Enya 120 4c modifying to petrol ?

[Paul De Tourtoulon]

I am waiting for it to arrive, any suggestions whether its worth modifying to petrol ?.

 

 I have a spare recel ignition and a few magnets with a spare walbro carb somewhere,

but no glow size plug.

[FlyinBrian]

I am sure more knowledgeable people than me will answer shortly but I do not think it is a particularly easy thing to do and get good results. It may be worthwhile contacting Morris Mini Motors who does these conversions to various makes of engine.

[Paul De Tourtoulon]

Thanks, but those conversions cost an arm and a leg, as I don't have a plane to put it in 'yet' and with nothing much to do at the moment,,,,?

 

 It's only for the fun,,,,

[Dale Bradly]

What are you trying to achieve?

I've had great success converting glows to spark ignition with the rcxel and they run a treat. For Mei found Idle better, throttle better and run a leaner mix. But staying with methanol fuel. Note however, those ignitions tap out at about 10k rpm, so if your engine would previously Rev higher, it won't on one of them.

 Petrol, you're on your own. Ask Jon when he pops along with his thoughts on that.

[Paul De Tourtoulon]

Achieve nothing really, except at 8€ the litre of Methanol against 2€ for petrol and of course what a methanol engine uses against petrol,,,

 

I get through around 60/80 litres of petrol a year on my models.

[Engine Doctor]

My current Enya 120 does throw its prop and no lock nut available due to short thread on shaft. You might be able to set timing to tame the prop throwing thing but will also need to lower compression ratio a little with a head shim as petrol engines usually run at lower comp . The shim also tames the glow version and it is a docile engine once a shim is fitted at the cost of a few rpm.

The twin needle carb might be easier to tune for petrol but a walbro carb, if you can make an induction tube adaptor would be better. It may benefit from a carb reducer fitted in the carb barrel if using the standard carb but again will reduce performance considerably compared to glow version.

All in all a lot of work to achieve lower power, but you will save fuel cost if it works.

Keep us informed of progress ?  

Edited October 20, 2021 by Engine Doctor

[Paul De Tourtoulon]

Thanks, my Enya 90c threw props till I made a bronze flywheel and put it in the cone in front of the prop,,,

[Jon H]

I wouldnt bother with it. I have never seen a petrol conversion work well enough for me to be satisfied with it. Maybe my standards are higher but still. 

 

I have two of the large enya engines. One 120 (up bored 90) and one 155. Neither are thirsty beasts and they run well on low nitro fuel which is cheap to buy/make.  

[Paul De Tourtoulon]

Yes probably right, but if I don't spend my time on it I will have to buy myself another plane to keep myself busy,,,?

[David Ovenden]

Paul, You can always finish off one of my planes if you don't have anything on! Tomtit, Tiger Moth, Condor re-build??? ?

[Paul De Tourtoulon]

I was looking for another bigger Spitfire or Hurricane, both of mine only have 15cc four strokes in them,,,?

[Mike T]

You might want to try an O.S. G5 plug.  I've removed the ign. unit (and battery) from my Moki 210 (2S) conversion and replaced the park plug with one of these.  All the simplicity of glow combined with the (relative) cheapness of petrol.  It runs a bit lumpier at the bottom, but I haven't spent any time dialling it in.

 

 

Edited October 20, 2021 by Mike T
brevity...

[Paul De Tourtoulon]

Yes maybe worth a try if I can't find a small spark plug to go into the glow plug hole,,,

[Paul De Tourtoulon]

Rimfire and rcexl both make a 1/4" 32 unf threaded plugs,,,, all on eboot,,,,,

[Paul De Tourtoulon]

I ran it up today, it was a bit shaky now I am looking for the threaded adapter for the exhaust it's around 15mmod fine thread, here is the nut ( not me )

any idea whether it's a 15 x 100 mm thread or what ?.

 thanks Paul.

