S197 Pinion Angle

[Steedagus]

I was having this conversation with one of my tech's today and I thought it would be great to post here to help others.

We were discussing how you can make a mistake measuring pinion angle on the S197 axle assembly. The S197 axle housing has a large flat beneath the pinion snout. That flat would be a very convenient place to measure the pinion angle from since an inclinometer can easily be rested on it.

The problem is that flat is not parallel to the pinion flange angle. It is actually two degrees off. As you can imagine, measuring pinion angle from this flat and not knowing there is a two degree difference in it would always result in a pinion angle that is two degrees from the intended angle. The correct, and only way, to properly measure pinion angle would be from the actual flange on the pinion. It is more difficult to measure from the pinion flange (in comparison to the flat on the housing) but unless you do it at the pinion flange you would be off by 2 degrees.

So moral of the story, stick to measuring from the pinion flange when measuring your pinion angle on S197 cars.

 

[tjm73]

Hmmm.. Thanks for the tip/heads up. I may have missed that when I install my adjustable upper this spring.

You could also adjust for the 2 degrees and still use the flat spot. Is the flat spot +2 or -2 degrees from level with the pinion?

 

[stkjock]

good write up that's been around a while


http://www.cherod.com/mustang/HowTo/LCA _adj.htm

 

[TexasBlownV8]

I use a 12" square, place is like "L", and rest the long edge against the flange and use the bottom for the angle tool.

 

[BoostedGT480]

Mine is at the shop now..they have a really nice laser rig that sets it up perfectly. I will run this by them though and see what they say

 

[skwerl]

Hmmm.. Thanks for the tip/heads up. I may have missed that when I install my adjustable upper this spring.

You could also adjust for the 2 degrees and still use the flat spot. Is the flat spot +2 or -2 degrees from level with the pinion?

Anyone here have an answer to this?

 

[fdjizm]

I guess the answer would be yes, yes you could. lol

 

[wabirch]

Grab those angles before you do anything as well. Save them for if you ever go back.

 

[kevinatfms]

it should be a -2 to be reduced from your actual reading if reading from the bottom of the housing as you are forcing the dial in the upward position to read the indicated pinion reading....IIRC....

 

[luillo]

I have a question for you math gurus.lol
I suck at math but need to know if I am doing the math wrong.

D I need to subtract or add the angles? My measurements are as follow by instructions I saw here:

Transmission flange -4.3. And pinion flange is -.8

If I subtract I think is like this right,,,,,, (-4.3) - (-.8). Need to be turned to add then is (-4.3) + (+.8)= -3.7 pinion angle. Am I right or wrong??

OR

Adding which is,,,,,, (-4.3) + (-.8)= -5.1 pinion angle....

I did an adjustment to test and this is how I put my pinion,,,,, Transmission flange -4.3 and pinion to +2.5.= -2.2 pinion angle according to my math at that time which I think is wrong because I was not sure if we ADD OR SUBTRACT THE ANGLES. The car feels good until 100 mph and it vibrates a lot when I let off the gas. so I am assuming my math was bad.

 

[BMR Tech]

Add the angles.

If the crankshaft center-line is at -4.3.....then you want roughly a +2.3 angle on the pinion flange.

-4.3 + 2.3 = -2

Are you using a 1 or 2 piece drive-shaft?

Stock upper and mount?

Does it vibrate when cruising along at 80 mph?

Does it ever vibrate under acceleration? 120mph, etc?

 

[luillo]

Are you using a 1 or 2 piece drive-shaft?

Stock upper and mount?

Does it vibrate when cruising along at 80 mph?

Does it ever vibrate under acceleration? 120mph, etc?

i have

1. Cobra Jet drag springs i think 1/4 front and 1/2 in the back lower
2. UPR ADJ UCA bushings
3. BBR LCA Bushings
4. Axle Exchange one piece aluminum
5. The rest is BMR PAndhard
6. LCA Relocator in the second hole

i just ordered the padhard relocator because i can not give any more positive angle in the pinion due to the rear cover touching the pandhard.

