Zetec dry sump oil pressure low?

[Kevp]

Hi. I have had my oil pressure light comming on at lower revs. When I flick to the pressure display the reading can be 10 - 15 psi at low revs. Picks up quickly on throttle. I don't know the normal driving pressure, but the revs are normally high so never discovered a fault.

Now I 've done some stationary tests. At cold on idle 25 - 40 psi. As the engine warms up (the water temp rises to 85), the oil gradually drops. At a low idle down to 0..

Picks up quickly on throttle. At 3000rpm (stationary) it reads 30psi. The flow looks good in the swirl/oil tank. If I take the rocker cover oil filler cap off I get a spray of oil. The oil is Ford spec (5-30) at the moment. I used to run Valvoline VR1 which was 20 - 50.

The engine is Zetec Silvertop, solid lifters, titan series 2 oil pump. The engine was rebuilt 3k miles ago. The crank (knife edge and lightened) was checked by the machine shop & new bearings fitted at the time. I just replaced the pressure sensor (no change). I have the Dunnell water rail, which keeps the water temp vary stable, unlike the raceline unit it replaced.

So -a) nothing to worry about ? Just change the oil spec and rev a bit harder
b) the bottom end is shot.
c) change the drive pulley on the pump as the original is for high revs.

Thanks in as advance.

[stevieturbo]

It should never read that low.

But of course the first obvious thing to confirm, is gauge/display accuracy. But as low as it is with a dry sump setup....could be relief valve sticking, or a major problem inside.

[Mignon]

Definitely not a) nothing to worry about. One presumes you know what pressures it was showing when the engine was first rebuilt or did you never check? Most likely is the pressure relief valve needs adjusting. Shim the spring up or use a stiffer spring or maybe it has some form of adjustment built in.

[99hjhm]

Once rebuilt a dry sump Duratec, sod all oil pressure at idle but fine at higher revs. Didn’t know what the pressure was before.

Turns out oil pressure relief valve was fitted correctly when it should have been fitted back to front to every other one i and everybody else who looked at it thought it should be fitted. Once swapped round giving more tension on the spring, oil pressure was fine all round. Stripped half the engine again before I found the fault.

[Mignon]

Just to give you an idea the oil pressures should ideally be like this. On cold start when the oil is thick it should go straight up to 70 psi or so. As the oil thins when hot it should stay at about 20 psi on idle, 40 psi at 2000, 60 psi at 3000 and maxing out at high rpms 60 to 70 psi.

[frodo_monkey]

5W30 in my opinion is far too thin for a Zetec; I used to run it (from online recommendations) and had low oil pressure/fluctuating temps on track (race car doing 45 minute races). I use 10W60 Castrol Edge now as do most people in my series; all now fine.

[Kevp]

frodo_monkey said:

5W30 in my opinion is far too thin for a Zetec; I used to run it (from online recommendations) and had low oil pressure/fluctuating temps on track (race car doing 45 minute races). I use 10W60 Castrol Edge now as do most people in my series; all now fine.

Thanks for all replys. I went to do some checks but the starter motor is now shot.
I was concerned with the oil, but thought the Ford spec would be best. I think the thinner oil was specified for the hydraulic lifters, but that doesn't matter to me. So I will try a different spec.
Also the oil pump is geared for 8- 8500 rpm, so may be to slow at idle. But should read something.
I have a Stack dash which doesn't show the oil pressure on the standard screen, only highlights when it's out of the set parameter. Also my data logger doors not record it, so can't go back & check that.

Thanks again.

[stevieturbo]

A datalogger that doesnt record oil pressure ?

Seems a bit pointless lol.

[Kevp]

stevieturbo said:

A datalogger that doesnt record oil pressure ?

Seems a bit pointless lol.

Well, as we were mainly doing sprints and hillclimbs, I didn't think it necessary. May well add one now..
...and possibly oil temp... fuel pressure.... fuel temp? ... and.. and..

[Justin S]

Kevp said:

Thanks for all replys. I went to do some checks but the starter motor is now shot.
I was concerned with the oil, but thought the Ford spec would be best. I think the thinner oil was specified for the hydraulic lifters, but that doesn't matter to me. So I will try a different spec.
Also the oil pump is geared for 8- 8500 rpm, so may be to slow at idle. But should read something.
I have a Stack dash which doesn't show the oil pressure on the standard screen, only highlights when it's out of the set parameter. Also my data logger doors not record it, so can't go back & check that.

Thanks again.

You are right in saying that Ford specified 5w30 oil. I am sure you could stretch the viscosity a bit but the hydraulic lifters are known to pump up and cause misfires etc by using thicker oil. I would look more at the pump and relief valve. Never had under 2 bar at tickover on my black top zetec , which is a similar bottom end even if the top had shimmed followers. It ran the standard pump albeit with a Raceline baffled sump in a Westfield.

[stevieturbo]

Kevp said:

Well, as we were mainly doing sprints and hillclimbs, I didn't think it necessary. May well add one now..
...and possibly oil temp... fuel pressure.... fuel temp? ... and.. and..

Of course the above...less so fuel temp. What's the point of a logger if it isnt logging vital information ?