Wd40 = after run oil?

[mr_lister999.]

The instructions in the tmaxx say to use wd40 is after oil. I never knew that. I am sure i have seen bottles of after run oil in hobby shops but it was quite expensive. Did anyone else know about this?

[rc-martin]

Model Technics do a bottle of after run oil, its about a fiver. You get about 500ml, which will last forever.

I'm sure i read somewhere that WD40 was a big no no, think its to thin and washes away the oil in the bearings or something like that.

Run em' till you wreck em'

[WillyChang]

WD40 probably isn't too bad as a anti-rust lubricant in the engine; better than nothing anyway. It'll chase away the condensation from the burnt methanol certainly! I'd think Traxxas recommends it because its pretty hard to flood your engine with WD40... you'll have to be spraying for a pretty long time to risk that.

You can buy little bottles of "after-run" oil or you can just use any light machine oil (eg sewing machine, 3-in-1, RCCA likes Marvel Mystery oil). Put 4-5 drops down the plug hole and 2-3 down the carb, then turn the engine over a few times by hand.

Oil in the chamber might make it harder to start next time; you can remove plug and crank it a few times, let the oil drip out. Or it'll make its way out the exhaust eventually anyway.

[Stu.B]

Any oil = after run oil! WD40 is ideal but you can just as easily use 3in1 oil or similar. After run oil like many 'special' R/C products is a needless rip off.

[aconsola(2)]

I give 2 thumbs up to Marvel mystery oil. I use it as after-run in my terra crusher, as well as for winterizing my lawn equiptment, and "summerizing" my snow-thrower

-Anthony

[Spike]

I always use Nova Rossi after run oil, especially when I lay my car up for any time. It's great stuff - WD40 will be cheaper but I don't think it will do the job as well

[dave.t1]

There are two issues to address when using an "after-run oil". The first is to cancel the corrosive affect that nitro fuel has. I seem to remember from chemistry at school that as the fuel left inside the engine evaporates it mixes with the moisture in the air and produces nitric acid which corrodes the engine (thats why anodized chassis plates get pited and lose their colour around engine mounts and the base of the fuel tank, etc). The amount of moisture present in the engine would not otherwise cause much of a problem as residual lubricant bonded onto the metal protects it. SO you need something to flush out the acid. In that case alone WD-40 would be ideal, its thin enough to act in a similiar way to fuel and would clean out the engine fine. Issue two is that what ever runs through the engine needs to have enough "stickyness" and viscosity to bond onto all the metal parts and keep them lubricated. Just like in a real car, most engine wear occurs during the initial start up period when the engine relies on the lubrication already present inside to do the job. In this instance WD-40 is so light that it has already run down the inside and collected in the sump/crankcase, causing the piston to run dry. It may also be true that the oil burns off quickly as the engine heats up and leaves unwanted deposits behind in addition to running dry. Thus the after run oil needs to be compatible with fresh Nitro fuel. In summary it must flush through residual fuel, maitain lubrication and not react with Nitro or leave burnt deposits....

[WillyChang]

quote:Originally posted by dave.t1

...Issue two is that what ever runs through the engine needs to have enough "stickyness" and viscosity to bond onto all the metal parts and keep them lubricated. Just like in a real car, most engine wear occurs during the initial start up period when the engine relies on the lubrication already present inside to do the job.

---

id="quote">id="quote">

No, 1:1 cars have oil in the sump, and you have to wait for the pump to build up enough pressure to start spraying oil around the works. This might take 30 secs... so for cars that haven't been started in a while, I'd disable the ignition circuit and churn the starter for a minute or two before letting it fire up.

Nitro engines however its vital lubricant is in the fuel. So the second fuel goes into the chamber its lubricated already.

Ideally your after run oil shouldn't get burnt... thus no deposits. It'll just get blown out the exhaust. WD-40 contains kerosene and is pretty light... so some of it probably does get burnt.

WD-40 does remove that brown carbon gunk that collects outside the engine though... some of it anyway!

