TimC

A friend was digging around his garage and found an old Yin Yan Silver Swallow .15. It was frozen up solid but I was able to free it up with Kroil and a heat gun. I did a little mining for info on the net and found that these engines were only good for about 8 hours running. He said he never could get it to run as far as he remembers. He had a can of Red Max that is almost full and still has a strong ether and acetone smell. I thought I would see if I can get it to run. I'd sure appreciate it if someone would give me instructions on how to set the T handle for starting and running and any other tips for a person who has never run a diesel before. Also, would the props for my .15FP work on this engine? Thanks, Tim

dennis

My Feedback: (90)

One of the problems with CS motors was a complete lack of quality control. Some worked and others wern't even good as sinkers. I have had quite a few of these pass through my hands and most were more trouble then they were worth. The amazing thing is that they are billed as a beginners motor in China.
With that out of the way there are a few things to look at to see if you need to do any work. Check the prop thrust washer and see if it is either too loose or driven so far onto the shaft that it has bound the shaft. About half of these usually need a spacer washer put in to take up the slop but it does happen that some are tapered wrong and lock the shaft.
Next turn the motor over slowly and see if it binds at the top. By that I don't mean compression resistance but if it feels like an abc motor it isn't and you have to finish lapping the piston to the bore. If your not sure how to do this then find someone who can do it for you. Don't trust this to a hack or your motor is toast before you start.
The standard needle valve is a really messy thing and usually leaks like a sieve, the spring ratchet retainer is really a useless piece of soft brass or copper. Spring for a PAW needle valve assembly and use that. better is the OS 06 NVA if you can find one.
Make sure that you use any fuel but Red Max especially if you don't know if it was made for a bushing bearing or ball bearing model,. Believe me if you use the wrong fuel and get it running it may not last till it would be broke in.
Recommended is Davis 1/2A fuel lots of oil and plenty of either.
Now to run this motor open the valve about 2.5 /3 turns and use an 8/4 prop, others may say a 9/4 but trust me on this if it's the usual CS it will overheat almost immediately on that size prop. Hand starting is recommended and you need to utilize the diesel flip which precludes and sort of whimpy flipping this propellor if you expect it to start.
When it starts you want to keep this motor really as rich as you can and not have it stop let the raw fuel and oil really pour out of the motor. use the compression screw to adjust the ignition. Do not overcompress or you will bend the rod. The 8/4 prop will not load the motor and you want it to just get a little warm to start seating and fitting the parts. Let it run about one minute and then stop it .Let the motor cool completely and then repeat this operation a few more times. with complete cooling between runs.
You can then start to lean the needle valve incrementally and adjust the compression to keep it running rich but not ragged.Pinch the fuel line occassionally to momentarily lean the motor. Make sure that you cool it off between each run. After about one hour it will start to behave, when it will hold a setting without sagging you'll be able to put it on your plane and fly it. Take it easy with it they take a long time to run in.
All the above info matters only if the thing will start and run and believe me there have been a few that nothing could persuade them to pop. On the other hand I've had a few that are so tight that after 2 years they still wouldn't empty a tank of fuel without overheating
When they are run in they are modest sport motors, they will start a lot easier as they break in, but they are not really any sort of powerhouse. Good for light planes and sport C/L models. I usually do not overprop these motors and use an8/5 or 9/4 after they are ccompletely broken in


Edit to comment on the 8 hour lifespan of this motor. Really thats so much BS. any motor will wear out prematurely if not broken in carefully and use the right fuel. If those 2 rules are followed then there is no reason to nothave the motor last less then any other motor in it's class.
Dennis

TimC

Thanks for all the info Dennis. It turns freely and has good compression with no binding at TDC. I went and looked again at the can of fuel and it has a sticker "For Ball Bearing Engines". I guess I'm dead in the water until I can get the right fuel.

TimC

"Now to run this motor open the valve about 2.5 /3 turns"
Dennis, I assume this is the needle valve. What is the starting point on the T handle on top?
Also, can I use a fuel tank set up for glow fuel?

Motorboy

Main needle set to 3-3,5 turns first time.

Rotate propeller and raise piston to TDC and turn compression screw (The T handle on top) down until it stop. (Do not turn hard!) Also contrapiston inside the cylinder hit top of piston. Then turn up 1.5-2 turn.
Flip propeller until contrapiston are raised up to compression screw.

