Torsional vibration absorber

[paultv]

After driving about four thousand miles over the last 6 weeks the old gal has developed a drive train vibration at about 60 mph.

The prop was balanced a while ago and the rear end is all pretty new.

I checked the tyres for out of round/flatspots and so on including balance by rotating the rears to the front and test driving...all good.

Got the car safely up in the air and did the old chalk test on the prop front and rear sections which revealed a slight out of balance but nothing bad.

I took the prop out to check the guibo and centre locator sleeve....all appeared fine but I noticed the torsional damper looked off center, so I reassembled the prop leaving it off.

Instant improvement and made better by the addition of 3 gramms to the rear prop section by the diff.

So now all is perfect but without the Torsional damper.

At 150 quid I'm wondering if I need a new one? I guess it will extend the life of the guibo as they are only fitted to the "performance" cars and the 325 as far as I can see.

Paul

[HJ1981]

Isn't that also known as the vibration damper? some models have it going right after the transmission flange, some have it with it behind the guibo. Are we talking about the same item?

[paultv]

On Real oem it's called a Torsional Vibration Absorber and lives with the Guibo

Torsional Vibration Absorber.JPG

and it sits here:

Torsiona VA..JPG

Its supposed to absorb vibration from the uneven rotation of the engine caused by cylinder firing in the same way the flywheel does to some extent.

Mine appears to be knackered.

Paul

[HJ1981]

Yes i suspected we are on the same page, just wanted to confirm.

Well, i did research on this months and months ago when replacing the clutch, apparently most owners removed theirs without any consequences at all. Infact, some report that one can not install the Z3 short shifter with it installed (i can not say from experience). Mine is rusted on and i could not removed it and i did not wish to smack a hammer to remove it.

Since you already removed it and there are no side effects (did you even try some high speed runs? maybe 200kph+ if possible just to verify) i would leave it removed, god knows i want to remove mine.

[Brianmoooore]

Confusion reigns because part 3 in the ETK diagrams refers to two different, but similar, parts.
The part on Paul's car is the one ending in 514, and was only fitted up to 1988.
The part ending in 254 is the one actually shown in the ETK diagram, was fitted from '88 on, and encloses the giubo.
254 is the one that fouls the short shifter conversions, and can be removed and binned with no ill effects. It was not fitted on late E30s, or any later BMW model that uses a similar propshaft. It's allegedly no longer required because of an improved design of giubo.
I've little experience of the 514 version, because I try not to get involved with pre facelift stuff, but I'd be surprised if it wasn't equally redundant.

[paultv]

Strange then as my car is 1990....some previous owner may have retro fitted an earlier prop??

I have a new guibo to fit...then I'll test it for vibration problems in the garage...I'm really only prepared to run the car to 150kph " on the bench" for safety reasons!!

Paul

[HJ1981]

Confusion reigns because part 3 in the ETK diagrams refers to two different, but similar, parts.
The part on Paul's car is the one ending in 514, and was only fitted up to 1988.
The part ending in 254 is the one actually shown in the ETK diagram, was fitted from '88 on, and encloses the giubo.
254 is the one that fouls the short shifter conversions, and can be removed and binned with no ill effects. It was not fitted on late E30s, or any later BMW model that uses a similar propshaft. It's allegedly no longer required because of an improved design of giubo.
I've little experience of the 514 version, because I try not to get involved with pre facelift stuff, but I'd be surprised if it wasn't equally redundant.

Strange as well, mine is a 06/1990 325i, according to this info and realoem mine ends with 254.

I know it was never fitted on (at least) the E36 328is, since we owned one for 10+ years and it never had it, but my late E30 does have one.

[paultv]

In that case maybe mine has been incorrectly refitted in the past - quite possible - and it should be around the guibo as in the drawing for my car on real oem.

The number stamped on the TVA is "BMW 1226527.2" and the date 04/90

Paul

[davidt]

This is the way its fitted on my 1988 facelift 325i .

S1035360.JPG

[paultv]

Yep...thats how mine was too.

Paul

[HJ1981]

Mine is installed the same way, sadly i did not take the time to look for stamped part number(s) or date(s).

I really would like to remove it to install the Z3 shifter, will do it at one point. But as i said earlier, mine is rusted on solid, would not even rotate a few degrees (as stated in the manual) and i was nervous smacking it off.

