Technical Drive shaft / rearend pinion angle

Then it isn't u joints, period. Try tires, is everything properly aligned? Could be toe in, could be a bearing going bad somewhere, wheel bearings give vibration, rear wheel bearings at the axle end will give a whump, whump type noise at speed, front wheel bearings will generally give vibration you can feel in the steering wheel, look for all the easy things first before swapping tires and spending tons of cash.

 

Take it from an import driver..
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sure as hell ain't the drive shaft angles if those numbers ya posted are correct.... probably tires..


On another note.....why does the world think 32 s are the cats ass...i mean there so much difference between a 32 and a 33...34......

Oj off my soap box.....

 

Could be wrong but I'm reading that as the two gong downhill towards each other and a drive shaft at 1 deg. downhill toward the front between them. Wouldn't that jive with a 2 degree difference?

 

Chassis rake is irrelevant to drive line theory in general.
But it's not irrelevant when it comes to fitting it into a chassis, and its very relevant to if it was raked before or after the drive line was set up.

Tanners engin is 2* down & pinion is 2* up wich is fine.
His engine 2* and 4* rake makes 6* fitting issue at the fire wall. Maybe that's irrelevant to some but its gotta fit into the car, period. And it's should look good doing it double period ..

Tanner has an offset pinion. That means someone needs to figure this angle and add it to his 1* in the driveshaft. To do that it takes some measuring and trigonometry. When running an offset pinion, you need to make sure the center lines are parallel on two planes not just one.

His description of the problem doesn't sound like drive line angles any way, it sounds like a balance issue.

 

I say balance the tires first, like a few others have said.

 

i like this video, and no i have never even touched a 32 ford, chevy yes.

https://www.youtube.com/watch?v=gmV4qwLfOMY

 

So, Ryan brought this back,
Lets get back to work

 

Thank you. This demonstration shows the whole phasing and angle thing better than any words can describe it.

 

Did you take me for a test drive in this yet

 

When you have a moment, see if there is any side-to-side play in the slip yoke, where it enters the transmission. It goes over the output shaft splines, and inside a silicon bronze bushing.

Those bushings can and do wear out, and are, sadly, often skipped by rebuilders.

I have found them to be an annoying source of difficult to locate "bracketed" vibtration (starts at one speed, stops at a higher one).

 

Been busy...haven't had a chance to take it back out........

 

Drop it off here, ill drive it around for you

 

Tailshaft bushing wear is a VERY common issue on T-5s in Fox Mustangs, for one.

And make sure the yoke isn't sticking too far out of the transmission if that hasn't been covered already.

 

added 1.5 degrees of pinion angle and pretty much cured the problem.......still think I'm about 1/2 degree off...at 50 I can still feel or hear a small bit of harmonics....at this point I think it is more MENTAL than a problem cause I've fought the problem so long........thanks for all the help.............I think the sprung weight of the u joints in a rotational mass at speed under diverse conditions caused the unsprung weight to mass such an amount of feel to it that it went away..........SOUNDS LIKE A DUMB ENGINEER DON'T IT....HEHEHEHEHE.......thanks again to you guys for the help

 

I got lost along the way, is the driveshaft balanced? I have always had my driveshafts balanced and never had a problem.

 

IT HAS A WEIGHT ON IT SO I TAKE IT THAT IT WAS.

 

Not true, I always have the shafts balanced and have never found one balanced that well out of a salvaged car. But then I almost always have them shortened (or something modified) when using them in a none stock application. When they are checked on the balancer they always show their off at least a little. Very cheap insurance! I take them to a shop that balances semi-truck shafts and they do an excellent job.

 

As a side note, the shop I use will provide and install the u-joints cheaper than I can buy the u-joints. They get all of my driveshaft business. The last shaft I needed I spent days looking through salvage yards and all of the shafts the size I needed were bent or damaged (the yards damage them moving the cars around). Finally found some in one yard and the prices were ridiculous! Went to the driveshaft shop and had them custom build one cheaper!

 

our only shop that balances has had bad reviews from some of my friends...still may have it checked

 

Hey I finally got back here and glad that the vibration issue is settled.

Sometimes angles are set up equal front and rear, but they "go out" under the pressure of actual running. You do feel this more in a light car, generally. That means the static setup can't be equal.

BTW the demonstration video Bud posted was excellent and deserves its own thread.

 

I've still got a litlle...I mean a very little at about 57-58 mph...I wonder sometimes if it's just me or is it really there...65-100 is smooth as silk.......other than the wind buffeting the car all over the road.......I've talked to a few more friends with '32's and they say they also have a vibration at certain speeds........and they all are around that same speed......maybe it's something to do with fiberglass cars....hehehe...cause my steel car doesn't have any vibrations anywhere.........I'm basically over it and going to live with and head to Pomona in a couple weeks.

 

Glad you got your 32 vibration figured out. My Eskimo snake breeder friend with a glass 32 Ford was gonna come over to help you. Personally I shake like hell over 65-100 in a plastic or steel car myself.

 

Does the speed at which it occurs change if you add a passenger or sandbag the car? If it gets better or worse, that will tell you which way to move the pinion,