Give some drops dieselfuel in the exhaust port and prime careful with finger over carburator 1-2 flip at propeller.

Now are the engine ready to start, flip propeller fast (not same as glowplug engine). Some flip after the engine will start and run. If hard to flip propeller, raise compression screw 1/4 anf try again until it will fire up.

Regulate compression screw until the engine will run fast (if overcompressed, the engine will go slower with hard sound or propeller oscillating). Then lean out until the engnine will go rough and turnback 1/2.

You need Thygon fuel line instead silicone fuel line.

Jens Eirik

TimC

Thanks Jens. I have copied your's and Dennis's reply and saved them for when I can get the correct fuel.

TimC

Can someone tell me if the threaded in back-plate is a right or left handed thread?

sigrun

I had one of their .09's (still have it in the box) and another friend had the one of the .15's. Were cheap, so picked 'em up as a curiosity item when they first released. My .09 went like the clappers.....for about 6hrs running ...if that. Problem surfaced with it getting progressively harder to start cold. Eventually it wouldn't hand start at all no matter how much ether or castor content. It was a copy of some English 50's or 60's diesel. Someone told me which once. Might have been an ED. Good design, ran well whilst it did, but utterly crap metallurgy.

Try and 8x6 or 9x4 on that .15. 15FP prop sizes are too small even for a PB diesel. For instructions on setting compression for starting, go to the Eifflander's PAW site and follow the instructions there. You'll figure it out with a little experimentation. Oh, and with the Swallow, use a chicken stick. If the compression is porked, it'll be a cranky starter if at all, and as you'll learn, even little diesels hurt.

Backplate should be conventional thread as memory serves. No reason for it to be otherwise.

sigrun

Sincerely sorry Dennis, but no other way to say it but you're wrong on this in the case of Silver Swallow. IME the metalurgy of these engines was CRAP. Mine wore out in about 6 hours running, and my mate's .15 was essentially no better. My very first model engine was a Taipan TBR diesel, still running strong 36 years later. In that time, I've learnt more than a little about diesel fuels. Super Tigre G15RV team race, G15's & 20s, ENYAs, PAW TBRs etc and the crankweb cracking Cipolla .09 here. So please, don't start trying to justify SS' invariable failure with "wrong brew" or mishandling allegatons. Silver Swallow 1.5cc and 2.5cc diesels circa 1990 were a reasonable design, but employed rubbish metallurgy.

TimC

sigrun, I was able to un-screw the head but the contra-piston seems to be stuck. Jens said to flip it through to raise the conta-piston against the compression screw. How tight a fit is the conta-piston?

sigrun

The contra piston is probably gummed up with stale castor, which can make it a very tightly lodged fit. Try as Jens suggested. Just back the compression screw right off, prime and flip it through vigorously a few times. The contra-piston should back off pretty smartly.

If it won't, use the special tool supplied with the motor which is hopefully still with it or in the box, and unscrew the cylinder from the crankcase. Again, as memory serves it unscrews conventional thread. Get a piece of appropriately sized wooden dowel, insert and tap the contra-piston free. Remove any hardened gum scum. Reassemble. You could remove the head as well if you wished and give the top inc piston and gudgeon (which will probably be gummed if the contra-piston is a thorough degumming. If you intend doing this, it's easier to remove the head before you remove the cylinder.

PS: If the multi-purpose tool for removing the cylinder and backplate is missing, you could make one up or just use a piece of suitable sized and shaped dowel to shock the thread free without damage after which it should be hand turnable. Apply a little thread anti-freeze of some type and let it stand and penetrate for 10 minutes beforehand if it proves initially resistant.

dennis

My Feedback: (90)

Yes your right the metal is crap,however if run in as described and you use 1/2A fuel with about 25/30%oil you have a good chance to get a reasonable lifespan out of it.
As i said in my initial post quality of these motors ran from adaquate to absolutely horrible with most of them being horrible. But they did make a few good ones and i managed to get a few. Still have one that is 3 years old and still running and a few 2 year olds. But i wouldn't trust them to be run hard or on anything but really oily fuel. Kind of like the old slag motors that recommended a mixture of 50/50 oil and gas.
I had better luck with the origional one my brother got for me in the early 70's
I never have to justify any motor! I just use them.
Dennis

