Driveline angle assistance

[Carbo]

I'm looking for some assistance. I have a 69 camaro with a sbc that I just recently installed a TKO 600 into. The car has DSE 3" lowering leaf springs. After measuring my driveline angle, the tranny is down 4*, my pinion is down 4* and my driveshaft is up 1*, but it is going up from the tranny to the pinion (meaning the pinion is higher than the tranny). After doing a road test at about 70-75mph, to no surprise, I had a vibration. It seemed to be more apparent on acceleration. That tells me that my pinion is too high. I need to lower my pinion but the question is by how much. I'm guessing by 2* for a total of 6* down so under power it will bring it up to approx. 4*. Does this sound right or am I wrong????

Just wanted to say that I did call DSE and asked their opinion. They told me they set their cars up at 4* down both at the tranny and at the pinion. They suggested I leave mine alone but not all cars are the same. Any ideas???

[Vegas69]

It can be confusing no doubt about it. If your driveline has 4 degrees of downward slope your pinion needs 3.5-4 degrees of upward slope towards the front of the car. Equal but opposite angles. I am running the exact same setup with no driveshaft vibrations. I am running a 4 link however and they don't have the pinion twist a leaf does.

DSE could be asking you to run 4 degrees less than your drivline angle at the pinion. That would mean your pinion would be level. You should double check with them or I'm sure someone will chime in that has leafs. You may benefit from a pinion snubber as the factory had in your tunnel.

[Turbo67camaro]

Here is a guide on this topic -

http://www.iedls.com/IEDL_PTS_LGL_091008_Secure.pdf

[Vegas69]

Great article and exactly what I was trying to point out. Your application does make a difference.

[Carbo]

DSE could be asking you to run 4 degrees less than your drivline angle at the pinion. That would mean your pinion would be level. You should double check with them or I'm sure someone will chime in that has leafs. You may benefit from a pinion snubber as the factory had in your tunnel.

I think this is what DSE was referring to but I'm not 100% sure. I would think this would be correct to allow the pinion to move up under torque. I am going to call them on Monday. Anybody else want to chime in with experience on this one?

BTW, thanks for the article.

[another69]

well here's my two cents. this only concerns leaf spring cars. i did a lot of research on this in the past and what i found and what makes sense to me is the engine and trans should point down 3 degrees max and the pinion should also point down 3 degrees max. (both equal). this is so that during acceleration the pinion on a leaf spring car will always move up, and if you start with the pinion pointing up, when you accelerate the pinion will only move up more causing too much of an angle on the u joint.

[Carbo]

I was looking up underneath the car the other day to see how much clearance I have from the tunnel to to the top of the tranny. I have probably an inch to play with. Would that be enough to achieve an extra 1*? As stated earlier, I have 4* pointing down. I guess another way to ask the question is how much would the driveline need to move up to move the tranny 1*?

[The WidowMaker]

i have to disagree with vegas69. the joint doesnt know where the cooresponding part is, only the angle its at. whether you end up with 4* working angles by doing this \ _ / or \ _ \ , it doesnt matter.

your problem is that your rear WA is 3* (4-1) and your front is 5* (4+1). you want the WA as close to 1* as possible and no more than .5* difference btwn them. you have a 2* difference.

if you raise the tranny, it will lessen the 4* of the tranny and the 1* of the DS. it may put your 5* WA closer to 3*. just remember, any change to the DS at the front, also changes the rear.
Tim

[Carbo]

i have to disagree with vegas69. the joint doesnt know where the cooresponding part is, only the angle its at. whether you end up with 4* working angles by doing this \ _ / or \ _ \ , it doesnt matter.

your problem is that your front WA is 3* (4-1) and your rear is 5* (4+1). you want the WA as close to 1* as possible and no more than .5* difference btwn them. you have a 2* difference.

Tim

Tim, thanks for chiming in. I'm still in the learning curve with this one. Can you tell me where I should be then, i.e. tranny down 3* and pinion down 2*. I just need a good starting point. I hate to go out and buy a bunch of angle shims only to end up using one set and having three or four sets sitting on the shelf. My biggest problem is getting started.

[Vegas69]

i have to disagree with vegas69. the joint doesnt know where the cooresponding part is, only the angle its at. whether you end up with 4* working angles by doing this \ _ / or \ _ \ , it doesnt matter.

your problem is that your rear WA is 3* (4-1) and your front is 5* (4+1). you want the WA as close to 1* as possible and no more than .5* difference btwn them. you have a 2* difference.

if you raise the tranny, it will lessen the 4* of the tranny and the 1* of the DS. it may put your 5* WA closer to 3*. just remember, any change to the DS at the front, also changes the rear.
Tim
You don't agree with the link Turbo posted?

[Carbo]

I spoke with DSE today and told them that the 4* down at both the tranny and the pinion didn't work. They recommended to move the pinion up 2* and that should cure the problem. So that what give me 4 down at tranny and 2 down at pinion. I'm going to give it a shot and see what happens. I can see this being a lengthy trial and error project.:hammer:

Anybody else think this might work?

[another69]

Try moving the trans up- its very easy compared to the pinion, plus you won't have to worry about wheel alignment. Just put some shims under the trans mount- 1/4" is probably more than enough.

