Oil Pressure Issues WBX

[Mojoh]

Greeetings. Great to be here.
I know the subject has been talked about extensively and I'm hoping an expert is around to answer a question or two. Referring to the WBX Engines, which high pressure switch (not sensor ) is the right one for the right engine? Brickworks lists three, black, grey & white. 1.4, 0.9, 1.8 respectively. I'm not sure which goes to which engine.
Secondly, customers keep asking for High Pressure Pumps in their engine rebuilds, but the pressure is controlled from the Pressure relief valve, so the only thing that could change things is volume. Seems these boxers run on pretty low pressure anyway, so providing everything is in order, is there any adantage to a high volume pump?, and if so, what make is regarded as the best on the market. (again, so much debate over this subject it seems).
My ultimate question is, how can I get more oil to the valve gear, because it seem perpetually starved of oil in almost all the engines I strip down.

Sorry, was a bit lengthy, but important.
Thanks in advance.

[KINGPRAWN]

Hey .. Feel your pain here !!!
I spent years with pitifully low op .. I had a recon motor not long after I bought the van so although I was probably 10 years in I refused to believe that the engine needed major work ! I tried everything... And although even after fitting gauges to and replacing pressure switch, relief valve, oil pump and anything else I could think of the only thing that helped was "Mobil 10/60 from halfords expensive but gave me half a bar more, which when idle was virtually zero was a lot across the range !!! I lived with it like that for years and it never sounded anything other that sewing machine quiet and smooth .. But always in the back of your mind is the Big Bang !!! So last year I binned it before it binned me and went TDI ... BEST MONEY I EVER SPENT ... EVER !!!! And got £600 for the old engine and exhaust ( which was stainless and syncro) ..

[Aidan]

1.8 bar is the wbx high pressure switch, the bod circuit expects to see minimum 1.8bar op at 2000rpm when hot which generally equates to about 1 bar at idle hot, should ramp up quickly as function of revs
0.9 and 1.4 are JX ones
quality pump and cover plate and correct end float and gasketing make the difference afaiu to output
Silverbullet is on holiday this week

[itchyfeet]

My DG is 0.9 bar grey
wider pump gives more flow which may increase pressure at the camshaft low pressure switch if the engine is not so worn it leaks everywhere
as said thick gasket can cause leaks (they are 0.15mm, endfloat max 0.1mm) as can bad fit of pump body.

My guess is poor oil condition is responsible as are too high oil temperatures

[marlinowner]

Fairly sure it should be 1.8 bar, but the Haynes WBX manual sows confusion - it says 1.8 bar in the wiring diagrams but 0.9 bar in the engine specs...

[itchyfeet]

Fairly sure it should be 1.8 bar, but the Haynes WBX manual sows confusion - it says 1.8 bar in the wiring diagrams but 0.9 bar in the engine specs...

my copy of haynes shows 0.9 bar in wiring diagram
Bentley says 0.9 bar also for wbx

Mojoh, I'm interested do you rebuild these wbx personally?
People are always on the lookout for traders who will fix these engines with care.

[marlinowner]

Had another look at Haynes and it gives 0.9bar on the wiring diagram itself and 1.9bar on the wiring key, so I guess typo in the key.

[itchyfeet]

Had another look at Haynes and it gives 0.9bar on the wiring diagram itself and 1.9bar on the wiring key, so I guess typo in the key.

Yes must be, mine says 0.9 in the key too, looks like mine was printed after 2004

