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Oil coolers for K series cars


Bob Corb

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I'm wondering whether to get an oil cooler for my Caterham (when it arrives, A@#^&star lost the order!). I know MGFs have high oil temp problems and in order to protect my investment I thought it would be wise to add a cooler. What sort of oil temps do R500s and SLRs get upto on sprints/trackdays etc and what sort of coolers are they fitted with if any??

 

My engine is an MGF VVC unit which will be converted to roller TB's and Piper 285 cams before installation, roughly 180BHP (at first) and will be dry sumped. I've got an MGF cup oil filter housing with integral take offs for a cooler (saved myself a few grams not adding a mocal plate!!)

 

Thanks in advance

 

BC

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Hi Bob

 

I've just fitted the Superlight Racer oil cooler kit to my R500 This is only needed for racing when slipstreaming causes temperatures to go much higher (or so Caterham say) the kit is approx 75.00 + VAT and comes complete with everything you need to fit to a dry sumped car

 

 

Jason

R500FUN

 

 

 

 

Edited by - Jason on 17 Mar 2001 19:29:41

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R500 owners have been debating this one quite a lot. I cannot say whether your car will need a cooler or not, but the firm advice from Minister is that the oil should not be allowed to exceed 110 degrees. As standard, an R500 does not have an oil cooler fitted, and as you can see from Jason's response, on a track you need one if you are going fast. I am afraid that for road use, a cooler will make the oil run too cool, so am not (at the moment!) planning to fit one myself, but I'll see how the oil temps do this Summer on track days.

 

The other bit of advice from Minister is that they prefer a good synthetic 15w/40 oil in their engines (rather than the 0W/40that K cars usually run), provided owners understand that they must warm the engine up thoroughly before using any revs.

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Another option may be an oil/water heat exchanger...

 

Advantages are:

 

- gets the oil up to "working" temp. (70-80degC) quicker than without

- prevents it getting too hot (>> 100degC)

- can be fitted pretty much *anywhere* in the engine bay

- more resistant to damage

 

Disadvantage is that I think it's a bit heavier than a trad oil cooler. And may be a bit more pricey.

 

I've yet to go on track with mine, or use it in the heat (yeah right) of summer, so can't conclusively comment on its performance. But so far it looks fine.

 

For typical day to day use though I believe Keith is spot on (i.e. that a K with a trad oil cooler [and presumably no thermostat] will run with its oil too cool most of the time).

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Thanks for the help chaps. I've got an oil to water type cooler sitting on the self doing nothing so I'll fit that with a thermostat if required. Being an oil to water type it should help heat the oil a little quicker too.

 

BC

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The big worry about the oil/water type heat exchanger is that you are not increasing the heat transfer capability of the entire system. At the same time as tying the oil temperature to the water, all that extra heat now has to pass out of the system at water temperature rather than oil temperature (less efficient transfer) and it has no more airflow to make use of (no more radiator surface area).

 

This is where you need the radiator capacity to be up to the job. Thankfully, Andrew Murphy has volunteered as the pioneer...

 

I will watch the results closely.

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Well I figure it's about time I pioneered something after blagging from the good work done by Mr Andrews, PC, MikeB etc.

 

Can I have volunteers for a shoulder to cry on if it doesn't work out smile.gif

 

Coming clean, however, I'm told that these have been run on a couple of race cars to good effect. Also I have the thicker ali' race rad' installed which should help (forgot to mention that before - sorry).

 

With a bit of luck I'll be doing the Le Sept thing so should get 3 track days in close succession in summer, plus a fair bit of fast road mileage. Should give it a good work out.

 

C7 AJM

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I've got one of those too.

 

I still think that the bigger problem with k-series cars, and definitely on the road, is getting the oil up to temperature rather than cooling it significantly.

 

As noted, for track days I've yet to test the whole set up so can't really comment, but I'll be surprised if the system can't cope.

 

Incidently, assuming fitting a more traditional oil cooler involves putting it in front (or behind) the water radiator, isn't the performance of one of them being compromised there too?

 

 

 

C7 AJM

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Our 1.6 Supersport ran hot at the Ring last year, and the year before, even though fitted with the Apollo.

Someone explained to me that the water radiator is not as efficient as it might be, because it is designed to improve the exhaust emissions. Changing to a more efficient cooling radiator could cool the whole engine, as well as the oil. I haven't had the time to investigate this further yet, and the Ring is looming. It just means that the long straight is used for cooling at the end of each lap, rather than fast blasting.

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"the water radiator is not as efficient as it might be, because it is designed to improve the exhaust emissions". Blimey I'd like to know what they were on. It's the job of the thermostat to keep the engine operating at it's optimum temperature.

 

If you make the radiator small enough to keep the engine above the temperature at which the thermostat opens then any rise in ambient temp. will cause the engine to overheat.

 

If you make the radiator big enough to bring the thermostat into play (which it should be) then making it bigger still won't make the engine run any cooler than the 'stat temp.

 

Mike

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Richard,

 

You can run the Apollo tank with the dry sump system. It is something I am seriously looking at as I have both of them attached to separate engines at the moment.

 

You will get about 2.5 litres more oil in circulation. In almost all circumstances, the Apollo tank will be doing nothing. In such circumstances as it comes into play it will do its usual anti-foam air/oil separation thing. Sounds like a good thing to me.

 

One thing to worry about is the Apollo tank's habit of draining when the car is left unused for a period of time. This oil will get down to the sump and on startup it may get pumped out into the catch tank. A non-return valve in the vent line will fix this.

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