Aftermarket cam tensioners

[MikkiJayne]

Hi all,

Has anyone used the aftermarket cam tensioners for the 40V? I just got a price of £478 from TPS which is totally untenable, and unfortunately our hosts don't have any used ones at the moment.

Background - lumpy idle, CEL for cam position sensor, compression 10-11 bar on 1-4, 12-13 bar on 5-8. Opened up the cam covers to see the 1-4 bank tensioner jumping up and down when I rotate the engine by hand. Seems that the top of the tensioner is loose and the bottom is locked solid so the chain is slack and the inlet cam is jumping around.

Very at the moment. I don't want to spend £1000 on tensioners to find there's valve damage, but very wary of putting potentially crappy Chinese bits inside the engine.

Thanks
MJ

[notorious]

My advice would be to go oem regardless of cost.
Yes, a8's are expensive to own.

[Goran]

Also, get it checked out by an expert to be sure if its the tensioner and which part of it thats faulty. I'm not sure you can determine faulty operation in the way you describe. There is a solenoid which is a part of the tensioner mechanism and this has no power going to it when you are rotating the engine by hand.

At least, follow the ElsaWin audi workshop fault guide for the tensioner to test it in the correct way.

[mannyo]

IIRC without the engine running the chain will be slack anyway, the tensioners need oil pressure which requires a running engine.

Do you get any constant rattling from the camchain area when the engine is running, do the tensioner pads show any sign of wear or failure visually?

[47p2]

My take on aftermarket parts

They don't always fit correctly, they don't work as effectively as original parts, they don't last the test of time

[MikkiJayne]

Thanks for the thoughts guys. I'm comparing the two banks to conclude it's faulty. Turning it over by hand the chain for 5-8 is taut on the tensioner and the cams turn smoothly. 1-4 however the tensioner jumps up way higher than the other one as the inlet is about open a cylinder, then as soon as it's past centre the cam jumps round off the rollers and the tensioner drops down.

This is what I found when starting to investigate the cam position sensor error:



Timing belt changed without the damper Tightening the belt and setting the cams with the bar I get bank 1 is about 2 bar short on compression compared to bank 2. I'm really hoping its this dodgy tensioner causing the lost compression rather than many bent valves.

I also discovered that the impeller has fallen off the crappy aftermarket water pump and started machining its way in to the block. Temperature was fine on the drive home from picking it up though (and it drove fine apart from a vibration at idle and an occasional misfire) so I'm hoping a new pump will be ok.

If it was just the tensioner then I'd buy a genuine one without question, but with the engine potentially fubar I'm not going to spend that on it until I know the engine is still ok. I think I'm going to put an ebay tensioner on it to start with to see if it runs properly and then change it out for a genuine one if the engine is ok. That way I've only wasted £100 and some time, rather than £500 if its toast.

In case anyone recognises the stupid orange pulley, yes this is the one from ebay. I bought it based on VCDS saying the cam position sensor was open circuit and it driving fine. No idea it was potentially going to need a whole new engine Bent valves would actually have been cheaper. Stupid stupid stupid.

Oh, and to add insult to injury, the really tricky bolt for the oil cooler under the manifold is totally rounded out so I've got to take the whole damn engine out to change the plastic pipe. Hard to convey how fed up I am with this car already. I've been looking forward to getting another D2 for ages but I'd have been better off just setting the cash on fire.