Pinion Angle?

[383man]

If you can get the trans and pinion angle both the same then you just add the amount of degrees to make the pinion down that you want. In other words if you have the trans main shaft angle at 0 and the pinion at 0 I would add 3 to 5 degrees down to the pinion. That way under hard acceleration it should bring the pinion back about 0 which is what you want when hard on the gas. I like to set my leaf spring cars with 3 to 5 down. You are just trying to make the trans mainshaft and pinion angles about the same when on the gas real hard. With that set the U-joints will have some angle in them to make them work and stay lubed. I dont usually worry about the U-joint angles because once you get the pinion angle right in reference to the trans mainshaft angle the U-joints will fall where ever they come out which should be fine once you set the pinion to trans mainshaft angle. Ron

 

[Doubleclutch]

The down angle is an offset for normal load at speed not hard acceleration. Your vibration is at normal speed and load. Lots of good advice above on the angle---I had a vibration problem once and had a battle. Turned out after retubed driveshaft and new control arms that it was the rear drums!! Notice that original drums sometimes have square balance weights. Mine were balanced with the axles as an assembly. Replaced the axles and guess what--vibration!! replaced drums--they come without weights problem solved.

 

[MikeyT]

I always thought vibration on decel= nose to high up? I would aim for 4degrees nose down.

Mike

 

[Meep-Meep]

So all this reference to a 0 angle can't be correct or I'm not following. U joints have to work, meaning there must be a slight bend, Right? I have the actual factory driveline angle checking tool as seem in the FSM and I deployed it on my 66 Charger. My result was the front angle didn't need changing but the rear does. And from the description it says my angle is too small so I need to roll the pinion up with caster shims.

 

[Supershafts]

The angle at load needs to be 0, you want that to be where everything goes under load.

The joints don't need to be or see lots of angle, in fact that angle is also dependent on use. Performance use you want no angle for the reason that as the rpm increases the joints can't handle the oscillation of those rpms.
This is something that has been a huge issue with chassis builders and marine builders, most chassis builders are now starting to understand this.

If you get the angle to zero under load your joint will still see and move thru angles at coast and rest, under light load it will also be at angle.
Most new cars are now being run at no angle

 

[Meep-Meep]

OK, by 0 angle you mean as if it was a straight shaft? After reading the FSM I can interpret this as 180 degrees, where the centerline of the pinion or slip yoke is at 180 deg from the driveshaft centerline - take a 180 deg protractor and swing a movable arm from 0 and go all the way around until it's flat again but on the other side. This is how I think the angles are described in factory manual.

Now that we have that clear.....That completely contradicts what I've been told over the years and what I have read. "You want a slight bend at the joint with parallel output and pinion shafts because U joints have to work." Just this weekend I was making adjustments on the hemi Charger and rolled the pinion up 1 degree to make the angle larger (closer to 180 degrees) and shim the tail shaft to make the angle smaller (less than 180 degrees) and I made an improvement but it still grumbles under light load (less on decel). The angles are still not equal from front to rear, which I believe is my goal while not having too much bend at the joint. I'm out of room in the tunnel to shim more so my next move it to drop the front of the engine.

My "racer boy" buddy drives, stores, modifies and maintains road race cars for his customers. Cars from spec Miatas to Panoz to GT Porsche cup cars and he says when setting up the Panos (conventional front engine rear drive) he makes sure the angle is close to 180 degrees (or commonly referred to as a slight bend at the U joint) but equal on both sides under load (pinion can be down a bit at rest). His are close to straight, or I think as you say, zero, but I'm not arguing with success since these cars are in the 150 MPH range and don't seem to have any driveline issues.

In now way I am saying you are wrong, and on the contrary it's looking like you and Panoz boy are in agreement, so I'm just taking in all the info and applying it to my car and recording the results. Thanks for your input as I will be following to the letter.

 

[98 SNAKE EATER]

OK, a little update.

Last week, I had dropped off the drive shaft to get balanced just to rule it out, but the drive line shop had a problem with their balancing machine, so I picked it up on Saturday. They had already installed new Spicer lubeless U-joints, but didn't charge me for anything since they weren't able to balance.

Anyways, I installed a pair of 6 degree shims today and most of the vibration is gone

I have yet to take new angle measurements as my flat lift is occupied, but here's another video showing the results...

http://www.youtube.com/watch?v=wNr0q5MI6LI

As you can see, under load, the DS looks straighter than in the previous video.