[paultv]

Just remove the prop front section - make sure you mark it for correct orientation when you put it back together - then you have the front prop on the bench,
much easier to work on, replace the locater in the end of the prop if it's in any way suspect -

Did mine yesterday to replace the guibo - and ran some balance checks - got rid of a little 40Hz waggle at 110 KPH -

Paul

[paultv]

After a test drive the car feels 100% better without the Torsional damper lump...I still have a minor vibration at about 110kph ....maybe a tyre balance issue but I'm going to run some more balance tests on the prop anyway. An external accelerometer with a magnet would help but they cost a bloody fortune.

Paul

[HJ1981]

Just remove the prop front section - make sure you mark it for correct orientation when you put it back together - then you have the front prop on the bench,
much easier to work on, replace the locater in the end of the prop if it's in any way suspect -

Did mine yesterday to replace the guibo - and ran some balance checks - got rid of a little 40Hz waggle at 110 KPH -

Paul

Sometime in the future i shall do this.

After a test drive the car feels 100% better without the Torsional damper lump...I still have a minor vibration at about 110kph ....maybe a tyre balance issue but I'm going to run some more balance tests on the prop anyway. An external accelerometer with a magnet would help but they cost a bloody fortune.

Paul

I got tiny vibrations at those speeds as well, balanced the wheels/tires twice at two different reliable shops and did nothing. One shop suspects, after a lot of inspection, that the tires (Hankook ventus) may be the cause. Since winter is around the corner and winter tires are going on, we shall see.

[paultv]

Do an easy test..run up to speed on the smoothest quietest road you can find, when the vibration peaks dip the clutch and drop out of gear...if the vibration remains its in the driveline, if it stops its a third order vibration from the engine...third order because its a six cylinder and fires 3 times per revolution...being a cabby makes all this worse of course.

The guibo I took out was a 6 year old Febi... it was a little distorted and softer than the new one, after installing it, it held the prop very firmly and correctly centered at the centre bearing...there's quite a lot of wiggle room in that mount which allows you to easily set it up with a kink in the overall prop position...more stress for the UJ's....and noise if they are worn as well.

I also found one of my Nexen Blue HD to be out of round...6 months old...I think a lot of shops are sloppy with balance and don't run a load test which shows this up immediately.

Paul

[Tzantushka]

I think a lot of shops are sloppy with balance and don't run a load test which shows this up immediately.

Agree on this.
I had a great experience with a tyre shop that cared.
i. they would reposition the tyre on the rim (rather than chucking more wheel weights on)
ii. they also used a road force balancing machine (Hunter, I think) rather than free spinning

That was the best fitted set of tyres I EVER had - zero vibrations.

[tha881]

To add a few notes on this, Barry replaced my prop and centre bearing a few years ago and I had the damper fitted. I dont recall it vibrating even though we discovered the dots were not lined up! So he refitted it with the dots aligned, removed the vibration damper altogether and it's been perfect ever since.

Also with the wheels and tyres, i visited a breakers a couple of years ago, they span a few used oem bbs wheels they had for sale on their balancing machine. These were without tyres so i could see how true they were. Most were fit for the bin, but they had one which was perfect. That is now on the front of my car and i have zero wobbles at all speeds. I think some wheels you will never get to balance correctly.

[HJ1981]

Thank you for all the tips guys regarding the vibrations and the tire balancing, i do live in a small town and my options are indeed limited.

I could dig around more to see who has a proper machine to really be certain the tires/wheels are indeed balanced, as well as the tires not being out of round (they are one year old Hankook Ventus with roughly 12.000-15.000 kms on them).

[paultv]

These guys have a Hunter set up..

https://msp-reifen.de/hunter-road-force-touch/

1 hour 45 mins from me...

Do a search for your area...you might be lucky!!

Paul

[HJ1981]

These guys have a Hunter set up..

https://msp-reifen.de/hunter-road-force-touch/

1 hour 45 mins from me...

Do a search for your area...you might be lucky!!

Paul

I shall, i just replaced the LCABs with M3 offset BMW ones from the dealer (€35 a pair) and i wish to get rid of the Meyle brand rubbish installed in the car (upper strut mounts, rear mounts and front/rear sway bar end links) then i shall go for tire balancing and alignment.