Webster IC Engine build log.

[raynerd]

Hi Nick, yes, it is based on Jan Ridders newest "Universal" vapour carb. The valve is massively simplified, so much so that I think I can give it a good go! I`m just not yet sure how to seat the fuel tank. It`ll be a little bigger OD than Jan's design due to the thicker solid body on mine. I`m strongly considering milling a flat on the bottom and just having it seated directly on the base!!

Chris

[raynerd]

Following on from the last pictures ...

I turned the OD of fuel tank / vapour carb down to make a nice looking brass cup


The top air intake is two piece. An M10 tapped insert soldered into place to allow filling of the tank and then a screwed insert for the air intake reducing the air intake to an 3mm hole tube. The shoulder of the insert is contoured on the shoulder to allow it to sit nicely on the tank. I couldn`t for the life of me think how to do this and so a friend and fellow madmodder suggested a two piece design, where a washer is used as part of the shoulder and the washer filed and sanded to shape. This worked really well but I would be interested to know how this could be made from 1 piece as per the plans


The fuel/vapour outlet tube was then made...not the best photo but all the parts here are ready for soldering..


My sophisticated soldering setup...the cooker top.


And then all polished up... I`m really pleased with it! I just need to make the main air intake insert and the nut which covers the additional air intake on the threaded outlet, glue on the glass viewing window and put it on a stand and then I`m done. Getting there...!  




I believe I`ll need a one way valve as a must as well, so they will be the next things to make.

[sbwhart]

Looking good Chris 

You're machining skills are really coming on.

Stew

[NickG]

Nice work Chris, your question about how to mount it made be think straight away (too late for yours), is there any reason you can't have the tank vertical?

[dbvandy]

There is no need for a one way valve with the webster.  The intake valve only opes with negative pressure from the cylinder, so, if there is any backfire, it will slam the valve shut and keep it out of the tank.  The only issue I have had with the otto and the vapor carb was timing the intake valve correctly, but that is not an issue with this design.

Looks EXCELLENT!!!!  All the way around.

Doug

[raynerd]

Hi guys...

Stew - cheers. I must admit, the last month or so, I`m feeling much more confident. I still make too many silly errors in my thinking and planning which I follow through to the machine(you know, think of something the wrong way around and then machine the wrong side for example), but my actual machining skills are getting better, parts are looking good and are more accurate. John mentioned much earlier in this thread that I seem to be taking my time more and that is definately true. I still need to take more time in my planning (but with little free time I`m eager to get onto the machines!) but that being said, I am more relaxed in my approach. I`ve always been eager to try and get my engines finished just so I can say they are, but now I seem to have calmed down and happy to take my time. That being said, the last few days I`ve become twitchy in the run-up for the first fireup of this engine!!!

Nick, not sure how it would work vertical. The viewing window shows your tank level and also shows the nice "bubbling" or disturbing of the fuel created by the air intake. Also, I`m guessing here, but I expect these vapour carbs work better with a larger surface area of fuel (more evaporation) ???? and I expect vertical it would reduce the surface area. I`m sure it could be done vertically with some thought!

Doug - got your message too late    I`ve just come up from the workshop after a few hours of building the one way valve. Damn annoyed to hear I didn`t need it but I read on HMEM that for the Webster engine I would. Your explanation as to why I didn`t need one makes perfect sense as it was my thoughts as well but I just listened to the advice that has been given on HMEM!!
To be honest, looks damn good and certainly looks the part attached to the valve block. I`m very chuffed with it! In fact, so much so, that I`m considering sneeking into the bedroom to get my camera out of my draw, but sha'n't for fear of waking my wife and getting a thump. I`ll post some tomorrow.

Thanks again for your interest and replies.      

[Bogstandard]

Chris,

As they say, patience is a virtue.

Thinking things thru and taking your time is the first major step in producing good results.

You have a choice, rushing things and still ending up with a lump of junk after a couple of goes at the same thing, or just taking your time and getting it right first time.

