Support Team Shaun_E Posted April 23, 2003 Support Team Share Posted April 23, 2003 I have been reading the thread on Laminova vs oil/air cooler and (not wishing to hijack that thread) started to think about oil temperatures. Some posts have indicated that 100 degrees is OK, others that a lower tempaerature is normal and that got me worried - at Llandow my oil temparature was up over 110 and peaked at around 115 at which point I came in to give it a rest. Is this OK or should I go out and change my oil immediately? I know some people change their oil after every track day but I haven't. On the road I rarely see oil temperatures above 85/90. Should I consider an oil cooler for future track days? What is the maximimum temperature that modern oils can withstand? The car was recently serviced by Caterham so has whatever oil they use in it. The engine is a 1600K SuperSport and I have had an Apollo tank fitted. Advice and suggestions appreciated. Shaun Yellow SL #32 Link to comment Share on other sites More sharing options...
16vastra Posted April 23, 2003 Share Posted April 23, 2003 i use millers 10w60 or castrol RS10w60 both full synth, these can take 120/125 degrees continuous and can withstand 150 for a short (very short i hope!) period of time according to the blurb Link to comment Share on other sites More sharing options...
Jason Plato Posted April 23, 2003 Share Posted April 23, 2003 One thing to remember is that the oil may be OK at 125 - 150C but will the various seals inside the engine be OK ? . I was told by an oil specialist that the ideal is around 85-110C . Quite how this is managed is another story ........ dave Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 23, 2003 Share Posted April 23, 2003 Be very careful. The temperature you measure is not the maximum temperature the oil sees. With a good modern synthetic, 110 indicated is the limit. You can fix this by not overfilling a wet sump K; much simpler than an oil cooler. The problem is not so much with the oil as with the things the hot oil touches (head gasket rubbery bits etc.) and the reduction in heat borne away from the working surfaces. Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted April 23, 2003 Author Support Team Share Posted April 23, 2003 It is possible that I overfilled it a little although the dispstick reading was within limits. The temperature is as displayed by Stack dash (using Stack sensor) - is this likely to be reasonably accurate? If oil level is OK and temperature measured accurately it would seem that I have a problem. Guess I need an oil cooler of some sort! How close a margin is there between safely filled to prevent (well minimise liklihood of) oil starvation versus overfilled? Is the high oil temperature caused by windage?(is that the correct term for reciprocating parts hitting the oil in the sump??). Finally how much is a Laminova and where can I get it fitted as I'd rather not do it myself? Thanks for the comments so far. Shaun Yellow SL #32 Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 23, 2003 Share Posted April 23, 2003 Yes it is windage that causes the excess heat. The Caterham shallow sump dipstick markings are 22mm higher than rover's max mark, relative to the crank. Rover research has shown large amounts of power (30bhp) sapped at high revs (above 7500rpm) when 8mm above their mark, so a Caterham shallow sump is in trouble from the start. The caterham mark is (I believe) set to almost exactly the point at which the dipstick emerges from its tube into the sump. I would try going 5mm lower than this. I have a spare tube and dipstick lying around so I can check this. Link to comment Share on other sites More sharing options...
Nick M Posted April 23, 2003 Share Posted April 23, 2003 Peter, Out of curiousity, does a dry sumped K run slightly lower oil temperatures than a wet-sumped one, all other things being relatively equal ? And with a dry sumped engine does the pressure that you run the oil system at affect the temperature ? I've always been sure to keep indicated oil temps at absolutely no more than 110 degrees (it's measured in the dry sump tank) when using fully synthetic oil (Millers CFS 10W60 to date) because the temps in the engine will be higher. Just curious to know if even this is a little on the high side. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 24, 2003 Share Posted April 24, 2003 Dry sumped Ks have very few problems with oil temperature. Obviously if ambient temps are high and no additional oil cooling is provided the temps will climb. That Millers oil sounds very high viscosity (60) for all but the very highest ambient temperature use. I can't think of an engine for which I would recommend an SAE 60 viscosity oil. Good oil pressure has a marginal but important effect on flow of oil flushing through the bearings. This cools the bearings and is important for this reason. High oil pressure will result in a smaller difference between the bulk oil temperature and the peak temperatures in the working surfaces of the bearings. Link to comment Share on other sites More sharing options...
Nick M Posted April 24, 2003 Share Posted April 24, 2003 Thanks Peter. Although the temperatures out here in Arizona can peak in the summer at over 40 degrees C, I doubt I'll be using the car in anger when it's that hot, not least because the driver is more likely to melt than the engine !! FWIW, I've got some 10W40 Red Line fully synthetic oil that I'm going to use in place of the Millers stuff, partly because I can't get Millers oil in the US but also because it was suggested by someone else that a 10W60 is probably a little on the high side in terms of viscosity. Especially when there's a mix of road use and track use. Good oil pressure has a marginal but important effect on flow of oil flushing through the bearings. This cools the bearings and is important for this reason. High oil pressure will result in a smaller difference between the bulk oil temperature and the peak temperatures in the working surfaces of the bearings. Forgive my denseness, but I think I've only understood part of this. I get the bit about oil flow flushing through the bearings and providing a small cooling effect. But I wasn't so sure about the bit where you said high oil pressure results in a smaller difference between the bulk oil temperature (I'm assuming this is the oil temperature of the oil in, say, the sump or dry sump tank ?) and the temperature at the working faces of the bearings. Is this a good thing ? Or were you implying that if the oil pressure is *too* high it can mean the oil never gets a chance to cool slightly before it's pumped round the engine again ? Again, FWIW, my dry sumped 1.6 16v VX runs at a max of around 65-70psi which I understood to be about right. Link to comment Share on other sites More sharing options...
