This car shakes so bad, it’s not drivable!

Continuing on with the Falcon, I move to the underside where I sort out a few known issues, and create a few new ones.

[@BlueOvalEdge]

Nice work buddy. I’ve done the pinion angle set job myself a couple times. Very confusing because people and/or online instructions often don’t describe the procedure correctly i.e., in a way that is understood by someone who has not performed the task. Years ago, I got so sick of the confusion, I put together a powerpoint presentation with pictures and math examples to help explain. I don’t think you said anything wrong, so I am just offering clarifications from someone who has done the job and has had to explain it, in writing, to people who have not done the job (yet). Yes, you are correct with the “equal and opposite” remark. Specifically, the goal is to have parallel drive planes under load i.e., when the car is driving where load is from axle windup. Note: Parallel drive planes has nothing to do with the driveshaft. As you alluded to, leaf spring cars “wind up” their axles about 2°-3°. Most chassis guys use 2° for leaf spring cars. Thus the pinion angle (not the driveshaft) must be -2° (down) relative to the drivetrain angle because it’s going to wind up +2° under load. Dirt simple example, if the drivetrain angle was flat (0°), the pinion angle would be set to -2° down (towards earth). Leaf spring axle windup is +2° “up” under load (driving) so that equals -2° (no load set pinion angle) +2° (under load pinion angle) or -2+2= 0°, which is the same as the 0° drivetrain angle. This is the simplest math example to illustrate a parallel drive plane which has nothing to do with the driveshaft. Now onto a more real world example. Drivetrain angles are always negative as is yours. Most chassis guys say a 4-link controls axle windup to 1°, so the math is the same just use 1° instead of 2° for the leaf spring car. If the drivetrain angle is -3° down, the pinion angle needs to be set to -4° down as axle wind up under load will move the pinion angle up 1° so you get your opposite and equal parallel drive planes UNDER LOAD i.e., -3° at the drivetrain and -4° (pinion set angle) + 1° (axle wind up) = +3° (equal and opposite). After test driving, adjust the pinion downward to correct acceleration-related vibrations and upward to correct deceleration vibrations. Plus or minus 1° is generally enough to cure the problem. There are a thousand youtube videos that get this dead wrong, however the guys at BMR racing got it perfectly right. Check out their video at the link below. I can email you the powerpoint I mentioned if you contact me at [e-mail]. Nice work on a VERY confusing subject which has burned me in the past. kzbin.info/www/bejne/l6C3apZ6mLmBr9E

[@rdspeedfab]

Great info! Thanks for laying it all out. I’m sure that will be helpful to a lot of folks. Myself included. I still think it’s a little bit of a dark art haha

[@BlueOvalEdge]

@@rdspeedfab I've always understood all of this and it was never confusing to me (my pants are on fire right now).

[@rdspeedfab]

@BlueOvalEdge 🤣🤣

[@Snakelegs-go8qo]

Awesome Rob,,, I'm calling it a transmishall from now on.. beautiful welds on that header mate..I know i'm watching the videos in the wrong order now,, but i feel like i gotta watch the old ones..since you made 'em. Time for a new video i reckon.......

[@rdspeedfab]

Haha heck yes. Watch em all! Thanks brother.

[@olboy1981]

That trans mount is meaty..

[@rdspeedfab]

Yeah it is. Way more than it needs but I made it out of what I had laying around.

[@georgegoncalves6907]

Are you running a t5 trans? And if so did you have to modify trans tunnel? Thanks. Nice work.

[@rdspeedfab]

Yes T5 in the falcon. No tunnel modifications needed.

[@sanchezjo78]

What engine do you've on your falcon and where did you get the power steering braket.. I'm looking for my mustang 289. Tks

[@rdspeedfab]

It’s just a .030 over 302 that I built for it. The bracket is a no name kit from Amazon I bought several years back. I just wanted to run the fox body PS pump.