cheezer1222

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I've been looking at various recipes lately for homebrew glow. It was a nice day today, so I pulled the trigger and made a small batch to test out. I used it in my nitro stampede. It has a cheap megatech engine in it, so it was the perfect candidate for experimental fuel.

Here was my recipe (all percentages are approximate):

68% Methanol
12% Acetone
20% Oil (80% synth. 20% castor)

In another forum, I read that 3% acetone is about equivalent to 5% nitro. So, that's where I came up with the 12%. I was looking for a 20%ish nitro equivalent.

I was kind of surprised when I yanked the pullstart and the engine fired up after two pulls. After messing with the high speed needle a bit, I had it running about right, and was able to run a full tank through the engine.

Here's where I need the help of the fuel gurus. The engine did not like idling. If I ran the car around at mid to high speed passes and came back it would idle for a while at my feet, but would inevitably die. When it did die, I wouldn't be able to get it to start without holding about half throttle or so, and if I released that half throttle, the engine would die again. I don't think this was a needle setting problem because adjusting the needles either way didn't seem to have an effect on the problem. I think it has something to do with my mixture. Maybe more methanol? Let me know what you guys think, or if you have follow up questions. Also, let me know if my guess on the acetone is correct, or if it's way too much. I was looking for a substitute for nitro, thus the acetone.

mighty9

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Small engines need that nitro to idle well . Maybe you need a hotter glow plug with acetone?Larger engines run well with zero nitro content .We never used acetone just methanol and caster oil on our moki 2.10.Nitro isnt hard to get if you have a speed shop around.

gkamysz

My Feedback: (19)

Acetone is not a replacement for nitromethane. It is said to help idle without nitro, but that's all. The make that car engine run well without nitro in the fuel the compression ratio must be increased. If you don't increase compression ratio you'll probably need a hotter plug. The needles will be set more rich when tuned for fuel without nitromethane.

aspeed

Usually low nitro needs a bit more compression.  I would have just gone with 3% acetone (or ether) I think 12% may be a bit much.  The acetone isn't supposed to give more power, but make things more manageable for idling etc.  It doesn't seem to be the case in your test. (but it is 12%)  I haven't tried it myself but may someday when I run out of fuel.You could make a bigger batch of 80-20 and mix it in with the 12%.  I guess that would be three times as much.  Then if it doesn't work good you have a lot of useless fuel.

cheezer1222

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Thanks everybody for the useful info. I'll try a hotter plug first, and see how that goes. Future mixes will have far less acetone. I had seen it suggested as a substitute for nitro, but everybody here seems to say otherwise, so I'm gonna scratch that thought. I'll just stick with 3% or so. Any other tips or thoughts are greatly appreciated. I'll keep everybody informed on my progress.

Also, what are some ways to raise compression?

Muddin_Mavric

if you take the head off the motor there should be at least 1 shim, maybe more between the head and block. take a shim out and see if that helps it run any better. if there are no shims to take out you could always take it to a machine shop and have some material cut off.

nonstoprc

My Feedback: (90)

Nitro helps idle and provides extra oxygen to help with the IC process. If you can get some nitro ingredient at a local racing shop, by all means get it. You engine will run well as with the commercial fuel.

I used to mix my 20-20% fuel for my YS engines and had some fun initially.

Since Methanol is poisonous (e.g., causing blindness), make sure you always wear mask, glasses, and gloves as protection.

cheezer1222

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I'm trying to find a recipe that doesn't use nitro. Just for fun. It'd be kind of fun to say, "Yeah, I just mix my own fuel. It costs like $7 a gallon" (or something to that effect).


Will do. Thanks.

cheezer1222

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Another update: I notice that some of my oil seems to kind of settle/congeal on the bottom of the bottle that I use to fill my vehicle. I wasn't expecting that. I use klotz oil (model lube (synth) and benol (castor)), and from what I had read, klotz was one of the better oils to use to keep things from coming out of suspension.

mighty9

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Id say thats from the high acetone content.

gkamysz

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Klotz Model Lube is not for methanol!!! You should be using Origninal Techniplate for methanol.

cheezer1222

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Good to know. Live and learn. The Benol will be fine, right?

cheezer1222

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Just ordered some original techniplate. I should be getting that in a day or two. I'll have to mix up a different batch with that stuff.

