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After Run Oil (Caster Oil)

8K views 16 replies 8 participants last post by  RogerDaShrubber 
#1 ·
Hi all
I have been searching through the forum, Google etc about after run oil and a lot have said to use ATF as ARO.

I have some Castrol M caster oil hear from when I use to mix my own fuel meany years a go and was wondering if I could use this as ARO? or should I forget it and just get some ATF to use.

Would the Castrol M just gum up the engine and make it hard to start?

Thank for your thoughts and help.
 
#5 ·
Thanks guys, I was hoping I may have been able to use the caster oil as I have it here already. I was thinking it may just gunk things up as Zoomer said, just wasn't sure.
I had read about the 3 in 1 oil but was not sure where to get it, I will go past Bunnings over the weekend and have a look.

Thanks for the info.
 
#7 ·
Slightly related I know.....Some of the heli/plank boys run plain (no nitro) fuel through as an after run as they believe it is the nitro that will do harm when left in the cylinder. I dunno but I thought methanol was hydroscopic so I reckon that theory goes out the back door imo. But apparently some of them have been doing this for years and have had no problems with corrosion, this also being an issue in helis due to the vertical mounting the rear bearing cops it. Good luck with running fuel with no nitro in a car motor I thought, but same thing again the heli motors run up to %30. :D
 
#8 · (Edited)
I have 4 Enya .15 control line plane engines under the house that sat around for about 15 years with out being run and no ARO (Didn't know about ARO then). The fuel that I used to run back then was only methanol and caster oil no nitro. These engines run bushes on the crank not bearings. When I got them out to have a fly with my boys they where very tight from being so gunked up. This is the reason I asked the question on using castor as ARO. I put some fresh fuel into them to clean out the gunk, some started after only a couple of flicks of the prop and some took longer. I think I will go and pull one or two of these engines apart soon and have a look as the last fuel I ran had 5% nitro and they have not been run for quit sometime.

I will be running ARO whether ATF, 3 in1 or from my LHS as I just had a rear crank bearing fail in an engine only 8 ltrs old and not sure at this stage if it was caused by rust in the bearing or something else. This engine was last stopped by blocking the end of the exhaust as we had a diff problem. I forgot to run the engine after this so in would of had a gut full of fuel in it. It then didn't get a run for quit sometime due to weather etc. I wiil be removing the bearing at some stage to have a better look.

Thanks for your help.
Col.

Interesting though when I did a search before I started this thread most of the similar threads listed below didn't show up.
 
#9 ·
The main reasons for using aro if you listening to the marketing hype is that it removes/neutralises the methanol/nitro that attracts/absorbes moisture. If you look at drag and racing motors that use methanol for fuel they have to flush the methanol out of the tank, lines and carby otherwise it absorbs water from the air and goes like a gel. I believe that ARO isn't only just to coat the surfaces to prevent corrosion but to neutralise the nasties. Just my
:)
 
#10 ·
Wobbly is right, for my old two stoke Bultaco race bikes that ran on methanol, after a meeting the tank was drained and petrol put in, carby changed to one jetted for petrol and the bike was ran then for a while to remove any trace of methanol, mostly because of corrosion. For the speedway engines, JAP and JAWA, tank and carby were drained only because of jelling, because of the materials used, corrosion was less of an issue with those.

I use a drop of light machine oil after using my nitro car, i also drain the tank and discard the fuel, i personally do not think that there is any difference in commercially available after run oils and light machine oil and one is also much cheaper than the other.
 
#11 ·
there's no "neutralising" required nor available... just cover iron in oil & it stops rusting (=oxidising)

after engine quits from empty tank, i'll on the gloplug and crank it over on starterbox
for maybe 20-30s - quite often there's enough fuel in lines/carb to pop a few times.

for engines where i have no plans to restart anytime soon (ie eternal storage)
i'll oil it with thicker oil (usually Mobil1) thru the carb, plug & rear plate.

Thicker oil just makes it harder to restart next time & doesn't burn off
so it'll come dripping out the pipe not sprayed out in the smoke.


Engine bearings are stainlesssteel anyways AFAIK, they won't rust.
But they definitely gunk up & seize if you've got the jelly thing happening,
so if engine is run again with races seized, that's not gunna end well.

Acetone usually dissolves that jelly gunk after soaking a few days.
 
#12 ·
Rust must be an issue in some motors Willy as the heli blokes talk about having rusted rear bearings all the time. I like the idea of Mobil one, it's synthetic yeah? :D
 
#13 ·
probably is bud :) i just bought Mobil1 'cos Brocky spruiked it.
I decant it into a small bottle and keep it in 'field' toolbox for all uses.
Bought a 1L bottle from McEwans and its lasted 20+ yrs...


Heli engines are pretty extreme huh? sound like they run full revs & rich for long periods
and they're stuck covered inside the cowling too. Planes get plenty airflow and
don't run full revs constantly, cars & boats even less so.

wonder if that brown castor &/or fuel dye stain is what ppl call "rust"
 
#14 ·
I have some Castrol M caster oil hear from when I use to mix my own fuel meany years a go and was wondering if I could use this as ARO? or should I forget it and just get some ATF to use.

Would the Castrol M just gum up the engine and make it hard to start?

I think using Castor oil would gum them up, that's why engines gum up, I use two stroke oil, it stays like oil and doesn't go "sticky'.
BB
 
#17 ·
I had a rather lengthy discussion with my brother about this, he is an race engine builder, building speedway and high performance 2stroke engines. In speedway bike engines where castor used to be predominately used, there was never any real issue from gumming or slugging of the castor, even in engines that sat for months. In our nitro engines he thinks that castor would still be better than standard 2stroke oil as it mixes readily with alcohol and will flush clean quicker than standard 2stroke oils which do not mix well with alcohol. Guess we now need someone to do some real world tests and see for sure.
 
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