Car-Tune

I have an OS .18tz modded and I have noticed that when I removed the head off the block the piston is kinda black/dirty and this may of happened for running too lean.

Does anyone know how I could clean that off of my piston without damaging it?

Any help is greatly appreciated.

bikeordie092

I would probably try putting some oil/fuel on a rag and use something small to rub the top of the cylinder to see if it makes a difference... I wouldn't recommend scratching it off, that black is carbon buildup which is common in full size vehicles, Idk if it is "common" in our nitro engines or not.. honestly, I probably wouldn't worry about it too much, but then again I'm more used to gas engines in cars than I am the nitro engine on my rc car lol

nitroexpress

Dirty black comes from running rich. Whatever method of cleaning you use, be sure not to damage the top edge of the piston. If it's not a massave amount of carbon, just leave it.

1QwkSport2.5r

Carbon does happen, and its usually from running fuel with mainly synthetic oils. The methanol and nitro burn pretty clean, the oil does not. If the engine isn't blowing glow plugs, don't mess with it. Run it a little richer and the fuel might dissolve some of it.

Car-Tune

Thanks alot guys. Been a great help.

JohnP2

I'd recommend spraying it down well with contcact cleakner before putting it back together.

Anthoop

...and use some lube after using contact cleaner. Never put an engine together dry.

JoeMaxx

Okay I am going to go old school on this and suggest WD-40 as an engine cleaner and lubricant. WD 40 is a very old school trick that many of us old timers use to clean and lube R/C engines. It can be used as an after run oil when you going to run the next weekend. Do not let the fact I have only posted a few times on this forum be my experience with R/Cs I have been a nitro guy since 1999 and have some experience with many different engine manuactures.

We used to use in the old days whenmostly castor oil was thelubricant in Nitro Fuelfor engines and we left fuel in them for weeks then the engine would gum up with deposits.

Nice thing about WD 40 is as an afterrun for short term is it cleans all the gum out of the engine and will not hydra lock it if you put too much in.

It will clean up most deposits in the engine and flow thru than lube up everything while it cleans.

Think of it as Duct Tape more than 1000 things you can do with it.

I am not blowing smoke here because it has the

WD-40, everyone's favorite multi-purpose problem solver for over 50 years, lubricates and protects against corrosion. It also removes grease, gum, dirt, & scuff marks. Enjoy the popular, newly expanded Official List of 2000+ Uses for <nobr>WD-40</nobr>.

Car-Tune

Thank you very much fellas!!!

johndavis

i agree with joemaxx.   if stored longer than a week  use after run oil. wd -40 is good, i use it alot for cleaning .

nitroexpress

Engine modders and others pretty much agree, WD-40 does not play nice in nitro engines. It will swell O rings and loosenthesilicone infilled cranks. Any afterun or lube that goes into a nitro engine should only be syntheticbased.

johndavis

you dont use wd-40 as a after run oil  its used as a cleaner.  wd-40 will not hurt for a few days  it will take quite a while for the wd-40 to hurt the bearings. if wd 40 hurt bearings right off my engine would have been done long ago.  ive used wd-40 for the past 2 years and no problems.   yea if wd 40 is left on the bearing it will ruin the seals  bot it has to be on there for a while .  as far as the silicon in the crankshaft i have no idea about that  but if you dont have a full race motor  it will not have the silicone in the intake port.

JoeMaxx

http://traxxas.com/support/How-Perfo...-run-Procedure

I never really like to argue a point but WD40 is a good short term after run oil.It will not harm your engine andwill clean your engine of deposits in the head and lower end. I have also usedin short term for many years and my most of my engines are over 8 years old and still running without any problems. I would never suggestsomething if I have not already done it and proven it works

For long term storage I use Marvel Mystery Oil because the WD40 will evaporate over a long period of time and become thicker but will not harm the engine.

Proper care also includes dropping your piston to the bottom of the compression stroke. R/C engines do not use piston rings and they use something called a pinch type compression. So dropping the piston out of the compression stroke while sitting will help your engine last longer. Why because over time leaving the piston at the top of the stroke will over time stretch the piston walls over long periods of storage. My engines sitfor winter storage about 6 months out of the year because I do not run them in the winter time.

