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!    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

[lordedmond]

Chris

reading your reply and Doug's post

I am 99% sure that its the fuel tract  I think its not getting fuel into the cylinder constantly

When ( many year ago ) I played with IC engine's I developed a pressurised fuel system with a flat slide throttle body for a 3 1/2 cc glow motor these ran on 95% nitro  at 30 k rpm, to set these thing up as the pressure for the ann was from the exhaust they could not pull fuel at crank so a quick squirt done the air intake would run the motor for about 30 sec I used these on 1/8 scale racing cars ,ring life ( dykes ) was 1 hour  , but they won me a few cups for the mantle shelf

back to the issue to hand have you tried disconnecting the vapour tank set up , open the inlet valve and squirted some lighter fuel ( that I believe you have ) ? and see if it will start up most times using this method ,if it does then the problem may lie in the bit you have disconnected

Stuart

[NickG]

Chris,

A better way to check the air tightness of the system is to just take the piston out and try blowing into the end of the cylinder with the valves shut. Even better, if you could take the cylinder / valve block assembly off with spark plug, everything in place, submerge it in water, blow into the end of the cylinder and look for where any bubbles come from.

Nick

[raynerd]

Hi guys, thanks for the continued advice. I`m at work today so will be trying your suggestions this evening and will reply as to how I get on.

Nick - this is what is confusing me! I have actually removed the spark plug and blown as hard as I can into the cylinder, nothing comes through the valves. They seem sealed - yet there is definately air coming back out the intake when I tried before work this morning with the plug back in the place and the piston creating the pressure and vacuum.     That being said, it is also "sucking" as it should through the intake on the piston back stroke.

I`ve removed the valve block and can blow as hard as I can through the port and the valve is sealed! Yet on the engine it clearly isn`t.

Also, the fact that air is moving through the valve block, all be it the wrong way, I`m confident that the seal is good between valve block and cylinder head.

[NickG]

Chris, It is pretty strange and frustrating. I'm wondering if the blow test isn't sufficient then. I think the webster has a compression ratio of 5 or 6 to 1, so the pressure will be around 75psi+ at the top of the compression stroke, whereas you can probably only produce 1 or 2 psi with your lungs.

If the engine gives sufficient 'kick back' when you spin it past the top of the compression stroke, I think you can rule that out anyway. Following Doug's action plan would give it the best chance. Taking the o ring off (providing the kick back is still there with it off) will eliminate the possibility of it being a friction problem.

If the valves are free sliding in their guides, use the lightest spring possible on the intake valve to make sure it's opening. Make sure the exhaust spring is strong enough so that it wouldn't bounce at speed, and as others said, that it shuts before TDC prior to the inlet stroke. There's nothing more you can do then with the vapour carb. The only thing left is ignition timing, if that's set to fire around TDC on compression stroke it should work!

What was your piston made from again? If it's aluminium and it's too close, it could be binding in the cylinder. It expands a lot faster than cast iron.

Hoping you get some luck tonight.

Nick

[raynerd]

Yes that is what I was thinking but the fact that I`m having it kicking back on the compression stroke, even if it is leaking a bit, then the seal still seems good enough.

Doug, I`m going to try and get an ignition timing light but they seem expensive at £40 a pop when I search the internet - I just can`t afford that!! I`ll see if I can borrow one.

Chris

[dbvandy]

If you think about what that check valve is doing, it is acting as a second intake valve.  If it is binding at all it will cause no fuel to enter the engine.  Take it off and connect the tank to the block directly with some tubing and see what happens.  The vapor tank is SOOOOOOOOOOOOO forgiving, you only have to be remotely close for the engine to run.  I can put just about any flammable liquid in my tank and it will run: rubbing alcohol, denatured alcohol, gas, coleman fuel, kerosene, sterno, are some of what I have run in the webster.

The "run for 20 pops and then nothing" I do not think is going to be fuel or mechanical timing (exhaust) as they are not that sensitive.  The unknown variable here for me is the ignition.

Spin it with the plug out and inspect the spark.  Could be a grounding issue with the ignition module as you have to have two connections to the plug, one hot, one ground.  Eliminate either and it won't run. Your ignition test video shows it grounded to the ignition module itself, (does not get any better than that) make sure you have a good connection between engine and ignition module.

Doug

[dbvandy]

http://cgi.ebay.co.uk/AccuSpark-H8000-Ignition-strobe-Timing-Lamp-/180660832618?pt=UK_Diagnostic_Tools_Equipment&hash=item2a1039896a

might be able to find cheaper...  any will work for what you are going to do with it...  as long as you are not making a living with it, an inexpensive one will be fine.

[raynerd]

Yea Doug, I`ll explain to my wife that it is "just" £16...  

that is what I did for the £16 5L tub of fuel, £5 set of magnets, £11.95 bearing (yes could have got it cheaper but got it from a model shop!), £10 lump of brass for the fuel tank, £8 for a new set of Allan Keys, £3.95 can of lighter fuel, £30 for silver solder rods and flux, ect purchased over the last 14 days!!    Not including the materials I got at the start!

hey, I`m not complaining   , it is my wife that is    I`ve just text my Brother-in-law, his Dad owns a local garage so should have one it is just if he is away as he spends a lot of time on his canal boat.

CHris

[raynerd]

Doug, serious point, what does the ignition light do? The only thing is that I can definately hear the spark when it jumps so will the ingition light tell me any more than this or will it just be a visual thing as well as the noise?

