Flame Eater questions

[Fuhrman16]

Hello, I'm new to the site. I'm on a team at school that are building twin cylinder flame eater engines based on Jan Ridder's design. While we were able to get air-tight fits for the pistons and valves, we are unable to get the engines to run. Due to tooling limitations, the cooling fins are only half as deep as per the design. Would this cause these design not to run? Any feedback would be appreciated.

 

[portlandron]

I don't think the fins depth are the problem. Their cooling effect should only come in to play after the engine has run for some time. This type of engine does not have much power so there needs to as little friction as possible. Even oil in the cylinder will stop them from running, use powdered graphite. I would suggest going through it step by step and check for any binding. Start by stripping it down to just the crank and flywheel. If it turns freely then start adding back parts one at a time. After you install a part again check and make sure it still turns freely. The single cylinder one I built is a little hard to start when it is cold.

 

[kcmillin]

Hello Furhman, I agree with portlandron in that you should use powdered graphite. And the engine should turn over with absolutly no resistance, besides the valve.

Also the position of the flame is an extremely small window of error on some of these engines. You may have to play with it.

What materials are you using to make the cylinder and piston?

Which Jan Ridders engine design are you making?

If you post a video of it running that would also help. (with sound of course)

kel

 

[bryan.seifert]

The engine that we're building is the 2-Cylinder Flame-Eater with internal valves. http://heetgasmodelbouw.ridders.nu/Webpaginas/pagina_happer_inw_schuif_2cilinder/inw_schuif_frameset.htm
We used stainless steel for the cylinders as well as for the valves and pistons. Could this be too much weight possibly? I'll work on getting a video posted of the engine, but it won't be running...

 

[kcmillin]

This engine is inherintly balanced with two pistons 180 degrees apart, so I dont think weight is a problem, I built the single internal valve design and my connecting rod is 3 times heavier than it should be, at it runs fine. One problem maybee you have the piston and cylinder made out of the same material, although I dont think you should have a problem with the stainless steel, but you may want to try a leaded steel for the pistons, if that is an option for you.

How freely does the engine turn over?

What are you using for lube?

What are you using for fuel?

Kel

 

[bryan.seifert]

We have gotten a few of the dozen engines we're making to spin for roughly 8 seconds without valves in the cylinder like Jan says they should. A few have issues with the piston rods staying on the bearings consistently and that's why we cant get them to free wheel for too long. WD-40 has been our lube so far, but I bought some powdered graphite this morning and will try it this afternoon which will hopefully help. We are burning denatured alcohol in our spirits burners and have tries small wicks as well as larger ones and tried to change the burners position quite a bit with no success. As far as the stainless we used on cylinders, pistons, and valves it is a T-303 free machining stainless steel.

 

[kcmillin]

A small dot of locktite will hold the connecting rod to the bearing quite well. Just be sure not to get it in the bearings.

Also, be sure to clean all the WD-40 out of the cylinder very thouroughly before using the graphite.

Patience is necessary, it may take a bit for the engine to warm up, these engines like to run about 180 degrees farenheit. Mine will not start until it is warmed up, then it will run for hours.

Everything els you described seems like it should work. I hope this helps, these are very fun little engines to watch.

Let me know how it goes, or if you have more questions.

Kel

 

[Fuhrman16]

Locktiteing the connecting rods may not be necessary, as installing spacers with bigger outer diameters seems to help keep them in place. Our engines seem to spin rather nicely at lower speeds, but higher speeds seem to cause binding. I'm thinking the problem may lay somewhere in the valve tumbler area. We'll give the graphite and see if that helps.

 

[Blogwitch]

This engine is still rather new, and I haven't heard of anyone making one and getting it running other than Jan.

With regards to the position of the vertical wick. A while back, I did a lot of experimentation with them using one of Jans other flame lickers, and that info was passed onto Jan, and others on here in my build. Jan took the recommendations on, and now uses a vertical wick for certain types of engine. I wouldn't stray too far from the positions Jan has given, because the vertical wick, although it solves a lot of the running problems and makes the engine less susceptible to stopping for the slightest reason, does need that critical positioning. 1/16" either way, and you could have a non runner.

I would suggest, you warm up the outside of the cylinder with a blowtorch before trying to start, play it on there for about 20 seconds in all different positions, then leave for about another 20 seconds to let the heat penetrate thru the material. That should get you somewhere close to running temp, and you should start to get the odd pop or two. Don't 'throw' the flywheel, just a gentle turn over so that it goes a couple of revs. If you have got things nearly right, it should start to pop over as the flames get sucked in, and once the inside of the cylinders are warm and all condensate is driven off, things should slowly start to happen.