This is straight from Traxxas a R/C manufacture which I have 4 of these engines in my collection along with a fewO.S Engines andother engine manufactures.


After-run Procedure

You must perform after-run maintenance on your Traxxas engine whenever the model will be stored for longer than a few hours. Taking the time to prepare your engine for storage will reward you with longer engine life, easier starting, and better performance.
When a nitro engine is shut off, some excess unburned fuel remains in the engine. The methanol in model engine fuel is hygroscopic, which means it easily attracts and absorbs moisture. This moisture can cause rust and corrosion on the steel engine parts (crankshaft, bearings, wrist pin and starter shaft) if the fuel is not removed from the engine. There are after run oil products available from your hobby dealer or you can use WD-40, a common household lubricant. To ensure your TRX 2.5R Racing Engine is protected from internal corrosion, use the following procedure:

1. Whenever possible, shut off the engine by pinching the fuel line closed. This allows most of the excess fuel to be consumed by the engine. Be sure the throttle is in the idle position. You may have to pinch the fuel line closed for several seconds before the engine stops.

2. Completely empty the fuel tank. Use your fuel-dispensing bottle to suck out the old fuel. Do not mix the old fuel with your fresh fuel supply. If you leave fuel in the tank, transporting or handling your Revo may cause fuel to run into the engine.

3. With the fuel tank empty and the throttle at the idle position, try to start the engine. The engine will most likely start and run for a few seconds as it uses up any fuel remaining in the engine and fuel lines.

4. Once the engine stops, clean the outside of the engine with compressed air or spray motor cleaner. Once the engine is clean and dry, remove the glow plug power wire, glow plug, and air filter.

5. Open the throttle fully and spray a one-second burst of WD-40 into the carburetor and into the glow plug hole (Caution! Wear safety glasses to prevent spray from getting into your eyes). If you are using after-run oil, follow the manufacturer's instructions.

6. Place a rag or paper towel over the engine to catch any WD-40 or after-run oil that may come out the carburetor or glow plug hole.

7. Connect the EZ-Start® controller to the model and spin the engine for 10 seconds.

8. Remove the rag or paper towel and repeat steps 5-7 two more times.

9. Clean and re-oil the air filter so it will be ready for use next time.

10. Replace the glow plug, reconnect the glow plug power wire, and reinstall the air filter.

While I do not follow these instructions all the way I put enough oil down the carb then turn over the engine a few times to pull the after run oil upthru the engine. I have never removed my glow plugs in the after run process and asI said above most of my engines are over 8 years old and still running

johndavis

great post joe maxx that is close to what i was talking about. more detail.

1QwkSport2.5r

You guys and your WD40....[&:] Using after run oil isn't a bad idea, but only for long term storage. If you run the engine dry and empty the fuel tank, no ARO is needed, generally. Using fuel with castor oil in it will protect your engine superbly! I put the piston at BDC so the crankcase can breathe and you're good to go. Never any rust in my engines.

Petroleum based anything in a model engine is hokum. I tried starting an engine that I used petroleum based ATF as ARO and it was the biggest PITA to get started. Never again will I use petroleum based anything for ARO.

I've been modelling for 16 years and have yet to get any carbon or "deposits" in an engine.

Oh yeah, Did I mention WD40 sucks?

If someone gets carbon buildup, run the mixture rich. The extra raw fuel will loosen some of it up. Though it rarely affects engine performance unless there is a lot of carbon.

Argess

I tend to agree with most of that. I havn't experienced any carbon build-up in any of my engines, and don't use after-run oil unless I am re-assembling an engine.

I do wonder about the running rich though. I would think that would tend to add carbon. In fact it may be the reason the carbon is there in the first place.

As I'm the curious sort, I looked up the chemistry of burning alchol, nitromethane, etc to see if carbon is produced during combustion. Basically, if the engine is tuned correctly, and you have a complete burn, carbon is not produced.

The equation for hydrocarbon combustion can be generalized by:

HC + O2 + N2 = H2O + CO2 + N2 (where HC is the hydrocarbon)

For example, Methanol:

2CH3OH + 3O2 → 2CO2 + 4H20

and nitro:

4CH3NO2 + 3O2 → 4CO2 + 6H2O + 2N2

so... no carbon, but yet some people find it in their engines, so what gives?