Tom @ Buzzard Bluff

Hi Tim,
You've recieved some good afvice, but may I offer a couple of alternative suggestions for freeing up the contra-piston that might well work and preclude pounding on anything with a hammer?
You said you have some old fuel that is suspect. Turn the crank to BDC. Remove the tommy bar completely. (T bar that adjusts the compression) Put the engine in a glass container that can be sealed tightly. pour in enough of the old fuel to cover it completely, cap it tightly and do other things for a few days or weeks. After it's had a long soak see if it will move. If it's still being stubborn break out your heat gun and get the cylinder head/cylinder hot enough to be quite uncomfortable to touch. That will usually re-liquify hardened castor enough to allow things to move. If none of the above work there's still the hammer.
I've had VERY good luck with the anti-freeze in a crock-pot method. So far I haven't yet had an old engine refuse to come unstuck after 24-48 hours of soaking in the hot anti-freeze, but I haven't tried it on a stuck contra-piston either so you're on your own there.
BTW, even if you get things freed up it's not a bad idea to use the heat gun to keep things free while trying to start the engine. I have had contra-pistons stuck so badly that they refused to move after starting. That can do bad things to rods and cranks. HTH, Tom

sigrun

Hi Denis,

With my .09 Yin Yang, I typically ran it on an all castor very oily PB orientated brew. eg: no IPN, Amyl or DII, just a straight 33% ether, 28% castor, 39% kero (clean burning heating kero). When it started to get hard to start, I upped the oil content to 30 and then 33% for a typically recommended idiot-proof low performance 33/33/33% PB brew of yore. Problem wasn't the fuel composition or constituent quality. It was just the metallurgy.

I don't know what you'd suggest a reasonable life for such an engine, but 6 hours even running minimum recommended prop and within maximum rated RPM wouldn't resemble even 10% of what I'd consider a "reasonable life" to me. I flog the living daylights out of my PAW TBR .15 diesels in Vintage combat running very high (for a diesel) RPM and low oil fuels. Apart from a singular rod failure due I suspect to the rear case partically unscrewing on one occasion allowing some longitudinal torsion or flexing induced load, they continue to run true and strong after over 15 years of such 'abuse'. Racing (of their day) Super Tigres similarly. Though the the G15RV does have a reputation of doing rotary discs, mine hasn't yet, and another mate's front induction G15 unit circa 1970 when we won Goodyear using it at the '71 State comps is still running strong!

Also never seen or heard of a "slag motor" diesel fuel recommendation of "50/50 oil and gas", nor understand exactly what you mean with a fuel which comprises 3 different components? If a model diesel engine is so bad a fit or worn/damaged that it ain't gonna run on 33% oil - which is heaps for a cold compression seal, more than adequate for cooling of the hottest running unit and way in excess of what is required for lubrcication - it ain't gonna' run period. Coincident with my own experience, upping the ether content beyond 33-35% in a PB unit isn't required except perhaps in a hottest most humid climate, and beyond 42% in anything effectively pointless if the many articles examining the subject over 50 years of "The Aeromodeller" accessible upon request from my state library's stack (archives) are any authority on the matter?

But back to Yin Yang's Silver Swallows. The experience with them of my particular flying pal of the time who was also a diesel fan with a tribe of diesels of all sorts was virtually identical. Several others remarked upon having 'enjoyed' an identical experience. Sounds like you lucked it with 'the'good one/s. Shame, as the design itself (.09) was reasonably powerful in class when it was running, and a reliable starter and easy tuner before that P&L wore itself out in such a short time. Though they can also produce some top performing and reasonably lasting units when they wanted to, it reminded me of typical Russian metallurgy and MARS diesels of the same era.

Hey. No manufacturer is perfect. I have a great little Cipolla .09 diesel here...well it would be it I had a crank which wouldn't snap at the web in double quick time in the course of ordinary running. Done two of them (cranks), as has everyone, without exception, I know of who owns/owned one. Strangely, the same engine in either glow version (PF7 button head or Junior conventional head) using the very same crank doesn't present with the problem. Seems the extra torque of the diesel just stresses the factory crank beyond it's limit. I've often toyed with the idea of having a strong enough crank made, but of course, cost benefit always triages in favour of just buying a PAW TBR instead.

sigrun

Perhaps such disinformative hyperbole could be avoided in future?

What was actually suggested was, quote: "Get a piece of appropriately sized wooden dowel, insert and tap the contra-piston free."

Quite different application of tool and technique from "pounding on anything with a hammer" - unless one is completely lacking in either comprehension or discernment?

