I am getting ready to install a new, OEM drive shaft in my Q45. Does the dealer supplied drive shaft require balancing before installation or is it already balanced from the factory?
Also: I read somewhere a treatise on phase balancing during installation. What exactly is involved here? Simply trying each of the four different positions that it can be mounted to the rear end and picking the one that provides the least vibration at the speed I want to drive?
What are the significance of the white marks on the new drive shaft??
Any advice is appreciated
Q45 propeller shaft balance?
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Q45tech
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1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
YES!"I read somewhere a treatise on phase balancing during installation. What exactly is involved here? Simply trying each of the four different positions that it can be mounted to the rear end and picking the one that provides the least vibration at the speed I want to drive?"
I have a vibration meter that reads the vibration level down to 0.001G........most just ride and pick the best of the 4 [3] postions at what ever speed...........hard to remember or judge small changes. A dyno [smooth roller] would be good to cancel out tire reactions to roads.Always change out motor, transmission, and diff mounts when you add a new drive shaft..........pretty useless when the front is sagging and bad motor mounts willl destroy a new transmission mount fast, which will destroy the ujoints/isolator mounts in the shaft.A few precision drive line shops have strobe and accelorometer vibration devices that they might be use at $100-$150 an hour..............guess $300-$450 might be fair to precision match the drive shaft at one speed.
Ideally one would weld tiny weights on the drive shaft, measure the angles [select a perfct thickness center washer] and play with things all day to get perfection........few can afford perfection.
T3 just swaps out new drive shafts [no indexing] as most find the price enough without tuning!
Great TSB on phase matching after you follow PD section requirements in FSM.
I have a vibration meter that reads the vibration level down to 0.001G........most just ride and pick the best of the 4 [3] postions at what ever speed...........hard to remember or judge small changes. A dyno [smooth roller] would be good to cancel out tire reactions to roads.Always change out motor, transmission, and diff mounts when you add a new drive shaft..........pretty useless when the front is sagging and bad motor mounts willl destroy a new transmission mount fast, which will destroy the ujoints/isolator mounts in the shaft.A few precision drive line shops have strobe and accelorometer vibration devices that they might be use at $100-$150 an hour..............guess $300-$450 might be fair to precision match the drive shaft at one speed.
Ideally one would weld tiny weights on the drive shaft, measure the angles [select a perfct thickness center washer] and play with things all day to get perfection........few can afford perfection.
T3 just swaps out new drive shafts [no indexing] as most find the price enough without tuning!
Great TSB on phase matching after you follow PD section requirements in FSM.
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Q451990
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TSB's are available on the web site http://www.nissan-techinfo.com/infiniti with a one day viewing subscription ($20)
From reading through them, I don't see anything earth-shattering there. Basically they say to match up the white marks as closely as possible. Rotate the shaft to tighten the bolts by turning the rear wheels (not the shaft), and try it in 4 positions if the vibration problem continues.
There's a TSB for 1992 models that addresses the bolts that are used to hold it on to the companion flange. I've always just marked the bolts and nuts and made sure they go back in the same place. The torque spec. in the TSB is 65-72ft/lb which I think is the same as what's in the FSM.
The only other tip I can think of is that when you remove the center carrier braket, two thick washers will fall off. Remember that these are spacers that go between the body and the braket - not between the bracket and the nuts.
I wouldn't take it to a driveline shop unless you do the replacement and find that you still have vibrations.
Heath
From reading through them, I don't see anything earth-shattering there. Basically they say to match up the white marks as closely as possible. Rotate the shaft to tighten the bolts by turning the rear wheels (not the shaft), and try it in 4 positions if the vibration problem continues.
There's a TSB for 1992 models that addresses the bolts that are used to hold it on to the companion flange. I've always just marked the bolts and nuts and made sure they go back in the same place. The torque spec. in the TSB is 65-72ft/lb which I think is the same as what's in the FSM.
The only other tip I can think of is that when you remove the center carrier braket, two thick washers will fall off. Remember that these are spacers that go between the body and the braket - not between the bracket and the nuts.
I wouldn't take it to a driveline shop unless you do the replacement and find that you still have vibrations.
Heath
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Most drive line shops haven't the experience with "on car" ultra fine tuning balancing. Some have old equipment that never gets used because of the labor time involved........Costs.
The other problem is the 4 point lift dampens the vibration and the rear suspension sagging down 4 inches.........need 2 screw jacks to support at normal road height so the half shafts are at normal angle.
If you have the money and find the right guy who will spend the 3,4,5,6 hours to get it right.......with a brand new shaft.........you can make that part of it act brand new.
You use big hose screw clamps and rotate them for fine balance then you weld on or remove weights..........we are talking 5-15 grams in tiny increments.
Don't waste time without new motor/transmission mounts/new transmission end seal, things may have sagged so selecting the critical offset [center mount washer thickness] is critical.
Check that the differential mounting flange is true [no runout] not bent from a previous bad drive shaft.
http://www.lx.net/jlynch/fieldbalance_r ... di....html
http://driveshaftmasters.com/t....htmlh ... ru...4.PDF
Remember that a vibrating drive shaft can take out the diff front bearings and the transmission rear bearings.
The other problem is the 4 point lift dampens the vibration and the rear suspension sagging down 4 inches.........need 2 screw jacks to support at normal road height so the half shafts are at normal angle.
If you have the money and find the right guy who will spend the 3,4,5,6 hours to get it right.......with a brand new shaft.........you can make that part of it act brand new.
You use big hose screw clamps and rotate them for fine balance then you weld on or remove weights..........we are talking 5-15 grams in tiny increments.
Don't waste time without new motor/transmission mounts/new transmission end seal, things may have sagged so selecting the critical offset [center mount washer thickness] is critical.
Check that the differential mounting flange is true [no runout] not bent from a previous bad drive shaft.
http://www.lx.net/jlynch/fieldbalance_r ... di....html
http://driveshaftmasters.com/t....htmlh ... ru...4.PDF
Remember that a vibrating drive shaft can take out the diff front bearings and the transmission rear bearings.