Author Topic: Close. But, no Cigar.......  (Read 1340 times)

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Close. But, no Cigar.......
« on: April 05, 2017, 10:52:48 PM »
Hello All.....

I'm just emerging, from the winter hybernation, spring cleaning, round toits, gonna do's, etc......  ::)

Mid February, another orphan flame licker arrived. This one's, tiny:headscratch:
 As I understand. Made in Germany. Travelled to Denmark. Then to Hereford. (UK). Finally, to my door, in Derbyshire.

No arrival pics. Here's, Little Munchkin.......







Bore, 13mm. Stroke, 11mm. Not ideal dimensions.......

The cam, was an eccentric.......




Now, it is a 120* cam. With 6mm lift.........




The undersize, alloy piston. Was replaced with graphite. The cotton wick replaced with s/s mesh.

I've done all I can think of, to bring this orphan to life.........

<a href="http://www.youtube.com/watch?v=Rn6aSbOUGEQ" target="_blank">http://www.youtube.com/watch?v=Rn6aSbOUGEQ</a>


Close. But, no cigar! (I think, I'm trying to change the laws of physics)......

Any further ideas? Anyone? Pleese.....

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Online b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10142
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: Close. But, no Cigar.......
« Reply #1 on: April 05, 2017, 11:05:50 PM »
It's close to running David. Got to be either timing, piston/valve seal or or not enough heat. There isn't much else it can be unless you feel some binding somewhere.

Bill

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 523
Re: Close. But, no Cigar.......
« Reply #2 on: April 05, 2017, 11:20:03 PM »
How does the new wick compare to the old one ? Could it be worth trying it after your modifications but still using the old wick ?

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Re: Close. But, no Cigar.......
« Reply #3 on: April 06, 2017, 09:16:57 AM »
It's close to running David. Got to be either timing, piston/valve seal or or not enough heat. There isn't much else it can be unless you feel some binding somewhere.

Bill

Hi Bill. Yes, that is the closest it has been to running! (Right on cue, for the camera).....

As you know, I've worked my apprenticeship, on these engines. Everything is correct, and spinning freely.
 The cam timing has been adjusted to the sweet spot. It makes the right noises, when spun over.

The only mod I can think of, now. Is to change the 1/4" dia steel shutter disc, for a shim type shutter valve.......
 Don't think it will make much difference.  :ShakeHead:

Frankly.... I think it is too darned small, to run efficiently. If at all......

Does anyone recognise the design? Is it a half sized copy, of an existing engine?

David.

David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Re: Close. But, no Cigar.......
« Reply #4 on: April 06, 2017, 09:26:09 AM »
How does the new wick compare to the old one ? Could it be worth trying it after your modifications but still using the old wick ?

I developed my mesh wicks, some time ago. They are more efficient, and don't burn away......

I have swapped back to the original, several times. Mine is the only one, giving any enthusiasm......

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Ian S C

  • Full Member
  • ****
  • Posts: 857
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Close. But, no Cigar.......
« Reply #5 on: April 06, 2017, 11:50:37 AM »
How good is the bore?  Have you tried with the original eccentric.

It looks as though the valve could be a bit tricky to get to seal.
Ian S C

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Re: Close. But, no Cigar.......
« Reply #6 on: April 06, 2017, 11:06:16 PM »
How good is the bore?  Have you tried with the original eccentric.

It looks as though the valve could be a bit tricky to get to seal.
Ian S C

Hi Ian.
 The bore is very good. It is very well/ accurately made. Just too small, to have enough power.

The original eccentric, hadn't enough lift. And, it kept the shutter moving, all the time. No dwell......

I dished the valve, to be sure it was sealing correctly. It now resists backward rotation, quite well.

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Re: Close. But, no Cigar.......
« Reply #7 on: April 23, 2017, 05:45:05 PM »
After some deliberation. I made a couple more mods.

New cam. This time, 180*. Which seems more logical, to me.......




