Hi all, Just moved to the tropic's and was wondering if there is any special engine care that I should be doing with the higher humidity?

Thanks

I'd make sure you use a good after-run oil and keep your fuel stored in well sealed containers.

Apart from that fly them all very regularly so they don't get a chance to rust :-)

G'day

I live in Dubbo in NSW which is hardly tropical but this winter it did rain quite a bit here and at one stage I forgot that I had left my ARF Kadet with its Saito 65 in the back of my ute under a tonneau cover. When I pulled it out a couple of weeks later, I just put it away and forgot it. When I started the engine about two months later, the engine ( which is less than a year old) was well down on power and sounded noisy in the bottom end. I pulled the backplate off and was greeted by a very rust rear bearing. Humidity kills. It now has some nice new ceramic bearings from RC-Bearings and is feeling much better.

Mike it will still pay to use a little ARO in that engine. Ceramic bearings still have metal races which can/will still rust if not properly cared for. Only the balls are ceramic.

Here i live in Bergen, Norway are very often rain and much humidity in autumn and winter period.

Store the engine well lubricated in the plastic bag and add the paper pack with silica gel into the plastic bag with the engine packed in the plastic bag inside.

Does anyone spray the outside of the engine with anything, I was thinking maybe a lanolin spray as it dries and dust won't stick to it?

Don't worry about the outside it's aluminium and that won't corrode.

If you're really worried, just wipe over any steel parts with an oily rag, that'll stop them from corroding but I've never seen the head-bolts or other parts of an engine get rusty unless they've been stored for a *very* long time.

G'day, yes I agree - ARO is always a good idea when there is moisture around. This was a rather extreme example of what can happen to bearings in a short time. I was quite amazed at how much moisture was in the bottom of the engine (judging from the "tide mark" that the rust left).

I only bought the ceramic bearings because they were so relatively inexpensive. I had also to buy a set of bearings for a rather battered Saito 120 which I was given but it only got the $6.97 solution. They do look fine though.

A good coating of castor oil sure seems to protect them. LOL those old Fox stunts can be almost black from castor oil stains because of their short venturi, but they sure clean up nice.

Actually it can, I lived on the coast for a while and the aluminum will corrode quicker than the bearings, but only on the outside. Never had a problem with rust even when living in Miami, and I never use ARO. Just make sure you use fuel with some castor, the oil left will protect the engine.

The thing about aluminum corrosion is that once a layer of aluminum oxide forms, it seals the surface and the corrosion stops (aluminum oxide is an oxygen barrier, unlike iron oxide). Actually, once your aluminum has formed it's initial layer of oxide do NOT clean it off....that layer provides protection. Iron and steel will keep on rusting until the part eventually disintegrates...aluminum won't. All that fancy anodized aluminum REALLY is is colored aluminum oxide created under controlled conditions.

I've seen some pretty nasty corrosion on the outside of engines. I had an engine apart in pieces on the bench. It was several months before I got back to it and the aluminum piston was pretty ugly. As with steels corrosion resistance varies substantially with alloy composition. I've been meaning to buy some Corrosion-X for storing engines, but have not seen it at stores here. I have Boeshield for my machinery, but that puts a thick waxy coating on parts.

It may protect it some, but not like copper. I have seen aluminum parts 1/4 inch thick corrode right through, the coating did not prevent this. You are thinking of anodizing and that is not the same form of coating as the white aluminum oxide. With sea salt aluminum will corrode fast, much faster than steel will rust.

The biggest cause of corrosion on aluminum is galvanic action.

If you put a piece of a aluminum on a steel bench or against almost any other metal in moist conditions then a small current will be generated between teh two metals. over time this causes a gradual erosion of the aluminum.

Also, different alloys have different levels of resistance to corrosion.

Pure aluminum (1000 series) has excellent resistance, as does the 5000 series (often used in boats) but some - like 7000 and 6000 series are alloyed with more reactive metals (zinc and silicon) so they will corrode more rapidly (albeit still *much* more slowly than steel.

Iron Oxide and Aluminum oxide are no different in their "protective" qualities. The "barrier" you are talking about simply refers to the fact that the aluminum (or iron) has reacted with atmospheric oxygen to form aluminum oxide. Once the oxide is formed, no more reaction can take place because the oxide compound is stable. Just as stable as the iron oxide compound. Atmospheric oxygen has a hard time making its way through the layer of stable oxide to the underlying metal to form more oxide, that is why it "protects" the underlying metal. But, for these reasons, aluminum oxide is no more protective than iron oxide. They will both eventually corrode through. However, iron generaly accepts oxygen much more readily than alumum, therefore producing the oxide compound more quickly.

Thanks for all the help guys, I have been running full synthetic fuel. Maybe it's time for some castor to go into my fuel.

Castor is your friend....messy, but still your friend (like that sloppy kid in school that was such a hoot to hang with).

Steel is more noble than aluminum, in the case you quoted the steel bench will not rust, the aluminum will. If exposed to any electrolyte the aluminum will corrode faster than steel. Even the methanol in our fuel will cause aluminum to corrode if left sitting in the crankcase without evaporating. The only case I can think of on the top of my head where aluminum outlast steel is when exposed to the air where there is little or no condensation and no electrolyte, then the aluminum will outlast the steel. But that is probably the case with most exposed steel and aluminum parts you are used to. If you want to talk about different alloy's there is steel where the rust does form a protective coating and is used for unpainted structures. And then there is stainless steel. So you see if you want to talk about all of the apples and oranges then steel will outlast aluminum in most cases or with the proper care.

Actually on most steel alloy's the rust is easily flaked off, which is why for just sitting out doors most steel will not outlast aluminum. But there are some that will simply form a ruddy red rust that is very resistant to flaking and rubbing off and that will outlast aluminum. Also if there is anything that will abrade the rust or aluminum oxide, say dust or sand storms, then the aluminum will corrode very quickly compared to steel.

High humidity will make the engine run as sluggish a here at 5000ft. Compensation is simply installing bit more powerful engine to compenate