Chris

[lordedmond]

Chris you say you can hear the spark ,is it in the right place inside the cylinder or is if outside , i.e. plug cap shorting

I would, although I may be wrong but I would have though you would not be able to here the spark if its the plug firing in the cylinder

a short note but I will leave it to Doug but a timing light will tell you when to plug is firing , but its it is not the plug that is firing but a stray spark it will sill tell you its firing



Stuart

[dbvandy]

The light has an inductive pickup that goes over the spark plug lead and senses when 25000 volts are traveling through the plug wire and fires the strobe light.  This tells you a few things:  the most important is that the plug is firing and the second is exactly when it is firing so you can adjust it.  Some times a coil can be weak and not have enough power to fire the plug under compression.  The light lets you know what is happening under actual engine conditions and not out in atmospheric conditions.

Chris you say you can hear the spark ,is it in the right place inside the cylinder or is if outside , i.e. plug cap shorting

I would, although I may be wrong but I would have though you would not be able to here the spark if its the plug firing in the cylinder

a short note but I will leave it to Doug but a timing light will tell you when to plug is firing , but its it is not the plug that is firing but a stray spark it will sill tell you its firing

Stuart

Good point about an external spark, but I think this would only happen if there is a short in the module or wire.  You should not be able to hear a spark with the plug installed, but should here a sharp crack with it out.  A bad ground would cause an external spark as well and lessen the good spark in the cylinder.

You can assume that the module is working correctly if you have a STRONG blue spark from the plug when it is out (like you did in the video) and it keeps going for 100-200 times.  This test will eliminate the battery issue.  You can time it by eye with the plug out by rocking the flywheel back and forth and seeing where it fires in relation to the position of the connecting rod.

The timing light is not mandatory, you can put it on the list of tools to get at some point....  it will not go to waste.

As for the wife...  Some flowers and a card on the way home to tell her how much you love her.  You can also tell her the motor is what keeps you sane in today's insane world and is cheaper than heroin and not nearly as messy socially  

[Bluechip]

You could hack this thing together. Costs virtually nothing if you have a bit of Vero-board or similar.

You can see if the plug is sparking, the gap is in series with it.

It's also possible to solder a 90V wire ended neon across the gap.

Like this if Rapid actually had the things in stock.  again .... if you took the words 'Back Order' from their vocabulary, they'd be speechless ..

http://www.rapidonline.com/Electronic-Components/Optoelectronics/Indicators/Wire-ended-neon/29275/kw/neon

No need for the series resistor.

Dave BC

[Rob.Wilson]

Hi Chris

Try these   http://www.abbeypowertools.co.uk/car-service-tools/car-electric-testers/showitem-8042-56495.aspx  ,, put one between plug and HT lead ,, rotate crank and it will flash
when the ignition fires ,,, you can also leave it on when running ,,,,,,,,, if the light stops flashing  when the engine is running ,you no its an ignition fault .

You can fined em in most car accessory /parts  shops  


Rob

or  http://www.abbeypowertools.co.uk/car-service-tools/car-electric-testers/showitem-5618-38898.aspx

[dbvandy]

question...  did you assemble the plug boot with the little wire spring that goes around the tip of the spark plug?

[raynerd]

Hi Guys, just come up from the workshop and had some success, I post at the end but to answer some questions and make some comments....

question...  did you assemble the plug boot with the little wire spring that goes around the tip of the spark plug?

The "plug boot" was already attached to the ignition box (and wire) when it arrived and so yes it does  have the wire spring that goes around the tip and also it has the C clip which tightens the casing of the plug cap onto the plug nut outer casing for the ground. The ignition system does come with the other large plug cap in a packet so the current cm-6 would need to be removed.

Bluechip and Rob - I`m going to go for one of those even when it is setup. I think it`ll look pretty cool and it`ll show if there is a fault with the ignition system.

Chris you say you can hear the spark ,is it in the right place inside the cylinder or is if outside , i.e. plug cap shorting

I`ve just had a listen and both Doug and Stuart you mention that I shouldn`t hear the spark. I can 100% hear the spark but it is a dull click that seems to come from inside the cylinder not outside. I turned all the lights off and couldn`t see anything around the case just the spark at the tip.


Anyway, finally something to show you.    I just think it is still far too temperamental! There seems little consistency, you think it needs a richer mixture and it cuts out. Then you try a leaner mixture, it cuts out. Then for example, in the video below, I tried starting up after the last attempt and it was just dead!  I hope that makes sense...I don`t feel as though I can find "best" settings because there seems now pattern of how to get there.

Well, I`m getting somewhere..... at least enough for a video this time. You guys know infinately more than me, does the video indicate any obvious issues as to why it is stopping so suddenly.

http://www.youtube.com/watch?v=0KcUA94-i5A

 

I just want to thank everyone for their continued posts in helping me get this running. I know I ask a lot of questions and can be a bit of a pita but I can assure you I put in the same efforts in my time in the workshop!

Chris
 

[Rob.Wilson]

Big smile   

Rob

[sbwhart]

Nice work Chris  

I always say you train an engine to run: bit like potty training a nipper, you build on sucess but have to be prepared for a few wet accidents.

You've got something to build on their, things will get better and better.

As for the abrupt stops check that nothing is comming lose or sticking.

Try different positions for the fuel tank try lifting it up a bit, so you get help from gravity, I've never built an IC so this may be just a load of tosh, but I know from other guys experiences this is the sort of things they did.

Good luck

Stew

[j45on]

Nice one Chris 

[Anzaniste]

The abrupt stop suggests tp me a tightening up probably as a result of piston expansion due to ignition temperatures. edited to add Forgot ro say well done. ..distracted by watching moon landing on Yesterday.

[saw]

Good to see it runn