ENGIN-EAR’S APPROVAL ITEMS. All have been tested and evaluated for use, service and value. The items supplied for review in this section have the ENGIN-EAR’S personal recommendation.OILS AND…….OILS – AN INFOMERCIALLet’s start with a nice little analogy. Most readers would know the old story of the flying instructor asking the students what the propeller was for on an aircraft. Various answers about tractor action, pulling the aircraft forward and the like were mumbled by the students but all were really amazed when the instructor said, “the purpose of the propeller is to keep the pilot cool.” This evoked considerable response of disbelief until he continued, “well, if you don’t think that is true, wait and see how much you sweat if it stops turning.” His poignant remark was, obviously, to push the point about the necessity to carry out all engine checks that are required before taking off.Now we come to my alerting story. What is the ingredient you feed into an engine to keep it running? Maybe ‘fuel’ was your answer – however – my answer is ‘oil’. Not convinced? Okay, you can pour all the fuel you like into an engine but, I can assure you, if it does not receive a supply of oil, it will stop….rapidly and with disastrous results.Oil is a common topic when fuel in mentioned. If you run a model diesel you would know the fuel is kerosene with ether added. A glow engine requires methanol with, maybe, nitro methane added and a petrol engine (gas – gasser if you insist) runs on petrol – 95 or 98 RON. To all those ingredients we must add a percentage of oil and here is the question – what type? Most regular readers know my feeling about castor oil – okay when there was nothing else but now – gone like the horse and cart….. both still around for those who insist but why would you? With that out of the way – we will now consider the synthetics and here there are several considerations. Again, regular readers will know my liking for Morgans Coolpower oils – I use this oil in all engines – diesel, glow and petrol. In extreme I have used it in an engine running in excess of 40,000 RPM and in an engine that was 30 degrees C overheated (for test purposes) and it has never failed me for operational use, lack of gumming and long term corrosion protection. I first tested the blue Coolpower well over 35 years ago and the results convinced me that this was the oil I would use in all my engines and all test engines. I also use the Coolpower red oil as a protective oil after I repair an engine so it has a god oily start when the customer fires it up. Works well for this purpose as I have never had a repaired engine returned due to a seizure on the first start.SO MANY.Here we will consider the petrol engines (aka gas engines or ‘gassers’) and here we have a few problems. The recommendation for an oil to mix with the petrol to produce a ‘petroil’ mixture is one designed for an air cooled, high performance two stroke engine. This eliminates the majority of the high performance (marine) outboard motor oils as most of these are water cooled so their reliance on the oil to carry away the engine heat is very little. An aircooled engine is a different story and even ‘aircooled’ is a bit misleading. Take, for example, a two stroke motorcycle in heavy traffic. The forward movement can be extremely slow and halting and stopped periods can be extremely long. For kilometres the air passing over the engine is not worth considering due to the slow forward movement and the long stopped periods. What cools the engine in these cases? Three factors – first is the oil going through the engine, second is the heat dissipation by the engine fins and third is the sensibility of the rider if he stops the engine during perceived long stops. One factor for sure – the oil must be up to the job or the other two considerations cannot save the engine. So….is this type of oil suitable for our model engines? Maybe not. Consider two factors – the load on the engine and the size of the internal components. The motor cycle has a gearbox that takes care of the load factor in the main. If you fail to change down a gear under a load situation – the engine will chug to a stop (or break a conrod). Our model engines are under constant load from the propeller. Want to check that load? Try the engine on a shaft run – no propeller – and see a great gain in RPM (before the final big bang). Let’s now consider the size of the engines. Admittedly some of the larger engines used for models are at the cross roads of matching or even exceeding small motorcycle engines but, in the main, most are smaller and – here’s the very important consideration, some have plain bearing connecting rods – certainly not used in motorcycle engines. As an extreme example – consider sewing machine oil – even 3 in 1 oil used for small moving parts and – for some sewing machines, extremely high speed operation. This is a special oil with a very low viscosity and, I can assure you – high performance two stroke oil does not go down well when used in a sewing machine.Another consideration is our usage of a model engine – generally ‘pedal to the metal’ (full speed operation for those non techno babble modellers) for almost the entire flight. The engine is under maximum load from takeoff until the throttle is pulled back for the landing approach – remember, I said ‘generally’ as there are fliers who do realise what the throttle control is for on their transmitters. Even a two stroke motorcycle in a race does not operate under such conditions. Again, the gearbox relieves the load on the engine and the straights on a race track are not very long – it is good throttle control and cornering that wins most races – not an engine running full RPM for the duration of the race.Going back to engine size, when you compare the diameter and working clearance of a plain bearing connecting rod in a, say, Saito 14 (13.4cc) or the NGH 9 (9cc) petrol engine to the size and clearances of a motor cycle engine with needle roller bearings in both ends of the connecting rod – you are considering the sewing machine with a gate hinge, so to speak. For the model engines, both two and four stroke, the oil of choice is very critical. I receive quite a few emails and phone calls from modellers who are having problems with their engine due to lower power, overheating, sticky feeling when cold and difficult tuning. In the majority of cases I put it down to the choice of lubricant – it just does not suit the model engine. I have no doubt there are some oils that might be suitable for some engines but maybe not for all. The lubricants for chainsaw engines would certainly be worth considering for many model engines but the suitability for a four stroke and/or a plain bearing conrod engine might come into question. My very simple advice is…why bother experimenting when we have oils that are proven to be suitable…proven over many years of use in all types of model engines by many thousands of modellers. Yes, I know, you will hear of modellers who have problems with one of those oils – oils that many other modellers use and do not have problems in the same engines…you can’t beat adversity no matter what the cause. Over many years I have tried quite a lot of different oils for various results. Some were not good corrosion preventative’s, some caused gumming, some were way too expensive without offering anything more than other lesser priced oils offered and some just simply did not do the job. I find that Klotz Techniplate and Nitroglide are quite suitable for model engine use but my preferred oil is Morgans Coolpower – as many readers would know. It has never let me down in any way, the price is quite reasonable and competitive, it is freely available if you take the trouble to inquire and it comes in three grades which we will now discuss to close this article.The first produced grade was the Coolpower Blue – a lubricant that still stands the test of time and it is suitable for all engines. It has the highest viscosity which is equivalent to the other suitable model oils. Recommended dilution for percentage mixes (diesel and glow) is between 15 and 20%. For petrol engines – use the ratio recommended for that particular engine.Red has a lower viscosity than blue and is popular with heli fliers and users of extremely high performance engines. Recommended dilution for diesel or glow is 18 to 24%. Suitable for petrol blends where a low oil content is used (say, 50:1 ).The ‘royal’ purple is for those who just cannot decide between blue or red but it will suit all blends where blue or red can be used. Recommended dilution is 16 to 22% for diesel or glow and the recommended ratios (per instructions) for petrol fuels.Generally I use the blue oil for my fuels with an occasional dip into the red and purple for some old engines or engines run under extreme loads. I use the red as a lay up oil when I consider it will be a long period before the engine is used and also for an assembly oil after repairs or internal inspections of an engine for testing.It is my strong opinion that a problem with an engine will not be due to using Coolpower oil – it is some other factor that you change or modify when you change to another oil. I use, on average, 32 litres of Coolpower per year – all test engines are run on it (plus any other lubricant requested by the distributor) and I have never damaged an engine on the test bench nor seen any evidence of abnormal wear.My recommendation is backed by many thousands of modellers worldwide.PHOTOS 1 & 2.1 The Coolpower family – choose your colour.2The red is also very good fro an assembly and storage oil.