Oil Pump Mod
 

Just changed my pump over to a 12mm unit and was going to do the old stick a washer in the plunger of the release valve mod but noticed there was already a washer in there? I bought a genuine Subaru pump so am assuming either they have either changed the design or I am missing the point and I am supposed to put another washer in there? Incidentally there was also an identical washer in my old 10mm pump. Please can someone enlighten me :wonder:

Anyone?

I would like to know more about this too. When they say modified 11mm and 12mm, what is modified 11/12mm?

can of worms here. i think that is just a shim to set the spring pressure but ive also heard the 12mm pumps arent really curing the problem and can have their own side effects. the problem isnt flow or pressure of the pump, it flows plenty, some say the release valve sticks, yes maybe it has happened but does it happen as much as ppl think, i doubt it. i have heard the 12mm pumps can out flow whats in the sump btw as the oil returns are crap especially if the car is tracked.

i did alot of research into this when i had my engine built and the guy who built my engine said the most likely cause of big end failure is det which can crush or mishape the big ends causing pick up or the loss of float.

btw 10 or 12mm is the size of the output of the pump afaik

Well I've gone without putting a washer down the relief valve for know, have got an oil pres gauge fitted so will be keeping an eye on that. Would help if I actually knew what pressure is normal if anyone knows? (gauge measures in bar)
Slightly worrying that the 12mm pump can out flow the sump but I suppose the usual regular oil changes and a good quality symthetic oil should lower the risk, I don't intend on using the car on track but I do drive extremely hard.

dependant on oil but on 10w 50 fully synth i would say 2.5 -3 bar when hot, 3 - 3.5 bar when warm but not hammered , thats idle btw, i think mine hits 7 bar at about 2.5k revs, see what i mean about flowing enough for the revs.

i`m guessing but yours will be hitting 7 bar at lower revs so you will be working the pressure valve more of the time than me and my 10mm pump is flowing plenty enough for the pressure valve to cut in at lowish revs, i dont know what pressure starts to activate the valve. the washer you are on about adding actually holds the valve shut for longer creating higher pressure and oil is still being pumped from your emptying sump, i have a feeling that mod on a 12mm pump could be very bad news.

i`m no expert btw so sont take my comments as fact, for a more definite answer ask the question on 22b forum where all the tuners go or do a search on there about the 12mm pump

Cheers buddy, will do