The little vibration I have left is most likely due to right rear tire that still has a bunched up tube I have to address.

 

[Supershafts]

OK, by 0 angle you mean as if it was a straight shaft? After reading the FSM I can interpret this as 180 degrees, where the centerline of the pinion or slip yoke is at 180 deg from the driveshaft centerline - take a 180 deg protractor and swing a movable arm from 0 and go all the way around until it's flat again but on the other side. This is how I think the angles are described in factory manual.

Now that we have that clear.....That completely contradicts what I've been told over the years and what I have read. "You want a slight bend at the joint with parallel output and pinion shafts because U joints have to work." Just this weekend I was making adjustments on the hemi Charger and rolled the pinion up 1 degree to make the angle larger (closer to 180 degrees) and shim the tail shaft to make the angle smaller (less than 180 degrees) and I made an improvement but it still grumbles under light load (less on decel). The angles are still not equal from front to rear, which I believe is my goal while not having too much bend at the joint. I'm out of room in the tunnel to shim more so my next move it to drop the front of the engine.

My "racer boy" buddy drives, stores, modifies and maintains road race cars for his customers. Cars from spec Miatas to Panoz to GT Porsche cup cars and he says when setting up the Panos (conventional front engine rear drive) he makes sure the angle is close to 180 degrees (or commonly referred to as a slight bend at the U joint) but equal on both sides under load (pinion can be down a bit at rest). His are close to straight, or I think as you say, zero, but I'm not arguing with success since these cars are in the 150 MPH range and don't seem to have any driveline issues.

In now way I am saying you are wrong, and on the contrary it's looking like you and Panoz boy are in agreement, so I'm just taking in all the info and applying it to my car and recording the results. Thanks for your input as I will be following to the letter.

Any car like that of a panoz style should have 0.0 angle at all times, any road car seeing those kind or performance goals should have it's driveline laid out from crank to diff perfectly zeroed, if it has IRS than it most likely has no angles anywhere.

The angle for the joint to work is more truck related than car, a car doesn't put the force on the joint as is loaded by trucks, trucks don't spin the driveline fast enough to really force the grease from the cross to the cap, the working angle in the truck and the needles having more turning will draw in the grease to keep the joint living longer or forever depending on the work and grease intervals.

The new cars have gotten away from the driveline losses of having angles, as are chassis builders finally seeing what was then is not now, and cars are smoother and vibration free.

IN the street world and performance street world there are some things that can be kept the same, but when you add performance and rpms are now beyond what the car used to do... 2100 and 2600 rpm the angles need to be relaxed as joints can only oscillate so fast before they cause a vibration from throwing the shaft, so as rpm increases angles decrease.
Nothing wrong with 0.0 angle and it has no losses and takes less hp lost from having to turn thru it.

. This is a huge issue i have been almost smashing boat builders in the head with, they are stuck on this angle needs to be there, well some are stuck on the idea of needing a working angle, for a african queen , yeah if you want to, but not for anything else.

.

 

[Meep-Meep]

The Panoz have 9" Fords if I recall - not IRS.

I am going to check some of my other junk that actually works and see how much different they are from the Charger. I'm hoping to see some major differences.

Here is a summary of what I have done: Car was undrivable first time out. Shim tranny mount 1/4". Hard to tell if there was an improvement but it seemed a little better. Have drive shaft straightened and balanced. Much better but still not close to being right. Put new tranny mount with shim. Notably taller at the tail shaft. Car is somewhat drivable. Roll pinion up one degree and add a second shim (.150" thick). Best yet but still has grumble. Next move is to lower front of engine and possibly adjust rear until front and rear angles match. If this doesn't work car is going over a cliff.

It didn't occur to me that I sort of hijacked this thread but then thought it's all related info and good info at that.

 

[Supershafts]

Yeah the panoz gt race car does use a live rear and does use ford stuff front to back, the street cars are irs, with all that nose you'd think they have some good power under there....

No hijacking, its still angle related.

When does the grumble happen ?

 

[Meep-Meep]

I think they have plenty of power. Running spec 351W's with about 400+ HP.

