Pinion Angle
#11
Sorry,but driveshaft angle DOES matter. It comes into the total called "working angle." It's more important on a lower car. If you tranny is down 2.5 in the back, and the car is lowered, the rear end will higher in the car, which means the driveshaft will have to be about level. So since the tranny goes down, and the driveshaft doesn't continue down at the same angle, you put more "working angle" in the u-joint. Exceeding working angle even if the angles are parallel. The aussie has excellent points.Axle run out is another good one that feels like driveshaft problems.The 69 we're building has a very low number on the tilt because of working angle. The faster the driveshaft turns, the less angle you want. 3.5 deg, I think the max is 4k drivesaft speed.
#13
The drive shaft is a steel 3.5" i think,maybe 3". We bought it through American driveline, the only thing that puzzles me is that it only has weight tabs on one end of the DS. ALl other DS if looked at around the house has one on both ends. But getting the DS down to get balanced tommarrow, but they say they can only balance to 2400rpms, they said that is all anyone can balance it to, is that correct?
The car has a grab-a-track 5 leafspring in the rear, with track bars. SO i dont think much axle wrap is happening, plus the car is putting 584hp to the flywheel, and 540 tq.
cprstreetmachine you exactly correct about it getting above the trans, giving the DS a positive angle. Thats why i suggested the 9", giving the pinion a lower stance for adjustments.
The car has a grab-a-track 5 leafspring in the rear, with track bars. SO i dont think much axle wrap is happening, plus the car is putting 584hp to the flywheel, and 540 tq.
cprstreetmachine you exactly correct about it getting above the trans, giving the DS a positive angle. Thats why i suggested the 9", giving the pinion a lower stance for adjustments.
#14
i'm not sure about their balancer speed but there are balancers that run at actual speed. the harmonic thing is a calculation that the DS guys would know about even if they cant balance at high revs.
did you think about engine speed when the vibe starts and does it pass or get worse?
did you think about engine speed when the vibe starts and does it pass or get worse?
#15
gold! see the second half on critical speed and see if any makes sense or exactly half critical speed matches the engine revs you experienced the problem at.
http://www.markwilliams.com/driveshafttech.aspx
http://www.markwilliams.com/driveshafttech.aspx
#16
Awesome link Aussie, thanx. Tagging that one,too.
#17
One quik thing Kalli
You said that as a car accellerates the rear end will rotate down.. Are you sure? as the tires rotate forward the housing should rotate up! equal and opposite reaction to the forward movement of the tires.
You said that as a car accellerates the rear end will rotate down.. Are you sure? as the tires rotate forward the housing should rotate up! equal and opposite reaction to the forward movement of the tires.