Brake rotor centering - Lateral-g Forums

**WSSix** · #1 01-09-2018, 09:26 PM

I believe I've goofed on my working angles and I'm way over the 3* limit. I had always taken my measurements with the car sitting at ride height. Well, tonight I took them with only the rear off the ground and it became obvious to me that I think I screwed that math up. I'll see what Lucas at Drive Shaft Shop says in the morning.

Thanks

**GregWeld** · #2 01-09-2018, 09:34 PM

Quote:

Originally Posted by WSSix

I believe I've goofed on my working angles and I'm way over the 3* limit. I had always taken my measurements with the car sitting at ride height. Well, tonight I took them with only the rear off the ground and it became obvious to me that I think I screwed that math up. I'll see what Lucas at Drive Shaft Shop says in the morning.

Thanks

Easy enough to do ----

Motor should be about 2 to 3* DOWN at the tranny pan --- REAR END should be about 2* UP --- and if the slip yoke is correct (they make all kinds of lengths) -- you should be close.

The other thing I've seen --- a too small diameter drive shaft for the overdrive tranny / rear end gear combo. The shaft has a working RPM and when exceeded can go into harmonic death wobble. LOL

Glad you're on it.

**WSSix** · #3 01-10-2018, 11:30 AM

Those values are actually pretty close to what I have for pinion angles now. The issue is my rear end if higher than the rear of the transmission so the drive shaft is down in front. The solution is to raise the trans more. I'm not sure I have the room due to my headers though.

I didn't want to get into it just yet as I'm waiting to see what the Drive Shaft Shop has to say, but I'm getting really concerned with some things about my build compared to what others have had to do with their similar builds. This whole car is a learning experience for me. I'm worried I may have missed or done some critical stuff wrong after all. We'll see what happens. I hope I'm just over reacting.

Thanks

**GregWeld** · #4 01-10-2018, 11:34 AM

Ah -- yeah that won't work....

Tunnel issues with the new bigger transmissions --- and combine that with our low stances --- yeah --- that's usually a tranny hump mod and driveline tunnel raise....

Those are easy mods even in a done car..... it's a carpet issue --- and back seat tunnel modification...

**WSSix** · #5 01-10-2018, 11:41 AM

I've already cut my tunnel once for the trans and don't mind doing it again. I'd like to do an integrated chassis brace and trans mount like DSE does while I'm there. I also don't mind doing the tunnel for the shaft as I have no interior now. It's the fact that many other people are running SBC/T56 combos in 2nd gens and aren't having these issues at all that concern me. Maybe I am just that low compared to them, but I'm concerned I'm doing a lot more than other's have had to do. That makes me questions what I've done wrong.

Thanks Greg. I appreciate the reply.

**GregWeld** · #6 01-10-2018, 11:53 AM

Ah -- gotcha Trey.

Your motor only need be down 2* - and assume you have a degree / angle indicator.... The car needs to be on it's own 4 -- so jackstands under the axle so the weight in on it.... and place the angle indicator on the face of the pinion... if it's up 1 to 2*....

Then it's a matter of suspension travel.... and that's probably UP 2" and down 2" or in there.... and of course there should be a "bump stop" of some kind to prevent the stuff from hitting...

Che70velle · #7 01-10-2018, 01:10 PM

Trey, my driveshaft is same way, higher at the rear than the front. A lot of guys with lowered vehicles are in the same boat...with no vibrations.
Driveshaft angle is irrelevant. You should see the angle of my brothers rear shaft on his 87’ truck. 17” of lift. It’s steep, and there’s no vibrations with 44” Boggers.
Engine/trans combo should be 2-3 degrees down. Even 4 is ok, I’ve done it. The trick is your rear must be up the same, whatever it is. These angles are also irrelevant of frame/chassis angle. Measure against shop floor, not chassis.
Are you using shims under the rear end to adjust angle? I’ve seen these shims not be exactly the same, and cause binding on the rear end housing when the u-bolts were torqued down tight. Angled lowering blocks can be the same way.
I know you’ve been all over this for too long now. Let’s hope the driveshaft change fixes it. DONT TORCH THE CAR!!!!