47-55.1 Driveline Angle?

[Rabid Anti-Dentite]

So I installed an LM7 5.3 with a 4l60e into my S-10 frame using Code504 mounts, and now I need to install a transmission crossmember. How much angle do I want on the engine? I am using the stock S-10 rear end with 3” drop blocks. I will be having a custom driveshaft made. If I position the motor at 0 degrees, I will have a little bit of an angle on the drive shaft. Is it more important to have a proper engine angle or drive shaft angle? Or does it really even matter?
Thanks for the help!

[Advanced Design]

The angles that really matter when setting up a drive train are the front and rear U joint working angles.

Please check posts 1083 and 1105 for a review of working angles.
http://67-72chevytrucks.com/vboard/s...627134&page=44

If you have questions please let me know and will try to answer them.

[mongocanfly]

Typically 3deg down on the trans and 3deg up on the rear is what most shoot for....
Just be sure you have it setup correctly....https://m.youtube.com/watch?v=Idk3BVDVHq4

Well Doug beat me to it....I'm typing to slow...haha

[Advanced Design]

Greg the YouTube video link is a good idea as this can be a confusing subject.

[MiraclePieCo]

Originally Posted by mongocanfly

Typically 3deg down on the trans and 3deg up on the rear is what most shoot for....

Exactly right Mongo, and be sure to level the frame when checking engine and rear end angles. A rake will cause all sorts of erroneous readings.

[whitedog76]

Before I pulled the 235 from my 54, I measure the angle the engine was sitting at. The frame was level to the ground, the motor was at a 5 degree rearward pitch. So, when I made my new engine mounts, I made them with a 5 degree pitch to the frame. With all that said, most vehicles sit at a 2-3 degree rake, so if you do the math. The engine is at a 2-3 rake rearward.

[Driver_WT]

Originally Posted by mongocanfly

Typically 3deg down on the trans and 3deg up on the rear is what most shoot for....
Just be sure you have it setup correctly....https://m.youtube.com/watch?v=Idk3BVDVHq4

Well Doug beat me to it....I'm typing to slow...haha

Just to be clear, the rear of the trans output should be pointing up and the front of the pinion on the rear end should be pointing down?

Thanks.

Wade

[mongocanfly]

No WT...you've got it backwards...trans output down...pinion yoke up....the angles need to be the same so they cancel each other out...they can be more than 3deg...that's just a loose number that most shoot for...my IH build was 9deg from the factory...I measured before dissambly...but I set everything at 3deg when I built it back..
Couple of pics to help.....

[Driver_WT]

Thanks Greg. But my confusion is coming from post 1105 in Advanced Design's build thread http://67-72chevytrucks.com/vboard/s...627134&page=45
"When a vehicle accelerates, the nose of the pinion wants to climb. If the driveline has been dialed in with the front working angle shedding water and the rear holding water, the climbing pinion isn't increasing the working angle beyond desired limits. In fact, the climbing pinion is reducing both working angles closer to zero." To me, this is recommending that you start out with the pinion down a bit and then as you accelerate it will come up.

You and Doug seem to agree in this discussion, but the pics and Doug's post #1105 do not seem to match up (at least to me).

Wade

[mongocanfly]

Back when we drag raced it was common on a leaf spring setup to point pinion down a few deg...when the axle wrapped then the pinion would point up under acceleration....when you accelerate or brake heavy the
pinion angle changes drastically....drive a truck with the bed off and you'll be amazed how much it moves.....the 3deg down and up is just a rule of thumb setup...just cruising down the road you won't have a lot of angle change....trucks with 4link,ladder bars,swing arms won't have the pinion angle changes while driving that a plain leaf spring will....

https://m.youtube.com/watch?v=54_6GaYJvWI

https://m.youtube.com/watch?v=08UIvr6Sotk

[Driver_WT]

Got it. Thanks.

[Advanced Design]

WT, sorry to confuse you. Greg and I were just discussing this subject last Saturday at an event in my shop. The “holding water” comment for the rear u joint is based on the intersecting angles of prop shaft and centerline of the pinion as viewed from the side. A pinion can be pointing up from level and still have a “holding water” angle as viewed from the side.

And as Greg pointed out, the front and rear working angles must be the same.

Here is maybe a better explanation of what I was presenting.
https://www.drivelinesnw.com/part-tr...ngle-problems/

[Driver_WT]

Thanks guys. I am installing a Ford 8.8 rear axle in my truck and will have to put on new leaf spring perches, so I would like to only have to weld them on one time. I am thinking that I will point the front of the pinion down a couple of degrees as I will have 400 lb ft of torque from my engine. Then ensure that the working angles are within spec.

