Large Model Association Forum

We all use petrol engines, and we all have glows, Just engines, who i respect enormously, are now marketing rxell systems, to convert to petrol, But what about th following,
Carb, can a standard glow carb atomize] the fuel as a walbro does. Is a standard carb a fire risk? We know just how much glow fuel drips out of the things!!

Would it be wise to fit a pump?

Would the engines o rings and seals withstand petrol? I used to drop th fuel needle with its oring,minto petrol, to swell inup, to give a better seal,

Have we really managed, in the JE system, to find the holy grail? To get away from depndency on horrid glomfuel?

Is it worth a discussion?

Gordon Whitehead has done a long thread on RCMF about trying to get a Laser V twin to run on petrol. He's been trying for years & it sounds a right pointless faff!

I tried it years ago, and white the engine ran, the carb needles are too coarse, giving about one click between too rich and too lean.

You'll need a lot more oil too, as very few glow engines have needle roller bearings in the big & little ends.

Why bother? Unless you want to do what Gordon is trying to do, use a Laser on petrol (and in any case they run fine on straight glow fuel) then its a pointless exercise. You want a small petrol, then I can recommend the Evolution ones. I have a 10cc (.60) that is excellent. Any bigger and a Z20 just works.....

I am sure the head would need shims as glow engines run with much greater compression. Purpose built will always beat conversions in my mind, and there is not much in the way of price difference now between the better make glow engines and petrol engines.

Steve

I have converted a Super Tiger 3250 to petrol using the Just Engines kit. It ran ok with the standard carb but i have converted it to a Walbro carb now.

I bought two units from JE to try and convert two SC 120 four strokes as I wanted to lower the idling revs.
After a lot of fiddling about on the bench I couldn't even get them to fire on petrol mix,so gave up.
Someone them said I should have tried the spark ignitions on glow fuel - couldn't see the point!!
So sold the units.
Pete

I did put shims under the head as a trial on petrol - didn't work.

This is aimed at the guy who has a drawer full of glow motors, i am looking at the larger ones, i cant see the point in converting an irvine 40, I have doubts, seems i am correct, i just cannot see hoe the carb, and seals, O rings etc, can stand the petrol,

Alan, well, well, well, I must be the lucky one. Only last week I converted an ASP 120 F/S using the RC exel ignition unit from JE.....These are my specs, sensor set at 26deg,made and fitted a 9 thou head shim made from a Schweppes lemonade can, [ after I'd mixed it with my whiskey ].
Used the standard carb, fuel mix 20-1 using Bel-Ray HR1oil....Ignition battery 4.8 volts.
Prop used for test Graupner 15 x8.
All set to go in my test stand.....Open throttle to max, close choke and flip 10 times with ignition
off. Open choke ,and close throttle to app 1/4, switch on ignition and you can believe me it started first flick .So far I have run it for 11/2 hrs, and at full throttle the rpm is just over 8000, and the tick over is steady at 1700 rpm.You can leave it on tick over for 5 mins, open it up and it goes straight to 8000 rpm with no sagging,
ps..Last year I built a DH94 for Tony Woodhouse, which he flew at last years shows, I am sure most of you saw Tony flying it...The engine was an old Saito 180 fs which Tony converted, and it's perfect.....Maybe we were just lucky, or it's because we are the famous Yorkshire Ole Farts.

Well Brian maybe I was the unlucky one ,I tried mine about 6 or 7 years ago so something might be different now,quite apart from you being the Yorkshire O F's.
Maybe I should join ?
Although Solly will no doubt pass an opinion on that!

All the best

Pete

Pete, just letting you know that I a m still flying the Mitsubishi. Maybe I will see you at Cosford this year.

i have had a good deal of success with http://www.morrisminimotors.co.uk conversion kits. initiall i converted an ASP .91 and i am soon to recieve a .52 4 stroke back from morris

https://www.youtube.com/watch?v=1A79YkA-i5Q

https://www.youtube.com/watch?v=pD3aRLYYhnk