[HunterZero]

I find that WD40 tends to remove any existing grease from the gears in electric cars anyway. After a few runs, the inside walls of the gearbox will be covered in a grease/WD40 mess.

Using WD40 in bearings was OK, but it will blast out all the bearing grease. This means the bearings will be solely lubricated by the WD40, and since it is very thin and evaporates readily, you will find you have to re-lubricate the bearings to maintain them more often.

I did run with a Singer sewing machine oil bath, that seemed to work pretty well.

- HZ

[WillyChang]

quote:Originally posted by HunterZero

Using WD40 in bearings was OK, but it will blast out all the bearing grease.

---

id="quote">id="quote">

Haha, I often use WD40 to clean my bearings. At $3/can its heaps cheaper than motor spray $15/can. Only drawback is the strong smell.

[c_a_r_t_e_r]

I love the smell of WD40 in the morning! []

Actually it really is rather a nice smell...

Willy.. would you say it's suitable as a motor spray replacement though? I don't want to go off and buy a £10 can of motor spray, when I have some WD40 just lying around, waiting to be sniffed! I mean used on my electric motors. [:I]

(Kids don't try this at home!)

Tim

[dave.t1]

WillyChang, I agree with you on the 1:1 cars that you need the oil pumped round to lube the engine and yes the lube is in the fuel in nitro engines, but it only takes a few turns of the engine without lube to wear/damage it and the fuel cannot immediately lubricate the whole of the working parts. The whole balance between existing lube present in the engine and the fresh lube from the Nitro is very subtle. Anyway, bottom line for me is that I would not run a Nitro engine after I had lubed it with a water displacement spray.

[mr_lister999.]

Wow, thanks guys, never knew there were so many issues to consider with nitro! Just goes to show that i'm a nitro virgin [:I] so to speak...

Well, it says use it in the manual and that wont invalidate their guarenmtee so thats what i will use. I do appreciate the advide though. Guess it will be a few years before i get it all worked out (or maybe a lifetime, you never know [] )

Another question is what is the life of nitro if kept in the original bottle once opened but kept tightly sealed. I know water ruins it over time but how long? Thanks guys.

[WillyChang]

quote:Originally posted by c_a_r_t_e_r

Willy.. would you say it's suitable as a motor spray replacement though? I don't want to go off and buy a £10 can of motor spray, when I have some WD40 just lying around, waiting to be sniffed! I mean used on my electric motors. [:I]

---

id="quote">id="quote">

Nah, don't use it on your motor. WD40 does leave a residue and the brushes will toast that to a carbony-brown, it doesn't do much for electrical contact after that.

GBP10 for a can of motorspray??

Geez, thought *we* were getting robbed @AUD15 (~US$9). [:0]

[WillyChang]

quote:Originally posted by dave.t1

WillyChang, I agree with you on the 1:1 cars that you need the oil pumped round to lube the engine and yes the lube is in the fuel in nitro engines, but it only takes a few turns of the engine without lube to wear/damage it and the fuel cannot immediately lubricate the whole of the working parts.

---

id="quote">id="quote">

Ya, too right!

But there's no chance of that, cos whenever the engine is apart for cleaning/restoration or even just taking the head off for a check - when its rebuilt I oil each and every moving part in the chamber. (ya, Come time to start there's usually about 1tbsp of oil coming out the tailpipe.)

Just a habit from mucking around with larger engines, I guess. With those I've usually poured in half the sump capacity by the time the head is torqued down.

(Even new engines should be opened up and checked/lubed. Occasionally there's some machining swarf left inside...)

[Voltar]

Hi all. For what it's worth.....on the last run or flight of the day, I run the tank dry, remove the fuel line, squirt a tad of WD40 in the carb line, put the fuel line back on and start the motor. It will fire up on the WD-40 for a second or 2 and then stop. A thin layer of WD-40 is now everywere it should be.

It's worked for me for over 20 years. These motors are way too expensive not to take the time to take care of them. Jim