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Broken RCV 58 CD


Paul Marsh
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Another update by OP:

 

Crank pin further cleaned up using some very fine wet & dry with oil as suggested by Jon in an earlier post. Engine reassembled, and then tested by having a tank full of fuel put through it at our field today (both right way up and inverted), as you can see below.

 

On getting it home again, I removed the crankcase lower housing once more, and everything including what I could see of the crank pin appears to be covered in a fine coating of oil - which is good I guess!

 

It’s now back in the model awaiting some more testing on the ground, to rebuild confidence before it takes to the air again.

 

 

Edited by EvilC57
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  • 3 weeks later...

So what happened next?

 

I put the engine back into the model with it's twin RCV58 for some further ground testing. Running the engine on its own went well, as per the previous running on the bench - see my video just above. However, once the other engine was also started, after a few seconds of running both at moderate to full power (a beautiful sound!), the repaired engine stopped again - twice, on two seperate attempts at running together with its twin - hmm 😐.

 

Further investigation after the stoppage on both occasions showed the main needle valve to be only 1/4 turn off the endstop, when it should be around 1 & 1/8 turns out. It was then that I noticed that the ratchet action of the needle against the retaining spring was weak when compared with the other 'good' engine. Feel free to disagree, but my surmising of the cause of the stop, and of the original likely leaning out, sudden stop and seizure of the engine is that due to the weak position retention of the needle, with the additional vibration in the airframe once the second enging was also running, the needle slowly screwed itself in.

 

I have subsequently removed the needle spring, bent it in to ensure that it better grips the knurled grooves on the needle, and run both engines on the ground and in the air, without any further problems. However for a simple visual indication of any further movement, I came up with the idea of some indicators similar to those used on lorry wheelnuts (see pic below), these I have 3D printed, and are a tight push fit over the needles. Hopefully this case is now closed, but it goes to show how (if I'm right) the simplest thing can lead to failure or in some cases an accident or disaster.

 

IMG_5353.thumb.JPG.9f00703daa3fb78e6850d14c0b091c6e.JPG

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Good idea E57 as I have resorted to small cable ties to stop the needle rotating on a rather old engine. It would tune and fly well for about 7 minutes the go off tune and stop in the end. Once on the ground a restart and tune would result in the needle being rotated to the position prior to the previous flight!

 

A bit like the lorry wheel nut indicators, simple and effective. 😉

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  • 1 month later...

I just got a second hand one off of the web for 50€, no plug and won't run 🤢 a quick strip down and the timing was out a tooth, the bearings are really sloppy,

fiddling around I did get it running quite well except the claimed good tick over, rummaging it my engine box I found a 'rubbish' carb, probably from an MDS ( stop laughing ) well it actually runs better with it, an extra 150 rpm and a much lower tick over, I ordered the 3 bearings as there is so much play in the front ones I am worried that the prop will yank out the crank shaft and hit me,,,

the front bearings are 2 off 26 x 10 x 8 and the cylinder one 42 x 30 x 7, ( yes metric ! ) I hope that's right as I ordered before stripping it down, next rummage about on the forum to see what is the best way to clean the outside of the engine, and maybe make another bronze bush for the con rod which does have a bit of play.

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All rebuilt, fitting the bigger bearing isn't for the faint hearted, no play anywhere so I tried all three carbs of which the Irvine .53 one gave me the best overall performance but still 200 rpm down on the old bearings and no better than around 4.500rpm idle ( if you can call it that ) it runs better when the plug (OS F ) isn't 

wired up.

Has anyone tried advancing and retarding the timing by one tooth either way, if so will it actually run ?, maybe tomorrow I will try that.

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1 hour ago, Paul De Tourtoulon said:

All rebuilt, fitting the bigger bearing isn't for the faint hearted, no play anywhere so I tried all three carbs of which the Irvine .53 one gave me the best overall performance but still 200 rpm down on the old bearings and no better than around 4.500rpm idle ( if you can call it that ) it runs better when the plug (OS F ) isn't 

wired up.

Has anyone tried advancing and retarding the timing by one tooth either way, if so will it actually run ?, maybe tomorrow I will try that.

