Sam's build thread

[h100vw]

20 would be a minimum based on the pressure switch installed by VW.

[sambb]

well the 5W-40 took it up to 16-17psi. That puts it in the realm of possibly gauge/sensor error being a factor. I'll get a mechanical gauge onto it to confirm idle pressure. If it is sub 20psi then I really don't know what to do ie whether its worth still throwing the TFSI turbo and exhaust at it and getting a year out of it OR doing the bottom end on the other motor right now.

[Sydneykid]

Is it making any noises? Big end knock or main bearing rumble? Rattling rockers or cam chain? Dash low oil pressure warning light?


Cheers
Gary

[sambb]

Thinking about it, the OE pressure switch must only be looked at by the ECU at start up. It'll always go over 20psi at start up even if your hot idle pressures are low like mine. Thats why mine has never blinked despite the low pressure and why you can unplug it with the car running and it wont bring on the dash light. Pretty sure its only there for start up pressure monitoring. For it not to hit 20psi at start up the engine would have to be well and truly shagged. Mines well off that, but yeah I think a mechanical gauge check is in order. I'm not convinced a coupler of psi below the min 20psi recommendation isnt nearly to be expected on a 150,000km engine.
I'm seeing quite a few stories of people having slightly lower idle oil pressures after fitting oil coolers and sandwich plates. Interweb discussion yes, but guys who reported their lowered pressures and then removed or bypassed their new coolers putting things back to stock and suddenly had their pressures back. Hopefully there's something in that. The cooler itself would have to represent a restriction. When up to temp the thermostat in the sandwich plate is wide open with the majority of the now thin oil having to go through the cooler and a good meter of pipe work. Come to think of it, it is when the oil is over 80 degrees (thats the sandwich plate thermostats cracking point) that the idle pressure gets below 20psi. hmmmm

anyone else seeing lower hot idle pressures after they've fit coolers?

[sambb]

Gary there’s no noises that would indicate an issue.
I spoke to the Mocal Australia dealers today and they said it’s not uncommon for a sandwich plate/cooler to knock a couple of psi off your idle pressures. Watching it last night I definitely have spec pressures till about 80 degrees after which the idle psi drops from above 20psi to roughly 15psi. That could be the oil thinning out but it’s a pretty marked step which makes me think it’s the longer path via the cooler that’s doing it. All other running pressures are fine.
As an aside I read that crankcase vacuum can have a part to play. Eg if your PCV gets its guts blown out of it and then the crankcase goes to a non-flow restricted vacuum it can really affect idle pressures. I have been running a pcv so I’ve disconnected that and will just run straight to the can which will only be drawn on by the turbo inlet now. I’ll see if that has any effect.

[sambb]

Oh and the erWin doesn’t spec a base pressure for the bjx 1.8T 20V. It just says that with the engine between 1.2 and 1.6 bar ( 17.4-23.2psi) that the oil pressure light needs to be off, which mine is. In practice this is only relevant at startup as after that pressures can actually fall below that without triggering the light. My light has never come on.
It then says that at 2000rpm @ 80 degrees that the oil pressure needs to be between 2.7 - 4.5 bar (40-67.5psi). Mine easily qualifies there and is pegged at 60psi from then on. The fact that I have healthy running pressure suggests to me that it can’t be the pick up.
I think it’s healthy so I’ll keep going on the turbo mod.

[Sydneykid]

I had a quick look at the data files last night, trying to find some non dry sump engine data with oil cooler and an OE pump. No joy, but I did find one that's close, my RB30 which has an N1 (competition) RB26 oil pump. It shows a 2 psi drop (that's through the remote filter and oil cooler) from ~28 to ~26 psi at idle, that's with Nulon 10W60 at 95 degC with a 900 rpm idle. It has 2 oil pressure sensors, one in the block (OE position) and the other one at the remote oil filter. Flow looks like;

pump -----> sanga plate ------> remote filter + temp & pressure sensors ------> oil cooler ------> sanga plate -----> engine -----> oil pressure sensor


Cheers
Gary

[sambb]

gotcha. Thanks Gary. The pressure sensor position is post cooler from what I can tell. The plate is stacked between the housing and the filter so I assume
pump ----> plate----> filte/cooler -----> plate -----> pressure sensor switch and pressure sender on housing -----> engine

so being post cooler and filter it will be seeing a drop yeah. I have been running just a Ryco recently because I got sucked in by a 2 for 1 deal a while back. Crappy filters can drop pressure a bit too cant they?

Oh and PCV had nil effect. Checked that the valve was ok and that the restricter was definitely in the line. No excess vacuum happening there and observed no difference so put it back.

[sambb]

Gary which type of one way door have you used on baffled wet sumps.


I'd prefer hinged doors that I can just rivet on. I know the Viton RCM/Cosworth style are popular but not sure about that push fit fitting method into a slot arrangement. I can get the RCM ones for 15 bucks each. The other option I was thinking is to cut louvres into the baffles aligned to aid flow into the pocket but not out. That wouldnt block flow out of the pickup entirely but would definitely slow it down yeah.

[sambb]

You're joking. My elec pressure gauge is crap. out by more than 10psi! This tool pro gauge says all is well. Sorry to waste peoples time with advice etc. Learnt a bit though.

Ok on with an exhaust and turbo!! oh and a refund for the gauge