william hanshaw

I recently acquired a Russian Elfin 149 ABC Repro that I've tried unsuccessfully to run. It's so tight it squeaks during hand turnover. I have gotten a few "pops" out of it - but no continuous run, even with prime at closed cylinder or three drops of fuel into venturi, with NV closed, etc. Pretty standard procedures. Does anyone have some positive comments other than using it for a paperweight? I've read that some pretty experienced dieselers (including Earl W.)have also been unable to run their ABC Elfins. However, I've read that some others seem to have had good results with their ABC versions. In my opinion, the engine seems to be pretty good manufacture, but I don't have ABC experience to speak of.

Also, what fuel should I best try using? I have Aerodyne, DDD non-1/2A, and various home-brew mixes. Anyone?

qazimoto

My Feedback: (1)

The topic has come up quite a lot on this and other forums. The problem is the cylinder taper is all wrong. Most of the ABC ones don't run.
I have seen one that did. They must have got the taper wrong :-)

This is part of my personal problem with some US diesel outlets that still sell older style diesels with running problems.

My suggestion is to put it in your engine collection and move on to other projects.

Ray

AMB

William I do not know if the following is true or old wives tale.. back compression screw very far or or take out completely use some oil only not fuel light oil maybe
maybe ATF?? spin with an electric starter for short bursts maybe 6 times or so, then see how it feels hand flipping, if better fuel, bring down compression screw and try a start martin

As loctite stated if taper is that bad may be a lost cause

earlwb

I have two of those Russian Elfin replicas and neither one ever ran for me, not even a pop. But they seemed to be leaking out of the top of the head via the adjusting screw, so I suspect the contra pistons aren't sealing up well on them. One of these days I'll see if I can fix them or not. it may be futile though if the cylinder piston fit is wrong too.

ffkiwi

They can be got to work Bill-but I suspect there are more bad ones than good ones. Nothing wrong with the design-but a little bit wrong with the execution! Mainly too much taper in the ABC liner-it is believed the manufacturer had a lot of experience with ABC glow manufacture-but little or none with diesel. The problem is with too much cylinder taper, the heating of the charge under compression as the piston goes up does not start until almost TDC-so is less effective-and there is less time to heat the charge-so the engine fires with difficulty, or not at all. With a more gradual taper, the heat of compression starts earlier on the upwards stroke, and occurs over a longer period.
This is one case where I would-VERY RELUCTANTLY-recommend the use of an electric starter, since it is cold starting that is largely the problem with these engines. You need to start with the compression well back. How easily does the contra piston move? If easily, then I would suggest the old trick of winding it in until it hits the piston-with the piston at TDC obviously!-then backing off one complete turn on the screw, and getting the contra to move back to this new reduced setting. This usually gets you to a position close to starting compression in most engines-I'd then back it off another half a turn to be safe when using the starter. You then proceed with caution, using an 8x4 or 7x4, and with the prop turned backwards against compression (to give the starter a chance to accelerate the piston) try applying the starter. Don't even think about trying it unless you have a spinner nut fitted to the engine-and don't use a jumbo sized starter! [conversely, don't try a 1/2A sized one either!]. I'd start with the needle about 2 turns open,-and don't choke or prime the engine-but ensure fuel is in the line up to the spraybar. The starter should turn the engine over fast enough to suck fuel through. Above all, avoid flooding it-this is concert with an electric starter will give you a bent conrod at best...........
If the engine fires-well and good-see if you can keep it running using the comp screw-if it doesn't fire-and fuel is getting through-try advancing the compression slowly until the engine starts to fire, at the same time as you're turning it over with the starter. [you may need another person to assist-depending on your engine mount and fuel setup]. DO NOT sit there grinding away with the starter-apply it for bursts of about 5-10 secs max-if the fuel is there, and the compression setting anywhere close, the engine will fire. Keeping it running is another matter. If no joy initially, open the needle half a turn, and repeat the process. If you ever get to the stage of flooding it, close the needle, back off compression up to one full turn, and apply the starter again in short bursts, slowly advancing the comp if needs be until the engine fires and clears the flood, then reopen the needle and resume! This whole process could take some time, and is likely to be frustrating............but the aim is to get the engine running-and keep it running. Hopefully you have a decent tank setup, -level with the needle valve etc etc.
If you can get the engine to run continuously-even if it peters out and stops after a relatively short period (you want it to run at least 30 seconds-and ideally for 2-3 minutes) then you're on the way. I hope by now you know the difference between too rich and too lean on a diesel. Bear in mind that ABC engines do not run-in slobbering rich on big props like steel P/L technology-but in short fast runs. If the fits are correct (and I'm talking piston-cylinder clearance here, not liner taper) in an ABC engine the P/L clearance is only correct when the engine is hot-the faster expanding brass liner has moved away from the piston to give the correct running clearance-which is why ABC engines are so tight when they're cold-and even worse when brand new. Its bad enough when dealing with a glow, let alone a diesel.........!
Best of luck-I have 3 of the Russian Elfins-one is great, one is average, one is a pig............