I work very slowly and only when I consider it right to work on a specific part. I force myself not to attempt to try to make difficult pieces just because it has to be done. If I feel in a good frame of mind, then I go for the hard stuff, if I don't, then I just make easy bits until I feel I am ready to tackle the difficult parts. I will also put down half finished items if I start to think it is getting a bit too much, and come back to it later.

You are proving not only to us, but to yourself as well, you CAN make great pieces when you put your mind to it. Do that with each part you make, and you will then be in the same league as many of the other people whom you admire for their workmanship.

ONE GOOD PART AT A TIME.


Keep it up.


Bogs

[NickG]

Chris, good point about the surface area ... which made me do more thinking! If it does have much bearing on the running, keeping it vertical could be an advantage - the surface area will be constant as the fuel runs down, where as with it on its side it will start off small and peak when half full then diminish again.

Don't know how long the tank is, but if it's 50mm diameter for arguments sake and it looks about 75 long? If that's the case, the max surface area with it horizontal will be 3750mm^2. With it vertical it would be 1963mm^2 but constantly - surely that means less adjustment would be required and it will get a similar fuel / air ratio until the tank is run out?

Having said all of that, I'm not sure how much effect it really has because all the ones I've seen have the tank horizontal and run very well! Something for me to try when I do mine ...

Nice work, getting close now!!

Nick

[raynerd]

John, you are correct, it is easy sometimes to get over excited want to try and build the entire engine in an hour. I`m getting there.

Well here are the pics. It all still needs a good polish.

Starting off with finishing the fuel tank. The images previous didn`t include the intake tube insert or the air intake adjuster nut..









Is that enough...or perhaps one more?   





Then I went on to make the little one way ball valve as per Jan Ridders plans:








I`m getting close...I can almost smell the fumes. I`m joking as I know for a fact this won`t run 

Infact, other than an exhaust pipe which I presume I don`t need to test it, I think that is everything other than a mounting block for the sensor!!

Chris

[raynerd]

Nick, you made your post while I was posting an update. Yes, it is a good point! I`m not too sure how or if you would put a viewing window in  a vertical tank, also the air inlet stream needs to blow down on the fuel to create the vapour. Jans first design was the bubble carb, where the fuel actually bubbled through the fuel. This seems like a really great way to vapourise the fuel so I`m not too sure why he changed it. With this new version, the tank is only filled about half full and the pipe intentially does not go below the fuel level. It is an interesting concept the vapour carb, I just hope it works for me  

[raynerd]

Thanks Ken. My parts a looking better but I`m a long way off your standard 


I guess we`ll hopefully find out how well it runs in the next few nights!

Chris

[dbvandy]

Nick, you made your post while I was posting an update. Yes, it is a good point! I`m not too sure how or if you would put a viewing window in  a vertical tank, also the air inlet stream needs to blow down on the fuel to create the vapour. Jans first design was the bubble carb, where the fuel actually bubbled through the fuel. This seems like a really great way to vapourise the fuel so I`m not too sure why he changed it. With this new version, the tank is only filled about half full and the pipe intentially does not go below the fuel level. It is an interesting concept the vapour carb, I just hope it works for me  

Your valve and tank look excellent.  One thing that my grandfather always told me...  got gas, got spark, got to go...

Not that I am an expert in the intricacies of the vapor carb, but I do have 30-40 hours perfecting my two incarnations.  The first one was based upon pictures of Jan's tank that I used on the webster with the threaded sleeve that covered the hole in the intake tube.  It works very well and little adjustment is needed to keep it running.  You will find that you do not want to fill the tank over half because it will slosh around a bit when running and raw fuel will get sucked into the intake and flood the engine.  Jan and I have been emailing about a better design that has the intake port coming out of the top of the tank instead of the side and that will prevent 99% of this problem and it looks like in some of his new videos that is exactly what he is now doing.



