Re: Castor = shite :-(

a dremel with a nylon brush should take off most of the carbon without scarring the piston. I'll be watching here for a better method myself.

remove my-wife to reply :-)

Unless it has a visible thickness to it, don't bother. It won't hurt a thing and is actually slightly beneficial in that it will insulate the piston from sone of the combustion heat.

The synthetic oil will eventually dissolve any soft deposits left.

Old-fashioned heavy duty paint stripper - the stuff with methyl chloride in it - will work, although it's getting hard to find. Dave Gierke's "Demon Clean" has it, but he charges an arm and a leg for it. Also, you can buy a gallon can of carburetor and small parts dip from an auto supply which methyl chloride in it.

That's right, the castor oil makes your engine look like a dog turd, but it's actually in like-new condition under that layer of goo. A few years ago I gave this some thought and decided that when I put an engine away into long term storage it would be a good idea to coat the insides with castor oil for protection. I know it will turn gummy, but that's OK because as soon as the fuel starts flowing through it again it will all dissolve. Having bought collections of engines and sold them on ebay, I have seen 30 year old engines with nothing wrong with them except a layer of crap. I have also seen 5 year old engines that look new on the outside but have rusty bearings.

I just use Brillo or similar generic soap pad.

Myself, I'd rather have the nasty castor goo and a gummed-up engine rather than a ruined one following a lean run.

Morris

Does the crock pot boil in anti-freeze treatment leave the aluminium crankcase bespeckled or mottled, or bring it up "as new"?

A piece of wood shaped like a 'chisel'. Just chip 'n scrape the carbon off the piston crown. The process is termed decoking.

Yes. That's the most important carbon to remove as it increases operating temperature but more importantly increases compression ratio as it reduces the effective combustion chamber size (TDC).

Removing the other carbon from worn engines, apart from any specifically around the ports if the carbon buildup is reshaping, blocking or reducing them in size (all of which restrict or alter flow) is not a good idea. Castor is messy, but it is a good lubricant for our two stroke engines.

You might find the lower viscosity of pure synthetic alters the sensitivity of setting the n/v and the performance depending upon the amount of wear already present. A matter of try it and see.

I agree with you in that I certainly prefer the cleanliness of synthetic, but use a brew containing both as find the addition of castor offers better running and less critical on the needle in my 2 stroke sport engines.

Iguana Bwana

Yep, that's right......opened it up for the first time after 2 years pylon racing use :-)

I'm going to use the engine on a sport model from now on, so it will never have to have the last possible rpm extracted from it anyway. If I was going to keep pylon racing, I'd have to keep using the CastrolM because we're not allowed to run synthetics.

I put it back together (after scraping the carbon off the piston with a hobby knife blade) and ran it this morning on 20% Klotz KL200 and 10% nitro. I got 12,900rpm on a bolly clubman 10.5x6 prop, running rich enough to leave a good smoke trail all the time. It also now idles and throttles properly......something it never did on the castor/no_nitro mix fuel. I'm happy with that :-)

MrBonk

Howdy, The engine came out looking perfectly normal.....no discolouration or mottling at all. I do have an old OS.40FP that came out looking 'dulled' when I used the crock pot to clean it. No idea why that was though.

I run all my other engines (including my 2 x YS.91FZ's) on pure synthetic (Klotz KL200) fuel mix, although I'm always careful not to run any of them lean at all. In fact, the instructions for the YS engines specifically state not to use castor.

I can certainly see the value in castor use in racing engines......if you're trying to extract the highest possible rpm from the thing, it's just too easy to have a lean run! However, I won't be racing with this engine anymore......it will be going on a sport model.

MrBonk

This is not a good idea! Most synthetics designed for gasoline use are not compatible with alcohol fuels and will damage your engine. Also, there is no oil that I am aware of that you can mix at 50:1 for glow engine use.

Leave it in the antifreeze longer. I bought an ST90K that was badly gunked up. After overnight soaking, the piston crown was NOT cleaning easily - so I tossed the parts back into the pot. After 24 hours total, the hard carbon gunk came off with a toothbrush.

David

Heavy Duty Easy Off

I was just wondering if oven cleaner might be OK for cleaning engines - designed to get baked on stuff off

David (who hasn't got any daggy engines to try it on)

Hey if you have any shine on your engine you will loose it all and it will look funky when you are done. Don't ask how I know!! Eddie Fulmer AMA 63713

were we not discussing a gas engine?

No, the posts were talking about cleaning the castor crap off an engine. I don't know of many people willing to use straight castor in a gas engine any more! And, this statement pretty much clinches it, "I'm changing over to synthetic oil and nitro fuel (seeing as how the".

designed to get baked on