Driveshaft Speed Sensor

[Heo]

I dont think you will have any problem
with the balance. As you say close to
center, fairly symetric machined
so I dont think there would be any problem

[machoneman]

You guys are scaring me about the balance.  I did not machine the parts so that they had screws coming from the opposite sides, so there is going to be some imbalance there.  Saving grace (hopefully) is that it is fairly close to the center of rotation, so hopefully it won't make any noticeable vibration.  I guess if worst comes to worst I can have the driveshaft rebalanced with the target bolted on, and then mark it somehow so that it is always installed in the same spot.  Or maybe just balance the target...

Critical speed for this driveshaft is over 8500 RPM, so I'm not too worried about that.  It is a 4" diameter aluminum driveshaft, and even though its a foot longer than the old one, according to the Mark Williams critical speed tables I won't come close.

Sorry Jay didn't mean to scare you! Still, you might want to take that shaft into a shop that can check the balance now rather than later. That or make a few progressively quicker runs locally while solely checking for any shake-n-bake!   

[shady]

you can always balance the drive shaft the poor mans way, (my way). I put the car on jack stands or a lift, take a hose clamp, install it on the front of the shaft behind the yoke, mark it's location  & run  the car in high gear. then turn theclamp a little at a time to find the sweet spot. takes a little time but usually works as the screw acts as the weight. nice thing it is not permanent should you change things in the future.

[Qikbbstang]

With all the pesky little problems discussed that go with forward mounting of the gear or "target" : complex driveshaft removal, limited teeth on the target, tight clearance issues, potential difficulties w/balancing etc I wonder if you considered going the OEM route and mounting the target on or near the rear axle flange as the car mfgs do for their ABS systems?.....
     Heck a trip to a pull your part junk yard could potentially yield a decidedly larger target with lots of teeth, matching sensor, mount and even heat shielded wiring etc for all of $10.00.

[jayb]

Modern ABS systems use a target on each wheel, not anywhere on the driveline.  I guess I could have gone the route of putting it on the rear end yoke, but I've seen them on the driveshaft yokes before so it seemed like the logical place to put it.

I have a balancer for balancing model airplane propellers.  I think I might just take the target off and try to balance it independently using that, if it gives me any vibration.

[WConley]

It's all good, Jay.  You're not going to hurt anything in the short term.  If the car starts buzzing down the road you'll know what the problem is!

[Heo]

Any way it wont be like when i worked at a tire shop
This guy with a El Camino came in and wanted two
tires mounted on the car. He had retreaded them at
a truck tire retreader.  He said he  had to be in the
Next town in an hour, So i dont had time to balance
them. I told him to come in next day for balancing
He came in and said there was some shaking in
the rear end.  Yea we balance that no problem
I put the wheel in the balancer and hit the go button
And all hell broke loose, It ripped the balancer from
the concrete floor all four 10 mm bolts The balacer
Jumped around  and tiped over hitting the El Camino
denting the door while i tried to hit the brake button
  The customer running out of the shop
  Yeeaaa right "SOME" shaking in the
rear end. When i finaly got it balanced it was 1/2 kilo
about one pound out of balance and he drowe that
for 60 miles

[BruceS]

Lars,
Lol, that must've been one big chunk of lead weight!   
I wonder how you got it to stick to the rim!

Bruce

[Heo]

The biggest clamp on wheights half the rim
inside and out

[TorinoBP88]

Jay, if you used 4 bolts, two on each side, you could position them outside the plane of the teeth, but this would have required more machining from a thicker piece of material.  The bolts would not interfere with the teeth that way.

[Qikbbstang]

A pound of weight: I wonder how you got it to stick to the rim!
SIMPLE
Just go to lowes and buy a bag of concrete and a couple bricks!

[57 lima bean]

Or chrome metal tape.Just like on the Direct Connection units.No balancing needed  

[gdaddy01]

have you ever gotten a large chunk of clay stuck on one side of a wheel ? more than a little  vib.

[Hemi Joel]

Jay, if you're concerned about the balance, use aluminum bolts, they hardly weigh anything.
I have my own balancing story. I put a 455 into my 67 Olds 442 that was basically a slightly freshened up junkyard motor out of a car with an automatic. I put a steel manual tans flywheel on it.
The first time I ran the motor while I was actually sitting in the drivers seat, I noticed a distinct vibration, that changed with engine speed. I wanted to make sure that it was not from an engine miss, so I did a power balance test by pulling one spark plug wire at a time and checking for constant RPM drop. That came out fine, so then I Checked the exhaust temp on each header tube with a handheld infrared thermometer. It seemed that all 8 where hitting fine. So I pulled the fan belt to rule out fan, etc. No change noted.
 Then I dug out the old flex-plate that had come on this motor, and sure enuff, it had a big ol' counter weight welded to it. I put the flexplate and a damper on the crank out of the old motor ( which was sitting on the work bench) to check the orientation of the flex plate weight in relation to the damper weight, and they were about 15 degrees apart.
 THen I looked at the flywheel in the car, and balancing holes where drilled in about the same location as the counterweight on the flexplate. Weird. The flywheel is drilled with a few different clutch mounting patterns, and those holes are threaded all the way thru the flywheel to the front. So I used one of the unused holes to bolt 5 ounces of lead the  front of the flywheel, in the location where the counterweight on flexplate was. After checking for clearance, I started the motor and it shook like a belly dancer. So then I took the weight off and moved it 180 degrees and started the car. It was way smoother, but still vibrated a small bit. I experimented with weight untill at 3.25 ounces, the motor was smooth as a babys behind. THen I made up a 3.25 oz. steel weight that I carefully ground to fit the contour of the flywheel to lock it in, and bolted it on with a locktighted grade 8 bolt. I think it is safely there to stay, and it works perfectly. I can't beleive I balanced my own motor without removing it from the car!

[mike7570]

I don't think there would be a balance issue if mounted on the rear end yoke?
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