my attempt at Rupnows imperialized ridders flame eater

[Cogsy]

Mine is set so the piston just creeps into the intake port. I went to a lot of effort to make sure the valve could not be driven open much further than just enough to uncover the entire intake port, and also is only drawn down the bore just enough to fully cover the port when closed. I didn't want to waste power on big movements of the valve. Mine runs (well it did before I let it sit on the shelf and get gummed up with dust) but I have seen others perform better.

 

[werowance]

hmm, so definitely half way over the intake port is to far. I measured and remeasured everything and I cant seem to find my mistake. I'm thinking of shaving the tip of the piston down just a fuzz or shortening the crank rod a little to see if I can get a better line up.

I'm at work and cant experiment with it right now but wonder if reversing the valve and the piston since one is thinner might work out?

 

[werowance]

also, I tried a little dry film Teflon lubricant (which I have since cleaned back out) but it seemed to actually help. wonder if it can stand up to the heat?

 

[Cogsy]

I don't think having the piston come up that far is much of an issue myself. It can't hurt anything or build any compression so I wouldn't worry about it. I know when I couldn't get mine to run I looked at every part trying to work out what I'd done wrong and it turned out to be just the flame position, height and cylinder temp. It was so incredibly frustrating that I've never got the courage up to build another one, though I would like to have a go at a poppin one of these days.

 

[Brian Rupnow]

So what's the real story here? Did you get it to run or not? Mine doesn't work worth a damn, and although it did run long enough for one short video, it never ran again. I think it is a flawed design, because everyone I hear of that has built this engine has a dreadful time getting it to run.---Brian

 

[mcdavidr]

I think the timing is critical on this engine. I quote from Mr Ridders web page
Adjustment of the engine.
As said there is hardly anything to adjust to this engine. The once-only adjustment concerns fixing the striker at the right position of the pusher rod. When this is done right you see the following when turning the fly wheel slowly by hand:
In the utmost right position of the piston: the internal valve is pushed completely over the flame hole in the cylinder with about 1mm overlap.
In the utmost left position of the piston: the valve is pushed by the cam on the piston so that it opens the flame hole except for the last 1mm. If the engine runs the valve will overshoot so the flame hole will be opened completely then.
Per these instructions my valve is pushed slightly too far because the port is completely open, it runs although not as fast as the example on his site. If I remember correctly when I built it the piston was pushing the valve too far and I shortened something. Then I had to adjust the lenght of the pin on the piston end of the actuator rod. The cylinder has to reach some magic temperature before it will start and the flame position must be in right position , but then it plugs right along.
I think maybe I’ll drag it out and play with it for a while.

 

[Cogsy]

I got mine to run eventually, but it took a lot of fiddling. I'm tempted to pull it down, clean it up and try and get it going again but it'll probably take as long as it did the first time to figure it out.

 

[werowance]

ok, so had the day off yesterday and I played with the engine most of the day. I modified the piston fork so that I could screw it in further thus moving the piston back a little. right now it creeps less than 1 mm past the beginning of the intake hole at tdc and at bdc its just less than 1mm from being flush with the outside edge of the cylinder. It wants to run (ill be attaching a video) and actually does run for a little bit. what happens is it gets a vacume lock every once and now kinda like a back fire or something which just makes it want to stop. I believe this is because I don't have enough threads sticking out past the piston and valve to prevent the valve from sucking shut to soon.

anyway that piston fork was horrible to begin with. I think I'm on like number 7 or 8 tries on making it right anyway.

let me get this video up to utube

 

[werowance]

oh, and I got some dry graphite lube to. that actually helps. but once you spray it, you have to let it dry for a few seconds, then work the piston and valve back and fourth to distribute it good else it will create a high spot of graphite in there and drag the piston. but once you spin it a few times it runs smoother than without it. and it doesn't soot up or anything when it gets got.

 

[werowance]

here is link

 

[Brian Rupnow]

Well, it does run. You appear to have your wick at least twice as high as is recommended in the original article.--Brian

 

[werowance]

yeah, I experimented with wick height as well, seems the carbon build up on the tip messes with it. if I cut that off then I can lower it back down and get the same results. I'm thinking right now that I need to have the 2 threaded tips that meet in the middle to prevent the valve from getting sucked closed to soon done correctly. that hiccup or backfire as I described earlier is where the valve is getting sucked closed way to soon and if I spin it really fast by hand it will actually stop the engine and reverse direction.

in the video I'm running "Heet" gasline antifreeze however I bought a quart of denatured alcohol at the hardware store and same results and same looking flame with it as well. the denatured alcohol even says "fuel" on the can.

