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Do's and Don't for plugs and oil

Roger Lee

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While I'm think of this I'll post it.


If you change your oil or a mechanic does it and you use a set of oil filter pliers absolutely do not grab the oil filter housing with them. The sharp teeth will put pin holes in the thin skin of the filter. If you use the pliers then grab the filter around the solid metal ring at the base of the filter.


When changing spark plugs you need to apply heat conducting paste. Never anti seize. When you apply the paste it should only be applied to the top half of the plug threads and a little goes a long ways. This is a spot where a little is better. If you get this on the electrode tip areas it will not burn off (silicone based) and will cause spark interruption. If you get a paste build up around the mouth of the plug socket you may be getting it on the plug tip when you insert the plug. Again this was most likely from too much paste. Use a rag and wipe this out. A little paste under the compression ring at the mouth of the plug hole would be normal.


I also hear some people don't use 3 qts of oil. Use it. One you can't hurt a dry sump engine with too much oil in the reservoir tank, 3 qts. puts it at the top of the filler mark, under filling may cause air injection into the system because of foaming mixed with plane attitude during flight, third, if you have a small leak and you under fill you just created a very low oil situation right off the bat (no margin of oil level safety here).


No need to use more than 3 qts. either. Use 3 qts., pre-fill the filter with some oil out of the 3 qts. and then fill the tank with what's left over. It is the right amount every time. Don't add more than 3 qts.


There is absolutely no good reason to under fill your oil tank.




Always remember we operate from what they call "Best Practices" and learn from every one elses mistakes over the years.


The life you save may be your own. Do it the right way, the Rotax way is a cumulative of 20 years of "Best Practices".

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Interesting article on lead fouling:


This problem can also be an issue with Microlight engines such as Rotax 912's. These engines are designed to run on unleaded fuels, but they will run on Avgas 100LL - indeed Public Cat aircraft, such as the Rotax engined Diamond DA-20's used for flight training, for must run leaded Avgas 100LL. A similar trick can be employed with this engine too when using Avgas 100LL. If you are running a Rotax 912, using the recommended NGK DCPR8E plug and you find it is fouling then try using a hotter plug like the DCPR7E (also allowed by Rotax). This should help as the plug tip will run hotter and discourage the Lead Oxide deposits from forming.


Any thoughts on the downside of using the DCPR7E if you're in a position to use 100L more than 30% of the time?

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