If your flame is burning slightly yellowy, try some new spirits, it should burn almost clear with a tinge of blue. The yellowing is caused by excess water absorbed by the spirit, and will cause you a truckload of problems.

Hope this helps.

Bogs

 

[bryan.seifert]

Here are some slow-motion videos of the tumbler assembly which I think is giving us problems. It seems like the valves are sticking open for a split second when they should be closed.
"http://www.youtube.com/watch?v=eJJ1Tx2XHbI""http://www.youtube.com/watch?v=2VEbvbor7iM"
"http://www.youtube.com/watch?v=IovcsYnxAqs"

 

[kcmillin]

I believe the flame should be a little closer than where you have it.

also, the valve seems to be opening because there is pressure inside the cylinder. Once the flame is in the right spot you should hear the valve get sucked close and a nice pop when it opens.

These internal valve engines can be quite difficult to get right, but it seems you have everything in order. So keep at it. I spent a full day of fiddlin before mine started.

Kel

 

[Fuhrman16]

I was wondering, would having the valve close too early, while the piston was in it's intake stroke, cause this engine not to run?

 

[kcmillin]

The valve should close before bottom dead center. This is to allow the hot gas to contract and create a good vacume before the piston goes up in the cylinder.

So the timing you have should be correct.

I also noticed that the flame is not really getting sucked in, the wick should cover about half the intake hole, and almost resting against the cylinder.

If you watch the flame the blue part should fill the intake hole verticaly from top to bottom.

make sure its about 180 degrees farenheit before you try to start it.

Also, do you have video with sound, this would help us diagnose the problem.

kel

 

[bryan.seifert]

Here's some more videos with sound this time. The first is the engine without valves in and the nest two are showing the tumbler assembly up close with the flame burning.
"http://www.youtube.com/watch?v=7Ybcf8zbdag""http://www.youtube.com/watch?v=JkiKRSDHxG8"
"http://www.youtube.com/watch?v=GcP3Uyml7Uw"

 

[kcmillin]

Bryan, It seems that when it is free wheelin it comes to a stop pretty quickly. So My suspicion would be too much friction.

What are you using for bearings? Are they sheilded or sealed?

When you turn the engine over, with the valves in, can you feel any stiffer spots?

How did you hone, or finish the cylinder?

The pistons should move completely free of any friction, and when you turn the engine over(without valves) it should come to a nice slow stop.

When I tested my pistons fit I used a vacume pump, used for automotive diagnostices and brake bleeding, I plugged the intake hole with my finger and when I filled the cylinder with a vacume up to 20hg it disapated in about 3 seconds. If the vacume stays in too long, your pistons may be too big, but only a tiny amount, about .0003 or so.

Give this a go, and see what you get.

Kel

 

[Fuhrman16]

The bearings that we are using are sealed bearings. We used this burnishing tool that's used for brake cylinders to hone the engines.
After some tweaking we've gotten the flywheel to spin freely, I'm thinking I may have put it out of alignment when I took it apart to clean it.
We'll try to borrow a vacuum pump from the auto department and test the fit.

 

[kcmillin]

The rubber ring on the sealed bearings actually rubs against the balls inside the bearing. Using an O-ring pick you should be able to remove the rubber seal, this will allow the bearing to run more freely. I had the same problem with mine, removed the seals, and presto, it ran freely.

Kel

 

[Fuhrman16]

Alright, so after testing, the vacuum dissipates between 6 to 15 seconds. So our clearances are too tight then, correct?

 

[fcheslop]

Hi to all, Ive been looking at this thread with great interest as its planned project when i look at the original engine built by the designer there seems to be some difference in the position of the valve rods to yours and the latch also appears to be a little stiff in the video.Ive built and designed a few of these flame lickers myself and could not agree more with advice already given in that they must be free running and the flame position and prewam up are important another thing i cant understand is that your engine appears to blow the flame away from the port and not suck it into the cylinder or is that just something to do with the camera shot any how good luck with your project and looking foreward to seeing it run.
regards Frazer

 

[kcmillin]

Alright, so after testing, the vacuum dissipates between 6 to 15 seconds. So our clearances are too tight then, correct?

It would seem to be.

My first piston for my jan ridders internal valve actually had a little slop, but it did run.
so if you take some light sandpaper (1000-1500 grit) and hold the piston in the lathe and lightly press the sandpaper to it while its spinning, you should be able to take a tiny amount off.

Dont use a bit to cut it down, its really easy to go to far.

Let us know how this works.

Kel