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Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 04 May 2026, 18:42
by maxstu
Getting a tad fed up with the poor quality aftermarket 10mm adjusters lasting less than 2K before they need replacing. Three times l've had to pull the valve rails and pull out damaged adjuster. Every time it is the aftermarket ones, whereas the genuine ones stay in top condition.

Brickwerks claim there has never been any issue brought to their attention.
Mr Metric Nut man in New Zealand also claims the ones he sells are properly hardened. They are not!

I can buy genuine 9mm adjusters and have these plus spare DG rockers in the garage. So what's the consequences of running a DJ2.1 with these instead?

If someone is willing to advise me how to share photos on here now, l took a few pictures. Have tried via Photo Bucket. But just end up with this icon

Image

Regards
Stuart

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 04 May 2026, 20:33
by silverbullet
The rockers are the same ratio but the DJ cam is longer duration, so *might* push the 9mm screw's end profile to the limit.
However, Type 1 tuners use the 9mm screws without issue and there is the option of using elephant foot style screws. Wish they were available in 10mm!

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 05 May 2026, 07:51
by maxstu
Thanks for your reply...

Never as straightforward as first thought!!

So using 9mm *could* end with premature wear on the adjusters. Exactly what l'm am experiencing now.

Might as well give it a go...

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 05 May 2026, 14:32
by ajsimmo
Heritage are now claiming their 10mm adjusters are genuine VW (they were selling the cheese ones not so long ago). I might get some to check, as I'm running very low on proper genuine 10s.

Due to the scarcity of VW 10s I've been using 9mm early rockers on DGs lately, even on lates as I don't see there is any reason not to (same camshaft).
I suspect a genuine 9 will still fare better than a cheese 10 in a 2.1.

(Ok, for the WBX techies/pedants/nerds possibly reading this and champing at the bit, I know the early DG had a different cam to the late, but they're all reground to the late spec now, and the lift was the same. It was just the valve timing that was different so it's a moot point )

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Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 05 May 2026, 17:53
by maxstu
Thanks for your reply Andrew.
:ok
At the moment l'm running three genuine VW adjusters and five aftermarket ones in the 2.1

Since last August l have changed out nine aftermarket adjusters. Every time the original are fine.

What's really annoying is they are so badly damaged it is not simply a case of releasing the locking nut and unscrewing the adjuster and replacing with new. The heads on these crappy ones are so smashed it requires removing the complete rail and feeding them forwards. In turn this means l have set up the pushrods and reset lash plus 1 1/2 turns on four valves or even eight if both side are affected.

A couple of hours work every 1800 miles it may be. But l'm not young anymore and getting under is not that appetising as it used to be. Unless a permanent solution comes my way soon l will be going for any other engine type. Getting to the end with these engine to be honest.

Will try 9mm on DG rockers when these last poor 10 mm versions go west.

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 05 May 2026, 19:51
by Aidan
So are the 10mm screws that are available all the same now, Heritage say theirs are genuine, and VW Classic Parts say they are "Genuine VW Quality", whatever that means - also says made by VW in the manufacturer info; I assume Heritage are selling the ones from Classic
Brickie sells VWIB ones but no longer the ones from Classic, I am guessing, because they are exempt from export to the UK cos they are made from Russian steel which is embargoed, but Simon/Michael can confirm
BusOK seem to say they make their own
CSP say they sell the ones from Classic
West Coast Metric sell sets with nuts, no declaration as to source
GoWesty just say quality aftermarket
CoolAir say JoPex which is JP Group
GermanSupply sell an interesting version with swivel head a la Porsche 914
Thorsten Pieper Valve Adjusting Screw
There's got to be something that is actually okay, otherwise none of the engine builders would be able to warrant their work, and they can't all be using good 2nd hand ones

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 06 May 2026, 14:26
by silverbullet
Those 914 followers are showing as out of stock and the listing states "do not use with hydraulic followers"

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 06 May 2026, 20:46
by maxstu
Yep. I read that part as well.

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 07 May 2026, 13:12
by Aidan
The manufacturer of the porker style one doesn't say mcuh about them linky
at that price worth a look if they are actually available, maybe for an oxyboxer build if anyone still does that

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 07 May 2026, 13:35
by silverbullet
And yet the manufacturer say for wbx engines :?

I'd have fitted them to the Oetti if I'd have known they existed in 10mm

Re: Replacing 10mm With 9mm Valve Adjusters in DJ2.1 Engine.

Posted: 07 May 2026, 19:37
by ajsimmo
Aidan wrote:The manufacturer of the porker style one doesn't say mcuh about them linky
at that price worth a look if they are actually available, maybe for an oxyboxer build if anyone still does that
I foresee possible clearance issues with this type, necessitating shims to create room for the swivel feet. This change of geometry can have unintended consequences, such as unusual wear patterns and shortened service life.

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