For the Otto I went with a completely new design that works extraordinarily well.  The entire tank is see through (glass) and the metering valve is a simple bolt that covers the air bypass hole to adjust the mixture.  This could EASILY be tilted upright to make a vertical tank. Once the super volatile fumes are burned off (30 seconds of running),  the engine only need minor adjustments to keep it at any RPM I would like it to be, from 700 RPM all the way to 5400 RPM.  ALSO...  there are two ways to control the idle revs; one is to make it too lean (less gas) by adding more air and the second is to close the air valve off and make it too rich (more gas).  The first method is less sensitive and the idle stays pretty constant throughout the entire tank (30 minutes of running).  One drawback is when it leans out, it runs hotter quicker, but it does not stink as much as when it is too rich and puffing out unburnt fuel.  Only when you get to the very bottom of the tank when only the crud remains is it harder to keep it at a particular RPM.

http://madmodder.net/index.php?topic=4425.msg50253#msg50253



You will also find that the air does not have to hit the fuel to make a vapor.  The vibrations of the motor disturb the fuel enough to make good vapor.  I had a tube that went to the bottom of the tank on the webster and it just made it slosh around more, not helping the vapor mix in the slightest.

Looks great, and as long as the valves seal well and you have sealed the valve block to the engine completely, it will run without a doubt!

Doug

[madjackghengis]

Hi Chris,  great looking set of parts you've got, you must be very close to running, and I'm getting a lot out of the questions and answers on the vapor carb which help, as I expect to be using one soon.  It makes perfect sense that you're getting enough vapor from vibration and sloshing, particularly with a small, single cylinder engine, and I would think if you needed more vapor action, the intake through fuel would be good, and you could use a "dome", as in a steam boiler, to prevent liquid from sloshing up into the intake if you ended up powering a traction machine with this engine or something of the like.  One of the things I like most about the vapor carbs is the fact you get to see what's happening inside, and can alter and adjust for what is visible, and not just guessed at.  I've put the equivalent of a "dome" in a gas tank for a motorcycle, to allow a sealed fuel cap, and still have a good working venting system which won't pour fuel when sloshed, and with a tube sticking up from the tank, the bottom 3/4 in of a CO2 cartridge over it, and a couple of holes drilled around the tube, which is soldered to the tank on the top, where it enters the "dome", and soldered at the bottom where it goes through the tank and vents down under the bike with a bit of hose, it works well as a vent, and keeps gas from venting on the paint, ruining the paint, as if that were an important issue.  I'm glad you chose to put a couple of blocks for a base, I didn't want to see you machine flats on the bottom of the brass, it looks real fine the way you did it.   Cheers, Jack

[raynerd]

Hi Madjack - Yes, the base is just a temporary fix, I`m still not thrilled, I think perhaps they need profiling a little more just to give them a nice look. That can come later! Vapour carb sure does look good, I hope it runs as well!


Doug, interesting post you made! Have you got any advice regarding the timing? I`ve been reading over the build notes and I`m trying to make sense of it!

Chris

[NickG]

Chris,

car engines usually fire at around 10deg before top dead centre. You might not need it as advanced as that so I'd prob just experiement starting from a couple of degrees ... that's degrees on the main crank, so the spark should occur a few degrees before top dead centre (compression stroke, both valves closed) what do the notes say?

That's assuming you meant ignition timing!

Nick

[dbvandy]

Doug, interesting post you made! Have you got any advice regarding the timing? I`ve been reading over the build notes and I`m trying to make sense of it!

Chris

There are two timings to consider:

The exhaust cam has to be timed to open about 20 degrees before bottom dead center on the power stroke and then close just after top dead center on the end of the exhaust stroke (to prevent blowback in to the carb from pressure in the cylinder).  You can adjust this duration by moving teeth on the cam gear and by adjusting the clearance between the exhaust valve and the tappet on the rocker arm.  It is not an exact science (a little different for all engines) and does not have to be PREFECT to get it to run, but once you have it running, you can fine tune it with small adjustments to get it to run smoother and idle better and run at higher RPM's.  The plans for the webster have what worked for his engine, but mine are a few degrees different due to manufacturing tolerances.  After weeks of fine tuning and tweaking I got mine to idle at about 600-700 consistently run at close to 5000 RPM wide open, but I do not recommend that because it could all go terribly wrong very quickly with parts flying at you at the speed of sound...  

