fbekholden.com

Long shots:
a) cardboard dampener inside of driveshaft has come loose and is playing around with the balance (shouldn't be, as shafts were balanced).
b) harmonic balancer has excessive runout (that's engine though, shouldn't be as it does it coasting).

Cheers,
Harv

my books says ... vibration at a particular speed is usually unis or angles ... if out of balance it increases with speed

That makes sense, oh wise one

This looks like a common problem Trevor -B on the fe/fc forum is having the same problem.

Down load the TREMEC app for your pinion angles mate it is designed for checking all drive shaft angles and easy enough to use


Sent from my iPhone using Tapatalk

For those of you who have been following this thread I am happy to say that I have solved the driveline vibrations. It was driveline angles! This morning I took reading of the angles of the gearbox shaft, prop. Shaft and diff pinion. I then slackened off the nuts for the rear spring / shock absorber plates, jacked up the nose of the diff to the same angle as the gearbox shaft, inserted packers (3mm in this case) at the rear side of the plates then retightened the spring plate. My dimensions are pretty crude but I ended up with the diff and gearbox at about 4 deg and the prop shaft at less than 2deg. I used my iPhone as an inclinometer and it only measures degrees, not part degrees. Any way the road test was great - no vibrations at 100 kmh! I do get a little vibration at 110 kmh but I never drive the ute at that speed so I am not bothering to chase that. All in all very satisfying. Tomorrow I will chase the same vibe issue in my FC sedan, then order proper wedges for a permanent fix. Cheers, Fraze
P.s. the guidelines published for drive line angles are: gearbox shaft and diff pinion shaft to be within 0.5 deg of each other and for the drive shaft to be less than 3 deg Angle at normal drive height.

Happy days Fraze

Good one Fraze. These sort of posts are very educational (for me anyway) so thank you for sharing.

Dave

Thanks for sharing the solution Fraze. Important info that helps us all.

Yep that is very good to hear Frazer


FB ute fixer upper, EK van on rotisserie

Interesting. I wonder if all FB/EKs had this drama from the factory? I would have though an older car would have sloppy/flogged out mounts and the angles would change, but with your new mounts that should not be the case.

Cheers,
Harv

Fascinating topic, enjoyed reading this, glad you solved the vibration issues

Hooray !!!!

The old girls were probably designed for 80kmh at the best.

Just goes to show that perseverance pays off in the end.

Greg

I do wonder how much the angles have changed in my EJ over the years, I really should go through this exercise and check all my angles, I think I will put it on the list, I haven't got excessive vibration but I think there could be more than there once was

Maybe I should wedge my diff a few degrees whilst it is still in the build stage ?
Might bypass some future issues.