Has anybody built the steam engine kit : (40701) Liegende 12/36 ?

[Neil WyattModerator @neilwyatt]

The poor design is (technically) using a piston valve without any drain cocks, this wouldn't be done in full size, although common enough in small models (I've done it myself). The 'perfect' fit of the Teflon rings makes it worse and there really is no-where for the trapped water to escape to.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Brian John on 11/08/2015 17:37:11:

Michael : Wait until I have the lathe ? How would I use the lathe to make a 90 degree pipe bend ? That is not something I thought I would be making on a lathe.

Jason : yes, tubes into a block should work.

.

Brian,

You have already answered your own question !!

I did not suggest using the lathe to make a pipe bend …I suggested making elbows.

You have already shown us elbows in your ebay link. I was suggesting that you made something functionally similar, but styled to your taste [and maybe even with screw threads]

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Brian,

You may find this thread, on HMEM, of interest.

MichaelG.

 

Edited By Michael Gilligan on 11/08/2015 22:26:23

[Brian JohnParticipant @brianjohn93961]

Now this is exactly what I have been looking for but it is designed for 5/32 pipe. Do you think it would work with 3/16 pipe ?

**LINK**

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Brian John on 12/08/2015 13:19:41:

Now this is exactly what I have been looking for but it is designed for 5/32 pipe. Do you think it would work with 3/16 pipe ?

.

Short Answer = No

Longer Answer = Given that they do two different versions, one for 1/8" and one for 5/32", I would very much doubt it; so let's say No.

MichaelG.

[Brian JohnParticipant @brianjohn93961]

I am very puzzled. This engine was running beautifully last week but I cannot get it to run well now. I keep fiddling with the valve timing but nothing seems to work. It only runs on the middle setting in both forward and backwards directions. The engine stops when it is put on slow or fast setting in either direction.

[Neil WyattModerator @neilwyatt]

Give it a liberal dose of oil and run it in on air for a few hours, re-oiling now and again.

Neil

[Brian JohnParticipant @brianjohn93961]

I have pulled the engine apart and examined it closely. Putting steam oil into the main cylinders does not help…just the opposite. I am surprised as the PM Research engines love having some steam oil direct into the piston. I suspect that this is because they use piston rings but the Liegende engine uses a weird Teflon wrapping arrangement which I do not like.

I also found that the eccentrics were binding a bit so I have polished things up with 2000 grit sandpaper. The engine is running much better now.

Some observations :

1. The engine runs better with my thumb over the main cylinder rather that the cylinder cover !

2. It does not like steam oil placed in the cylinders which makes me wonder if fitting a displacement lubricator is a bad idea ?

3. The length of the main piston rod does not seem to make any difference at all to the running of the engine whereas the length of the control valve rod is crucial and slight adjustments result in major fluctuations in speed.

4. I am very surprised at how quickly the various nuts and screws work themselves loose on this engine. This does not happen on the two PM Research engines I have built.

Edited By Brian John on 16/08/2015 07:47:59

[JasonBModerator @jasonb]

1.Check the piston wa snot hitting the end cover

2. The steam oil in teh cylinders can't be compressed so you are hydralic locking the engine and could damage it, a displacement lubricator will add minute amounts of oil which will be carried out of the cylinder again in teh exhaust rather than a big blob from an oil can. Also don't use steam oil when running on air as it is too thick at the lower temperatures.

3. The control rod alters the timing therefore when and how much steam is admitted to the engine, a bit of leyway on the piston won't stop it running but would affect things if the engine were put to work

[Brian JohnParticipant @brianjohn93961]

1. No, it is not hitting the cylinder cover.

2. Okay, thank you for that information. I thought it might be compressing the oil.

Jason : Please have a look at number 4 above. I think I added that after you responded.

[Neil WyattModerator @neilwyatt]

1. The engine runs better with my thumb over the main cylinder rather that the cylinder cover !

As your main problem seems to be hydraulic lock, made worse by putting an appreciable amount of oil into the cylinder this is not a surprise – you thumb is elastic and can deform allowing the piston to push past dead centre, the cylinder cover can't.

