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Webster IC Engine build log.
Bogstandard:
You wouldn't believe how many working engines are sitting under benches waiting for the owner to gain the experience to actually get them running.
Flame lickers are a very good example, the flame in some cases only has to be 1mm out of position and they won't run. It will be exactly the same with your engine.
What you must NOT do is try to look at too many suspect areas at the same time. You can end up totally buggering everything up.
To me, from my experiences with ic engines a while back, it sort of points to carburation problems, the mixture is weakening off as the engine gets running. Most engines will run with a rich mixture, even eight stroking, but not with one that is too weak.
Bogs
lordedmond:
Chris
What colour smoke if any do you get when it tries to run
if none it may be to lean , as it runs for a few revs does it speed up just before it stops , it may then have been flooded while it stands and not getting any while it runs the few revs thus stopping
Just my 2 cents thinking on the key board
Stuart
NickG:
Hi Chris, sounds like you're so close. Going back to what doug said, what are you powering it with? Do you have the required voltage? You'll need plenty of juice.
If you think friction may be too high that's an easy one to try. Just take the ring off, it's easy to do and reversible so worth a try for sure. If it doesn't solve it, nothing lost just put it back on.
Nick
raynerd:
Hi Chaps,
Another 3 hour session and still nothing. Got a few explosions early in the first hour and then it ran for a few cycles, took over the started drill but then stopped.
To power it I`m using a variable votage power supply set at 6V but I also have a cell of 4 x AA batteries and I`ve been switching between the two - not that it is making any difference.
Stuart - smoke varies from not visable to white but there just seems to be no concistency. Like I tried to listen to Bogs advice and rather than adjust everything at once, try one area at a time to get best results and move on but there just isn`t pattern! So like I can turn the air intake on the vapour carb and get it popping, I can adjust it to get more consistent firing, it looks to be getting better and then all of a sudden stops - I don`t mean because it starts going the other way (getting worse), I can take it back to where it was good and nothing happens. There just doesn`t seem to be a pattern.
I tried what Stew said and have used a longer tube from the vapour carb.
I`m still not convinced with the valve block - I just noticed that on the compression stroke I`m getting blowback from the inlet like the valve isn`t sealing properly on the compression and exhaust stroke!! I opened up the valve block and just a simple test of blowing on the valve, you can`t get anything through so that puzzles me! :doh: I wondered if the spring is too weak and not holding the intake valve closed but then should the return pressure not force it closed?
If this is the case, this would link in with Bogs idea that the fuel isn`t coming into the cylinder? There is some compression but maybe it is pusing some back down the line. The one way valve is helping stop this but clearly it shouldn`t be happening. I`ll have to investigate this tomorrow.
Chris
dbvandy:
the ignition is a SUPER easy thing to rule out. Get yourself a timing light and hook it up to the plug wire. If it flashes when you turn it over with the drill, then you can eliminate it as having anything to do with it not running AND time it perfectly at the same time.
Don't put too much credit int he vapor carp inlet length. It is not running long enough for that to matter. Now granted, I do have both of my engines with rubber hose connecting the tanks, but the engine does not have the power to cause that problem that quick.. 5 minutes of running? maybe, but what you will probably find is the venturi action in the tank cools it so much, you can hardly touch it. You might try eliminating the one way valve and going direct from carb to intake.
Pull that oring off and try it now that you have the crank timing fixed. It will run without it if you have a close mate piston to cylinder, but not as well as when it is seated properly, don't worry about what a video of an engine looks like after it has run 50 tanks of gas through it. It will be super smooth and loose by then.
Did you put a gasket between the cylinder and head? I cut a paper disk and put it the and it seals wonderfully.
With the spring issue... as long as the exhaust is harder to press by hand than the intake, it will work. The exhaust is mechanically timed and this has to be pretty close. Visually make sure it is not closing too soon because if there is compression pressure in the cylinder, you will lose a ton of intake vacuum as the piston has to travel deep into the cylinder to neutralize the extra pressure left by the exhaust stroke.
action plan:
eliminate ignition problems with timing light (easy easy easy) Try C cells if you have them or a 6v lantern battery (the big square one) You can take the plug out and spin the engine with the drill to see if the plug keeps firing or dies out due to lack of battery
fuel is eliminated with vapor carb, there is no problems there from the pics I have seen of yours completed (maybe check valve. as if you have a Strong spring there, then it will not open and suck in fuel. it is not helping you to have it there....)
verify exhaust timing and spring pressure, intake softer than exhaust
verify compression, you should not be able to spin it over with moderate spin of flywheel, it should hit compression and spring back
verify exhaust timing... opening AND closing, better to stay open a few degrees too much than close a few degrees too early
you are right there!!!!!!!!!!!!!
I think it is ignition voltage or exhaust timing... mostly ignition voltage... but could be the check valve...
Doug
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