 

[BMR Tech]

Hmm.

Well try and get it into the -1 to -2 range and see what happens.

 

[luillo]

Add the angles.

If the crankshaft center-line is at -4.3.....then you want roughly a +2.3 angle on the pinion flange.

-4.3 + 2.3 = -2

Are you using a 1 or 2 piece drive-shaft?

Stock upper and mount?

Does it vibrate when cruising along at 80 mph?

Does it ever vibrate under acceleration? 120mph, etc?

thank a lot by the way. this car is killing me.LOL i was very confuse as of adding the angles or subtracting them. if i get the pinion up by getting it positive it looks very weird like is going nose up a lot compare in relation to the trans and drive shaft that is why i was confused too.

 

[luillo]

Hmm.

Well try and get it into the -1 to -2 range and see what happens.

my next step will be:

• Pull the DS and verify transmission flange angle again to see the -4.3
• then the pinion and see where is at again should be @ +2.5
• then adjust pinion to +4.3 to equal 0 degree
• then give 1 degree neg pinion angle @ +3.3 **** -4.3 + (+3.3) = -1

If that doesn't work i will:

• set the pinion at 0 degree then test
• if still have the problem then i will give 1 degree negative.
• then if it wont work i will burn the damn thing.LOL

 

[BMR Tech]

Sounds good.

Keep us updated.

 

[luillo]

I just got a regular angle finder to make sure the measurements are correct then i will verify with the digital but to make sure guys.

Can you tell me if by looking at the angle finder on the front the left numbers are negative and the right numbers are positive????

i did this on my 2009 and for the love of God i cant do it now.LOL

if i am right then i think i got the math wrong by using the digital one.

If that is right then my trans flange was -4.3 but my Pinion flange was +.8,,, -4.3 + (+.8) = -3.5 which i think is right because i did not had much vibration @ 100 mph.

No with my bad measurements i adjusted to trans flange -4.3 and pinion flange -2.5,,, -4.3 + (-2.5)= -6.8 like this the pinion flange looks like is going up that is why o thought it was positive but if you put the angle finder in relation to that angle with a carpenter square is actually negative.

Please anybody correct me if i am wrong.

So, what i will do is to set the pinion flange angle to +4.3 with the right side numbers on the analog angle finder to 4.3 and then take 1 degree to make it negative @ +3.3 on the right side of the angle finder hopefully i get -1 pinion angle and it works on the test road.

 

[skwerl]

If you're that far off then you should be able to just look at it with your bare eyes and see it's wrong. Driveshaft and rear pinion should be almost in line with the pinion pointing slightly below the driveshaft. If you're 6 degrees off then you wouldn't be able to drive it.

 

[luillo]

Add the angles.

If the crankshaft center-line is at -4.3.....then you want roughly a +2.3 angle on the pinion flange.

-4.3 + 2.3 = -2

Are you using a 1 or 2 piece drive-shaft?

Stock upper and mount?

Does it vibrate when cruising along at 80 mph?

Does it ever vibrate under acceleration? 120mph, etc?

sorry i did not see this but...

no vibration on acceleration up to 90 mph and then i might get some vibration.

90-100 i have vibration and if i let off the gas it goes crazy with the vibration.

Vibration under acceleration only happen when i hit 95-100.

If you're that far off then you should be able to just look at it with your bare eyes and see it's wrong. Driveshaft and rear pinion should be almost in line with the pinion pointing slightly below the driveshaft. If you're 6 degrees off then you wouldn't be able to drive it.

it driver fine until 95 mph and if i let of the gas in neutral coming off 90 mph.

I thought it was wrong by looking at the bump stop of the rear end they are tilted back. I was just trying to follow the damn math but i suck at it. I almost go by eye on the adjustment. I think i got it now for tomorrow when i do it again.

Analog and digital angle finder to be sure.LOL