Minor changes in piston position won't make a difference as long as there is some clearance volume at each end.

Until you get it running without water/oil the cylinders will be jarring as they turn over causing excessive forces and vibration.

I strongly suggest running it in on air as described earlier.

Ironically, its the combination of a piston valve and the much better seal of the teflon rings that appear to be causing your problems. To get it to run successfully on steam you may have to fit drain cocks.

Neil

[Brian JohnParticipant @brianjohn93961]

Yes, I am starting to doubt that this engine would ever run successfully on steam. Compared to the PM Research engines, I do not think that it has been designed well. I was thinking of making some proper pistons with piston rings using my lathe when I get it but I am not sure that this would solve all the problems. Finding Teflon piston rings to fit could be a problem too.

[JasonBModerator @jasonb]

This pair seem to be running reasonably well on steam

[Brian JohnParticipant @brianjohn93961]

Yes, and he does not seem to have any problems with piping the steam away either. I will have another go soon with live steam when I get it running smoothly on air. I am also waiting for a new 3/16 pipe bender to arrive.

[Brian JohnParticipant @brianjohn93961]

My engine is running quite well in forward and reverse but only on the medium speed settings in either direction. Last week it was running on slow, medium and fast in both directions. The problems all started after I tried running it on live steam but I am not sure why.

[Brian JohnParticipant @brianjohn93961]

I think I have had some luck. There were two parts in the kit which are not mentioned in the instructions. I was told that they were probably ''spares'' as this kit has been modified many times over the years. One part was a thin brass spacer : two of them (parts 59) go either side of the crankshaft to keep it apart from the support brackets. I have placed the third one between the straight rod eccentric and the outside of the crank support. This stops the straight rod eccentric from rubbing on the crank support.

There was also a 6mm ID brass bushing (part 8) which is shown in one photo but not mentioned in the instructions or the diagrams. I had placed this on the axle between the flywheel and the crank support as it seemed to be almost the correct distance for the flywheel to be. But I have noticed that the bent rod eccentric does tend to splay out a bit on the axle and this causes things to bind up. I have drilled and tapped the 6mm bushing to take a 3mm X 3mm grub screw and the bushing is now firmly up against the bent rod eccentric. (My serial taps and grub screws only arrived yesterday !) The bent rod is now staying in place and the engine is running much better.

Where can you buy 6mm ID brass bushings or thick walled brass pipe to make your own ?

 

Edited By Brian John on 18/08/2015 03:31:34

Edited By Brian John on 18/08/2015 03:37:50

Edited By Brian John on 18/08/2015 03:40:28

[Neil WyattModerator @neilwyatt]

Brass pipe with a ~3mm wall thickness will be hard to come by, but some 10mm /3/8" brass rod and drill out once you have your lathe. fixed bushes don't need a perfect hole.

Neil

[Brian JohnParticipant @brianjohn93961]

Now that my taps and dies have arrived from the UK, the solution to the exhaust problem was obvious. I took two of the PM Research 90 degree L's which are threaded 3/16-40 and tapped one of the holes with my new 5mm X 0.5 (fine scale) serial taps. The L's have now become 5mm to 3/16 adaptors. Cutting the 5mm thread was easy as I simply used the 5mm plug/bottom tap on the existing 3/16 thread…no drilling required at all. I will cut some longer brass pipes tomorrow or perhaps bend some copper tube when my new pipe bender arrives. When you have the right tools then everything is easy !

 

Edited By Brian John on 20/08/2015 07:30:21

[Brian JohnParticipant @brianjohn93961]

The only pipe bender you will ever need (no moving parts) ; it does 3/16, 1/4, 5/16, 3/8. It produces a perfect bend with no kinks in brass or copper but I chose brass because I wanted to put a thread on it. I still can't thread copper tube…can anybody ?

