on the intake is approximately 0-0.5* down. I have heard you want to shoot for 2-3* driveline angle, i this correct? Also, should I set my pinion at the equivelant angle up as compared to the output? Or shoud I set it a little below this to allow for movement in the suspension(ie: pinion creeping up during acceleration)? I will be running a truck arms w/ monoballs. The perches will be welded solid to the rearend. I don't foresee much movement of the pinion w/ this setup. What is everbody elses opinion?

Thanks in advance,
Joe

[redss86]

Come on somebody surely has some input on this. I have done a search but didn't get very good results.

TIA,
Joe

[hiwayman]

yea me too i wana know

[Norwoodx55]

I don't think you should compare driveline angles to your carb pad. Some intakes are milled at a downward angle towards the front.I think your best bet is to compare to inclination angle at the crankshaft flange. JMHO, I am no expert here. Hopefully one of the authourities such as Chicane will respond here.
Brett

[kamaroman68]

I dont know if you own Tony Huntimers pro touring book or not but he gives a pretty good description of how pinion angles and transmission angles work and the proper phasing of them. He has given a couple of different suspension types as well (leaf spring, 4 bar) setup angles. I do not know if thats enough information for your car... i dont think its enough information for hiwayman or myself but a start. Chris

[formula]

Wait, you mean you don't just match the pinion angle to the output shaft angle @ ride height? I always thought those two were supposed to be in synch...

[kamaroman68]

formula from what i understand especially with a leaf spring car you do not want the angles to be the samedue to leaf spring wrap up. If you were to set them identically, as the rearend tries to rotate upwards under forward acceleration that angle changes and puts a bind on the ujoints causing premature wear. Chris

[redss86]

formula from what i understand especially with a leaf spring car you do not want the angles to be the samedue to leaf spring wrap up. If you were to set them identically, as the rearend tries to rotate upwards under forward acceleration that angle changes and puts a bind on the ujoints causing premature wear. Chris

That's what I was getting at. I am just curious what "the experts" say. I know I won't have as much pinion movement as a leaf spring setup, but I don't know if I will have any at all. I am wanting to know before I go welding the perches on the housing. I know I can always use shims, but don't want to if I don't have to.

Yeah, you want the angles to be equivelant. I was giving the carb surface angle, because you don't want the carb to be to far off level. If it is very far off then it might run a little rich or even a little lean.

This is the info I have found so far.

Joe

[formula]

That's what I was getting at. I am just curious what "the experts" say. I know I won't have as much pinion movement as a leaf spring setup, but I don't know if I will have any at all. I am wanting to know before I go welding the perches on the housing. I know I can always use shims, but don't want to if I don't have to.

Yeah, you want the angles to be equivelant. I was giving the carb surface angle, because you don't want the carb to be to far off level. If it is very far off then it might run a little rich or even a little lean.

This is the info I have found so far.

Joe

I'm in the same boat with my 4-link. I would presume pinion change would be much less than with springs?

[CarlC]

You can set it 1-2* down and try it. I run mine at 1* down vs. the transmission at ride height and it's fine. I'm not going to wrestle the shims for another 1*.

Do not use the carburetor and/or manifold as a measurement point. Intake manifolds can be angled. Use the transmission output, harmonic damper, or other defined surface with either a parallel or perpendicular surface. Using the slip yoke is the best.

[jpdeuce]

Starter mounting pads are the easiest place to check from. Those are at centerline also.

[redss86]

I do check the output shaft, and the pan surface. If you reread my first post, I stated the output shaft angle, and gave the carb angle as a referance. They are both at 4* down. So if I set my pinion at approximately 3* up, I should be okay correct?

[cagedruss]

Yes, it is correct. We set the rear end pinion from 1-3 degrees down at ride height. It is one of the last things I weld up before paint. Finish the car at ride height at check for proper alignment. Leaf springs wrap up and if you you a Traction type bar they will limit it. My Rear end shop is saying the trend is 0 or at the same angle as the output shaft. I tried that but the cars sit to low. Works ok on some Pick ups I guess.

[redss86]

Yes, it is correct. We set the rear end pinion from 1-3 degrees down at ride height. It is one of the last things I weld up before paint. Finish the car at ride height at check for proper alignment. Leaf springs wrap up and if you you a Traction type bar they will limit it. My Rear end shop is saying the trend is 0 or at the same angle as the output shaft. I tried that but the cars sit to low. Works ok on some Pick ups I guess.

I'm confused, first you say, 1-3 down, then you say 0? Is 1-3 down for leaf only? Please clarify.

[Josh]

Don't get confused, you are understanding things well. Set the pinion 1-3 degrees down relative to the output shaft(one degree street and 3+ degrees race). Coil spring cars have less pinion movement so they can usually ride closer to 0 than a leaf car.

[BRIAN]

That is one of those questions with tons of answers.


On SBC if you go 4 deg down your carb pad should just about level. Your rear should be approx 3 deg up giving you a 1 degree working angle. That number can vary from 1 to 3 degress depending on who you ask and what you are running.

Measure at your output shaft and rear u joint mtg surface with car at ride height. Put ramps under front wheels and jack stands under axle which will allow access to measure.


Best part is if you set up with the old $20 dial style angle finder than check with a digital it will drive you crazy you now have say a 4.12 vs what you thought was just 3.5. No fudge factor with the digital deal.

Good luck

[redss86]

I went ahead and set it up at 1.5 deg. down in relation to the output shaft. In other words it is right around 1.5- 2.0 degrees up. I figured if I have to I can use shims to change it.

Thanks for all the help,
Joe