Member postings for Brian John

Update : with a sharp scalpel I trimmed away as much flash as I could from the ball valve and it ran for a full two minutes before stopping. Why does it stop ? If it runs for 2 minutes than surely it should be capable of running for 15 minutes ! My only conclusion is that as the ball bounces around it eventually ends up in a position that is not giving a good seal. Bring on the Nitrile balls !

I have built a crankshaft like this before for the Bengs flame eater and I did not have any problems. But when I attempted to build a second one with the supplied crank plates I found that the small and large cranks are out of alignment ie. not in the same plane when looking from the top. What went wrong here ?

The holes are already predrilled (about 5.9mm). I only had to ream them out to 6mm on my drill press as I did before.

Edited By Brian John on 23/07/2016 08:08:35

Edited By Brian John on 23/07/2016 08:08:55

I have ordered a set of 3/16-40 drain cocks from Live Steam Models in the UK which have not arrived as yet. In the mean time I remembered that I did not polish this flywheel because I did not have a lathe when I built this engine. The flywheel was machined but not polished. So I mounted it on a mandrel, gave it a light machining to removed the paint and a few wobbles and polished it up. The engine runs very well now that a displacement lubricator has been fitted.

When fitting drain cocks, should some sort of thread sealer be used or is it not usually necessary ?

Edited By Brian John on 23/07/2016 08:00:25

This air compressor has worked fine for about three years but it is now losing power and barely pumps enough air to run my airbrush let alone my steam engines. Before I go opening up this air compressor can somebody tell me what the problem might be and what I should be looking for ?

Still no luck with this : I have cleaned up the exhaust as Jason suggested. It looks much cleaner now but it has not helped. The plans only call for the hole to be drilled, not reamed so I did not have a 5H7 reamer on hand to do the job. One is on order now from HK but that will take 3-4 weeks to get here.

I called Allied Bearings this morning : they have no Nitrile balls but they will try to obtain something from ''down south'' (meaning closer to civilised areas). They did not even have a 6mm steel ball bearing...only 6.35mm. I have ordered some 6mm steel ball bearings from HK.

Who can supply Nitrile balls in the UK ?

Jason : I have made many experiments with the timing. That is what I meant about the setting of the slide valves. It is done with the cam. Moving it from where it is now and the engine runs badly ; there is not much leeway with that. At least I know that is in the correct place.

I was already having some doubts about the seating for the ball. But before making any changes there I will try a steel ball or a Nitrile ball as suggested.

I had a few more goes today but two more 60 second runs is the best I can do. The slide valve is easy to find the correct setting : 1mm of change either way and you can tell it does not like it. The ball valve has about 2mm of adjustment up and down ie. the engine will run within that range. I would not have thought it would be so hard to get this engine running because the correct settings are easy to find.

1. What else could I use as a substitute for the ball valve ? It is made of rubber and is 6mm in diameter.

2. What makes the pop sound : is it the ball valve or the slider plate ?

Nick : aha, I think I see what you mean now. If you look at the dates of those earlier comments you will see that there has been quite of bit of swarf under the bridge since then (please excuse the mixed metaphor).

Howi : I have built two of the Bengs Stirling engines and one flame eater engine (not quite operational yet). I am not keen on machining the column in one piece as I think it would require the use of a steady which I do not have. I will take note of your advice regards the flywheel : I agree that the smaller wheel might look a bit odd.

I always try to make sure I have plenty of replacement nuts, bolts and bar stock on hand before I start any project. I do not like to be held up for weeks waiting for parts to arrive in the post.

I had intended to build the ''John'' Stirling engine from Bengs as my next project but Mr Sjani from youtube said he found that quite a difficult build ; getting it to pump water was very tricky. You can see from his videos that he is a very talented engineer and if he had problems with it then I think I should stay well away from it !

Edited By Brian John on 20/07/2016 17:43:46

Not blunt...just unclear ?

I am lining up my next project and it looks like it might be this beam engine. The problem is that it has a 100mm flywheel but the maximum I can turn on my lathe is an 80mm flywheel.