Wade

[mongocanfly]

Unless your drag racing it I wouldnt recommend that...

[mr48chev]

If the engine has a carb most folks set the engine in the frame so the carb mount surface is level. That pretty well comes out to the line of the crank and main shaft in the trans angling down at 3 degrees. That means that the pinion has to angle up at 3 degrees to have both U joints working at the same angles. That is the key to the whole thing no matter what the angles are or if it is lowered truck, stock height truck or jacked 4x4. the angles that the U joints on the end of the shaft have to match each other.

This is a pretty easy to follow tutorial on how to work your way though it. https://www.drivelinesnw.com/part-tr...ngle-problems/ Just good info on driveshafts too.

[FAKKY]

Think the confusion is 2 parts.

1) Driveline v Working v Pinion angles and even phasing (if you read on it) and how to measure etc

2) That a lot of builders recommend as much as 7 degrees of pinion angle for movement on leaf springs. example in this thread

https://www.quickperformance.com/Pin...ent_ep_45.html

So what WT is refering to is he's worried if he sets it at -3 and +3 .... that when he accelerates it will no longer be a good angle.

Thats my interpretation from reading.

WT if thats correct - my understanding is ......

1) Set your Engine and trans approx 3-ve. This was mainly done to carb and allowing more tunnel clearance. It can be more ..... but -3 was just what was always done.

2) Set pinion to +3 measuring at the yolk or diff. This will get your working angles close enough to only have a slight offset under accelaration that your ujoints work well.

3) If you want to be more accurate ..... follow the process Doug outlines in his threads above

posts 1083 and 1105 for a review of working angles.
http://67-72chevytrucks.com/vboard/s...627134&page=44

Hope I caught your concerns correctly.

[Driver_WT]

Yes, I have a carb. I will try what Mr48Chev and Fakky suggest with -3 on trans and +3 on pinion.

Thanks to everyone for the clarifications.

[dsraven]

another important angle to consider is the engine center line in relationship the the rear axle center line viewed from above. these 2 center lines need to be at 90 degrees to each other. the engine can be offset to one side or the diff can be offset to one side etc, as long as these 2 angles stay at 90 degrees to each other so the u/joint angles cancel each other.if you use the frame as a "straight edge" and "baseline" your engine crank center line should be parallel to the frame, or parallel to the forward line of motion of the car if the frame rails are not parallel to each other. the rear axle center line, drawn from rear whell to rear wheel, should be 90 degrees to the frame or forward motion line of the vehicle. this is to ensure the ujoint angles, viewed from above, are the same so they cancel each other out. this is as important as the angles of things viewed from the side that need to be the same so they cancel each other out as well.
if you have leaf springs and are worried about spring wrap up, from lots of power applied to the wheels, you can use a ladder bar set up to keep the springs from flexing too much and causing vibration under load or, at an extreme, u/joint or driveshaft breakage. this can be very important for guys who have removed a leaf or 2 to achieve a lower stance. this effectively weakens the spring pack so spring wind up would happen with less power applied. back in the day we used a simple traction bar set up with a rubber snubber block that bottomed out on the frame similar to the second link below. if using a ladder bar set up do some research on the frame mounted pivot point in comparison to the spring mount pivot point. if it is outta whack the suspension can bind up.

http://www.4x4wire.com/jeep/tech/susp/axlewrap/

https://www.speedwaymotors.com/shop/...4-16-314-31219

[Advanced Design]

Here is a better explanation on working angles than what I provided, included in this thread on vibration diagnosis.

http://67-72chevytrucks.com/vboard/s...85#post8108885

[Rabid Anti-Dentite]

Thank you all for the information. I built my crossmemeber today and set my trans angle at 3 degrees. I installed tapered lowering blocks with the larger end at the rear of the truck, and my pinion angle is 1 degree, so I think I need to flip the lowering blocks around and have the tall the towards the front of the truck. This should raise my pinion upowards and increase my pinion angle.
Posted via Mobile Device

[mongocanfly]

are you spring over axle or spring under axle?....
turning your shim around can have different effects
spring under axle will raise the angle of the yoke of the rear
spring over axle will lower the angle of the yoke of the rear

[Rabid Anti-Dentite]

Originally Posted by mongocanfly

are you spring over axle or spring under axle?....
turning your shim around can have different effects
spring under axle will raise the angle of the yoke of the rear
spring over axle will lower the angle of the yoke of the rear

It is spring under axle, s10 frame. I need the yoke to point up towards the bed a few degrees.
Posted via Mobile Device