WD-40 as After Run Oil for Big Glow Engine
 

Good Evening Gents: I have a near new (2.5 gallons of fuel through it) O.S. BGX 35 cc GLOW engine, on an 2m wingspan Yak 54. My question is, can I use WD-40 as after run oil on this thing before I put it away for the season? BTW I was flying yesterday, Nov 5th, at our flying field in Sudbury. Don't think I was ever able to do that before! Thank you for reading.

Eduardo

Re: WD-40 as After Run Oil for Big Glow Engine
 

I would reconsider using wd40 as a after run oil. It leaves a sticky residue and can make quite a mess in your engine. I Just leave mine as they are. When the opportunity to open an engine up has come up there has been what i think is a good amount of residual oil left in the case.

Re: WD-40 as After Run Oil for Big Glow Engine
 

The problem with WD40 it removes all moistures it doesn't lubricate.The after-run oil adds an anti rusting agen + keeps the parts lubricated. This is why i believe this is the best thing to put inside a engine.

Re: WD-40 as After Run Oil for Big Glow Engine
 

Long time ago tests were done using WD40 and unless you want to change glow plugs often until the engine is emptied of all traces of WD40. It coats the glow element and giving very poor performance more affecting idle. Makes for very poor combustion. Also using any other silicon base lube will do this as well. This information came from Clarence Lee the guru of model engines.

Re: WD-40 as After Run Oil for Big Glow Engine
 

This topic comes up repeatedly and I believe WD40 is an "Aeromatic Solvent", meaning almost all evaporates away.

As hayabusafmw stated, it is designed to pull moisture away from what you apply it to, then simply disappear. What it leaves behind is not very good at what you are intending and if what stegl mentions is true, may actually be detrimental.

In 3 decades I have not altered what I use, a 50/50 mix of transmission fluid, (ATF) and Air Tool oil, (ATO, basically turbine oil). Either one is perfect for long term protection and lubrication of parts and I only mixed them together to try and widen the spectrum of coverage. One other advantage is cost, ie. they last forever when you consider only a few drops are required each time.

On that note, I once added in a special formula "Metal Protectant". Ended up costing me dearly as it hardened over time, even when surrounded by the other two. This destroyed bearings and broke rings when I pulled them from storage.

Should have stayed with the standard mix as it has served well for ARO, penetrating and even assembly lube. In fact, I have often pulled engines from 20+ years of storage and fired them up with no problems.

NOTE 1: I also believe neither ATF or ATO will negatively affect seals, gaskets or other synthetic compounds. I seem to remember a warning with WD-40 to stay away from Teflon and other similar components.

NOTE 2: One of the reasons for ARO over short or long term storage is to prevent corrosion. That occurs since the engine will "Breathe", taking in atmospheric moisture as it cools and changes temp over time with alterations in the surrounding environment. This moisture can combine with any nitro remaining and begin to attack ferrous parts immediately. You can minimize that effect by controlling entry points. I use flexible tool caps to block off carbs and exhaust outlets at the end of each flying session and on engines that are in storage they are sealed in heavy plastic bags.

Unfortunately cowled and 4-strokes are often impossible to get this treatment and I accept the consequences.

NOTE 3: ATF is wonderfully useful. Years ago I found when mixed 50/50 with Varsol it made one of the best penetrating oils. From what I could gather the Varsol would tend to get through or at the parts you needed to free up and the ATF would follow along behind to lubricate.

Re: WD-40 as After Run Oil for Big Glow Engine
 

I use a 50/50 mix of air tool oil and tranny fluid just like the post above. Air tools will never rust as long as they have oil in them. Tranny fluid has lots of detergent in it keeping your motor clean. I've filled up the mufflers of my 4 strokes and let them sit and the oil does seep into the motor. All my engines get oiled. I even take the cam cover off my OS Alpha's to get oil in them. Cheers floyd

Re: WD-40 as After Run Oil for Big Glow Engine
 

Here is my viewpoint:

If you suspect there is moisture in the engine, float flying, flying in the rain or below freezing temperatures, go ahead and flush the engine with WD40. That is what it is designed for. But... ! Don't stop there! As others have said it has little to no lubricating value so follow up with a good dose of real oil. ATF is my favorite here. The ATF/ATO mix sounds good too.

P.S. About the penetrating oil mix... ATF and acetone or lacquer thinner works even better than varsol! But it must be mixed as needed as the acetone/thinner evaporates in storage.

Re: WD-40 as After Run Oil for Big Glow Engine
 

I used Varsol as I had it on hand. I would think your idea to work as well. The purpose was to find an aggressive solvent that did not evaporate quickly.

Re: WD-40 as After Run Oil for Big Glow Engine
 

Thank you all gents for your illuminating comments. I think the take home message is stay away from WD-40 as an over winter lubricant, rust protector. Maybe the easiest thing is to just get some Singer oil, or proper after run oil, and go from there. Thank you all once again.

Re: WD-40 as After Run Oil for Big Glow Engine
 

You can use ATF fluid, Rislone, air tool oil, or what I used to use for years......Marvel Mystery oil. They all work well. Some will harden after time, but they will all prevent rust. WD 40 will not.

Make sure the bearings are well coated as well as the other rotating parts.