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Chain Adjuster Question

barryrs

Trainee
Joined
4 Feb 2015
Messages
98
Hi guys, wondered if anyone could give me some advice/feedback?

I have a rattle on startup which would appear to be related to the chain adjuster; however, having looked at the diagram could it be a worn pressure pin?

Which leads on to my question. If I replace the adjuster can I also replace the pressure pin whilst it's out?
 

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They're tensioners not adjusters. They're worn and not maintaining pressure.
 
Very common and probably won't even go away with new tensioner pads.
As long as it goes off within a second or two I wouldn't worry.
They're oil fed and take a second to pressurise.

If my car has stood a while (I'm talking months not weeks) I pull fuse C4 and turn the engine over until I see the oil pressure build up on the gauge.
To be honest though you still get the rattle, only in slow motion and it sounds even worse. :grin:
At least there's oil to the heads before start up though.

Basically it's just a quirk. Some cars do it, some don't. 3 out of 3 996s have done it for me. Changed tensioners on 2 of them and they still did it.
Don't worry about it. :thumb:
 
Thanks both.

I assume it's the reason Porsche changed the design to a spring in the later cars but unfortunately it appears that isn't an upgrade option on the early cars.

For the sake of £50 I will probably change it but it would be nice to know if I can change the pressure pin at the same time.
 
The tensioner (item 35 in your diagram) has an internal spring which is supposed to take up the pressure when the engine is switched off and the oil pressure is lost.
These springs sometimes snap so are then operating at a reduced length. That can cause a rattle on start up as that's the exact thing they are there for, to keep at least some pressure on the chain.
 
Just a quick update.

I swapped over the Chain Adjuster (this is what Design911 call it) with the updated part today and it is a direct replacement.

It's slightly longer when compared to the original with a large outer spring to maintain tension.

Will see if this resolves the issue.

This is the original and what design911 show on their website
99610518059.jpg


And this is what arrived
996-105-180-58-M100.jpg
 
I've not seen an upgraded tensioner with external spring for the cam chains like this before but I could be wrong? The one in your picture with the external spring is to tension the crank to IMS chain not the cam chains? There should be rings machined into the top of the tensioner ends to identify which is which so that they don't get mixed up?

Double check what you have before you fit it as it should be the same length as your original one and may cause you a problem if it is the wrong part?

EDIT, your top diagram even highlights the crank to IMS tensioner, if you want the cam tensioner it is part 34 in the diagram
 
Please confirm that is the correct tensioner .

The Bank 1 tensioner and the ims chain tensioner are different .

35 would appear to be the ims chain tensioner and not B1 .. pin is part of the guide .

On the nut end you will have either 1 or 2 rings .. there is the same marking on the head .. 2 rings and 1 ring and its incorrect ... 2 and 2 .

As per Infrasilver basically .. check it :)
 
That's fine then .. the noise for 5 seconds on start up tends to be the B1/B2 tensioner though .

Early cars and it's the chain on the camshafts that can cause this noise .

In short .. a sound clip helps people hear the noise and can give a better opinion .
 
Does that also apply to 996 turbos?
 
...he's back !

...Iain I mean :thumbs:

....we've missed you buddy :D
 
barryrs said:
It is the IMS tensioner.

I wouldn't have though the IMS tensioner would cause a rattle, it's usually the cam chains that do and why your new part confused me? You do mention the original one you removed looked like the first picture too but I can't have done as the one you removed should also have the external spring around it?
 

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