Has anybody built the flame eater "Nick"?

I have the kit for "Big Nick" and this comes with a 2 axis adjustable burner, it looks like yours but a little higher sliding on two 3mm rods operated by another hand wheel and M3 studding. Hope this helps.

Paul

Could scan the drawings if you would like.

That would be a big help. I have a fairly good idea what I need to do but drawings would help clarify the matter. I am not sure why they have not supplied such a burner with this kit as it really does need to be adjusted in 2 axis.

After much fiddling about and trying many things, I have realised that this burner as built cannot be fitted with horizontal adjustment. Any horizontal adjustment would mean raising it higher and even 4mm higher places it too high. I think the vertical adjustment on this is totally superfluous : at its lowest setting is where it is supposed to be so why raise it higher ?

Having ascertained that the burner must be fitted flat to the wooden base, then that means the adjustment wheel must hang over the edge and that means bringing the engine base in closer. The diagrams show the engine base to be right on the edge at the other end but that would mean it would be about 20mm from the burner flame...not very useful ! The engine base must be 18mm from the edge of the larger wooden base and this should put it in the correct place (hopefully). I have had to take the whole thing apart to redrill two more holes so I can shift the engine base.

NOTE 1 : the instructions do not give any measurements for placement of the burner or engine on the wooden base.

NOTE 2 : perhaps reducing the length of the wick nozzle would allow for some vertical adjustment. I might try that if I build another of these engines.

Edited By Brian John on 09/07/2016 09:28:53

Edited By Brian John on 09/07/2016 09:29:52

Edited By Brian John on 09/07/2016 09:33:16

The spare parts arrived from Bengs so I have had another go at some of the parts which previously gave me problems. I have started machining the flywheels but this time I did not ream then out to 6mm; I just drilled them out to 6mm and I now have a perfect fit with the supplied crank and there is no wheel wobble. Same thing with the crank plates : they were drilled out to 6mm and not reamed for a perfect fit.

I did try to silver solder the cylinder bracket (part 19) but that was not successful as my soldering tile which was mounted on a wooden saw horse exploded due to the high heat. It really went off with a bang.

Lesson learnt : home made soldering station is only for soft soldering !

The instruction do not say which solder to use for part 19 but I have since received advice from Bengs that it is to be soft soldered.

I was going to silver solder the second crank shaft to the crank plates to see if it would distort as warned in the instructions but I think I will just stick with soft soldering it together as I did with the first set. I have had enough excitement for now.

Edited By Brian John on 12/07/2016 09:36:13

For a brazing hearth you,v got to be careful with the materials used, I find the best to use is the soft Hebel bricks, they reflect the heat into the work, and don't absorb it. I'v only got bits of these bricks, and my hearth is a angle iron frame with old fire bricks from an old fire place, these are not the best as they absorb the heat.

Ian S C

I tried to get this engine assembled and running today but I came across some unexpected problems. Because I made the slide control with a bush which is held on the shaft by two grub screws I forgot think about how I could adjust this once the engine was assembled. I had to drill some extra holes in the cylinder bracket (photo 9) so I can get the tool through there. The other grub screw can be accessed through the meths burner.

So I had to keep taking the engine apart until I got everything where I wanted it. The slide valve bearing which rubs against the eccentric gave me problems too and I ended up using bearing lock to hold it inside the brass sleeve.

But the biggest problem is the last : the slider plate will not stay on the slide control and falls out of the cylinder head (photo 10). I measured everything to see if I might have made the cylinder too long but that is all correct. At this point I am not sure how to fix this and I will have a think before doing anything. I might shave 0.5mm from each end of the cylinder. I could also leave out the gasket which fits between the cylinder and the cylinder bracket. All that should give me another 1.5mm which might be enough to keep the slider plate on the slide control.

 I have looked at photos of other builds and I notice that some people bend the end of the slider plate so this must be a common problem. I did try bending it but it still comes off. The end of the slide control rod is a bit too small to drill for a pin.

Edited By Brian John on 14/07/2016 09:55:05

Edited By Brian John on 14/07/2016 09:56:54

Edited By Brian John on 14/07/2016 09:58:11

Edited By Brian John on 14/07/2016 09:59:04

I just realised that if I make the cylinder length shorter than I will have to move the meths burner in closer. That is why I tried to give the burner some horizontal adjustment : I knew I would need it eventually. As you can see from the photo, the vertical adjustment is pointless. I am really not sure why they designed it like that. Maybe it is a burner initially designed for another engine ?