ChrisM
'ffkiwi'

Diesel Die-hard

I have a couple of the iron-and -steel replicas from the same maker. Both run quite well. I'd recommend sticking to that technology with these engines. It worked in the originals ...........

ffkiwi

Aye-but they only made the ferrous ones after the stuff up with the ABC ones..................

ChrisM
ffkiwi

gcb

Mine doesn't run either. It will start but the cylinder expands, then it quits. I thought of cutting a groove for an "O" ring on the contra, but never bothered.

George

qazimoto

My Feedback: (1)

I'd rather fit a large fine pitch prop and fill a thermos flask with boiling water.

Take it to the running bench, and fuel the motor up for running.

Decant some hot H2O into a foam coffee cup and pour it over the cylinder while carefully shielding the engine orifices.

Immersing the cylinder in the water would be best but presents a few other problems.

Get the cylinder nice and hot and prime and hand flick hard etc.

It's worked for me with very tight AAC and ABC diesels and glows for the first few initial runs with no bent rods etc.

Ray

qazimoto

My Feedback: (1)

Actually another ABC Elfin solution just occurred to me. I've had some good results sending ABC liners to Ray Aronica the well know US Cylinder "pincher".

It's a long shot but he may just have a r/c car engine jig that would fit the Elfin.

It's quite possible that he may be able to reset the taper enough to run it.

His details are: [email protected]

http://www.rayaracing.com/

Ray

AMB

EARL Just an idea if the contra that leaky how about machining for an O ring?? martin

Recycled Flyer

Ray, perhaps restoring pinch in the lower portion of liner above the ports may encourage the piston rim to catch in those ports edges, much the same as a ring would in an unbridged port.

The upper portion of a squeezed liner has no such problem.

qazimoto

My Feedback: (1)

Have you ever seen an Elfin 1.5cc diesel?

I don't think so!

earlwb

Yeah I was thinking that very same thing too. But the contra piston actually fits into the top of the cylinder on these engines. So maybe it won't work.
I was rather irked with the engines, so I was letting them sit until I am not irked so much with them, before I tried fixing them.

I was thinking about giving it a go by heating up the engines with my heat shrink tubing gun. Then see what happens.

They are likely doomed as the cylinder is ABC. I just took a look at the photos I took previously. But maybe with some work on the contra piston they might run. Hard to say for sure.

AMB

Think Loctite nailed it had they stuck with ferrous you can lap to get the right fit you are SOL on the ABC will not work martin

AMB

Earl thats makes 2 Locktite and you and the ABC liner issue martin
they do it cheap there also no plating would have been needed and the ferrous thing has worked for what 50 or 60 years??? surprised they did not follow suite

earlwb

Also the OP as well, has a engine that doesn't work.
I think someone who knew model engines had the idea that they could make the Elfin clone better than the original. The prototypes probably all worked great. But when they went into production was when it failed due to things like piston to cylinder fit and the contra piston fit.
There may be something else too. Maybe the intake ports weren't cut correctly or not at all. I remember on engines like this the intake ports are usually just below the exhaust ports. There were some other engines that had problems with that too, not just these Russian ones.

Using ABC or AAC cylinders and pistons does work with model diesel engines as Enya, Parra and some other Russian specialy engines all do it with success.

Diesel Die-hard

Quite right - one of my all-time favorite diesels for powering more recent designs is the blue-head Webra Speed 28 diesel from the 1990's. An ABC masterpiece which starts and runs superbly.

AMB

Earlwb I agree with that one whether Classic steel cylinder, iron piston ringed, not ringed AAC ABC if made right they all start, run and last,
In the engines picked for conversion heads that Davis has made since 1975 no issues, they just have to be made right to begin with. martin

Of course you can have a failure in any product thats why we have warranties on the quality stuff

roo

William, I would try one more thing if all the good advice you have been given here does not work for you. I had a similar problem with a chinese diesel. After countless flicks and attempts with an electric starter I fitted a HUGE heavy propellor and added more ether to the fuel. Flick starting then worked!! Short runs then gradually resulted in longer ones until I could slowly reduce the propellor sizes. Worth a try before you bin it. Regards. Paul.

earlwb

You know, I was thinking of trying more ether too. I need to get some John Deere Starter fluid, but maybe a squirt of it in the exhaust port might get it to start and run shortly too. Or just add it to the model diesel fuel.   I wonder if the Elfin clone could handle the old Drone engine formula of 75% ether and 25% mineral oil. At least to get it to run for a while.

