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Oil pressure drop after fitting a cooler
Trollyjack - 2/10/14 at 07:45 AM

Hi
I was getting 50psi on start up but found oil to be running hot when on track. this then dropped dramatically at 125°c
So decided to fit a oil cooler.

Cooler now fitted but on start up only getting 30psi not had it on track so dont know if oil gets hot. or drops in pressure.

What would you surgest try it and keep a eye on the oil pressure and temp. or fit a high pressure pump.

Engine is a 1300 crossflow running Valvoline VR1 oil.


bi22le - 2/10/14 at 07:51 AM

Are you using a thermoatatic take of plate?

I am using a mocal 80deg one so the rad does not even come into play until the oil is +80deg.

I have seen no drop in oil temp with my large cooler fitted and cheap hoses. I do have an accusump as well.

But then if you have been following my oil temp woes then who knows what is going on with my car !!

I have a 1600cc CEC for your reference.


steve m - 2/10/14 at 08:09 AM

How bizzare as i had exactly the same issue, recently but on idle i had ZERO pressure
this was also on a xflow 1600

I have now fitted the old pump, and removed the oil cooler, and at idle i now have 30 ish psi and 65 plus at revs

The only thing that sprang to mind with my setup, was that the oil rad is 10" higher than the pump
and my guess is, that at low rpm the pump does not have enough pressure to feed the rad ?
i could be very wrong !!

steve

[Edited on 2/10/14 by steve m]


Trollyjack - 2/10/14 at 08:37 AM

No thermostatic plate (not thought of that) could be a option

Mocal 13 row 115mm wide cooler with top quality pipes.

Oil cooler lower than pump level with sump.

It Idles at 30psi had water upto temp still holds 30 psi but oil only 55°c

Think i may need to give it a run to see when oil temp comes up and oil a little thinner pressure may increase also.

Description
Description


britishtrident - 2/10/14 at 12:09 PM

Which grade of VR1 ? there are 6 different grades

VR1 is a highly refine mineral oil, with any oil the upper viscosity index rating is measured at 100c above about 125c that the viscosity drops quite rapidly and also mineral oils start to break down and show a permanent change of viscosity i.e. it becomes more viscous at the cold end and less viscous at the hot end so the viscosity of a 20w/50 oil behaves more like straight sae 40 grade.

With synthetic oils at very high temperatures the viscosity doesn't fall of the cliff quite to the same extent as mineral oils and a synthetic oil will not be degraded by over heating to anything like the same extent.


Trollyjack - 2/10/14 at 02:19 PM

Using 20/50
that why I want to get it down below around 115


adithorp - 2/10/14 at 03:37 PM

Only way fitting a cooler can effect pressure is if it's restricting the flow too much. I'd get it properly hot and see if the pressure improves once the oil thins and flows better. That might take some effort to get hot with not oil 'stat, unless you mask off the cooler. The alternatives are a bigger cooler for more flow or thinner grade oil; 15/40 might be enough... but too thin and it'll wee out of a cross-flow