At this point the simplest solution is to make that small piece on the end of the slide rod longer so it is less likely to slip out of the slider plate but I am not quite sure how I can do that. Perhaps I can solder a small piece of brass onto the end of it...maybe !

Edited By Brian John on 14/07/2016 12:30:54

I did manage to drill a 1.1mm hole in the end of the slide rod. I then fitted a U-shaped piece of brass wire through the hole to keep the slide plate in place. That seems to have solved that problem but the engine will not run. I experimented all afternoon with various valve settings but no luck.

1. The instructions say that the slide plate should be closed just before bottom dead centre : is this correct ?

2. I am also puzzled about the ball valve : how high should I set this using the M3 screw in the exhaust ?

3. I do not like the look of the meths burner. The picture shows it on its lowest possible setting but is this still too high in relation to the cylinder opening ?

1. sounds about right

2. try 1mm of ball lift

3. don't have so much wick sticling out then the flame will be lower

Edited By JasonB on 15/07/2016 10:27:57

2. Only 1mm....do you mean the ball should not rise any higher than 1mm ? I had it much higher than that. Would that have stopped it from running ?

Edited By Brian John on 15/07/2016 10:34:48

I trimmed the wick so that it was very short but the engine blew the flame out. I then removed the burner from the wooden base and trimmed about 3mm off the brass nozzle with the dremel tool. The flame seems to be at the correct height now. I will leave the burner unscrewed for now so I can experiment with the flame distance

The slider plate continued to give problems by getting stuck in the raised position so I removed the main cylinder and shaved 1mm off the cylinder head end. Upon reassembly the slider plate is now sitting correctly on the slide control valve so that problem seems to be solved. I should have done this in the first place.

I am now getting a very encouraging ''pop pop pop'' sound when I turn over the engine. It will only run for about 15 seconds before stopping. I tried lubricating the piston and cylinder with machine oil as I did with my Stirling engines but this made things worse and the engine seized up. I think the flame being in contact with the cylinder burnt the oil and resulted in heavy carbon deposits on both the cylinder and piston.

I cleaned the cylinder and piston with 2000 grit and I now have an excellent fit between piston and cylinder. It is even better than before. This time I lubricated by rubbing the piston with a lead pencil. Tomorrow I must buy some powdered graphite.

I have found the best setting the for the slide control valves. It is just as given in the instructions : the slider plate is closed just before BDC. Other than experimenting with the ball valve I am not sure what I can try next. It is very close but still no cigar ! Unlike a Stirling engine where you have to adjust both work and D pistons/cylinders, this engine has only one piston and cylinder. It should be relatively simple to get it going from here but I am fast running out of options.

Edited By Brian John on 16/07/2016 08:58:26

Edited By Brian John on 16/07/2016 08:59:22

I have found the best setting the for the slide control valves. It is just as given in the instructions

Now there's a surprise

Edited By roy entwistle on 16/07/2016 11:32:40

Yes, it is a surprise. These instructions are translated from German into English and things are not always as they seem.

The main problem now seems to be that what is a good piston/cylinder fit when cold is not a good fit when everything is hot...and things get hot very quickly. I might have to try for an undersize cold piston to get a good fit when hot. Piston rings would solve the problem too but nobody else seems to need piston rings when building a flame eater. Anyway, I have no idea how to make piston rings so I will try to keep it simple for now.

Edited By Brian John on 16/07/2016 11:40:55

Edited By Brian John on 16/07/2016 11:41:19

Brian you do not want piston rings of any sort, friction, or the lack of it is more important in these motors that in a Stirling Engine. Just remind me what is the cylinder and piston made of?

Ian S C

The cylinder is brass and the piston is bronze according to the instructions.

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 ?

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.

Although the brass piston and bronze cylinder have fairly similar rates of expansion (brass slightly greater), the metals obviously work ok. Rather than oil or graphite, the best thing before a run is a wipe with a paper towel, there is a small amount of gunk left from burning meths.

I,m sticking with steel cylinders, and cast iron pistons, this combination has a lower coefficient of friction than the copper alloys.

Does the piston pass the test of sliding through the cylinder under it's own weight, then almost stopping if the end is blocked.

Ian S C

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

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