Duratec 2.3 Oil Pressure

[Hedgetrimmer]

I recently purchased a 2.3 Duratec Caterham that's running a Raceline wet sump.

The oil pressure reads around 40psi - 45psi at higher revs and 20psi on idle when up to temps. The readings are from a Racetech mechanical gauge so should be accurate. The oil pressure also seems to oscillate from time to time when at steady revs.

Can anyone confirm whether 40-45psi seems correct?

Also anyone experience pressure oscillations on a mechanical gauge? r

Cheers

Carl

Edited by Hedgetrimmer on Wednesday 30th September 12:53

[Hedgetrimmer]

Thanks. I managed to speak to Raceline and they confirmed that the 2.3 is very sensitive to shell clearances and can vary on oil pressure, and therefore my readings are ok. They also mentioned that the oe oil pump is massive and the fluctuations are due to oil pressure relief and the volume of oil the pump can scavenge.

[Hedgetrimmer]

Thanks. I managed to speak to Raceline and they confirmed that the 2.3 is very sensitive to shell clearances and can vary on oil pressure, and therefore my readings are ok. They also mentioned that the oe oil pump is massive and the fluctuations are due to oil pressure relief and the volume of oil the pump can scavenge.

[Hedgetrimmer]

I am now not convinced as i went for a longer drive and the pressure settled at circa 38 psi at lowest when holding revs at 4500 but was moving around more than normal under hard acceleration. I thought the oil pressure relief valve might be stuck open so I unscrewed the relief valve bolt and there wasn't a spring!

Therefore:
Should there be one on a duratec raceline sump?
I assume the spring couldn't be injested beyond the pump valve?

The problem is bugging me so your wisdomn is much appreciated.

[Hedgetrimmer]

Thanks I'll take a picture later but the bolt is accessible from the outside of the engine at the front on the drivers side just before the engine mount.

[Hedgetrimmer]

Hi apologies for the delay. You are right, the bolt had nothing to do with oil pressure! I now need to get the sump off and find out whether there is a leak in the pick up pipe or whether the valve needs replacing. The engine is generating some high pressures under acceleration but they drop of when revs are held so I think there must be a problem with oil getting dumped back in the sump. I am not overly concerned as the pressures are still well within tolerance but it's disconcerting.

[Hedgetrimmer]

Max pressure is 65 psi so not too high when revving to around 7k. I get around 50 psi when the oil is hot when I first lift the revs to 4.5k then it drops back down to 40 psi after a couple seconds if I hold the same revs. It feels like the initial increase in revs generates enough flow to outweigh the pressure valve then the valve kicks in and the valve drains oil back to them dump.

Is the valve a replacement item? I think this or a leak in the pick up pipe could cause the symptoms as there is 65 psi at times indicating that the pump itself and the bearings must be ok.

[Hedgetrimmer]

On further investigation it looks like the Cosworth oil pump may be defective. The engine builder confirmed there was a batch of Cosworth pumps that were built which ended up with defective seals. Overall oil pressure has been fine and the bearings are unmarked.

As the engine is coming out for a new pump I am going to take the plunge and convert to dry sump and sell the current Raceline wet sump set up.

What's the general consensus on which dry sump kit to go for?

Edited by Hedgetrimmer on Thursday 5th November 08:44

[Hedgetrimmer]

Thanks. Raceline DS was high up the list as it is good value and the pump is integral. I always worried about the belt coming off on my R500k.