Watching with interest Paul, for outcomes.

Manish is right, your idle is in fact cruising speed, and in flight you could not land with 4500 rpm.

That motor can idle 1900 - 2000rpm and 2500rpm would still be a fast idle.

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16 hours ago, Paul De Tourtoulon said:

All rebuilt, fitting the bigger bearing isn't for the faint hearted, no play anywhere so I tried all three carbs of which the Irvine .53 one gave me the best overall performance but still 200 rpm down on the old bearings and no better than around 4.500rpm idle ( if you can call it that ) it runs better when the plug (OS F ) isn't 

wired up.

Has anyone tried advancing and retarding the timing by one tooth either way, if so will it actually run ?, maybe tomorrow I will try that.

Good top end and poor idle often suggest advanced valve timing while good idle and knocking or prop throwing suggests retarded valve timing . One tooth will do it. If it was a conventional poppet valve design then piston hitting valves is noticable but being rotary no valves to interfere with. Many poppet valve engines can have the timing out by one tooth . I bought a new Magnum 120 years ago , OS copy , and the timing was retarded one tooth from the factory. Test run it idled very slowly but on opening the throttle it spat the prop off denting the dide of my caravan ! 

Fortunately only one set of cogs to align unlike Enya and laser 

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22 hours ago, Paul De Tourtoulon said:

 

sadly no traces of  Castor oil.🤣

Have a chat with Alan at Weston about Castor oil ....... but be warned hold your phone away from your ear ! He hates the stuff after repairing engines ruined by it over the years .  Horses for courses . Castor ok on older lower powered engines with cast iron pistons and old diesels again with iron pistons . Still very messy but doesnt bake on due to lower running temp and plenty of excess fuel passing through engine . Even then it can have detrimental effects.

Ive just sorted out an old PAW 0.9 BB diesel that's been run on castor fuel. The outside resembled an old chip pan ! The top of the cylinder and the piston crown both had a good 0.75 mm of hard carbon deposits and was stubborn to remove  ! not too much of a problem in a diesel as comp is adjustable but, in a glow, would have serious effect on running and probably have damaged the engine . The BB was a solid block of congealed hard Castor varnish . Modern synthetics would have avoided this.

Before RCV engines there were many rotary valve engines that came and went over the years. One of the main problems was that castor oil would set hard like varnish on the rotary valve causing wear and poor compression so most were consigned to the spares or scrap box . Move on to present day and many of those engines would run happily with good modern synthetic oil albeit with low power compared to modern engines 

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I fiddle with it yesterday the ring is really worn, for a laugh I turned it around, and the engine did have a lower idle, I am still waiting for Western UK to sent me the quote for a conrod and ring, phoning is a last resort as it cost a bomb to ring the UK, from France,,

 

looking at the conrod it is OK so only a piston ring will do.

 

 It does get hot maybe a radiator from some electronic thing fitted at the place of the original head would help.

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Yes the RCV's do run hot. When i bought the first one, a 58 CD ran it on the bench and was really disappointed with how hot it ran. To an extent that the engine was put back in the box. 8 or 9 years pass, cut to first Covid lockdown, confined to home, took the engine out only to realize that the bearings have rusted and the engine locked up(no castor was used). Tore the engine down and when the lockdown was partially lifted managed to get the bearings, assembled the engine back and ran. It still ran hot but since had put it in a model where majority of the engine was hanging out in the breeze was not worried. Its run good since then

Edited by Manish Chandrayan
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I got a radiator ( some electronic thing ) from a model club member that I will be fitting to replace the original one, or maybe the head off of my dead Irvine .53,

no air ducts are required it on a ply plank in the shade in my garden.

 

 mailed Weston UK 'again' hoping that they can send me a piston ring.

Edited by Paul De Tourtoulon
e
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21 minutes ago, Paul De Tourtoulon said:

I got a radiator ( some electronic thing ) from a model club member that I will be fitting to replace the original one, or maybe the head off of my dead Irvine .53,

no air ducts are required it on a ply plank in the shade in my garden.

 

 mailed Weston UK 'again' hoping that they can send me a piston ring.

Would be interesting to see the original radiator you mention

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