Bare Posted April 24, 2003 Share Posted April 24, 2003 AS an oil.. may I suggest Mobil "delvac" in a 15/40 weight.. Fully synthetic this is an absolutely Excellent Synth oil for use in a Saab turbo tweaked for serious power.. heat simply becomes a non issue.. more than adequate for any K series yet assembled ;-) Do a web search for details and source. Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted April 24, 2003 Author Support Team Share Posted April 24, 2003 Thanks Peter - I'll try lowering the oil level and see how that goes. If I still get high oil temperatures I'll look at fitting a Laminova. Yellow SL #32 Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 24, 2003 Share Posted April 24, 2003 Right I better clarify my ambiguous comments. Oil pressure is a consequence of flow rate, constriction and viscosity. - It is desirable to have a high flow rate through your bearings. - Engines have design clearances and you can't change them without a rebuild. - You can change the oil for lower viscosity. Oil pressure is also determined by the presusre relief valve which: - alters its restriction to flow based on pressure - some OPR valves are adjustable If you change to a lower viscosity oil, for the same pressure, there will be more flow through the bearings. My previous comments were ambiguous because I didn't specify where the "high oil pressure" was coming from. If you flow more oil through the bearings, the temperature rise of the oil in the bearings will be lower. this will actually transport *more heat* out of the bearing, but will do so at lower temperatures. The maximum temperature that the oil sees in service will be less significantly higher than the bulk temperature. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 24, 2003 Share Posted April 24, 2003 Bare, Isn't Delvac Mobil's diesel oil brand? I can't find any data sheets on a petrol Delvac and I am not an oil technician so I don't know enough about the differences in composition of a diesel oil compared to one designed for petrol engines. I would imagine the additives packages are different to cope with different contaminants from blow-by gasses. If this is the case I would not recommend the use of a diesel oil over an optimised petrol oil although some oils are now gaining API ratings for both petrol and diesel use. FWIW, the problem with temps in the K-series is more to do with the seals that the hot oil touches and the effectiveness of cylinder cooling. The ability of the *oil* to cope with high temperatures is not the issue. For 99% of K-series implementations a 15W rating is too viscous for cold startup and the engine will be better served with a 0W or 5W cold-rated viscosity. The problems for an oil are somewhat different for a natasp engine revving at above 9000rpm compared to a turbo running high combustion pressures at lower revs. Link to comment Share on other sites More sharing options...
Slipper man Posted April 24, 2003 Share Posted April 24, 2003 One point to be aware of with regard to comparing the oil temperatures for dry and wet sump engines. In a wet sump car, the oil temp sensor is in the engine somewhere (in the sump), whereas in a dry sump car, the sensor is in the remote oil tank. Before the oil gets to the tank, it has to go through a long pipe, which will act as an (inefficient) oil cooler. The sensor is showing you the bulk oil temperature. Jez Coates has told me that if the bulk oil tank is showing an oil temperature of 95 deg C, the oil inside the engine is likely to be over 120 deg, which is at the top end of the acceptable limit. On a wet sump car the oil temp on the gauge will be much closer to the temperature of the oil in the engine, which is why you will find people saying that 95 - 98 deg is the maximum allowed on an R500, say, whereas in standard engines they appear to be willing to tolerate more. The difference is just the location of the sensor I would get an oil cooler - a good investment at £60 from Caterham complete with all the pipes etc that you need Link to comment Share on other sites More sharing options...
Swiss Tony Posted April 24, 2003 Share Posted April 24, 2003 Remember that Bare was the guy that told us to worry if our gearbox temps were ever more than ambient. Link to comment Share on other sites More sharing options...
Marius Posted April 24, 2003 Share Posted April 24, 2003 I´ve seen temperatures of 118°C during a warm day at Zolder/B, measured by a Stack-instrument, sensor fitted into the dry-sump-tank. I´ve been told by quite a few people, that this nothing to worry about with a 16V VX. K´s are more sensible on oil temperatures I heard. Marius Link to comment Share on other sites More sharing options...
Jason Plato Posted April 24, 2003 Share Posted April 24, 2003 I found on investigation , that the belltank temps were almost consistenly 20C lower than the scavenge temperature . These were measured using an industrial probe and tell tale temperature strips . This reflects Keiths and Jez's theory . I'm still going with the thermostatic oil cooler ....... dave Link to comment Share on other sites More sharing options...
mav Posted April 24, 2003 Share Posted April 24, 2003 Keith, In a wet sump car, the oil temp sensor is in the engine somewhere (in the sump), Unless an additional sensor is fitted, then there is no Oil Temp for a std K in a caterham. The apollo is where you will most commonly find the temp sensor, on cars with a wet sump, (asuming the apollo system is fitted of course). Regards, Martin Link to comment Share on other sites More sharing options...
tom7 Posted April 24, 2003 Share Posted April 24, 2003 ISTR The Rover engineering sign-off for maximum oil temperatures on a K is 150C. The most critical 4 cylinder installation for cooling was the MGF, although the VVC engine in the S1 Elise installation did exibit temp readings at this level during some high-speed testing. i.e. 12hrs at VMAX at Nardo. Tom Link to comment Share on other sites More sharing options...
Nick M Posted April 24, 2003 Share Posted April 24, 2003 If you flow more oil through the bearings, the temperature rise of the oil in the bearings will be lower. this will actually transport *more heat* out of the bearing, but will do so at lower temperatures. The maximum temperature that the oil sees in service will be less significantly higher than the bulk temperature Brilliant - much clearer thanks Link to comment Share on other sites More sharing options...
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