ffkiwi

I may have said this before on this-or perhaps another forum. A synopsis of the Elfin 149 debacle. In the mid 80's, Ivor F-the man behind the earlier highly successful Doonside Mills 75 and Sesqui 1.5 glow and diesel projects commenced work on a replica Elfin 149 PB-these engines being deemed the best of the British vintage 1.5cc/09 cu in designs of their era. Bear in mind that this was before Ebay-and the only alternative to getting lucky and buying a very second hand original, was to produce a replica. And there had been the very successful Mills replica project and the Burford deezil and Elfin 249 replicas.The projected market for the 149 was the Australian and NZ vintage fliers, general sports use, and collectors. Equally bear in mind that the only 1.5 diesels available new anywhere would have been the PAW 149 and the Russian MK17.A number of Australian modelling luminaries were involved, making different parts for the engine. Sadly, there was little overall coordination, and most of the bits-though beautifully made-would not fit together [I have personally witnessed this in Ivor's workshop-and seen all the bins of hundreds and hundreds of completed Elfin 149 parts-that won't fit together. I was there with Lloyd Willis-we were there for the entire afternoon-and in that 4 hour period Ivor managed to assemble 2 engines-one of which I own!]. At this stage the project had lost $50,000 or more-with little hope of recovery. This was back in 1990-22 years ago. Ivor then negotiated with the Russians (who exactly has never been made clear) to produce 1000 Elfin 149 replicas, which could be quickly sold to recover part of the costs-and partially restore the damaged reputation-of the Australian Elfin project. He stipulated that he would personally inspect each engine before finally accepting delivery. The Russians duly went ahead and delivered the engines as contracted-except that they were all ABC (the few Australian made ones had been ferrous)-'I didn't tell you to make them ABC' said Ivor. ''Well zis is the vay ve make zese engines" said the Russians. Mutter mutter mutter went Ivor-and proceeded to make good on his promise of checking each and every one.....
The outcome was something along the lines of 'these 250 are OK-the rest are junk, and I'm not paying for them.....' Mutter mutter mutter went the Russians and went off in a huff uttering dire threats.

So Ivor ended up selling ABC engines that met his quality standards-these are the Doonside ABC Elfins, and they come with a hand written dated certificate from Ivor. The russians of course, now found that they had inherited a lot of dodgy unsold Elfins that THEY now had to get rid of to recoup THEIR costs-so they offloaded them all over-some in Australia, some in the US, some in Europe. Subsequently-perhaps when things had cooled down a bit-it was decided that there was nothing basically wrong with the production methods-and that good old ferrous technology was better in this design-and then the steel Russian made Elfins appeared. I am unsure on exactly when this occurred-my best guess is the mid 1990s. I am equally unsure whether a single Russian manufacturer was involved-or several [I suspect initially there was one, but subsequently manufacturers may have changed.]. So the sequence went: Australian made Elfin 149 (steel)->Russian 149ABC->(sold by IvorF)->reject ABC engines sold elsewhere->Russian steel version produced->sold widely->now both Russian versions available from several sources. Total production unknown-but probably at least several thousand

There is a slight corollary to the story. A supplier-Mach East- in Australia, sold the russian Elfins and a variety of other russian engines-MDS glows etc. He had a NZ agent, the late Des McAnelly, who was a noted CL speed flier and engine man. The Elfins and MK17 diesels were the biggest sellers in NZ, and Des realised the that basic problem with the Elfins was that they were set up to tight and with too much taper. He checked every engine that passed through his hands, and having both the equipment, and the engine knowledge, honed the liners to improve the fits. So a Des McAnelly breathed on Elfin 149 reject was actually a better engine than one of the 'passed Ivor F QC' ones. I should know-I have four in total-an original Ivor F steel, an Ivor F ABC one, a Des McAnelly honed 'reject' ABC Russian one, and an ABC one obtained second hand of unknown status (but probably one of Des' ones). That being said-the Ivor F steel is the best handling one, the Des McAnelly treated reject is the fastest on an 8x4 or 7x4, the Ivor F ABC a bit hard to start but runs OK, and the 'unknown provenance' one has only been bench run and is a pig to start.

So when it comes to replica Elfin 149s its a very tangled web..................

ChrisM
'ffkiwi'

earlwb

That is a great story, thanks for sharing.

ddd

To free up your engine attach an electric drill after putting some tape to protec shaft t. Lightly oil and back out compression screw. run the drill in reverse for a few hours oiling periodically. The chrome will not wear but the piston will. After you have freed up the engine to flip ready state invert the top of the engine in a glass of water and check for air leaks.

123Cat

Try a heat gun on the cylinder and really big prop and lots of ether and it should go

Looks like a classic Diesel

Or some of the Gurus here can hone the piston for free