Flame licker won't run, seems like nothing helps

[Stuart]

that spring will not be helping it that position you need a very light compression spring like the ones found in a retractable ball point pen. between the guide and the yoke , it needs to be only just strong enough to hold the ball bearing on the cam

also as has been stated the brass needs to be a lot smoother lap it on a surface plate with some 1200 grit wet and dry paper also do the valve

another point is the flame big enough it will need to be about 30mm high when it runs you will be surprised how small the flame looks when its pulled into the port

the engine when timed and fitted up should make a farting sound when turned over

take a look at a little blazer for the spring and valve timing , the position of the flame is very critical to get a run

my little blazer runs like a mad thing but only when I use paraffin as a fuel I cannot get a run out of meths , mine has a aluminium cylinder and a cast iron piston carefully fitted

Hope that helps and good luck

maybe it would have been better to cut your teeth on a proven design but even then they can be tricky then move on to create one of your own


Stuart

[90LX_Notch]

Riddervold-

The valve should be  fully closed some where around 45 degrees BBDC as frazer stated.  In your video the valve should be  fully closed around the 0:10/0:11 mark which it is not.

-Bob

[b.lindsey]

Riddervold,
It does not seem that friction is a problem. As others have said the timing could be off slightly, but another thing worries me a bit now after seeing the video. I am wondering if the piston diameter is large enough. On both my Duclos designed engine as well as the poppin, the ratio of the piston diameter to the cylinder OD is much larger....meaning that the cylinder walls are thinner. I don't know the limits of the design parameters required to get a flame licker to run, but I think you may be below the minimum as far as piston diameter.

Bill

[mklotz]

Riddervold,
It does not seem that friction is a problem. As others have said the timing could be off slightly, but another thing worries me a bit now after seeing the video. I am wondering if the piston diameter is large enough. On both my Duclos designed engine as well as the poppin, the ratio of the piston diameter to the cylinder OD is much larger....meaning that the cylinder walls are thinner. I don't know the limits of the design parameters required to get a flame licker to run, but I think you may be below the minimum as far as piston diameter.

Bill's comment is right on.  If the thermal mass of the cylinder is too large, it will remain cool enough to "quench" the hot gas before the valve has a chance to shut and maintain the vacuum.  One of the reasons these engines are tricky is the fact that the cylinder must be warm enough to not prematurely quench yet cool enough to quench when the valve is shut. 

As a test of this conjecture, try playing a flame on the cylinder while trying to run the engine.  If keeping the cylinder hotter allows it to run, we'll at least know we're on to something.  [Sadly, if it doesn't run with the extra heat, that doesn't prove the conjecture wrong.]

[Arbalest]

I've pre-heated mine with a hot air gun to good effect.

[NickG]

Again agree with all the comments, valve is definitely shutting too late. With regards to quenching effect that is true too, my Ridders flame licker needs to heat up for 10 minutes before starting or blow torch as Marv says whereas my poppins with graphite piston both start from cold.

[Ridddervold]

Alright I've made a new aluminum cylinder with 21.3 mm bore and a steel piston. The fit is perfect and I'm using graphite as a lubricant. The valve is smooth and creates a prefect seal to the cylinder. However it doesn't want to start. I've shot a new video of it: <a href="https://www.youtube.com/watch?v=msHGo4fLpTQ" target="_blank">http://www.youtube.com/watch?v=msHGo4fLpTQ</a>

[Arbalest]

Flame position can be quite critical as well. Move the flame closer, it's too far away in the video.

[Ian S C]

Here is all the information I had to build my flame licker.  Ian S C

[NickG]

Aluminium cylinder and steel piston is asking for
Trouble due to differential expansion. I tried an aluminium piston in steel cylinder, result was that after 5 minutes of the flame being near it seized completely. I expect the clearance in yours is getting larger as it heats up. Think the valve is closing too late too and flame position is wrong. The port may be too large too.

[mklotz]

Was the cylinder preheated before trying in the video?  Get it good and hot and give it another try.  Nothing to lose.

My Poppin has an aluminum cylinder and a stainless piston, oil lubricated, and it runs well.  Unlike yours, the cylinder is finned.  I don't know if that's important.

[fcheslop]

Is the timing correct as it looks as if the flame is blown away from the port and I cannot hear the characteristic noise of it exhausting and you also seem to have a vacuum at the wrong time ?????
When you turn the engine over can you hear it exhausting a bit like an old man farting  .

[b.lindsey]

Try preheating as Marv suggests first. While I don't know it to be face I have never seen a design without fins so that could still be an issue also. I still think the piston is too small as well relative to the cylinder diameter (and thermal mass). Don't give up on it...you will be glad you didn't once you get it running well

Bill

[fcheslop]

See if this is of any help.Its A Duclos engine and in my opinion he designed the best runners to date.
She is now over 25 years old so forgive the rattles
The crank is at bottom dead centre and turning the flywheel clockwise
Note the position of the valve
 
This is at Top Dead Centre the valve cover half of the port

This is the engine turning over by hand you can hear the exhaust

Start up no pre heat needed on this engine

Running at tick over at no time do you see the flame blow all over the place

The only time I can get the engine to vacuum as you show is if I turn the engine the wrong way.
It maybe a timing problem.
I have built these engines with a 3/8 bore and 1/2 stroke with no problems but the smaller you go the more important free running becomes.
Good luck
kind regards
frazer

[90LX_Notch]

My observations-

I agree with frazer; the timing appears to be off.  It's hard to do with YouTube, but a frame by frame doesn't show the flame being drawn into the port anywhere near where it should be. 

The color of your flame is yellow;  alcohol should be burning blue as in frazer's picture.  When my burner starts running low on alcohol and flame turns yellow, my Poppin stops running.

Try going to the john-tom site and looking at the plans for the Poppin engine and study the cam.  Part of your timing issue could include your cam design.

-Bob