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-   -   Brake rotor centering (https://www.lateral-g.net/forums/showthread.php?t=56008)

Vegas69 01-12-2018 07:56 AM

2.5 degrees UP from level.

Your tailshaft is DOWN 3-3.5 from level. If this is true it puts them close to the same plane.

This is exaggerated: Tailshaft: \ Driveshaft: / Rear: \

randy 01-12-2018 09:10 AM

i just dont see his driveshaft going up from the trans to the rear diff. My car is Low and i know its a 1st gen but i still have 1 degree down on my driveshaft angle. If his driveshaft is going up my guess is that he is measuring his engine angle wrong. The crank pulley and fuel rails were the easiest spot for me to measure.

SSLance 01-12-2018 09:51 AM

Trey, make sure whatever you are using for an angle finder is EXACTLY straight front to back for each measurement. It being just a bit off skew can really mess with the numbers.

And run to harbor freight and get a digital gauge if you don't have one already. The needle gauges are way inaccurate in my opinion.

WSSix 01-12-2018 09:57 AM

Quote:

Originally Posted by Vegas69 (Post 671575)
2.5 degrees UP from level.

Your tailshaft is DOWN 3-3.5 from level. If this is true it puts them close to the same plane.

This is exaggerated: Tailshaft: \ Driveshaft: / Rear: \

Thank you. That's what I've been thinking and saying but the number of articles and information pages I'm reading that say the pinion angle is the difference between the drive shaft angle and the angle the pinion is placed at is staggering and it pisses me off, lol. It's just confusing me because in my mind the difference between the angles is the working angle not the pinion angle. Just wanting to make sure I'm communicating properly.

Quote:

Originally Posted by randy (Post 671582)
i just dont see his driveshaft going up from the trans to the rear diff. My car is Low and i know its a 1st gen but i still have 1 degree down on my driveshaft angle. If his driveshaft is going up my guess is that he is measuring his engine angle wrong. The crank pulley and fuel rails were the easiest spot for me to measure.

I measured at the balancer just a minute ago and it's showing 2.5 to 3 degrees up from level which causes the tail shaft to point down. I think I'm going to invest in a digital angle gauge so I can stop expecting this manual gravity one to be accurate. It's hard to read as well.

If you stand on the driver's side of the car moving from front to back, my drive line looks like what Todd posted \ / \ .

Thanks everyone

Vegas69 01-12-2018 01:58 PM

The face of the U Joint is the best place to measure all the angles. I used a socket and angle finder, but a magnetic finder would be much easier as you could stick it right on the u joint.

randy 01-12-2018 04:15 PM

Quote:

Originally Posted by WSSix (Post 671585)
Thank you. That's what I've been thinking and saying but the number of articles and information pages I'm reading that say the pinion angle is the difference between the drive shaft angle and the angle the pinion is placed at is staggering and it pisses me off, lol. It's just confusing me because in my mind the difference between the angles is the working angle not the pinion angle. Just wanting to make sure I'm communicating properly.



I measured at the balancer just a minute ago and it's showing 2.5 to 3 degrees up from level which causes the tail shaft to point down. I think I'm going to invest in a digital angle gauge so I can stop expecting this manual gravity one to be accurate. It's hard to read as well.

If you stand on the driver's side of the car moving from front to back, my drive line looks like what Todd posted \ / \ .

Thanks everyone

that makes no sense. the engine cant be angled up and the trans pointing down at the same time.

I have this one
https://www.amazon.com/Floureon-Incl...l+angle+finder

WSSix 01-14-2018 05:05 PM

Why not, Randy? The balancer is in front of the engine mounts which are a pivot point and the transmission is after the mounts. The tail shaft is slanted down at the rear and the balancer is slanted upwards.

Lance, your reply came in just before mine. I agree with the tilt of the gravity angle gauge. I always work to make sure I'm pointed straight down so that the pendulum swings and doesn't get pinned. There's an HF down the road. I'll swing by tomorrow I think.