The grumble is worst when you float it, and by that I mean driving down the freeway from about 50 + MPH and just as you take your foot off the gas - that little spot when the driveline is not loaded in acceleration OR coast - is when it happens. Under decel it's not that great either but acceleration is fine. I can hear it right under the floor right by the drivers seat pretty much where the front U joint is. Also, there is just a slight amount of clutch chatter (not relevant) but if you are slipping the clutch at low RPM as if you were creeping to move into the garage, there is a point where you can hear all kinds of rattling going on during the chattering period. Almost like there is some mechanical looseness. It may be the sum of all the gear backlash but it does seem a little odd. You have to catch it just right for it to chatter the drivetrain like that but on average it's fine. I'm just wondering if that is related somehow because it's almost the same type of noise.

Since this is a hemi Charger I have often thought of modifying my driving technique to ensure the car is under constant supervised acceleration as an alternate method to eliminate driveline vibrations. Still working on getting that by law enforcement.

 

[Supershafts]

Factory mounts are being used ? factory rear ? When it comes off power it could be off just a little and it puts it just enough to have a negative effect.

How is that at 65mph ? does the same thing ?

I would like to see that by law and maybe get a few amendments to it for other stuff

 

[Meep-Meep]

Well, I'm pretty sure it does have repo motor mount brackets because I can see the edges of the bracket that looks like they were water jet or laser cut, and I'm starting to suspect those. I bought this car not being able to drive it and slowly finding a lot of things that need fixed. Much has been fixed and I'll be quite happy when this saga is over! I just bought a digital level too so that might make measuring more accurate.

65 MPH is pretty much the same. Nothing under accel but grumbles when floated.

How about adding an endorsement to the vehicle reg that says speed limit of this vehicle is governed by oil pressure and coolant temperature.

 

[Cranky]

The little vibration I have left is most likely due to right rear tire that still has a bunched up tube I have to address.

Was going to mention checking your right rear. Not saying that it's the root cause but worth looking at but you already know about it. Noticed it about half way through the vid....cool vid btw.

 

[98 SNAKE EATER]

OK, a little update.

Unfortunately, she's been down cause I munched the ring gear a couple weeks ago

Now she's got a new Yukon gear set with a solid spacer and I'm taking my time breaking her in, but I noticed the small vibe has gotten worse (could be from the amount of rubber I burned off when I munched the ring gear lol)

Anyways, I just got her back on my level lift to re-check the angles and picked up this fancy schmancy digital angle gauge from HF

With a full tank and roughly ~100lbs. worth of junk in the trunk, the adjustable pinion snubber has about 1/8" clearance.

It used to touch at rest, but has since worn down a bit.

Anyways, I calibrated the digital gauge on my lift and used the regular meter to confirm.

Here's what I got:

Trans Yoke: 2.5*
Drive Shaft: 1*
Pinion: 7.5*

Re-checked using the regular meter and was slightly off:

Trans Yoke: 2*
Drive Shaft: 0.5*
Pinion: 7*


This is with 6* shims

Should I step down to 4* shims?

 

[98 SNAKE EATER]

Some of the numbers just didn't seem right compared to my initial measurements, so I figured I'd start fresh and pulled the shims (the lifts are finally free and I'm bored)

I also went back to the OEM snubber for now until I get the angle sorted out (the adjustable will definitely touch without the shims)

Measuring from the driver's side, I now have -2* at the trans, 0* on the drive shaft and +2* at the pinion.

Confirmed this using both the analog and digital angle meters.

 

[98 SNAKE EATER]

OK, in case I got the + and - mixed up, here's a little rendering of what I have....

Gunna shim the trans up a bit and re-check later today

 

[5.7 hemi]

Will this help?
http://www.google.com/imgres?imgurl...-_UcvCK8agywGu-YHQAg&ved=0CC4Q9QEwAA&dur=5293

 

[98 SNAKE EATER]

Will this help?
http://www.google.com/imgres?imgurl...-_UcvCK8agywGu-YHQAg&ved=0CC4Q9QEwAA&dur=5293

Is the trans supposed to have an up or downward angle on the B-Bodies?

Reason I ask is because I just got her on the lift and noticed she doesn't have a proper trans mount, just a welded angle bracket bolted in place.

There's a new rubber trans mount in the trunk and just eyeballing it, it looks to be taller than the bracket I have now.

I figure this could be the reason why she's got 2* down at the trans?

 

[lynchroad]

Can't figure out how to link this, but here is a useable article.
www.moparts.com / Tech Arcive / Rear Axle / Pinion Angle.