[Vegas69]

I spoke with DSE today and told them that the 4* down at both the tranny and the pinion didn't work. They recommended to move the pinion up 2* and that should cure the problem. So that what give me 4 down at tranny and 2 down at pinion. I'm going to give it a shot and see what happens. I can see this being a lengthy trial and error project.:hammer:

Anybody else think this might work?

Your first post doesn't agree. When you say pinion 2 degrees down do you mean from level, or are you referring to it being on the same plane as the driveline? Since the pinion points towards the driveline, down would mean below level, and up would mean above level. It sounds like they want you to have your pinion 2 degrees down from being on the same plane as the driveline to fight pinion wrap. Raising the driveline to 3 degrees will allow you to run less working angle which is a good thing. You will still need to adjust your pinion.
I didn't have any more tunnel clearance so I was stuck running 4 degree which is factory spec anyway. Intakes are normally milled for the carb to sit level with 4 degrees driveline angle. Mine is perfectly level. I am running 3.5 degrees of pinion angle. I have a four link and it called for 1 degrees less than driveline. I don't have any vibration under accel or full throttle so I left it to keep the harmonics better.

If you have a vibration under accel that does mean you need to move your pinion angle down until it goes away. You could start with 1 then to 2 and so on.

[Vegas69]

I'm looking for some assistance. I have a 69 camaro with a sbc that I just recently installed a TKO 600 into. The car has DSE 3" lowering leaf springs. After measuring my driveline angle, the tranny is down 4*, my pinion is down 4* and my driveshaft is up 1*, but it is going up from the tranny to the pinion (meaning the pinion is higher than the tranny). After doing a road test at about 70-75mph, to no surprise, I had a vibration. It seemed to be more apparent on acceleration. That tells me that my pinion is too high. I need to lower my pinion but the question is by how much. I'm guessing by 2* for a total of 6* down so under power it will bring it up to approx. 4*. Does this sound right or am I wrong????

Just wanted to say that I did call DSE and asked their opinion. They told me they set their cars up at 4* down both at the tranny and at the pinion. They suggested I leave mine alone but not all cars are the same. Any ideas???

After reading this again ,it sounds like your pinion is in fact below the center point or level. Drive line \ / Pinion When they should be \ \

[Carbo]

Try moving the trans up- its very easy compared to the pinion, plus you won't have to worry about wheel alignment. Just put some shims under the trans mount- 1/4" is probably more than enough.

I definitely have enough room for 1/4." That's no problem.

Todd, thanks for the input. Yeah, you caught it on the second time around. I leveled the car off and was measuring from level. So the tranny is 4* down from level, the pinion is 4* down from level and the DS is 1* up (front to back) from level. I have to say this is all new to me so I appreciate everyone's input.

According to DSE, they told me to raise the pinion up 2* so that would put me at 2* down from level on the pinion. Does that sound right? I'm just having a hard time understanding the measurements and working angles.

[Vegas69]

The vocabulary is what screws everybody up in my opinion. You need the pinion 2 degrees above the center line of the car/ level according to DSE. When DSE says down they mean from you driveline angle which is 4 degrees. Your rear end under acceleratio will tend to twist the pinion towards the floor of the car. That inland drivline link is really good.

[Carbo]

Todd, so what you are saying is I need to move my pinion up 6*. Is that right?

[Vegas69]

Yes sir.

[Carbo]

O.k. I think I got it now. I'll try it out and post my results.

[The WidowMaker]

You don't agree with the link Turbo posted?

no, didnt agree with the following.


If your driveline has 4 degrees of downward slope your pinion needs 3.5-4 degrees of upward slope towards the front of the car. Equal but opposite angles.

but as you stated later, its all a matter of vocabulary. i think we're on the same page, but at the time, it wasnt clear.

right now on my car, the pinion sits higher than the tailshaft. so, if i pointed my pinion up, it would greatly increase the angle of the DS and therefore increase my WA's. so, i pointed the pinion down and i have WA's of 1.5 in the front and 2 in the rear. when the pinion wraps up on my 4 link, i'll still have less than a .5* difference btwn working angles.

check this site out.... there is a trial of a program that can be downloaded and will most likely help. i ran into some issues with it (its suggestions and my trig didnt agree), but for basic stuff its good.

http://www.vibratesoftware.com/html_help/html/Diagnosis/Reference/Powertrain_Angle_Configurations.htm

[Carbo]

I do have one question about the shims. When installing them do you have to remove the upper isolator pads? I would think that the shims would sink into the pad when torquing down the bolts therefore cancelling out the angle of the shim.

[67Camaro RS/SS 350]

Carbo, did you ever get this resolved? I ask because I am going through the same thing. I have a SBC and a TKO. I get the vibration from around 65mph to about 80mph where it begins to smooth out. I have had my tires road force balanced and it's still there. I am lost also with driveline angles. I can't get the dow up part of it.

[Carbo]

Carbo, did you ever get this resolved? I ask because I am going through the same thing. I have a SBC and a TKO. I get the vibration from around 65mph to about 80mph where it begins to smooth out. I have had my tires road force balanced and it's still there. I am lost also with driveline angles. I can't get the dow up part of it.

Yes, fortunately I did. I ended up with the tranny down 3* and the rear end up 2*. That gave me the smoothest ride. My mirror is even smooth enough where the cars aren't blurred anymore.

It took me a while to get there but it paid off.

[Vegas69]

Good for you man....

[Carbo]

Thanks. I guess patience is virtue.