Hello. Just kicking around the idea of converting a couple of my glow engines to gas. I'd like to try to convert my Saito .30 4 stroke and also my OS .52 Surpass. I think the Saito is a non-ringed engine, so not sure if conversion can be done. Can anyone give me a link or a website or name of company that has the hardware for these sorts of conversions? Any and all info would be appreciated.

The Saito 30 is ringed

None ringed engines do not work well on gas

due to the difference in air-fuel ratios between Glow fuel and gasoline, the glow carburetor is very sensitive on gas

You have to run a high oil to gasoline ratio because of the bushed connecting rod in a glow engine

The better conversions to gasoline are larger than the engines you have suggested

Thanks w8ye. I have heard about the higher oil contect that you have to run in a converted engine (about 16:1 or so?) and also that the more successfukl conversions are usually of larger engines....but curiosity being what it is I'd still like to try a conversion on one or two of my my smaller engines.

Have a look at my FS-52.

[link=http://www.dieselrc.com/project1.html]FS-52 on spark.[/link]

Greg, you are still runing glow fuel arn't you? I would be interested in the modification you did to allow the valve train execee into the intake. It wasn't obvious from the photos.

One of our guys has an O.S FT300 on ignition using glow fuel. His is an older setup using a mechanical advance and that gives him a bit of problems, but when it is in the grove, it ia a great running enginge.

From what I have read, and what I saw with our guy's Ft300, the only down side is see is the RFI from the spark. Seeing that the gassers handle this with a little common sense, I think the glow to ignition sould be a good conversion.

By the way, have you looked at the carb stack off the O.S 56" I'm running one on my O.S 52 now and it is doing a great job of keeping the cowl clean. The performance is also imporved. I'm cranking a Zintler (sp) 12x6 wood at 10800, off peak by 400rpm. I can idle at 2400 without problems, but the idea of a 2K idle or less and good performance has me still thinking.

Don

I lived in the south for a couple years recently and there were two guys with CH ignition on their glow four strokes. There was a double rocker OS 120 and a OS 91 Surpass I. They were in different towns. Both ignitions were the older CH. They were fixed advance. The 120 was on a Cub and the 91 was on an Endecker

Here`s everything you need for a conversion. http://www.justengines.unseen.org/ac...s_Systems.html The problem with your saito .30 is that you will effectively double the weight of your engine by doing this. It depends if your plane can handle the extra weight and don`t need alot of power to keep airborne. My friend Yallaair uses this hardware on his AX 120 to run gas and it works like a dream.

I was running 8% oil and balance methanol in the FS-52. I'll be trying gasoline and E85 as soon as it warms up a bit around here. I will be making a velocity stack for it. I don't think mine will idle at 2k. Actually, it will, but I can't tune for a good transition.

You often hear that "high oil content" argument. It goes on, "you'll foul the plugs with all that oil." Do a little arithmetic and you'll see that 16:1 is a lower oil content, percentage-wise, than you run on glow. The reason is that gasoline is inherently oilier than methanol, so it needs less oil added for good lubrication. People run ignition all season on 20% glow fuel with no problems. But the argument goes that you can't do it on gas. Go figure. Take a look at the glow to gas conversion sub-forum for the straight skinny.

CR

Prior to 1947 ALL model engines were spark ignition. They typically ran on 3 parts gasoline to 1 part 70 wt motor oil.

jess

Wow I'm surprised you're getting away with that small an oil content. Actually, I'm surprised that you tried it at that percentage. Did you just sort of work it down?

CR

I had a few conversations with a few people running glow to gas conversions. 16:1 ratio seems to be the optimal ratio. 8 ounces oil to 1 gallon gas or 5.9% oil.

The people I talked to have had no problems with there conversions running on the oil content over a year or more. The smallest engine was a Supertigre 51. I would guess the larger engine would need less oil since it passes more fuel per revolution.

All engines were ringed. I have a ST G90 converted to spark and a zama carb. I plan on running 16:1 with Pennzoil air cooled 2 cycle oil.

I hope this helps.

I know it's already been mentioned above but gasoline has more lubricity than methanol hence the need for less oil. I ruined two rods on my ST51 trying to run the ratio in the 25:1 range. It now has over 75 hrs at 16:1 so that is what I have adopted as my standard. My G90 that is still running the bushing rod might get away with the 25:1 ratio but I haven't been willing to push my luck. The one with the needle bearing rod (like Ken Lambert's and the BME) works just fine at 40:1 and Ken says his is OK at 50:1. I am running my Saito 91 converted to gas at 22:1 and have had zero problems with it. When I remove the back cover to check the condition there is plenty of oil inside.

I'm with the others that anything smaller than a 50 size might be adding too much weight. Some of the weight is offset by the need for less fuel to get the same flight time though. About half the fuel for the same run time on all my gasser conversions is normal and the Saito might be just a bit better. More like 2.5 times.

The ST51 is running on race gas with a much increased compression ratio (no head shim and a GS40 head which has a smaller chamber) which makes the power almost identical to the same engine running on 15% Nitro/Glow fuel. For those curious it turns a 10X7 15,100 on gasoline and before anyone chastises me for the high rpm's understand I am a pylon racer at heart and love hearing em scream. I also need to add the 15,100 is not with the stock muffler and the port timing has been altered as well. I changed the throttle barrel slot angle just slightly for improved transition and midrange and that's the only mod to the carb. It ran OK before the slot mod but is as smooth in transition as any factory gasser after the mod. As w8ye mentioned above the carb is quite sensitive to adjust and probably isn't good for those who are not extremely good at tuning but it can be done. With all that said I will add the SuperTigres have a little finer thread on the main needle than some others and that helps with the sensitivity on adjustment which is one of the reasons I chose to try ST for my first conversion. Good luck with yours if you decide to give it a try.

No, I didn't work my way down. I knew it would work. 5% was mentioned in Peter Chinn's four stroke book. I'm going to go even lower this year, but only with four strokes.

Jezmo, I ran 1 Lithium cell on the FS-52 with an RCEXL ignition. I think it's still comes out lighter with the smaller fuel load. I should actually weigh things. I'm working an FS-30 now, but will be using a smaller ignition, also on 3.6V or single Li.

I never thought about weighing it with a single Li cell. On the oil issue, Saito is running the FG36 at 32:1 after break in which is about 3.2% so I would think you are quite safe with your ratio.

Uh, I should have done the math. 8% is a higher percentage than the 16:1 mix I used in the Saito 1.50. BTW, I went down to Schertz and picked up some E-85 fuel. I need to pick up some Klotz oil to mix it up. Going to try it in a ST 3000 on ignition I have going into a Lanier Extra 300L ARF that I've had sitting around NIB for 5 years or more. Putting it together now.

Seems I read somewhere that some guys are mixing it with more gas or with glow fuel.

CR