The other timing is the ignition timing.  This to does not have to be exact to get it to run, but you will find that if you fire the spark about 10 degrees before top dead center on the compression stroke, it will run throughout the entire range of RPM's very well.  On the Webster, I use ignition timing to control RPM in addition to the mixture on the tank.  It is like a 1903 Harley with 15 different adjustment on the handle bars to keep it running perfectly.

With your electronic ignition (very envious of this by the way...) make sure you have fine adjustment as a degree or two will make a difference in how well it idles and revs up.  also, the electronic ignition should allow you to idle it down to 200-300 RPM once it is running and tuned in.  It looks like your magnet is on a cylinder that has some set screws so you can move the magnet to the exact right place, so this should not be a problem.  You can set the initial timing by eye by just looking at the position of the connecting rod big bearing.  When the connecting rod is parallel to the base of the engine, you are at bottom dead center and top dead center respectively. If you have a strobe timing light for a car, this will make timing easier.  There is a video of timing the Otto in the build log, the webster is done the same way.

http://madmodder.net/index.php?topic=4425.msg49931#msg49931

I would recommend getting a one way bearing from an RC starter (most are 6 mm) and use a drill to turn the engine over when tuning it...  if not, don't get discouraged if you have to wind the string over 100 times before you hear the first pop and even longer to get it to run perfectly.  The physics are there and the design is very forgiving, so it WILL run...


http://www.amazon.com/One-Way-Bearing-Recoil-Starter-G-27CX/dp/B000X4Q2GY

I am very excited for you!

Doug

[NickG]

I went to start my modern lawnmower with briggs and stratton engine the other day and honestly thought it wasn't going to! Took about 20 or more pulls of the starter! As doug said, if you've got those few vital ingredients it should run but they can still be tempremental so keep trying if it doesn't go first time!!

[raynerd]

Well no such luck as yet 

I have had a few "pops" so clearly fuel is getting into the cylinder but I can`t see the valve being pulled down due to the negative pressure of the cylinder. On models I have seen, you can visibly see the valve twitching down. Now before you see it, I went to an amazing place after work today just on my door step - Pennine Springs, thousands and thousands all hand made. Anyway, after about 30 minutes of searching I got a selection - I currently have the softest on, which is incredibly loose. It is enough to seal the valve but should definately be week enough to allow the intake valve to be sucked open - at present I just can`t see it happening.

I`ll keep it at tomorrow. Just before I had to leave the workshop because it was getting late, I could hear the spark plug randomly sparking. This had NOT been happening through the evening so I don`t know what is causing this and hope it stops tomorrow.

I think I need a drill mechanism as recommended to get it going. Winding the string isn`t helping and I think it needs a longer more consistent start. I honestly think it went for a few cycles a couple of times .... at least it isn`t totally dead!

Chris

[dbvandy]

SWEET!!!!!!!!!!!!!!!!!!  way to go.. you are just about there!

A few things...

You can't really see the intake valve moving until it gets going good. 

when you have fresh fuel in the tank, it has to to wide open with air bypass (depending on how big the hole is.)

set the ignition timing at top dead center as it will be harder to start advanced.

check compression by turning it over by hand.  on the compression stroke it should be very difficult to get past the compression stroke.

did you use the oring?  it will help if you didn't...

double check the exhaust valve timing...  make sure it is closing fully before the intake stroke starts. 

Doug

[metalmad]

Hi chris
I try to make sure the exhaust valve opens just before bottom dead center and is closed before top dead center
if your ignition is set at about top dead center then try to start with the fuel needle only open half a turn,but u will need to change this even if it does start.
Pete
opps different carb lol

[NickG]

sounds very promising Chris, well done.  I was wondering whether you'd put the o ring on or not.

[raynerd]

Thanks for the replies.

