Harmonic Balancer/Crank Pulley question/information

[ro80rob]

Background

Had a strange noise occurr a few weeks ago now. A sudden rattling/squeel noise that happened over a few hundred yards then went away. I had no other occurrence.

I have now noticed that at idle, the engine is appreciably louder and has a definite rattle/knock. This disappears when I drive off or rev up (maybe over 1500 RPM).

I did a little research on the forum and came across the harmonic balancer issues. It seems common enough for it to separate and the pulleys become in some way detatched from the securing centre boss. There is even mention that the pulley retaining bolt can come loose (I've seen that happen on a Jag).

What I haven't found on this site (tho it maybe somewhere) is how to actually inspect it on the car (i.e. without taking anything off) to confirm the problem, in a way that doesn't require the engine running (rotating machinery etc).

Anyway, I thought I would have a look at it today (engine stopped, all cold). I find I can reach down to the steering pump belts and if I pull on them, I note that I can waggle the pulley about. So much so in fact that I can make it knock on something (probably the timing cover). I can't seem to make it go in and out (restrictions of access accepted), but it 'tilts' easily in my opinion.

Main question

What should I expect? Is this indicative that the pulley rubber jointed balancer has failed, or is the pulley loose? A cross section drawing of this item would maybe help show me what has failed here.

Cheers... Rob.

[NiftyNev]

The Harmonic Balancer has the inner twin pulley as part of the unit. The two outer ones are a separate bolt on pulley. If the inner pulley moves it's probably stuffed. If only the outer moves maybe the bolts are loose.

Nev

[ro80rob]

Just to be clear
The whole pulley (as a set of pulleys) moves together. I can't detect any differential movement between the pulleys separately.

In that case and from what you say, the balancer is toast and I should get another from Milners.

Cheers... Rob.

[POPEYE]

These may help, one is the balencer from behind the black ring is the bonded joint, i thought mine was suspect so for now painted a line across the balencer and the other two pullys so if there was any movement i'd see it, from the sounds you describe i'd say your needs replaceing, about £80 from roughtrax, you wont realyy tell till you remove some stuff tho

[ro80rob]

Thanks for the pictures. Unfortunately they don't inspire me with confidence that the thing could not come apart so the next and only time I'll be driving it is the 10 minute drive to my mechanic who will install the new pulley for me. Maybe change the timing belt as well whilst we are at it.

Cheers... Rob.

[ro80rob]

Well
I got a new pulley from Milner and I could then reaaly see how the pulley is constructed. It seems that only the two actual pulleys 'float' on the rubber insert. The outer pulleys for all the additional drives bolt to the centre part of the pulley boss, so should not be moving.

I had the whole lot moving as a yanked on the belts, which could mean but one thing.

The crank pulley itself was loose!! How has that happened (however I do know the previous owner had changed the water pump as I got the old one with it).

Anyway. I managed to remove the fan assembly and move it to one side, allowing me to get a socket on the pulley bolt. I then tightened it using a good piece of 2 x 2 and a hammer from above the radiator.

The pulley now seems tight and the engine runs quietly again at idle.

So. Question is, should I swap to the new pulley (and woodruff key). Perhaps mine may have worn on the internal plane faces where it slides over the crank end (or worse could the crank end be damaged/worn) and should I go for the new timing belt as well?

Cheers... Rob.

[NiftyNev]

So. Question is, should I swap to the new pulley (and woodruff key). Perhaps mine may have worn on the internal plane faces where it slides over the crank end (or worse could the crank end be damaged/worn) and should I go for the new timing belt as well?

Cheers... Rob.

If the crank bolt was loose I would remove the pulley and check the end of crankshaft for damage. Being loose would probably cause some damage to the woodruff key itself at least.

Nev

[TonyN]

I'd say its safer to pull the crankpully and check the crank and key. Loose pulleys make a mess of the crank.

But if you've done it up tight and it runs true now then you're probably OK.

Would be nice to check the woodruff key though. If you need a new cam belt soon, then you can check it then.