About Oils I Used in Engines

i use ACF-50 samples as after run oil. they're free, they're small, my dad has a ton of em, and acf-50 fits the description of after run oil well- its a rust protecting oil.

ATF = automatic transmission fluid is a good after run and long term storage lubricant for model engines....its biggest advantage seems to be its lack of any tendency to dry out or congeal with long term storage of the engine-I've seen engines stored for over 2 decades with ATF, still be loose and quite 'normal' when removed from storage and turned over with a prop on.

ChrisM
'ffkiwi'

Thanks. I didn't try ATF for a long time storage. ATF has too much ingredients if I am not wrong. I couldn't find a reference about ATF is compatible with rubber and delrin. But because you say that it is safe to use, then there's no problem

Well, another great topic that can bring up a good debate! As I know and also trust ffkiwi, and would believe him, levent brings up an absolutely good point that I had not ever thought about before. I had also read that there is proper ATF to use, and one not recommended. As I type, I cannot look this up. But regardless, of which type, the great point levent had brought up is the compatability with rubber and delrin. Rubber I am not so worried about, but the delrin had me thinking. Back a long time ago, I had crock-potted a postage stamp engine, backplate too........ It got all white and hazy and brittle after its bath. I had dared NOT try this ever again, even with regular antifreeze unheated and see if it was due to antifreeze in general, or was it heated antifreeze that caused this? Hence why I may be a bit aprehensive of using ATF in a Cox engine, but only any having any delrin parts. A standard Bee, or any variant thereof, I may try it one day. But as of now, I have just started to use air tool oil, and it already has me liking it better than the 3-in-1 I had been using till now.

I suspect there is quite a variation in ATF blends and components across the world....much like brake fluid-what is available where you are might differ significantly from what I use here.  All I can say is that I've had no trouble with it-nor the others I know of who suggested I try it as an engine preservative for long term storage. There is some anecdotal stories that glows can be a little hard to start after storage on it if the ATF is not flushed out before attempting to start-but I mainly use it on diesels in any case-which are especially prone to gumming up over time-and it doesn't worry them...in fact give them a quick quirt of CRC 5-56 after storage and they quite often fire on it when you flick them over-and run in you hand for about a second or two-before seeing any normal diesel fuel.

ChrisM
'ffkiwi'

PS others elsewhere swear by gun oil....a lot depends on what you have sitting around available I imagine-air tool oil mentioned by new222 above also has its adherents-others I know-with aviation connections swear by turbine oil

NEW222 wrote:Well, another great topic that can bring up a good debate! As I know and also trust ffkiwi, and would believe him, levent brings up an absolutely good point that I had not ever thought about before. I had also read that there is proper ATF to use, and one not recommended. As I type, I cannot look this up. But regardless, of which type, the great point levent had brought up is the compatability with rubber and delrin. Rubber I am not so worried about, but the delrin had me thinking. Back a long time ago, I had crock-potted a postage stamp engine, backplate too........ It got all white and hazy and brittle after its bath. I had dared NOT try this ever again, even with regular antifreeze unheated and see if it was due to antifreeze in general, or was it heated antifreeze that caused this? Hence why I may be a bit aprehensive of using ATF in a Cox engine, but only any having any delrin parts. A standard Bee, or any variant thereof, I may try it one day. But as of now, I have just started to use air tool oil, and it already has me liking it better than the 3-in-1 I had been using till now.

A further point arising from new222's post-I am not entirely convinced that Coxes DO use Delrin for the plastic parts-Delrin (and I use the stuff extensively in my modelling) has excellent machining properties and is generally tolerant to hydrocarbons, solvents and neutral chemicals. Secondly it is normally supplied in rod and sheet form only-not generally moulded-and AFAIK is only available in natural 'off white' and in black. I think the material used in Cox engines is closer to a modified nylon than Delrin-which is an acetal polymer.

That being said-there is no doubt that the plastic used in Coxes is susceptible to ageing in use-and perhaps accelerated ageing as a result of some solvents...eg glycol. This might be the time-if anyone has any broken or 'past usable service' plastic components ex Coxes...to do a bit of experimenting vis a vis ATF, etc

ChrisM
'ffkiwi'

I read somewhere that some Cox plastic parts are moulded delrin. Perhaps some of them are moulded nylon or another kind of plastic. Once I tried to mend a red plastic fuel tank with soldering iron but it didn't melt and smelled bad. So I think that it is made from delrin.

Levent Suberk wrote:I read somewhere that some Cox plastic parts are moulded delrin. Perhaps some of them are moulded nylon or another kind of plastic. Once I tried to mend a red plastic fuel tank with soldering iron but it didn't melt and smelled bad. So I think that it is made from delrin.

Yes I've read that too-but it was written a long time back-the early 60s IIRC...and I suspect the writer had no familiarity with the feel and texture of real Delrin then. Unless I hear to the contrary from someone who actually worked at Cox, and was in a position to know exactly what plastic WAS used, I'm continuing with the view that whatever the plastic used by Cox for mouldings on the TD series and other Cox engines was, it wasn't Delrin...

ChrisM
'ffkiwi'