[Jon H]

DO you have the 120R or the 120-4c? they have very different exhausts

[Paul De Tourtoulon]

A good question,,, it has a 9mm carburettor,   and this  exhaust in the picture, bolted on, not screwed in like my .90,,,so I guess it is the R.

 

 someone forgot to adjust the valves, no play at all,,,

[Denis Watkins]

11 x 0.75mm thread

 

 

Edited October 22, 2021 by Denis Watkins

[Paul De Tourtoulon]

Thanks but it is not 11mm, its over 14mm measured on the inside of the thread.

 

I just ran it after adjusting the tappets, an Apc 14 x 7 prop on 10% nitro and 17% oil gave me 10.075 rpm

 and the fuel consumption is around the same as my V 8 in the garage,,,?,,, 

 

[Jon H]

if you have a photo of the engine it would help with identification but i suspect its the 4c version as a 14x7 is way too small for the R. I used 15x8 on my 4c and saw around 7500-8000 if i recall

 

If you use 5% nitro and 15% oil fuel consumption will drop significantly. Mine was in a hangar 9 pulse 60 and i think they came with 14oz tanks? anyway this was good for more than half an hour if i was gentle. 

Edited October 22, 2021 by Jon - Laser Engines

[Paul De Tourtoulon]

It has '52' on the left mounting lug, before I did the Tappets it turned a 16 x 6 Master Airscrew at 8050 rpm with a lot of vibration, it was new and unbalanced.

[Jon H]

Thats an R. Savage brute of an engine with loads of grunt. I would use a 15x8 prop and expect to see around 8000-8500rpm depending on the brand. 

 

The 120 4c is not as powerful as its a bored out 90. More compact, but not with as much oomph. A friend has an escale seafire fitted with one of the R versions and its a complete animal. I have a model fitted with a 155R (a bored 120R) and it too is a beast. They do tend to rattle and shake so that is normal. He also found it ran better on 5/15 nitro/oil than 10/15. 

 

These are great engines and the only things that hold them back are their slightly weak valve gear (valve spring and rocker failures arent unknown), their out of date air bleed carbs, and their donkey exhausts which do nothing to reduce noise. 

 

What i suggest you do is make a new flanged header to fit the head/retaining plate and thread the other end for something suited to an aftermarket exhaust. 

 

Be careful though, my 155 eats exhausts for breakfast especially if they are heavy. The 120 and 155 also run really hot on the exhaust gas temperature and my 155 melted an aluminium baffle i installed in the exhaust..and by melted i mean melted, there where splatters of molten ali burned into the wing leading edge. 

 

I love these enya engines, but they are savage animals. I currently operate a 155 and a 53 on 5/15 fuel and in the past operated the 120-4c on the same. I also have a super yummy VT240 which is complete animal and laps up the 5/15 fuel. Economy is good and it nearly matches a laser 300 for power bu has a totally different character. 

 

Its a shame Enya engines are gone as they were the best of the japanese brands in my view even though their designs are very 1980's 

 

 

 

 

[Paul De Tourtoulon]

Thanks Jon, I don't want to change my fuel mix as I use it on anything and everything, all my 4 strokes, Os .61 open rocker Enya 90c HP 21vt Saitos and even my Laser,,,,

and of course 2 strokes including my Raptor 50 with it's OS .50 hyper, Rossi 90 RV, os .45 etc etc etc,,,,,

 

 I with balance my 16 x 6 and see what it runs like, and see what plane to modify and try it out in,,

[David Ovenden]

Paul, your engine's exhaust looks modified. I found these pics of a new engine and exhaust. Or perhaps yours R120 is a newer (or older) version?

[Paul De Tourtoulon]

Thanks David, it's the one you have in the picture, I have taken the ring off to free the nut,,,

 

I will be running it up again in the garden today with the 16 x 6, if you can hear it at your place just tell me,,,?

 

It's doesn't idle for long, so I might modify my Perry carburettor and fit it  to see what that does, but first a new glow plug, I have no idea what it is  but it isn't an Enya 3/4 or OS F, which a few forum recommend.