I should have known that model lube wouldn't work with methanol. It says it right on the website. I'm sure it also says it somewhere on the bottle. All I was looking at was "Full Synthetic." Oh well, it's all part of the learning process.

cheezer1222

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Is there anything I can add to get the oil to mix in nicely? Maybe a touch of gasoline? Or is it not going to mix as long as there's ANY methanol?

gkamysz

My Feedback: (19)

Chances are without the 12% acetone you already have in there all of the Model Lube would be at the bottom of the jug. I can't think of anything you could add that would result in a useable fuel. Yes of course, Benol is fine.

Warbirdguy

Removing a shim from under the head will increase compression. Removing anything between the cylnder ( I think that is what you meant when you said "more between the head and block") will not only increase compression, but will also alter the port timing if its a two stroke engine. In effect, lowering the port will lower top end RPM. Maybe no by much to hurt you. Depends on how much you lower the cylnder.

WBG

pe reivers

here's the drill on glow fuel additives:

Ether will improve cold weather starting, but will induce heavy detonation in glow engines. Use 0.5% max. I suggest not to use it.
Acetone improves cold weather starts, and prevents detonation and 4-stroke prop throwing. It tends to harden silicone lines. Use up to 5%. 3% is a good value.
Gasoline as glow fuel improver is useless. Acetone does a much better job in oil solving and freezing weather starting. Above 5% mixing with methanol will become difficult, unless Acetone is used as solving agent.

None of the above are replacements for Nitromethane. Nitro improves the cold weather starting. It very much broadens the allowable carb settings. Above 5% there hardly is extra power gain unless the engine is adapted, but allowable carb tuning even gets wider. Throttle response improves. It makes badly designed engines behave like good ones.

downunder

As others have said, 12% acetone is far too much. About 3% is the usual recommendation for 2 strokes (5% for 4 strokes) but only in fuels with no nitro. Even then it's only used to give an idle approximately what you'd get with around 5% nitro although it may give slightly easier starting. Acetone is a moderately good fuel but not as good as methanol so with 12% you've actually given away a bit of power. It's usually not even necessary because even a stock engine will run very well on just 80/20 fuel (4 parts methanol and 1 part oil) but use a hot plug. Methanol is poisonous but masks, glasses and gloves is going a bit too far . Use common sense and don't drink it, that'll kill you.

As far as raising compression goes, you can take out shims but generally they're too thin to have much effect so machining the head is usually needed for any worthwhile increase. Whichever way you raise the compression, make absolutely certain there's at least a .005" clearance between the head and piston at TDC. Ideally with zero nitro you need to get the compression up to about 13:1 (geometric, not trapped compression).

aspeed

For getting the oil to mix with the methanol, at high school we mixed a bit of detergent with the oil and water to make it soluble. Maybe you could try a small sample. I wouldn't add much detergent if I was me. I did fail chemistry just as a side note.
The head spacer can be taken out as long as there is some space between the piston and head. At least .010". If it is too close it will blow plugs. It could also detonate but the plug will usually blow before that happens. A hot plug may help. I haven't seen any production motors with a cylinder shim provided except the Norvel .049 style. I have always had to make them. Keep trying. I se Mr. Downunder posted while I was typing. Great minds think alike.

Airplanes400

My Feedback: (349)

I also heard that adding two or three drops of Armor-All per gallon will prevent foaming of the fuel.

init4fun

Ive read the same thing , , , but , since ive not yet had problems with the pre mixed fuel I use (powermaster brand) I havnt had to try it . Maybe its already an ingredient in pre mixed fuel ?

cheezer1222

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Yeah, I must have misunderstood the information when I originally read it. I think I read it as giving the same power as 5% nitro, when really I should have been reading it as giving the same idle characteristics.

As far as the model lube oil goes, will it not mix as long as there is any methanol in the mixture? Because I was thinking I could try a small batch that looks something like this:

25oz Batch
48% methanol
28% gasoline
4% acetone
20% oil (80/20)

My thinking is that, along with the acetone, the gasoline might help the oil to stay mixed in. Is my thinking off on that? I'm not desperate to use the model lube oil. It's just that I had some extra sitting there and I have a couple days before I get my original techniplate in the mail.

gkamysz

My Feedback: (19)

If you add that much gas the model lube might stay in solution. The trouble is your fuel probably will not work well. Gasoline will further reduce the power output and require even leaner needle settings. The needles will be critical and midrange probably fat.

I'd simply make a batch of methanol - Benol and be done with it.

Greg

spaceworm

I have heard that Armor-All contains silicones that will fuse on the glow plug element and render it useless.[]

spaceworm

You may want to look at the gas-glow forum for running gasoline/glow fuel mixes with a glow plug. They have lots of experience and successes.