Modded the wick tube, slightly. To give a wider flame, at the port area......




The test, (not quite), run......

<a href="http://www.youtube.com/watch?v=U9OV1JcVd-o" target="_blank">http://www.youtube.com/watch?v=U9OV1JcVd-o</a>


That's the second time, it has perked up, on camera!
 Though..... Mrs. Drillin was doing the filming. (We all try harder, when She's around).......  ;)

Seems. The only mod left, is to ditch the 1/4" dia saucer, and fit a shim valve. Like Poppin(?).....




Beginning to feel a little desperate, now....

Thanks for looking in!

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline kev

  • Full Member
  • ****
  • Posts: 210
  • Portsmouth UK
Re: Close. But, no Cigar.......
« Reply #8 on: April 23, 2017, 06:52:30 PM »
if anybody can get it to run its you mate :)

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Re: Close. But, no Cigar.......
« Reply #9 on: April 23, 2017, 08:29:02 PM »
if anybody can get it to run its you mate :)

Thanks for your confidence in me, Kev!

I've realised. I knew nothing about vacuum engines, when I started this hobby. Still don't fully understand 'em.....  :ShakeHead:

David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Online b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10142
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: Close. But, no Cigar.......
« Reply #10 on: April 23, 2017, 08:30:06 PM »
That is definitely getting closer David, too close to give up now.

Bill

Offline yogi

  • Full Member
  • ****
  • Posts: 294
  • Duncannon, PA USA
    • Yogi's Workshop
Re: Close. But, no Cigar.......
« Reply #11 on: April 24, 2017, 01:00:40 AM »
Very close in deed, David!
Have you tried to play with the "timing" of the engine? One of my vacuum engines needed quite a bit "advance" meaning the valve needed to close before BDC.
Don't give up...


Offline Ian S C

  • Full Member
  • ****
  • Posts: 857
  • Stirling Engine Maker Darfield Canterbury N Z
Re: Close. But, no Cigar.......
« Reply #12 on: April 24, 2017, 12:11:48 PM »
I was wondering if the valve spring might be a bit too strong, it's a bit of a balancing act to get it just right.
Ian S C

Offline Stilldrillin

  • Full Member
  • ****
  • Posts: 659
  • Staveley, Derbyshire. England.
Re: Close. But, no Cigar.......
« Reply #13 on: April 28, 2017, 10:04:07 PM »
That is definitely getting closer David, too close to give up now.
Bill

I've had a definite wobble, this week, Bill!  :embarassed:


Very close in deed, David!
Have you tried to play with the "timing" of the engine? One of my vacuum engines needed quite a bit "advance" meaning the valve needed to close before BDC.
Don't give up...

Yogi.
I've found these engines settle down, to a timing of... Open, 45* btdc. Close 45* bbdc. Which is how this one feels at it's best....

I was wondering if the valve spring might be a bit too strong, it's a bit of a balancing act to get it just right.
Ian S C

Ian.
The valve spring, is, what it is. I can't do much with it. It has very light contect pressure.
 Frankly. The port is much too close to the operating lever, which moves in an arc......



Anyroad!
 After making two, shim valves. Which broke... As they couldn't stand the necessary bends, to seal the port......  :facepalm2:

I went onto something else.


A rig, to allow all day running of my low temp engines, on show days......

<a href="http://www.youtube.com/watch?v=71h_hNiPrSo" target="_blank">http://www.youtube.com/watch?v=71h_hNiPrSo</a>


A decent result, at last!  :D

Thanks for looking in.
David.
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline zeeprogrammer

  • Full Member
  • *****
  • Posts: 4956
  • West Chester, PA, USA
Re: Close. But, no Cigar.......
« Reply #14 on: April 29, 2017, 12:35:50 AM »
Way to go!

It's often useful to remember the successes. Reminds you that you can do this. You can!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you', whistles, and certain dinner bells.
"Found a peanut."
To work. To work. Zee-The Thread Trasher.