Forum Index => The Garage => Topic started by: mopar 318 on August 18, 2010, 00:06:46
Title: pinion angle vibration
Post by: mopar 318 on August 18, 2010, 00:06:46
So its been about a month since I swapped a 8 1/4 into my fifth. Since the rear was out of a cherokee I had to set the pinion angle. At about 110+ kph I get a bad vibration, which I think is caused by an incorrect pinion angle. I have air shocks on the back of this car and I was wondering whether lowering the car via the shocks could correct this vibration?
Title: Re: pinion angle vibration
Post by: doomedgame on August 18, 2010, 01:37:39
What is the pinion angle set at? any more the -2 will make a vibration
Title: Re: pinion angle vibration
Post by: GrissomRacing on August 19, 2010, 18:51:00
From my personal experience, incorrect pinion angle will ,more often than not, cause a vibration when starting from a dead stop, not at high speeds. I think I would look elsewhere for the vibe. Possibly tires. One thing about tires that most don't know is that it is not possible to perfectly balance a wheel/tire combo for "all speeds". When balancing a tire, all you are doing is moving the imbalance to a speed that is not normally driven. This is the same principal as a harmonic balancer on an engine. All it does is move the imbalance to a speed beyond what the engine will ever run. I really don't think it will end up being pinion angle. Tires, driveshaft, steering parts, etc.
Title: Re: pinion angle vibration
Post by: mopar 318 on August 19, 2010, 23:24:30
I have a feeling that it might be tires also, since my driveshaft was just balanced about a month ago and new u joints were installed at the same time. I am going to replace the tires on the front and get the rear tires rebalanced.
Title: Re: pinion angle vibration
Post by: S-type on August 22, 2010, 14:28:45
So its been about a month since I swapped a 8 1/4 into my fifth. Since the rear was out of a cherokee I had to set the pinion angle. At about 110+ kph I get a bad vibration, which I think is caused by an incorrect pinion angle.
If the vibration started right after the axle swap, I would guess that is a good place to start. If not, tires/wheels would be my vote at that speed.
Title: Re: pinion angle vibration
Post by: mopar 318 on August 23, 2010, 01:26:45
Well heres the story,my first combination in the car was a 360 magnum with a 904 and 71/4 rear with some odd ball 2.45 gears (with no vibration issues). Then I swapped in a 518 transmission and shortened the driveshaft myself (With minor vibration but, I was going to change the rear so I waited to get the driveshaft properly balanced). Next I put in the cherokee rear and I had a bad vibration. Upon further research I found out I had been running the wrong flexplate, so I swapped out the flexplate for the B&M unit. The vibration is now minor and only exists at higher speed.
Title: Re: pinion angle vibration
Post by: doomedgame on August 23, 2010, 11:55:14
It could be the tires but could be the pinion angle or a combo of the to If you have a angle finder it would be the angle driveshaft angle + rear end angle from the u joint saddle = pinion angle ds should be + rear should be -