Hi all,

Thought this would be an interesting discussion for the knowledgeable ones one here.

When I removed the clam on my Exige I was looking at the other systems on it and was drawn to the oil coolers. I can imagine that they, err, cool the oil but I wondered how it worked. It looks like where the filter is, two pipes leave there and go to the front of the car with two little radiators, one either side of the motor. The oil flows out of the engine (by the filter?) and then into cooler 1 and across a pipe into cooler 2 (coller 1 and 2 have a pipe between them) and then back to the engine, is that correct? What causes the oil to flow that way? Is it under some form of pressure?

Secondly, I read some horror stories on US forums about the pipes giving way and that seems to be quite a bit more of a mess than a radiator splitting.... some resulting in complete engine failure.

Does anyone have any info about oil coolers, how good they are and how often they explode? The more I read, the more I wonder how it is not constantly broke. Everything about this car makes me nervous that something will implode and cause me to be stranded

Doesn't half go like stink though when on song

 

Our business is looking after LARGE oil cooled air compressors with big oil coolers
The failures are 99% the hoses, either perished or split at the fitting. We routinely swap failed ones for braided hydraulic hoses. Occasionally we see a core or the weld on the side go. When they fail it makes a right mess
A car system is the same principal but with an oil pump providing the pressure, but a lot more risk of a mechanical seizure

 

The oil pump provides the pressure, you take the clean oil from the pump, into the oil cooler, and then back out and through the engine.

Generally, most of the issues with pipes splitting, or the fittings on the oil coolers doing likewise, is because they haven't been mounted correctly, you must not hard mount an alloy oil cooler, the vibrations and stress from the lines flexing fatigues the hoses and fittings, and aluminium, unlike steel, will fatigue under the lightest of loads.
Saying that, in many year of building racers, all running over very rough terrain at high speed for a living, all with oil coolers - I've never had a single one fail, nor a hose - and as you say there are hundreds of thousands, if not millions, of OEM cars with oil coolers that have no issues either.

 

Thanks buggy. Those are comforting words. I will consider pausing on the grand pipe swap :-)

 

 

There is alot of oil pressure compared to say the coolant system on the S2000. I used to quite often see spikes of 100psi on cold start up on my S2000 when i had no aftermarket oil cooler fitted. Its best to take it easy for the first few miles to let the oil thin up abit and then the pressure relief valve on the oil pump works alot better.

I fitted a midsize Laminova heat exchange oil cooler to my S2000 and it caused a noticeable restriction to oil pressures when the oil was warm. I done some reading up and it turns out that at 6000rpm the S2000's oil pump is flowing 60 litres of oil a minute. So if gives you an idea on how quickly the engine would dump 5 litres of oil if there was a hose failure. I had to change to the larger Laminova to stop the restrictions, its funny because from my reading the Kraftwerks supercharger kit used to supply the middle size oil cooler which means there is alot of cars out on the road that are seeing less than 66psi during Vtec which isnt something i would be happy with.

I currently use Pushfit hoses, i read alot of horror stories about them but after seeing the installation photos it becomes apparent that people use the wrong hose for the wrong job. Bend radius and heat rating are all important factors but alot of people seem to forget that and fit a hose rated to 300f next to an exhaust manifold.....
I have done one trackday with the pushfit so far and had no problems and no slipping of the hose on the pushfit fittings. I didnt buy cheap rubbish thou i paid for the best hose and the best fittings. 2k for an engine blow up vs £100 worth of fittings.

Oh and the factory fitted cooler on the S2000 is useless because during high oil flow rates it bypass's the cooler meaning you are getting little to no cooling from it.

I have tried mocal, setrab and AQS oil coolers in the past and found that the mocals are weak where the fittings have to tighten up to, overtime they can weaken through vibration. The setrab was bulkier in that department but the O-ring seal they provide done naff all sealing and everytime i assembled the cooler it would leak.

I love the Laminova, its easily accessed, no risk of it being damaged by road debris and if you do your maths you archive hardly any oil pressure drops.

 

That is a problem and oil temps can soar.

OTOH the air-to-water OEM ones are less prone to dumping all the oil instantaneously...

 

Is that what you do? Explains a lot, Positive-Displacement-Boy!

 

yep it pays the bills
As the yanks like to remind us there's not replacement for displacement!

 

Soooo, no PD screw for the Aston (or S2000) just yet?