[Aidan]

my earlier reply is based on a reading of etos and a cross check on partsbase.org, but as usual with the vw parts catalogues there are mistakes and confusion depending on which model and year you look at but in the listings that show the 1.8bar switch as 2A ie the high pressure switch it clearly only shows that as the correct one for all wbx and the 1.4 as diesel 2A but in other listings where the 1.8 is shown only as (2) the 0.9 is also listed as (2) and both are shown as being for wbx
however the bod circuits for petrol and diesel are different, indicating they expect to see different pressures, but I haven't got Bentley here to look through and check the specs in there for testing the bod circuit funtionality and as Bentley doesn't do diesel post 1986 the info will not be in there anyway so for a definative answer someone would have to consult the bod info in the VW JX manual or more likely the VW european post 1986 dash wiring manual which I don't have
if you have a 0.9 switch in a wbx you won't get bod till pressure is below 0.9 at 2000rpm which is on the low side, you might already be experiencing flickering oil light at idle anyway if your pressure was that low, but you won't know that it has dropped below 1.8bar at 2000 which is what the dynamic oil pressure system is trying to warn you of
That's my reading of it, but I haven't sat and double checked in Bentley or a VW wbx engine manual such as the DJ one that's online

[marlinowner]

Well what Brickwerks says is on WBX with buzzer, 1.8bar until model year 88, then either 0.9 or 1.8 may be fitted from factory, no reason given.
Similarly with diesels, after 88 have either 1.4 or 0.9.

[itchyfeet]

https://club8090.co.uk/wiki/Al ... and_causes" onclick="window.open(this.href);return false;

Low rpm/low pressure sensor - 028 919 081 C (0.3 bar BROWN) - Early original fit?

Low rpm/low pressure sensor - 028 919 081 D (0.25 bar BLUE) - Later replacememt for all .3bar switches

High rpm/low pressure sensor (Petrols) - 068 919 081 A (0.9 bar GREY) - Std. 2.1

High rpm/low pressure sensor (Petrols) - 068 919 081 E (1.8 bar WHITE)

High rpm/low pressure sensor (Diesels) - 068 919 081 A (0.9 bar GREY)- common with petrol sensor

High rpm/low pressure sensor (Diesels) - 068 919 818 (1.4 bar BLACK)

[itchyfeet]

Perhaps it was lowered due to being triggered too often.
the 2 bar test at the low pressure switch position is at 80 deg C the oil can get a lot hotter than that so a 1.8 bar buzzer even at the higher pressure position will likely trigger with very hot oil unless your engine is tip top

[ghost123uk]

Secondly, customers keep asking for High Pressure Pumps in their engine rebuilds..... how can I get more oil to the valve gear, because it seem perpetually starved of oil in almost all the engines I strip down.

Mojoh, I'm interested do you rebuild these wbx personally?
People are always on the lookout for traders who will fix these engines with care.

Too true
Who are you?
Where are you?

Oh, and welcome to club 80-90

[Mojoh]

Didn't I just post a reply?

[Mojoh]

Gentlemen......... THANK YOU all.

Aidan, I thought you were far too busy, so a special thanks to you.
Itchy feet too, for such in-depth details.
And of course everyone else for their input.

OK, so we've established that up to 1988, those later engines (post 1984) use two oil switches and the high pressure one is meant to be 1.8 bars... The WHITE ONE.
After that, VW would used the GREY ONE, which was 0.9 bars, yes a lot lower but as someone has hinted, probably a lot less trouble for VW with customers coming back with buzzers from hell buzzing away in France on a hot day. I'm getting similar comebacks.

Back to the pumps.... I'm using Shardek which under the microscope and feeler gauges seem fine. I've been slapped for using too thick cover gaskets & I've put this right. Some improvements. I'm also using Febi Bilstein pumps, also good. I'm going to use up my existing stock on the WBX rebuilds I have scheduled in and then return to stock items, the make I haven't decided on, but will probably revert back to Febi. I'm just not convinced about these high delivery pumps. My German Supplier Gunżul Classic Parts have gone very very silent on me despite three letters to Peter. He refuses to answer me on questions about quality aftermarket parts. This I find infuriating as I spend many thousand of Euros with him every year!... what's that about???

OK, . FYI, All engines that come out of our workshop are properly reconditioned (within reasonable limits), so, we grind cranks when needed, replace pistons when needed etc etc. Camshafts, Hydraulic Lifters etc etc. We replace an awful lot of Cylinder Heads for sure, cracks between valves. Oil pumps and poor pressure are the issue we have trying to improve on.

Thanks again,
Mojoh