More oil doohickys

[trooper1212]

You may remember my low oil pressure on idle problem. Replacing the gauge with a racetech one gave me an extra 10psi across the range and an accurate water temperature, so that was a nice, cheap fix! I was hoping it would also fix another problem that i've had a few times, but as it happened again today with the new gauge, no luck on that one.

Every so often (it's happened about 5-6 times in the past year, so not frequent) when I brake relatively firmly the oil pressure drops to zero and the oil warning light comes on when the car comes to rest. A quick prod of the accelerator brings it back up to healthy levels and it's then happy idling away with a good pressure.

Any idea as to what could cause this? It seems like it should be an oil starvation problem due to G forces, but i'm not braking hard, just "firm". Oil level is at max on the dipstick.
Should I be right to trust the dipstick, it's at the rear of the engine as it is an early Cerb, and there is only a 1 litre difference between min and max, which is different to the 2 litre gap in later Cerbs I believe?

I don't know how the oil pump and oil lines are in the Cerb V8, could I have a dodgy pump or crap in the sump that occasionally blocks the lines? Is replacing the pump an engine out job?

Any thoughts appreciated.

[Tyre Smoke]

I might be wrong in this, but I thought all Cerbs were dry sumped with a seperate oil tank. could be a problem with the oil pick up in the tank but suspect Joo will be along in a moment with an explanation.

[FourWheelDrift]

Tyre Smoke said:

I might be wrong in this, but I thought all Cerbs were dry sumped with a seperate oil tank.

AJP V8 - Wet sump
Speed Six - Dry sump (& missing 2 cylinders)

[J_S_G]

Tyre Smoke said:

I might be wrong in this, but I thought all Cerbs were dry sumped with a seperate oil tank. could be a problem with the oil pick up in the tank but suspect Joo will be along in a moment with an explanation.

S6 engines are all dry sump. Think the AJP in racing Tuscans is also dry sump. But don't think the Cerb's one is. Could be wrong on one or more counts...

[Byff]

Wet sump on a Cerb.

Mine occasionally does this when the oil level is getting to the min mark on the dipstick. Stick a bit of oil in and it's ok.

I find that checking the oil level with the dipstick at the back of the engine is nigh on impossible. Every dip reveals a different level.

I always drive with one eye on the oil pressure gauge and any slight deviations when braking or cornering will have me checking the oil level twenty times to try and get an average reading.

[trooper1212]

Byff said:

checking the oil level twenty times to try and get an average reading.

I'll give that a go and see what happens I really don't trust the dipstick, but I guess the only way to know for sure is to make sure it's maxed, drain it of oil and measure how much comes out. How much should it hold in total?

[SXS]

The 4.2 AJPV8 in the challenge car is dry sump and produces 450bhp!!
Come on, a wet sump thrown around like those babies would be engine suicide!

The 4.5 AJPV8 is a 'floating' wet sump - slightly different to a typical wet sump I believe.

The Speed 6 AJP-6 is dry sump.

The Speed 12 is dry sump.

The Speed 16 is a no sump!

[rob_h]

Neil

Had the same problem myself. HHC were very helpful and said it was sometimes due to not enough oil. I'd been having problems getting a reading on the dipstick so i put about 3 litres of mobil 15/50 in and hey pressto got a reading on the dipstick ( probably too full if anything ) and dial stopped going to zero when braking. Also my pressure is up to around 60.

Regards

Rob

[trooper1212]

rob_h said:

Neil Had the same problem myself. HHC were very helpful and said it was sometimes due to not enough oil. I'd been having problems getting a reading on the dipstick so i put about 3 litres of mobil 15/50 in and hey pressto got a reading on the dipstick ( probably too full if anything ) and dial stopped going to zero when braking. Also my pressure is up to around 60. Regards Rob

Never had a problem getting a reading on the dipstick. Checked it out this morning and no matter how many times I checked and re-checked, it was always in the same place just below the max line. The car is on level ground.

I might look at getting it replaced with the later variant at the next service, although that is £100 for the parts alone, so god knows how much to fit it.

I'm guessing there is no way to know for sure if the dipstick is correct, except by draining the system and seeing how much comes out.