wondered what the pressure range should be for a 2.0 zetec. its running a dry sump system. on cold start up about 45/50lbs, that drops as it gets warm down to about 20 on tickover and when really hot 15 on tickover. as i rev the engine it goes up in line with those revs: so 2k = about 25, 4k = about 40 etc. the engine builder thinks that it 'should' be fine, but 'should be' doesnt fill me with confidence! i've heard other owners say theirs has much higher pressure, but being a numpty not sure if the dry sump part of the equation has any bearing ? the gauge is correct, swapped the old one for a new mechanical one. chrs mark
it should be fine. its when you dont have any oil pressure thats when you have to worry.
Mine (from memory as its currently in bits)
Cold start jumps to about 70 or 80 psi at tickover, but does nosedive as temps build up
fisrt 5 mins or so if revs go above 2k gauge goes off scale (only reads to 90 psi IIRC?)
once at running temp its about double the rpm/1000
(so 2k = 40psi 3k=60psi)
BUT doesn't do this all the way through the RPM and seems to cap out at about 60 to 70 psi (again this is from memory) where it will sit pegged -
higher RPM does not make it go higher
(guess the bypass is doing its thing?)
When it has been on a very long run/thrash mine used to drop to about 15 psi at tickover (800 RPM ish)
I wonder if yours is blacktop or silvertop?
Mine does like to clack a tappet when it gets this low on pressure after a thrash- which is why mine is in bits....:-(
If yours is getting enough pressure to keep the tappets pumped up I wouldn't worry
Regards
Rob
Fully warmed through my blacktop runs 45 psi at 750rpm, by 1500 its up to 70 psi where I'm guessing the bypass valve opens.
It has solid lifters of course, but its silent throughout.
As above ^ r1pete mine starts off around 72psi and when at full revs but drops off to around 40 at idle.
greenwood03 - mine's about the same as yours, and that's been rebuilt with new oil pump, new crank, new bearings, etc and runs fully synthetic 5W40 with hydraulic lifters . If you surf the net there are huge variations quoted, from around 50 psi (3.5 bar) at 4000 rpm to 70-80 psi. As someone posted earlier there's nothing to worry about if it's 50 or 70, it's when it drops to 2 or 3 it's time to worry. I'd sleep soundly if I were you.
thx for the advice guys. having spent a few bob having the engine built i didnt wantto see it end its life due to low pressure! thing that puzzled me is the fact that none of the garage folk that ive taled with seem to have a definite opinion....as i said before the word 'should' didnt fil me with confidence. thx again.
Oil pressure at a cold start is normally determined only by the pressure relief valve, this makes me suspect the gauge readings.
Are the pressures measured with a real bourbon gauge or an electric one -- if the latter you might want to check the calibration either by
screwing a bourbon gauge straight on to the engine ( you can buy very cheap (about 6 quid) small hydraulic pressure gauges with 1/8"NPT fitting
off ebay) or test by applying a known air pressure to your existing gauge sensor.
quote:
Are the pressures measured with a real bourbon gauge