1. Do you think the beam engine would run okay with an 80mm flywheel ?

2. Would you turn the aluminium central support as one piece or three pieces ?

Mr Sjani from the youtube link I posted above suggested that the ball valve might be part of the problem. The rubber ball valve is not perfectly round and there is a bit of flash or mould line around the centre. He suggested putting a 0.5mm pin through the ball so the pin sticks down the exhaust hole and this keeps the smooth area of the ball in contact with the hole...not the raised edge which would cause a bad seal.

I tried that and it has helped. I got the engine to run for 60 seconds under its own power today. That is a big improvement. I think the slider plate is still getting stuck sometimes so I need to look into that next. The engine is very sensitive to slide valve, ball valve and flame placement : all three have to be just so.

I am a bit puzzled that many youtube videos of flame eater engines say that they have to preheat the cylinder to get things going. Mine works best when cold ; the instructions confirm this.

Edited By Brian John on 20/07/2016 09:38:46

Yes, I am using methylated spirits. I am getting a bit confused with the terminology here...sorry !

Put it this way : what could I use as fuel that will burn even cleaner and not leave sooty deposits ?

Edited By Brian John on 19/07/2016 18:35:02

Yes, supposedly the same stuff but why is the inside of my cylinder contain black soot after 20 minutes ? This interferes with the smooth running of the engine by increasing the friction.

I am using the supplied fibreglass wick. I do have some Kevlar wick material on order which should be here soon. Perhaps that will make a difference.

Edited By Brian John on 19/07/2016 18:30:33

Edited By Brian John on 19/07/2016 18:32:47

This engineer uses methyl hydrate to run his flame lickers and he rarely has to clean the cylinders at all. Have a look at his other engines. He does some nice work.

**LINK**

I watched a few youtube videos today and one guy uses sewing machine oil in the cylinder of his flame eater and it runs very nicely. So I decided to try that again with no luck. I am getting an excellent seal ; it is very difficult to push the engine in reverse because the seal is so strong. I do not think the piston/cylinder fit is the problem here but I do not know what is.

I am wondering how I can turn this into a Stirling engine .

Edited By Brian John on 19/07/2016 09:46:36

Do you mean the slide valve (not the ball valve) ? Yes, that can be disconnected.

I am also thinking of trying a drop of motor oil in the piston/cylinder as this has a higher flash point than the sewing machine oil I used in the Stirling engines.

I watched a youtube video of a flame eater engine yesterday : the guy took about 10 minutes to get it going !

Edited By Brian John on 18/07/2016 13:18:10

Edited By Brian John on 18/07/2016 13:31:33

No...still no luck. I know it is very close but I am not sure what else I can do to tip it over the line. I might put this aside for a few weeks and move onto something else. I may get some ideas in the mean time.

Edited By Brian John on 18/07/2016 11:26:43

Yes Ian, it does that but I will make a second piston anyway.

The second piston is a slightly tighter fit with better suction. This one does not drop through but it will push through so I want to try it. After a bit of mucking about with the valve settings it ran for about 15 seconds under its own power then promptly seized up. At this stage there is no graphite powder as I wanted to see how it went without it. I will let things cool off, add graphite powder and try again later.

I think flame eaters are more difficult to get going than Stirling engines : you cannot add light machine oil to the cylinder to help things along.

Edited By Brian John on 18/07/2016 09:34:14

I have just reread the instructions to see if I may have missed something :

''When given a push the engine should diesel for another 2-3 rotations and not stop abruptly.''

My engine runs for about 10 revolutions ; I should have more friction/resistance. Tomorrow I will make another piston and see if I can get a better fit. I doubt it but at this point I will try anything.

I solved a few problems today. The graphite powder works well and the piston is now a very smooth fit in the cylinder, even when hot. I polished out the etch marks from the inside of the cylinder head cover as I suspected that this was causing the slider plate to stick. My assumption was correct and the slider plate is moving more freely now and never gets stuck. It still would not run so I fitted a gasket between the cylinder head and the exhaust plate just in case I did not do a good enough job getting a good fit between those two parts. I found making the cylinder head the most difficult part to make without a milling machine.

After all that, it still will not run....very close but no ! I am fresh out of ideas now.

Does the presence of the ''pop pop'' sound indicate that I have a good sealed system ?