To quote from a Google result:

If there is too much fuel for the amount of oxygen present, the carbon portion of the [fuel] is unable to be oxidized into carbon dioxide and remains as free carbon molecules after the hydrogen has been stripped away. This is "soot".

I'm no Chemistry expert and feel a little uncomfortable psoting all these chemical equations, but it looks to me that by keeping your engine well tuned, you can avoid carbon build-up quite easily.

As far as cleaning, Brake Klean (keep away from plastic parts) or other solvents can help, but remember to apply lube during assembly. If you have tough deposits on the piston top (I'm thinking ancient lawnmower here), a plastic scraper (made from a toothbrush handle, etc.) or a wooden one (popsicle stick) can help. Maybe even a little Scotchbrite soaked in solvent. However that's for the piston top. I would suggest NEVER scraping or using abrasive material on the piston sides or inside the cylinder sleeve. Paper towels with a bit of applied solvent should handle those "delicate" surfaces.

Just be gentle. Patience is the name of the game. People without patience can sometimes get the urge to use a wire wheel or other motorized methods for cleaning, and that will no doubt ruin parts very quickly.

Be very careful cleaning the inside of the engine block. Last thing you want is "bits of something" to get in the bearings. I use Q-tips to wipe things inside, and then a spray cleaner to wash away the residue. Even then, I apply lube to the bearings and ensure they spin freely with no "gritty" or "sticking" feeling.

Complete cleaning of the outside of the engine is a real help in keeping debris from finding it's way inside once you start the dissasembly. I put clean paper on my workbench top to put the engine on, and change it a few times. I don't want dirt from previous projects gettng inside the engine (my workbench is rough wood, so it's hard to get it perfectly clean). White paper makes good contrast when working on the enigne.

hmmm... can't think of anything else at the moment

1QwkSport2.5r

The carbon comes from the oil burning, not the methanol or nitromethane. Most car fuel has primarily synthetic oil for lube with a minute fraction being castor. Your average synthetics burn off much sooner at a lower temp than castor so it lends to why more carbon will show up. Now if you run richer fuel mixture, you are running more oil through by volume and consequently at a lower operating temperature. Remember, alcohol burns much cooler and slower than gasoline. A gasoline engine will have more carbon because of the fuel AND the oil, glow engines get carbon from the oil only.

I mix my own fuel and use a 50/50 oil blend of castor and klotz in my car engines. Running at peak mixture still results in no carbon because of all that castor. The oil comes from the exhaust a nice dark brown color.

Crappy fuel like Traxxas is a good carbon producer, probably due to the high synthetic oil content. You have to lean it down so much to get nice throttle response that the crazy oil amount just burns.

smokeymaronejpfxb8

Hi all, does anyone know if ATF & air tool oil will hurt the silicon on the crank in a race engine ? It's been stored for a yr & a bit !  cheers.

rccheech

No it will not, better to use air tool oil or after run oil.

1QwkSport2.5r

Most ARO is ATF anyway. When I actually use ARO, I use mineral ATF and Seafoam mixed at 4:1 respectively. Seafoam mixes with petroleum and alcohol. When the engine gets fired back up, it blows all of the ATF out. This mixture also does wonders for minimizing carbon.

rccheech

ARO and ATF are completly different, ATF has detergent, wich will foul glow plugs, ARO and air tool oil are pretty close. WD40 will also foul glowplugs and cause headaches if used as ARO. For cleaning wd40 would be fine, but after i wouls spray it off with brake cleaner, and lube with machining oil or after run.

smokeymaronejpfxb8

Thanks matey, i thought ARO was ATF, $15 for a 50ml bottle of ARO against $9 for a ltr of ATF ? bit of a joke aye .

Insanity99

WD40 is just fish oil. I have cleaned my motors out with it and haven't had any issues with longevity and starting. But I also don't use aro after I'm done running. I just burn all the fuel out of the motor.

Anthoop

Is this some kind of idiom?

Insanity99

No look it up, sounds silly doesn't it