10w-40 oil?

[alvinlwh 5895]

A question about greasing up the gears in the tips sub forum triggered a thought I had 12 years ago when I built my Lunchbox. Looking at the "oil" cap on the CW-01 gearbox (I think I had seen the same cap on a few other gearboxes) I was thinking back then maybe I can seal up the gear box, drill a "drain plug" at the bottom, and fill the thing up with 10w-40, and drain and change the oil every, idk, 100km. Is it possible? Perhaps with o-rings on the drive shafts to stop leakage that way. 

Nothing serious just a thought exercise. 

[Willy iine 18805]

You can, but would it not become a mess..?   You don't have seals like on a real car transmission, so oil will probably seep out the seams?   My M38 has holes on the side of the gearbox for adding oil.. I never use it.  Rather just disassemble and rebuild.
 

Also you don't really need oil on the gear teeth themselves; some of my cars run dry gearboxes as with all open gear touring cars and direct drives with dry gears.  I use a very small amount when I do use grease on the gear teeth.. for the sake of making myself feel good following instructions..  

You will want to lube bushings and bearings.   

[alvinlwh 5895]

4 minutes ago, Willy iine said:

You can, but would it not become a mess..?   You don't have seals like on a real car transmission, so oil will probably seep out the seams?  

It probably will, like I said, it was a thought from 12 years ago that got triggered by a recent post. I remembered staring at the gearbox halves thinking it could be possible to seal them up, permanently with cement, glue, or something - OR - insert some kind of rubber gasket into the grooves. 

Like I said, nothing more than a thought exercise. 

As to the why...? Well, to make it more like a real car, maybe even make up a dip stick. 

[djmcnz 754]

You'd add a terrible amount of drag and a multi-viscosity 1:1 oil would never get up to operating temp in a 1:10 (~100*C). The additives might also break down some of your internal components. It you wanted to go wet (which I don't think is a good idea) you'd be better off using very thin RC diff oil.

 

[SupraChrgd82 1425]

I suggest staying away from automotive oils for RC's.  Not only do oils contain hydrocarbons that can degrade plastics, they contain detergents and friction enhancers that can further damage plastics. 

I can confirm that wheel bearing grease will cause Hornet gearboxes to become brittle....

[Willy iine 18805]

19 minutes ago, SupraChrgd82 said:

I suggest staying away from automotive oils for RC's.  Not only do oils contain hydrocarbons that can degrade plastics, they contain detergents and friction enhancers that can further damage plastics. 

I can confirm that wheel bearing grease will cause Hornet gearboxes to become brittle....

Very true.  

[alvinlwh 5895]

Thanks for all the answers. Like I said, just a thought exercise and nothing else. Very insightful. 

[Original Jardasius 97]

1 hour ago, SupraChrgd82 said:

I suggest staying away from automotive oils for RC's.  Not only do oils contain hydrocarbons that can degrade plastics, they contain detergents and friction enhancers that can further damage plastics. 

I can confirm that wheel bearing grease will cause Hornet gearboxes to become brittle....

NEVER use automotive oils and greases in RC's the additives and viscosity properties are never heated up enough to actually take advantage of and yes as you mentioned they will, with time, erode and make plastics very brittle and weak... If you must use oils use only those especially designed for plastics.. I personally use a full synthetic gear grease on all sealed gear sets inside trannys & axle housings on all of my RC cars and have not had one single gear issue in the entire time I have switched to full synthetic gear grease

[Juggular 4964]

As mentioned, motor oil may break down plastic parts. (That's why Tamiya gives us ceramic grease, and we use aftermarket silicone grease.)  Tamiya Ceramic grease contains finely powdered sand. Microscopic glass beads are okay with nylon gears, but not really good for aluminum pinion gears.  Aluminum gears become like sand-blasted after a season, because that's what's happening. 

But ceramic is cheap and lasts forever.  Tamiya's goal is not to sell THE Best stuff on earth.  If the cheap ceramic grease lasts a dozen years, that's fine. But of course, the aluminum pinion would turn into dust after 2 seasons.  

I prefer microscopic plastic beads (Teflon) instead of hard glass beads of ceramic. Plastic is much safer on plastic (and aluminum).

And much slicker too.  On teflon coated surfaces, the round teflon beads are far and between.  Yet these are the slickest substance.  

You only need to have a very thin coat of it (like 1/100th of 1mm).  So one small tube lasts 3 dozen builds.  I've been using it for about 20 years, starting with Wild Will 2 in 2001.  

 

But I do use 10-30w on motor axle bushings.  Most fans in my house do not have bearings.  So I take them apart and dab it with a tiny screw driver dipped in motor oil.  That gets this motor turning smoothly for about 8-10 months (5,700 to 7,200 hours).  So motor oil is very good at reducing metal-to-metal friction. 

On that note, the two spots you can use motor oil is on both ends of a 540 motor (you shouldn't let it leak out. if the oil can be seen between the axle and the bushing, that should last dozens of hours).  

So, motor oil has its uses.  Just not on any plastic parts.  

 

[Unknown Driver 262]

Thoroughly enjoyed this read. I *was* a big proponent of using axle grease in my big trucks (TXT-1 for instance) but I didn't realize it causes embrittlement. That would explain some things though...

Nice contributions all.