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Engine Oil

Oil + Camguard for Lycomings

I just learned that moving from a synthetic oil with additives such as AeroShell 15W50 (or the identical Total oil) to a straight mineral oil and Camguard is not the right thing to do with a Lycoming engine. Lycoming engines require a friction modifier additive called LW-16702 to protect the camshaft lifters from spalling. AeroShell 15W50 contains this additive but Camguard does not because there were problems with slipping starter adapters on Continental engines.

Buying LW-16702 separately and adding it would solve the problem but isn't very smart because the additive costs more than the whole load of AeroShell 15W50 which includes the additive.

This is rather annoying because I have a lot of oil in stock now which I can't use...

The additive for Lycomings is included in straight 40 wt and 50 wt Aeroshell Plus, with the 'Plus' denoting that the additive is included.

Unfortunately there is no non-synthetic (i.e. all mineral) multi-grade oil with the additives. I now have four cases of AS 100 and Philips X/C which I both can't use...

Ah, I get it :-)

I initially understood the word 'straight' to mean monograde, not non-synthetic.

Hope you can find a use or buyer for the extra oil!

Is your oil the kind for running-in engines and new cypinders? If so you'll have no problem selling it.

Maoraigh
EGPE, United Kingdom

I don't know what engine you fly but not all Lyco engines need the LW-16702. so check for your specific engine. As for the Philips oil it is one of the best in the market and you should not have a problem in selling it.

Only one Lyco engine needs the additive by AD but the problem (top camshaft, oil drips down and lifters corrode because they are not covered in oil) applies to all Lycos.

This is true, but if you fly the engine for 2h a month the engine will be covered. Note that the Lyco. additive is not meant to prevent corrosion, it is to reduce the friction between the parts.

Recently reading an oil manufactures blurb where it stated that straight oils lubricating properties are inferior to that of dispersent oils. However I remember reading on an american GA website where posters said that there is not any difference in lubricating properties. I’ve also heard from an engine rebuilder who said that when he strips and engine he can’t tell if it has been run on straight oil for all its life or a dispersent.

I am sure you cannot tell if you just “strip” an engine.

If however you built the engine originally, measured all the parts with a micrometer, and then re-measured them after the engine has done X hours, you will find differences.

The highly regarded US shop I used in 2008 did that when they did FAA certification tests for Camguard, and they found considerably less wear. I am finding the same on my oil analysis – there is clearly a lot less engine wear.

The “user wisdom” from the USA (where the vast majority of the world’s GA lives) appears to be that if an engine is run say once a week, it doesn’t matter which oil you use. It is for the rather more common cases in private GA (where many people fly much less often than that) that other factors come in. Multigrade makes winter starting easier, for example.

What I doubt anybody has done (and went public with the data) is a before/after test like the above, but with just different oil types. One would hope the oil analysis companies might have data because they see lots of patterns but I haven’t heard of anything like that. The reduction in wear with Camguard is really obvious but maybe not so between different oil types.

For a few years I used to alternate between Shell 15W50 and Exxon Elite and never saw any meaningful difference on the oil analysis. Elite used to produce a lot of watery sludge around the dipstick (and more worryingly under the cylinder head rocker covers) and eventually I stopped using it for that reason. 15W50 never does that. And I fly once a week and never less than about 1hr airborne.

Administrator
Shoreham EGKA, United Kingdom
124 Posts
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