Wheel wobble not what you think!

2.9 V6 24v TFSI - 444 bhp
Rusty Racer
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Re: Wheel wobble not what you think!

Post by Rusty Racer » Sun Nov 05, 2023 9:58 am

How would you identify a DECA engine?
2018 RS4 B9 Carbon Edition
2014 RS4 B8

Jools
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Re: Wheel wobble not what you think!

Post by Jools » Sun Nov 05, 2023 9:52 pm

To my knowledge all B9 & B9.5 6V twin turbo RS4's are DECA engines.
Check your build label found either in your handbook or in the boot under the floor tray.

The pre 2019 engines were fitted with the old 'chocolate' rocker arms, I don't have exact build dates but you can check by using an endoscope down the oil filler cap and looking towards the front of the car. With enough fiddling you can see one of the rockers.
I think that the bad rocker arms aren't only used in the DECA engines so there may be others out there with a ticking time bomb ready to go off. I was lucky, if you call it that, a needle roller collapsed and stopped the outer race turning, scouring the cam lobe but the bearing stayed in one piece.
The bad rockers use small diameter needle rollers, the outer race expands and allows them to make a break for it where they usually end up spread around the head and on occasion in the sump!
The updated rockers use fewer larger diameter needle rollers that to date seem to be OK.

There are several YouTube videos on it.

The picture below shows an old, but still good rocker arm on the left and the collapsed one on the right. You can see how the outer race is offset to the central pin. The cam lobe between them is the one that was scoured.
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stuartbarriskell
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Re: Wheel wobble not what you think!

Post by stuartbarriskell » Mon Nov 06, 2023 3:43 am


Jools wrote:I agree, stunning landscape, lovely people who nearly all speak very good english.
There is nothing like being able to drive for half an hour or more and not see another sole!

I think there speed limits are a bit low, I have never got such good fuel economy!
Mind you the autobahn's changed that :redrs4:
There were 5 of us there on the bikes in 2007 Jools, we caught the ferry from Rosyth (now freight only) to Rotterdam, 1st stop Hamburg up through Denmark over the mighty Øresund bridge into Sweden and wound up in Oslo, spent 2-3 dicking about the capital and then made our way to Stavanger, the road I most remember was E134, it was incredible, 2 of us broke away from the group, there was one section where we must have sat between 70 to 100 mph for a good 90 minutes and barely passed any cars with zip in front of us only a big wide road and crystal Blue lakes.. sensational.. we still talk about it to this day.

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elchet
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Re: Wheel wobble not what you think!

Post by elchet » Mon Nov 06, 2023 11:26 am

Jools wrote:
Fri Nov 03, 2023 4:35 pm
I'm the same as you I've always wanted an RS4 from when they first came out. As a daily driver its just the right amount of sensible and lairy on tap when you want it!
As mine is a 2018 plate I had the chocolate rocker arms fitted which had to be replaced (not under warranty) chough :FIREdevil: 69000 mile mark!
Collapsed rocker arm bearing and a scoured cam the result.
Hm, mine's an 18 as well ... I've been paying for the extended warranty each year but I doubt it'd help with this if (when? :cry: ) it comes up.
Jools wrote:
Fri Nov 03, 2023 4:35 pm
If you don't already I always get a 4 wheel alignment (by someone who knows what they are doing) after fitting new tyres, no point wrecking them for the sake of £80 after having just spent £1000 on rubber because your tracking is out :bash:
Have you ever had a need to recalibrate radar, sensors, front camera etc after doing the 4 weheel alignment? Bit worried that it might end up being a very expensive wheel alignment if the sensors get thrown out.

Appreciate the detailed reply!
2018 B9 RS4 Daytona Grey

Rusty Racer
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Re: Wheel wobble not what you think!

Post by Rusty Racer » Mon Nov 06, 2023 2:38 pm

I had 4 wheel alignment last year, when the rear felt a bit out of whack but no issues with and sensors or the 360 degree cameras.
TPMS took a few miles to calibrate when I had 4 tyres fitted, despite a MMI reset but came back okay too.
2018 RS4 B9 Carbon Edition
2014 RS4 B8

Rusty Racer
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Re: Wheel wobble not what you think!

Post by Rusty Racer » Mon Nov 06, 2023 6:43 pm

So obviously I do have a DECA engine… having looked on the production label. I’ve also looked at a few YouTube videos on the early rocker arm issue that makes grim viewing.
2018 RS4 B9 Carbon Edition
2014 RS4 B8

Jools
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Re: Wheel wobble not what you think!

Post by Jools » Mon Nov 06, 2023 8:48 pm

Elchet
My car doesnt have the city assistance pack which means I don't have radar, front camera etc.
Doing a 4 wheel align shouldn't effect any of the above as they are separate systems and are not connected to the steering.
I say that, as to my knowledge the radar and front camera are fixed and do not physically turn left to right as they don't need to. The radar only feeds back info on distance or rate of change of distance to a target in front. The front camera has a wide angle lens and can see all it needs to. The only thing I can think of is the angle sensor on the steering column might cause a problem BUT.

If a 4 wheel align did effect anything Audi would insist you went back to them for it to be done and fleece you for the privialge.

Jools
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Re: Wheel wobble not what you think!

Post by Jools » Mon Nov 06, 2023 8:51 pm

Rusty
If you ask Audi they should be able to tell you what type of rocker arms you have on your engine following back the info on the build record
Worth a try

Jools
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Re: Wheel wobble not what you think!

Post by Jools » Sat Nov 18, 2023 7:34 pm

Well it seems like I'm not the only one with wobbley wheels full of dirt.
Check out Matt Armstrong https://www.youtube.com/watch?v=Wr5WSzH-IQg at 6:45.

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