Engine Maintenance

CantThinkOfANam

Hi all, just a few general questions:

1. I have old nitro fuel (10years+), can I use this to clean the air filter?

2. For how long a period can I leave the engine idle without spraying WD40 into carb. & cylinder?

3. Should I heat up engine with hair dryer before every engine start from cold?

4. I have no temperature gauge so I use the water technique, water on top of cylinder doesn't sizzle but if I put it directly around glow plug it does, is engine too hot?

5. If I let engine idle it decreases in rpm after a few seconds and can be sluggish to accelerate, is it too rich? And which needle needs to be adjusted?


Thanks alot, I know they're a bit mixed!

coolwings

CantThinkOfANam wrote: »

1. I have old nitro fuel (10years+), can I use this to clean the air filter?

Not a good idea. the fuel is 15 - 20% oil and will leave the filter sticky.

CantThinkOfANam wrote: »

2. For how long a period can I leave the engine idle without spraying WD40 into carb. & cylinder?

Forever. The oil in the fuel protects against rust. After run oil keeps it from gumming up. If you use WD40 it replaces the protective oily coating already there with a dry (water-free) surface just waiting to get peened (worn) when you startup. An engine should never be left dry.
WD40 is only useful for putting on the electronics.

CantThinkOfANam wrote: »

3. Should I heat up engine with hair dryer before every engine start from cold?

Why bother? It's more gear to worry about. If set up properly your engine will start hot or cold.

CantThinkOfANam wrote: »

4. I have no temperature gauge so I use the water technique, water on top of cylinder doesn't sizzle but if I put it directly around glow plug it does, is engine too hot?

I have never heard of that. It sounds odd to me. I can't imagine what the boiling point of water has go to do with engine temperature?

CantThinkOfANam wrote: »

5. If I let engine idle it decreases in rpm after a few seconds and can be sluggish to accelerate, is it too rich? And which needle needs to be adjusted?

At idle the main needle has virtually no effect. Adjust the idle needle for a leaner setting, adjust the idle screw in 2 minute (as on the clock) adjustments.
It's a good idea if new to this, to write down what changes you make in case you need to restore the situation as it was.

2 Espressi

I've read about this in American mags. Spit on the head, if it evaporates immedicately, the heads' too hot, if it takes a second or two, the heads' OK, if it doesn't boil, then the heads' too cold...

coolwings

Outside temperature has little to do with it.
The engine is all different temperatures around it's outside while running.
If outside temperature was what decides the running of an engine nobody would get automobiles to start cold.

Measuring the temp outside only tells you the temp outside, not how it will run.
You might have wrong fuel with too much nitro (= over-high temp) combined with a too rich setting on the carb (= over-cool temp) and get an outside temp that seems OK but the car runs like a pig.

It is how it tunes that matters.

Plug

coolwings wrote: »

The oil in the fuel protects against rust. After run oil keeps it from gumming up. If you use WD40 it replaces the protective oily coating already there with a dry (water-free) surface just waiting to get peened (worn) when you startup. An engine should never be left dry.

Thats wrong. If nitro fuel is left in the cylinder it will turn to gunk and then rust. WD40 protects against this. Most manufactors recommend this.

FuzzyWuzzyWazza

WD40 isn't a great idea for a cople of reasons. As the name suggests, WD = Water Displacment, it will stop any rusting happening as it removes any water, but if there are any silicone parts on the crankshaft WD40 will erode them. I would only use WD40 to clean out some parts of an engine, and I would dry them afterwards, and use a good quality genral purpose lubracant or a specific after run oil.

I only mention this 'cos apparently some high performance nitro engines use silicone inserts on the crankshaft to smooth out the flow of fuel/air.

coolwings

Plug - The piston, liners, crankshaft and bearings should be "wet" always. Even if the engine is not being used.

If you spray WD40 in through the glowplug hole or into the carb air inlet pushing away the protective oil coating, The surface of the metal dries completely. Then later you rotate the engine by pulling the recoil start, and your piston edges will scratch the dry liner sleeves.
Note the damage is done by movement and abrasion without lubrication, and not by "rusting" or corrosion.

Think about it ... when you get a new engine from the factory, it's already oily inside. The makers put a light machine oil on the moving parts for the same reasons.

WD40 has no place inside an engine. It protects against moisture, repelling water, but your engine is made from metals that cannot rust - stainless steel, aluminium, brass, chrome. No mild steel.
Now your receiver and the outside of the car that's another story. WD40 can help there.

The fuel does not change to "gunk". The methanol evaporates leaving the thickened oil behind. And that dry thick oil still protects the surfaces of the engine, so it is a nuisance but causes no harm.

syl77

I have to aggree on what coolwings and fuzzywuzzy have said and thats from seeing what WD40 does first hand, it does dry out over time.
if your storing an engine, flush any residue out with solvent, then when the solvent has evaporated, use any good quality oil or after run oil. Then seal it in a zip lock bag with a small bag of silica gel if you've got any.

coolwings

Speaking of WD40 ... anybody tried spraying it on fishing baits and lures?
It's all the rage in the US as a fish attractant. :-)

seamus-2k7

random. i haven't heard of that but try it and let us know:D