Thread: TD5 vibration 2500-3500 rpm

Originally Posted by Graeme

I have GY Silent Armours after MTRs, but as the harshness is revs-related (occurs in each gear at the same revs), I doubt there's any connection with the tyres. Thanks for the thought anyway.

I haven't yet run a belt around the gbox soundproofing, although it really doesn't seem to be something light vibrating. The harmonic balancer wobbles at idle , but at almost $600 for a new pulley I wont be changing that without expert advice.

Graeme

I'm not a TD5 owner ... but a wobbly harmonic balancer is a problem
If it lets go it will cost you more than $600
Can stuff the crank / seals / etc & if it comes off because it is rubber mounted then it will cost you what ever part it jumps into (radiator?)

Go and find a second hand one and replace it ... Plenty around ask the folks

Mike

I considered that it was not moving enough to become a problem itself, but now you've got me thinking. I will try to measure the run-out and maybe speak with some local engine rebuilders, although as it was obviously balanced (the floating section has some holes at 1 spot), it must be out of balance now anyway. 10 years ago I had a tractor's HB re-rubbered because I thought it shouldn't be wobbling but it didn't take long for it to start wobbling lots again, so its been ignored since, and I was content to leave this one be.

I'm not keen to try a s/h one as it might also have run-out. However I might remove the floating section and see what effect on the vibrations it has, and if there's enough change but still has vibrations, I will consider getting a new one. I think the TD5 is the 1st vehicle I've ever owned that uses an HB, as I remember friends' old Holdens always having problems with theirs.

I've just taken the time to read all the threads in this post
This vibration has been there since November 07

If you "borrow" a second hand harmonic .... then this will help in eliminating this item
I am sure of one thing ... If rubber mounted / they do let go and slip about
They put the vibrations through all your bushes & seals that are connected to the crank and that inturn causes early failure to the engine

Make sure the bolt hanging onto the harmonic is not loose .... My bro had to get rid of his car due to a harmonic coming loose ... It had cut out the end of the crank & stuffed the seal // to fix it he would have had to buy a new crank

You have a "precision" engineered motor that does not tolerate extremes
Your 10k experience might help in explaining my thoughts here



Mike

I may have identified the source of the problem.

I removed the harmonic balancer from the pulley after discussing the situation with my son-in-law who is involved in the manufacture of engine ancilliary equipment, including their NVH characteristics.

Now the engine has very much less vibration going through the 2500-3500 rev range. It gets noisier as the revs increase but no longer seems to have that very bad patch. Gradually increasing cruising speed from 100 to 110 produces a gradual increase in cabin noise and accelerating through the range doesn't seem to produce the previous significant increase in reverberation. The engine pulls smoothly right up to 4500 rpm in 3rd, with no harshness-related reason for changing-up before 3000 rpm.

I will try without the HB for a while (maybe several weeks) to be totally convinced then will probably install a new one. I will most likely refit the accoustic cover in a few days.

Running sans Harmonic Balancer is a pretty good way to destroy crankshaft.....

Originally Posted by Lucus

Running sans Harmonic Balancer is a pretty good way to destroy crankshaft.....

I think they're like sensors - a good one is better than none at all, but none at all is better than a bad one.

My SIL plans to discuss the role of the HB and my situation with motor engineers of one of the large car manufacturers over the coming days, so I should have some feedback from current specialists before long.

Graeme,

Did you replace the HB or are you still running without?

Still without the HB.
Feedback received was that they're usually for occupant comfort reasons (NVH) but nothing specific for the TD5.