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Enya 120 4c modifying to petrol ?


Paul De Tourtoulon
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Fed up waiting on 'friends' getting me bits, so I bought a union for copper tubing, I threw the olive away and turned it down to replace the steel nut and bolt that I can't find, a brass ring spacer was turned down and soldered to the stainless flexible outlet, for the moment only 'sweat' fitted and I found an old 4 stroke silencer with a 10mm outlet ( I can't remember where from ) and another aluminium spacer was made and all was roughly fitted to my engine running jig, so when the rain stops,,,

Enya raccord-2048.jpg

Enya exhaust bits.jpg

Enya exhaust ready to run.jpg

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Reading through, your flexi- pipe Paul

You tested non magnetic

So, soldering non- ferrous metals differs from normally magnetic ferrous stainless steel

This may be why that bit failed.

 

I doubt the engine bolt failed in one go, and was probably sheared previously.

 

And I don't hold much hope for the drilled out carb being of any use any more, though you may have swapped this out.

 

keep going.

I still stick by " tank pressure " for running a regular make 4 stroke.

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Yes non magnetic 18/12 stainless steel, braise with silver solder ( 0% ) which hasn't budged.

 

The break is 12mm after the end of the solder.

 4 New bolts that have 'lasted' around 10/12 minutes running, yes it does vibrate a lot !.

 

 Carb still doing well it started first time today after 5 days sitting in my workshop dust, and ran really well, nothing on the carb was touched.

Most ( not all ) of my 4 strokes have a pressure take off, if you can call a nipple on a saito .45 straight pipe with no silencer a pressure take off,

 I have 1 x 45 and 4 x .45 Specials running that way, my OS .61fs and .61 open rocker,, and probably a few more,,,

 

 Thanks for your input, it makes sense,,,

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Thanks,,

 

 The timing was the first thing that I checked when I received the engine as it just wouldn't start, eventually it would start at 3/4 throttle and also run flat out but no twiddling with the carb would it idle, not even at 5.000 rpm.,

 

I tried different glow plugs, as all my 4 strokes the best was the OS 'F', I tried 2 copper joints on it and as it didn't make any difference I left them both in place, a 'trick' I learnt when starting 1.5cc to 3.5cc car engines, it saved the customer coming back within the hour with the hand starting cord and a spring starter in his hand,,,?

 

So next step shimming the head will it soften the vibration, I have Litho printing sheet ( whatever it's called in English ) of 0.1mm and 0.2mm so should I just go into the deep end with the 0.2mm ?.

 

Exhaust temperature, I didn't take thermometer to the model field I forgot it,,, so any idea what temperature it peaks at ?, I was thinking of using a length of silicone tube in between the exhaust outlet and the flexible.

 

Off to the beach for the week end but I will be in touch thanks,,,,

 

 

 Ps, the engine mountings in different hard woods and ply ended up crushed from the engines vibrations, so I went for thin angle iron.

 

 

Edited by Paul De Tourtoulon
engine mounting
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Hi Paul swimming the the head won't stop an engine vibrating per se. I assume you have balanced the prop and spinner ?. A head shim will lower the compression ratio and retard the timing a bit allowing a smoother burn and help prevent pre ignition. You may find that the original shim / s are missing as many folk I have spoken to think that raisingcomp ratio is a first step to tuning and engine ?

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Re the flexi exhaust pipe. I believe that the "flexi" description is not to allow flexing when running as the metal will quickly work harden and fracture . It's  to allow easy bending prior to fixing in place. Don't confuse it with the flexi exhaust you can buy for car exhaust as that is completely different construction designed to move during use.

Have you checked the Enya for a bent crankshaft ? Even a tiny bend will cause serious vibration and is often why they are sold. They can usually be straightened if you have access to a lathe.

I have a CRRC PRO  45cc that used to vibrate badly from new. I stripped it and found that 1, the bearings were turning in the cases. 2,the crankshaft was twisted and had not been properly assembled. 

After a new set of bearings fitted with "loctite Bearing Fit " and aligning the shaft it is now a smooth a petrol engine as you can get. RCGF are a cheap brand so still have QC issues . Might benefit from a strip and check?

 

Please note my Last post should read "shiming" and  not swimming as my tablet decided !

Edited by Engine Doctor
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Thanks I will check the crankshaft it is possible that it is bent although the prop seems to run straight,

I have had the same problems will club members Rcgf engines where the crankshafts were badly turned and blocked the bearings when tightening the prop,

I got the flexi pipe to replace a fixed one it was only there to couple everything up, but the heat and vibration thought better, I was worried that a fixed one would break the exhaust mounting bolts in the head, my Enya 90, 4c lost all of it's thread even though it was the proper Enya spare part with the same sort of flexible tubing.

 

 

Ps At the beach at Sausset les pins, so I thought that you had seen me swimming,,,,

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The Crankshaft is straight , the prop did run straight,  the crankshaft  bearings have a little play and both 'dropped out', a first for me,?no fridge or blowlamp or even a hammer !, so ordered and will be put in with locktite.

 

 The front one, 12 x 28 x 8  Ref N° 6001 zz

Rear                  15 x 35 x 11 Ref N° 6202 zz,

 Both metric.

Next step taking the head off and see what sort of joint / gasket it has,

 

 Then back to the exhaust and maybe fitting it onto a plastic 'Seagull" engine mounting to see what that does while waiting for the bearings.,

 

engine mounts-2048.jpg

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15 hours ago, Paul De Tourtoulon said:

The Crankshaft is straight , the prop did run straight,  the crankshaft  bearings have a little play and both 'dropped out', a first for me,?no fridge or blowlamp or even a hammer !, so ordered and will be put in with locktite.

 

 The front one, 12 x 28 x 8  Ref N° 6001 zz

Rear                  15 x 35 x 11 Ref N° 6202 zz,

 Both metric.

Next step taking the head off and see what sort of joint / gasket it has,

 

 Then back to the exhaust and maybe fitting it onto a plastic 'Seagull" engine mounting to see what that does while waiting for the bearings.,

 

engine mounts-2048.jpg

On the other hand, the very small camshaft bearings in the rear cam box are not at all easy to replace!! Hope they are OK. Just a thought- are the cam gears correctly synchronised with each other and the driving shaft?

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i have just read the engine 'tests', it was delivered without a head shim installed but one in the box of 0.016" ( .40mm )

which in the test said it did run better,, so lucky me I had the right thickness litho plating,,?

 I also noticed that the main bearing was open there weren't any seals in it and the front one shows one side also without the seal, so

3 of the 4 seals will disappear before I fit them.

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