I appreciate the replies. I was out of town all weekend so I haven't touched the car. Hope to get back on it soon.

Thanks

randy 01-14-2018 05:36 PM

The yoke is on the same plain as the crank shaft balancer. The engine if angled up the trans yoke is angled up. All of this is being over complicated.

Get the engine or tail shaft angle
Driveshaft angle
Rear pinion angle

And then you will have all the front and rear operating angles that you need.

GregWeld 01-14-2018 09:31 PM

Trey ---


One of the things that gets messed up is trying to make it too complicated....


And remember that you want the PINION angle DOWN -- because as the power is put to the rear end - it tries to rotate the pinion UPWARDS.... The type of suspension you have makes a difference in how much this is allowed to rotate from a "negative" to the positive. A race suspension which allows hardly any movement -- should be set about 1 to 1.5* Down (at the pinion).... and a rubber suspension would be 3.5 to 4* down - because it's going to rotate up A LOT.... Urethane bushings would be "harder" and can be set at 2 to 2.5* Down etc.

So you need to know the suspension set up and adjust accordingly.

The motor is going to be 3 ish * down at the tranny ----- and the diff should be set according to the appropriate down angle (allowing for it to climb back to about zero in hard launch mode) according to how much movement it should have (a little - moderate - or a lot) -- and the working angle of the driveline will mathematically work out to about 1 ish * (the angles should cancel each other out, but they should never be 0 ----- is should always have 1 to as much as 2 degrees "difference".

So let's say the engine is down 3* -- and the driveline is down from the motor to the rear end 4* -- and the pinion is down 2*

Use this calculator to help when you're measuring



http://spicerparts.com/calculators/d...gle-calculator

WSSix 01-15-2018 05:08 AM

Quote:

Originally Posted by randy (Post 671659)
The yoke is on the same plain as the crank shaft balancer. The engine if angled up the trans yoke is angled up. All of this is being over complicated.

Get the engine or tail shaft angle
Driveshaft angle
Rear pinion angle

And then you will have all the front and rear operating angles that you need.

This is why communicating properly is important and why I wanted to make sure we all understood each other. We're saying the same thing but we're looking at it differently.

To clarify, when I say the pinion is pointed 2.5 degrees up, I mean the nose is pointed up. The gear is pointed down. Using the link/calculator Greg posted, they consider the pinion to be sloped down.

Quote:

Originally Posted by GregWeld (Post 671666)
Trey ---


One of the things that gets messed up is trying to make it too complicated....


And remember that you want the PINION angle DOWN -- because as the power is put to the rear end - it tries to rotate the pinion UPWARDS.... The type of suspension you have makes a difference in how much this is allowed to rotate from a "negative" to the positive. A race suspension which allows hardly any movement -- should be set about 1 to 1.5* Down (at the pinion).... and a rubber suspension would be 3.5 to 4* down - because it's going to rotate up A LOT.... Urethane bushings would be "harder" and can be set at 2 to 2.5* Down etc.

So you need to know the suspension set up and adjust accordingly.

The motor is going to be 3 ish * down at the tranny ----- and the diff should be set according to the appropriate down angle (allowing for it to climb back to about zero in hard launch mode) according to how much movement it should have (a little - moderate - or a lot) -- and the working angle of the driveline will mathematically work out to about 1 ish * (the angles should cancel each other out, but they should never be 0 ----- is should always have 1 to as much as 2 degrees "difference".

So let's say the engine is down 3* -- and the driveline is down from the motor to the rear end 4* -- and the pinion is down 2*

Use this calculator to help when you're measuring



http://spicerparts.com/calculators/d...gle-calculator

Thanks for the link Greg. You're correct about over complicating it. What you've just posted is what I've always thought and worked towards. Until I started having problems that is. Then, I decided to learn more and ended up where I am now. :knokwood:

Luckily, I have 6* of angle shims under the rear so tilting the pinion nose down won't be hard. I'm going to remove the snubber/bumper on top of the transmission too so I can lift it a little more. We'll see where I can get the angles to go to from there.

Thank you all.


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