Strange rattle starting from cold

[drjonts]

Thanks Simon.

I suppose the best case scenario would be to find pulley bearings are all OK and just a readjustment of tension and pulley set up is required. If that were the case I suppose being super careful to just compress the tensioner in situ until the pin fits in (and not fully release tension), I could then carefully readjust the pulley position as per INA instructions to recover the tension, tighten the pulley bolt and then release the tensioner again.

That's the least I could possibly get away with...but would only know once everything is opened up for inspection...and then it may be a case of do the job anyway!

I think I have read somewhere (or watched a video?) about making sure a 'hydraulic' tensioner like this is operated very slowly in and out 3 times in a vertical orientation before fitting to ensure air is bled from certain parts. Will try and find it again. I assume the tensioner piston unit must be 'sprung' in some way with a hydraulic damping feature so that it doesn't bounce back and forth during operation? I have heard of hydraulic springs (but these usually rely on deformation of the cylinder walls into which a piston is pushed - usually very high load applications). Could they be like mini gas struts inside? (I'd be worried about that going weak eventually in service).

Has anyone stripped a KV6 tensioner down for a lookie? If I end up with a new one, maybe I will!

Jonty

[drjonts]

Found it:

https://www.youtube.com/watch?v=UxuVLga1Lno

Seems that perhaps some designs (if not all) shouldn't be 'bled' or compressed for fitting horizontally in a vice! Wonder if new KV6 tensioners have any advice notes with them? Anyone?

And another from NTN/SNR https://www.youtube.com/watch?v=WeXGzfmHtBA

Jonty

[SD1too]

Originally Posted by drjonts

If that were the case I suppose being super careful to just compress the tensioner in situ until the pin fits in (and not fully release tension), I could then carefully readjust the pulley position as per INA instructions to recover the tension, tighten the pulley bolt and then release the tensioner again.

Theoretically you are correct Jonty but compressing the tensioner in situ could be tricky. If you find you need to remove the pulley for access then the belt will fall off and you'll need the special tools to reset the timing.

Originally Posted by drjonts

Seems that perhaps some designs (if not all) shouldn't be 'bled' or compressed for fitting horizontally in a vice! Wonder if new KV6 tensioners have any advice notes with them? Anyone?

RAVE does not give any warnings.

What you need to do is to get hold of the special service tools which will enable you to set the valve timing and belt tension correctly. The cost of buying a set is not excessive; far less than the bill at a garage.

Simon

[drjonts]

Evening fellow tinkerers!

Well, went back out to the ZT-T just now to look at the cambelt tension again. It really looeds like the tensioner piston had returned back into the barrel to where it was before I tried to tease it out by levering the idler carrier away from the tensioner piston body. I can only assume from this that my tensioner has gone weak for some reason and is unable to overcome and fight against any significant belt tension for a length of time.

I have levered the idler carrier away again and the piston has moved out in sympathy - I have levered it a bit further than last time. The belt is not slack at the moment and I will leave it as it is without running it tonight and see if it is still tight tomorrow.

Onwards to....probably deciding I need a new tensioner unit eh!

Jonty

[SD1too]

Originally Posted by drjonts

It really looks like the tensioner piston had returned back into the barrel to where it was before I tried to tease it out by levering the idler carrier away from the tensioner piston body.

What appears to be happening there is that the incorrectly adjusted pulley is bearing upon the tensioner piston and pushing it back into its casing.

Simon

[trikey]

Good luck setting the tensioner with it bolted to the engine, they are difficult to do off the engine!!

[drjonts]

Originally Posted by trikey

Good luck setting the tensioner with it bolted to the engine, they are difficult to do off the engine!!

Thanks Andy!

[SD1too]

Originally Posted by trikey

Good luck setting the tensioner with it bolted to the engine ...

I managed to do it Trikey so anyone can according to your mate from Tyneside.

Simon

[trikey]

Originally Posted by SD1too

I managed to do it Trikey so anyone can according to your mate from Tyneside.

Simon

I didn't say it wasn't possible, just very difficult!!

[drjonts]

Originally Posted by SD1too

What appears to be happening there is that the incorrectly adjusted pulley is bearing upon the tensioner piston and pushing it back into its casing.

Simon

Thanks Simon.

I'm trying to get my head round what might be happening. Can you explain a bit more fully how that incorrect adjustment could make the carrier bear on the piston and push it back in please?

Cheers,

Jonty