hllywdb

I believe there are additional differences in the carb as well, idle, maybe bore as well. The GX carb will run nitro, but not so much with the AX carb running gas.

hsukaria

I suspect you're right. I converted from GX to. Ax. I did not try it the other way.

SKuhn68

That's exactly the kind of info I was looking for. Thank you gentlemen!
SKuhn68

hllywdb

BTW, my original is still running great after all these years. I didn't get a lot of flying in last year so I did end up cleaning the carb and replacing the fuel lines to the tank.
I have seen a couple of bent rods on these, but always due to wrong mixture or electric starter. Due to the high HP/CI and HP/LB ratios, they are a bit more sensitive than your average weed wacker motor to fuel/mixture/abuse. I've never bent a con rod on a low power OS FP, but then again, I've never had a problem with a blower explosion on the wife's mini van either.

the Wasp

My Feedback: (1)

if you go to YouTube and search, you will find a lot of guys running gasoline in their glow engines, most of these people are outside the USA where Alcohol is hard to buy

Jim

SKuhn68

Do you know if this is simply a fuel change or are there modifications to the glow engines involved?
SKuhn68

the Wasp

My Feedback: (1)

a lot of the people on YouTube I was telling about are Heli flyers, so if you search YouTube search for Heli engines (OS Hyper 50, Hyper 55, Hyper 91) running on Gasoline. some of the videos tell you just what they have done to their engines, of course most use an E Ignition, some do use the stock Heli carbs, I tell you this, if you decide to run gasoline in a glow engine you could buy a gasoline carb made for these engines, such like the the GX40 Crab, or even a Saito gasoline Carb,,

if you decide to buy the OS 40AX you may really want to think about the OS 50SX or 55AX for the extra power, if you find one and wish to try a glow Carb I have a couple (brand new) OS Fine Needle Heli Carbs,I will be willing to sell one, they will fit the OS 50s and 55s, I think they will fit the 40 and 46 too.
BTW, you could buy a (new or used) Heli Head for the OS 46sx, 50sx, 55ax to help keep them cooler.

Jim

Billsky

My Feedback: (37)

Just use below noted carb if you have a 46AX,55AX, or ASP engine in the same range. I have all three running on gas with the carb.

Carburetor Assembly: 8GX/10GX2 (EVOG08801B)

Hawk21

My Feedback: (7)

Just run the gx40 for the first time and I am simply amazed how good this engine run.
I still wonder why are there no more engines like it except for the 2 O.S.
I know it do not have the same power as glow but is cheaper.

hsukaria

The web site Mike Goes Flying sells a .36 gas engine for a reasonable price. But I have no personal experience with it.

aspeed

The .37 looks like a nice motor. It seems like the same as their glow motor except with more fins and the turbo plug. I see that it has a G on it presumably for gas. Likely an extra hot. Our dollar is quite low right now and he is not shipping outside the US anyway, so it is not a great option for me just to experiment with. I suppose I could pick it up at a post office address in Detroit if the border opens up some day. Looks very interesting. The instructions for fuel mixing may be a good thing to know/share if anyone has one. To be honest, I have made quite a few Turbo style heads for my smaller motors and wonder if gasoline would work considering the use of a bronze bushing on the rod. Not because of the fuel cost, but the oil cost. I really don't like the smell of gas in the van. On the one review it has mentioned 16:1 fuel mixture with half and half Klotz and 2 stroke oil.

hsukaria

I was tempted to purchase a SH .37 gasser, but I really want to wait until there is more info out there

Looking back at my experience with the NV Engine 40GX, I think it failed because they were pushed to perform as a glow 46 instead of a regular 40. Whenever I convert back to GX from AX, I will add a head shim to reduce the stress on the crankpin. The failure of both GX engine I know of were due to crankpin failure.

Charley38

The rod bent on my 40GX, not the crankpin. I replaced the rod but it wouldn't run right. I sent it back to Russia. The factory techs said nothing was wrong with it but they replaced the
carb. ?? Haven't run it since.

CR

Bob2.0

I converted a Traxxas rc car engine to gasoline inspired by the Norvel GX40. I stuck with the glow plug so my engine could keep using the high rpms it was built for. I had to modify to a gasoline carb, high compression cylinder head, and the hottest plug I could find(os LC3) the engine actually ran pretty good. I eventually converted the engine back to nitro primarily because it would quickly overheat and it was always showing symptoms that the glow plug wasn't hot enough.

​​​​​​
If I ever try doing it again, I think I will try a ceramic coated high compression turbo head, os P3 plug, and the biggest heat sink that I can find. That should help with the bad fuel combustion and the overheating issues.

I also own a Norvel GX40. I just recently bought off eBay. I haven't run it yet but I am excited to try putting it on my aerostar 40 that I am Finishing up. My goal is a relaxing and fairly cheap rc plane to fly but to still have some power when I want it.

SKuhn68

OS makes a glow plug designed specifically for use with gasoline, it's the G5 plug. Have you tried that? It may resolve your "plug wasn't hot enough" issues.
SKuhn68

Bob2.0

It would be nice to run the OS G5 glow plug. It doesn't need as much compression to run which may help the engine lifespan. The reason I haven't bothered with them is that they cost $15 a piece and only last for about 8 flights if I remember right. In a small rc car engine that doesn't burn as much fuel as these a 10-15cc gas engines it could actually increase the cost of operation. On the other hand I thought I heard that many of these airplane guys have put many gallons on a single P3 glow plug in their Norvel GX40's.

I do have an actual question about the Norvel GX40. I recently got a used one for a decent price. Anyway, what fuel runs best in it? I have a bunch of 88 octane ethenol free sitting at my house, but I thought that I read somewhere that these engines like to have some ethenol in their fuel.

DaveR

My Feedback: (7)

While this engine isn’t snake oil, I’ve never heard of anybody getting even close to the OP’s tach numbers. Has anybody gotten close to 13k rpm on an 11/6 APC? I think most are lucky to get 12k. It’s so tempting because the fuel is so cheap, but nobody did as well as the OP “testing” the engine, and so many have problems with it.

hllywdb

This starts to get like the guys that buy a new Harley and immediately take it and do a dyno run hoping to get numbers they see on a forum. Almost all of my NV engines get stronger the more I run them, especially the 1/2a ones, and I think most here have the same experience. Same goes for Cox engines and especially the old Fox engines. I wouldn't think of starting a new engine and trying to get peak rpm out of it for a while. And just like dyno runs, environment also counts. I'm running in FL at dead sea level. That same motor will run different in the winter with cool temps and low humidity than it will in July at 95 degrees and air soaked with water vapor. Gasoline quality also varies, along with ethanol content and how fresh it is. I ran 93 octane Shell or Sunoco. I found it ran best with the clear gas tubing and a crap filter that also stopped the bubbles. I've run 3 of these and eventually they all ran within 300 rpm of each other.

It's easy to vapor lock a gas engine running high compression and a glow plug and break stuff using an electric starter. Pick your poison on what you think should break 1st, but something will. Ask the guys running million dollar funny cars about vapor lock or how much damage is done when you foul a plug halfway through the run. You want fool proof, buy the non-BB Big Mig 40. Less performance but it runs like a Timex and your grandkids can tune it and it will take a high speed impact on asphalt to break something.

If your version runs 12k then just run it and have fun. It's rare that I spend much time at WOT when flying anyway. So I probably wouldn't notice. I do care about how well it transitions and I don't mind being 20 minutes into a flight and not worrying about having to land quickly