 

[werowance]

and I also picked up some corded wick instead of braided from my mom (she does curtains and covers couches etc) that she had. not sure what she used it for but Ill see if the corded wick will work any better or the same. the corded looks like rolled up fabric instead of braided rope.

 

[Cogsy]

If I remember correctly, spinning it by hand with no flame should produce a 'backfire' like you're talking about - that suggests your fits are good. If it's doing it with flame but only when you spin it really fast it might be the valve bouncing back from its travel stop and closing early.

To me, it just looks like your flame position needs a little tweaking and it should be good to go. Possibly, the base of the wick is a tiny bit high? It could be there is some cool air being drawn into the bottom of the intake port and messing with it. I'd try with a slightly shorter burner (changing the wick height won't affect the bottom of the wick). And then Just moving the burner around by 0.5mm at a time until you find a sweet spot (that coincides with correct cylinder temp at the time) and it will be off and running. Good luck!

 

[werowance]

thanks Cogsy, ill give that a try. on the base of the wick, notice I didn't mill out the base plate for the burner but what I did do is make the burner shorter to compensate and by measurements its actually shorter right now that what it would be if I had milled the recess out in the base plate and made the burner to proper height. but I can certainly file down the burner wick tube just a tad shorter as a test.

 

[werowance]

ok, so I have a new game plan. last night I decided to make a new piston rod fork since my current one looks like it was whittled out with my pocket knife. the new one I will put the cross drill closer to the base/threads and also make the threaded portion longer. this will give me the ability to adjust the piston position in the cylinder by screwing the piston fork out until it hits where I want it. then I will cut the excess threads off after I measure where the valve needs to be, then a dab of locktite and see what we get.

only progress I made last night was turn a piece of mild steel down to the right diameter and called it quits. hope to get more accomplished this weekend

 

[werowance]

I made the new piston fork (for about the 8th or 9th time) and it turned out just about perfect as I wanted it to be. I made the fork shorter so that it could screw further into the piston thus giving me piston position adjustment forward or backward as needed in the cylinder. last night I put it all back together and had it adjusted to where I thought should be, lit the wick and let it heat the cylinder for about a min. then I gave it a very light flick just to help circulate the heat and I turned my attention to some paper towels and trash I needed to pick up. well GOOD news is that that little light flick turned into a very high speed run all on its on. it was running as fast as if I had spun the flywheel with everything I had. BAD news is that it only ran about a min and a half. but it picked up its on speed. what had happened is that the cylinder evidently was not hot enough and had sucked in enough gunk to build carbon or something in the cylinder. I could feel the drag on the piston as I tried to start it again. i disassembled and cleaned everything up with alchohol then blew it out with the air gun and things were free and clean again.

it never tried to run again though. wife got home with dinner so i gave it up early last night and veged out on the couch with a full stomach and the remote control in hand. I'm hoping that after i disassemble and clean once again, maybe i didn't get it clean enough or perhaps things are in just a bit of a bind after taking it all appart, that it will run again for me.

I'm using denatured alcohol that even says "fuel" on the can from the hardware store. burns and smells the same as "heet" fuel line antifreeze did.

one more cool thing i learned making the new fork: i do not have a slitting saw blade as thick as the piston rod is so was having to make multiple passes to get the fork as wide as needed. i had the idea of stacking different blades onto my arbor till the right thickness was achieved. this worked wonderful. my blades have no kerf on the teeth so once stacked and the teeth lined up with the other blade with my finger nail i sinched down the screw on the arbor and i couldn't even see a line where the 2 blades met. and the width was just perfect and the cut was made with ease.

 

[werowance]

well, I can get a somewhat reliable run from it now using my mothers sewing machine oil. its some sort of industrial oil she gets in 5 gallon buckets. its clear, super thin and doesn't smoke. however it is still just a little to thick, but this lets me know that my piston/valve to cylinder fit is off since the oil gives the amount of vacume I need to make it run properly. I think ill hone the cylinder again and also give graphite another try. ive contacted Becker graphite for a quote for a 1" x 12" stick, hopefully it wont cost an arm and a leg.

my mom does commercial upholstery and drapes etc. so she has several industrial size sewing machines, this is not regular 3 in 1 oil from the hardware store. wonder what mineral or baby oil would do? wonder how hot its smoke point is?

(edited) - I said hone but meant "lap" the cylinder again

 

[Brian Rupnow]

Be advised--You can not oil graphite pistons. I had my engine running briefly (damned briefly, just long enough to make a short video) with cast iron pistons and light oil squirted into cylinder . I changed over to graphite and it wouldn't run at all.---Brian

 

[werowance]

Brian, just a thought, if this last ditch effort doesn't work, how much would you charge to redesign it as a finger engine? just the plans that would re-use as much as possible of whats already there