WBXlog

[itchyfeet]

I decided to o ring the pump just to rule it out.

when I pulled the pump the DirKO HT was well stuck to one side or the other so looks like it was doing the job so I had not much hope of improvement, the inlet didn't look so good so perhaps drawing in air.

P1100173 by Paul_Barr, on Flickr

P1100174 by Paul_Barr, on Flickr

I have done some measuring of WBX cases and pumps new and old

Engine pump bore is approx. 70.1 measured at inner edge

All pumps measured at inner edge too

2x Old VW pumps 70.04-70.06

Old used 22mm Schadek pump 70.02

Old unmarked Pump 70.00

Approx 3 year old Meyle 22mm Pump 70.00 ( just removed )

Brand New 30mm Schadek pump 69.90 ( Purchased last week)

1 year old 30mm Schadek pump 69.92 ( just fitted)


So the 0.1mm end float measurement is comparable with the approx. 0.2mm difference in the diameters with some aftermarket pumps
While in theory this is half that all the way around you can’t guarantee the pump won’t pull itself off centre


Groove depth needs adjusting to suit pump diameter, I went for 1.5 deep which gives an uncompressed o ring dia of 70.5, its a firm fit ( 0.2mm compression on a 1.78mm dia oring) and so the sharp edges of the oil ways need rounding off on the crankcase or they cut the oring

20180423_125122 by Paul_Barr, on Flickr

P1100191 by Paul_Barr, on Flickr

tapped it in gently ( I test fitted it before to check the oring wasn't damaged)

P1100195 by Paul_Barr, on Flickr

ran it up to temperature yesterday, there maybe a small improvement or 0.25 bar but a road test is needed.

Next I'm going to try 20W50 and see what happens, I will be getting a quality brand.

[ajsimmo]

Next I'm going to try 20W50 and see what happens, I will be getting a quality brand.

What about trying some 15W50, like this one?
https://www.opieoils.co.uk/p-69400-fuch ... e-oil.aspx" onclick="window.open(this.href);return false;

Sent from my ONEPLUS A3003 using Tapatalk

[itchyfeet]

Next I'm going to try 20W50 and see what happens, I will be getting a quality brand.

What about trying some 15W50, like this one?
https://www.opieoils.co.uk/p-69400-fuch ... e-oil.aspx" onclick="window.open(this.href);return false;

Sent from my ONEPLUS A3003 using Tapatalk

yeh I thought about a better quality 15W40 first but my tin top has great pressure on the very same oil, Tripple QX

I might try both in the name or research, I was going to try the Millers classic 20W50, it has extra ZDDP also

oh E D I T 15W 50

[937carrera]

Millers do some decent oils.

If you're interested in research, then you might want to consider this stuff http://www.millersoils.co.uk/products/cfs-15w60/141.

I doubt a WBX will get anywhere near stressing this oil

Better oil pressure at higher temps.

[itchyfeet]

Millers do some decent oils.

If you're interested in research, then you might want to consider this stuff http://www.millersoils.co.uk/products/cfs-15w60/141.

I doubt a WBX will get anywhere near stressing this oil

Better oil pressure at higher temps.

Thanks but not at £45

[937carrera]

Bargain compared to the cost of a rebuild or other ways of improving oil pressure in an engine....

[300CE]

I currently use this in my bus Paul - not sure if it will assist in your testing:

https://www.opieoils.co.uk/p-73741-valv ... e-oil.aspx" onclick="window.open(this.href);return false;

[itchyfeet]

Bargain compared to the cost of a rebuild or other ways of improving oil pressure in an engine....

yeh I see your point but would you need a rebuild with the pressure I have? it's over VW spec.
lots of people may have similar pressure and be none the wiser.

It's not as good as the tin top DG which is why I know it can be better and I'm trying to work out how.

Suspects

Big end tolerances
Crank tolerances ( blue bearing are NLA)
worn tappet bores
worn tappets ( I tried some cheapies in the tin top and the pressure was terrible)

you are right all of these are more expensive then oil.

[itchyfeet]

I currently use this in my bus Paul - not sure if it will assist in your testing:

https://www.opieoils.co.uk/p-73741-valv ... e-oil.aspx" onclick="window.open(this.href);return false;

he he a secret what oil thread

[937carrera]

yeh I see your point but would you need a rebuild with the pressure I have? it's over VW spec.
lots of people may have similar pressure and be none the wiser.

It's not as good as the tin top DG which is why I know it can be better and I'm trying to work out how.

I think the fact that you have the gauges is what is giving you concern by comparison, as you say, the oil pressure is within VW spec.

That's why I suggested the alternate fully synthetic oil. I do use Millers Nanodrive, generally I'm using Millers 10W40 CFS/CSS. Synthetic instead of mineral should enhance protection if the engine is under stress. Way over-engineered to what was around when the T25 was made.

You've already identified the key potential reasons why this engine has lower pressure than your tin top, and it looks like the oil pump seal mod will give you back another 0.25 bar. Do you want / need to do more ?

[itchyfeet]

. Do you want / need to do more ?

yeh, OCD maybe

[itchyfeet]

Road test today, the idle test at 80 and 100 is one thing but on the road is different, because it gets past 100 deg C on a DJ most of the time.
I get down to 1.5 bar when very hot at 2k rpm.

oil pressure is a little higher than before the oring very hot 3k rpm but no higher 2k rpm and below.

Going to go with Andrews suggestion first Fuchs Titan Superma 15W-50, I have asked for a data sheet.

interesting Opie oils are a bit cheaper off ebay then on their website, this is often the case.

Another thing that occurred to me is a better oil cooler....

https://www.ebay.co.uk/itm/Fuchs-Titan- ... xyEoFSZQIG" onclick="window.open(this.href);return false;

[weimarbus]

watching this with interest Paul, my freshly built MV now 5 years old has lowish pressure and after your results with the different tappets wondered whether to consider changing these. The engine has the standard water/oil cooler, I seem to remember SB's 2.5 engine build there was some mention of pressure loss through these and he did not use one, I have a thermostatic sandwich plate for an oil cooler which is located in the bottom of the rear corner (below vent) this means that I have used a shorter oil filter to avoid damaging it and see that you tried one of these with resultant pressure drop. My next move will be to remove the standard cooler and replace the oil filter with the correct larger one to see if this helps. I am using Valvoline racing 20/50 ( also use this in the buggies DG based engine which runs with a better pressure) I have noticed that at the beginning of a motorway journey the MV pressure is not too bad, but this drops as the journey gets longer although the water temp stays constantly at 80 degrees, I therefore doubt that the standard cooler does much in transferring the heat from the oil.

[itchyfeet]

watching this with interest Paul....

did you measure the pump diameter and do anything to seal it?

[weimarbus]

I didn't measure the pump, it is a standard vw wbx but I did make an attempt to seal with red Hylomar it also has the Reinz pump cover gasket. It appears from your oil temp research that if the oil temp is going above100 degrees and the water temp remains at 80 degrees then no heat is being lost through the standard water /oil cooler, does this prove that it is ineffectual?