In any case, if you pardon my mirth at the false alarm raised at the contemplation of the contra-piston being "pounded", precisely what to do you think the piston and contra piston do to one another upon each power stroke in a diesel? As long as a wooden dowel is used to avoid facing damage to any of the components, one could "pound with a hammer" as hard as liked without fear of damage, preferably with persuasion of a suitable lubricant, surface cleanliness and common sense of course prevailing. If it proved particularly stubborn, one could also use an oven to assist the process albeit with then associated handling irritation or even resort to rigging up a crude press. But why bother when tools readily and cheaply available to all such as a hammer used in conjunction with a suitably sized piece of dowel as a drift applied to the task with reasonable intelligence can safely and conventionally achieve the desired result in a fraction of the time?

TimC

I've got the head and backplate off and the engine is cooking in a crockpot full of anti-freeze. The contra-piston is still stuck hard after much Kroil and a heat gun.

Tom @ Buzzard Bluff

My, my, touchy are we?

No comprehension problems at this end. I readily comprehend that the dowel or drift or punch is merely a device to transfer energy from the hammer to the contra-piston. The end result is as intended, the force of the hammer blow winds up being expended on the contra-piston. Comprende'?

And please pardon my mirth at the assumption that it is others who are lacking in the comprehension of simple physics. Tom

sigrun

Less so that you're making quite apparent you are. In short, I just don't like disinformation or exaggeration.

Really? Well by that admission we can only presume the illiterative exaggeration was a deliberate attempt to disort?

Thanks 'me old china plate'. I 'comprende' completely. You are trying to make me appear stupid, but instead ending up achieving that result only for yourself.

Your alarmist nonsense in suggesting that the age old practise of using a wooden drift made of soft pine dowel, which will give first and absorb any excessive applied force, in conjunction with a modicum of applied intelligence in doing so will cause damage to the steel contra-piston is simply silly, and attemping to rationalise it with the pseudo-scentific nonsense written above does you no credit.

Fortunately Tom, gift from God or otherwise diligently endowed, I lack neither the attribute of capable comprehension nor an excellent and above average understanding than the layperson of mathematics and physics, though thanks for your expressed 'concern'. However, if you'll excuse me suggesting so albeit in a more helpful vein than you intended, you might benefit from application of an ounce of common sense, though in your case, it appears it might be best applied as suggested, with all the subtlety of a hammer. [/quote]

peterburford

Sigrun,
You have it right.
It looks like a real one, but 'it aint'.
Tim,
Do yourself a favour, put it on the shelf and get a 'proper' diesel engine.
Peter

TimC

The engine is out of the crock pot and the head is now minus much of the blue anodizing. It's spick and span though, and the contra-piston is still stuck. I tapped it a bit with a dowel and it went further into the cylinder. It looks like if the cylinder un-screwed from the case, it could tap it clear through, or go the other way with it. Does the cylinder thread off right handed?

injunnut1

Tim,
Yes, your engine's cylinder has right hand threads.

sigrun

Tim you should have a tool like this (see pic) supplied with the Yin Yan unit to unscrew the cylinder. Once you have, just tap the contra piston out and clean up the entire assembly.

As you haven't used diesels before, I'd reinforce what Peter said. Unless you are incredibly lucky, this one will probably make you hate them once you get in on the test stand. The Silver Swallows are not characteristic of any ½ decent diesel engine.

A well manufactured diesel engine is an easy start and tune, particularly the TBR variants. Once warmed and tuned, they are a single flick start every time and should give ultra reliable running for years.

AMB

Have been following this post guess I am lucky the only engine that I got burned on was an Indian made copy of the taplan twin
It came with a destroyed center bearing compression screw hole on one cyclinder stripped very CRUDE hand file marks on some parts
it NEVER ran just popped a couple of times and it was not cheap I sent it up to AJ to take a look at beyond hope and not worth his or
anyone elses time to fix 3 pc pinned crank has bearing trapped a total POS martin
I noted on the posts that one of the guys has one and its fine -- maybe different maker??

Hobbsy

My Feedback: (102)

An even better choice is a piece 1/4 inch ply across the head end of the cylinder and use a C-clamp to push the contra to the top of the cylinder, this still works if the contra is in the head. This way you have some control and less violence.

TimC

I don't have the tool for removing the cylinder. Would it be possibe to run a flatbar of the right size through one exhaust port and out the opposite port with the piston at BDC?