Yes, I put an O-ring on and I have to admit, it made a difference. I cut the groove a little deeper than I calculated as it was just binding a bit too much.

When I put the engine together, I put the piston in the cylinder and spark plug on the end. I couldn`t compress the cylinder with my finger over the hole in the cylinder head. Likewise it hurt my finger sucking on it when I pulled the piston out. I`ve definately got a good cylinder/piston seal.

I put the valve all together again and actually gave it a bit more of a grind in its seat. Sucking by mouth through the valve block with the springs in position doesn`t let any air through so I`m sure the valves have an excellent seal. (Before I gave it the extra grind I think there was a little air getting through one of the valves).  The valve block is perfectly flat and I`ve used a small amount of hylotyte red between the head and valve block - only a small amount but just something to seal it for sure.

I`ve also remade the flywheel. The steel one, although with a lovely hub was not heavy enough. This cast one seems much better. I used Johns suggestion of tapping through small holes between the cast iron outer rim and the brass centre hub, screwing into these and then facing the heads flat. This was a super idea and has locked the hub in position for sure.

I can hear the spark plug, like I said, I had an issue with some seemingly random sparking last night which I`ll investigate later but hopefully it has stopped   I think I need a connection between the engine base and the electronics box to ensure that the spark isn`t tempted to jump across to the outer sleeve of the spark plug cap rather than sparking at the cap.

It all seems good to me and with Doug telling me that I won`t necessarly see the top spring moving until it gets going then I`m more confident.

My only issue is that when packing away last night, I got a small drop of fuel in the pipe. Turning the engine over by hand, you can see the fuel moving up towards the valve block (cylinder) by the suction of the piston moving out on the intake stroke but it also moves back a little during the compression stroke and even a little on the exhaust stroke. I don`t know if I should worry about this, I thought the valve should be shut during the compression or exaust stroke and so the fuel shouldn`t go back down the line...then again only a tiny tiny change in pressure would cause this to happen.

I can only presume it is my timing and as I said earlier, I need to start it with a drill for testing rather than a pull string.

Chris

[dbvandy]

Excellent!  I would not worry so much about the drop of fuel if when you have the valve block installed you can feel compression.  you will not need a ton of compression to get it running.

The nice thing about using a drill is you can check the spark timing with a timing light.  They are not very expensive and good to have in the tool box for the bigger machines as well.  You should be able to find one at any auto parts store and even Wal-mart or the big discount stores have them.


http://www.google.com/products/catalog?q=timing+light&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&cid=14281284705065655206&sa=X&ei=xaHCTbDpFYKltwfvovXWBA&ved=0CHAQ8gIwAw#

you are right there!  don't hit it with a hammer just yet...

 

Doug

[madjackghengis]

Hi Chris, we, a friend and I, just got his 51 Harley chopper project running after three years of work building.  It took two weeks of troubleshooting the engine before it actually started, and the brand new electronic ignition with single fire was the problem with the wires not liking the installation and being moody to the point of being replaced with a new distributor, one with a better reputation for reliability.  The engine started right up then.  When You've got fuel, compression, and spark at the right time, it will run.  They are always finicky when fresh, although you don't have to deal with oil getting past un-seated rings.  There's always little things which sort of have to get acquainted with each other before they work and play well with each other.  By the way, the "clutch needle bearing" is available from various bearing suppliers in different sizes and is reasonable in price and easy to get one to fit most standard shaft sizes.  Can't wait to see the running video, when everything's sorted out.  Cheers, Jack

[dbvandy]

One thing about the clutch bearing...  the shaft needs to be hardened or at least tough steel as the bearing will tend to dig in over time.  I hardened mine by heating it to cherry red with a torch and then dipping it in used motor oil until cool.  makes a stinky plume of grey smoke, so do it outside, but should harden the outside of the shaft enough to not allow damage by the bearing.  It has to be used so the carbon suspended in the oil bonds to the steel and thus makes it hard (that is what they say anyway...)

Doug