NOTE : the engine is running very nicely now. Putting that bushing against the eccentrics seems to have helped a lot. I will try it out on steam again soon.

Edited By Brian John on 24/08/2015 03:00:39

Edited By Brian John on 24/08/2015 03:01:44

[Brian JohnParticipant @brianjohn93961]

Update on steam testing : The first test produced a lot of water leaking from the packing nuts so I repacked them with TFE tape but the engine still refuses to run well on steam. As soon as water gets in the pistons then it locks up and it only has to be a tiny amount of water. As soon as I blow the air out by hooking up to a compressor then all is well again.

I have tried only half-filling my vertical boiler with water but that does not help. I have also raised the engine above the level of the boiler to see if that helps but it doesn't. That seemed to make it worse. I think my only options here are to either fit cylinder drain cocks but there is not much room on the cylinders :

http://www.ajreeves.com/cylinder-draincocks-316-x-40-4-6551-p.asp

or when my lathe arrives tomorrow to make proper pistons with piston rings as per the PM Research engines which do not have these problems.

Where would I buy or how would I make piston rings for small pistons like this ?

NOTE : the extra gland packing has made a huge difference to how this engine runs on air. Turn the compressor off and the engine seems to run on forever so that is some good news.

 

Edited By Brian John on 24/08/2015 07:45:08

Edited By Brian John on 24/08/2015 07:47:30

Edited By Brian John on 24/08/2015 07:52:12

[Neil WyattModerator @neilwyatt]

Hello Brian,

I think you may be disappointed.

The difference between the two engines is almost certainly the piston valve in the latter one. The first engine's slide valve happily releases over-pressure.

If you make a good job of the piston rings, they will be equally effective at sealing the piston and you will still get a hydraulic lock.

If piston rings solve the problem, it will be because they are leaky and although the engine runs, it will be inefficient 9which may not matter)..

The answer is either drain cocks or rocking the flywheel gently back and forth until enough steam works through the system to heat it through.

Neil

[JasonBModerator @jasonb]

Neil, the PMR engines are also Piston Valve not slidevalve, they do have the exhausts at the side which may help a bit.

Edited By JasonB on 24/08/2015 10:06:53

[Brian JohnParticipant @brianjohn93961]

Okay, so perhaps the difference is that the Leigende engine's piston valve has two very efficient Teflon seals (see photos at beginning of this thread) whereas the PMR engine has no seals ie. it is just a metal piston in the cylinder and that this arrangement allows water to escape via the exhaust.

Perhaps my first job on the lathe is to make a valve piston with no seals and see if this helps. I would copy the Liegende piston and make it slightly larger in diameter.

I do not think there is enough room on the Liegende cylinders to fit drain cocks. There would have to be four of them wouldn't there : at both ends of both cylinders ?

Edited By Brian John on 24/08/2015 11:24:03

Edited By Brian John on 24/08/2015 11:25:03

Edited By Brian John on 24/08/2015 11:26:04

[Brian JohnParticipant @brianjohn93961]

When my lathe is operational I am going to have a go at making a piston valve and a main piston. I don't see the point in mindlessly churning through scrap : I want to have an idea to work with. The Liegende engine runs beautifully on air and I want to see it running equally well on live steam.

The piston valve will not have any rings and will be made of brass. Both this engine and the PMR engines valves are made from brass. Will it have to have that curved part in the middle or will a straight shoulder suffice ? The PMR engines have a straight shoulder.

The main piston on both this engine and the PMR engines are made from steel. Would it be okay to use aluminium instead ? I intend to make two pistons : one with and one without a piston ring to see how they both run.

Edited By Brian John on 01/09/2015 14:28:06

[john carruthersParticipant @johncarruthers46255]

Have you tried pre heating the cylinder to reduce condensation until the steam 'gets going'?

I have an engine that has to pump the steam feed pipe clear of water and heat the cylinder through before it runs smoothly, can take several minutes. A rag helps contain the exhaust of scalding water/oil mix until it's hot and happy.

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