Author Topic: Webster IC Engine build log. (Read 244001 times)

raynerd · « **Reply #100 on:** March 21, 2011, 01:11:27 AM »

Doug, thanks for the info regarding the groove depth for the piston ring, I`ll be using that!

I`ve had little time over the last few weeks to spend much time on the Webster but I feel the few hours I had at the end of last week has pulled me back on track. I`ve finished the con-rod, drilled and bored true for the bearings in the main supports for the crank and also made the crank as well.

I decided to solder the crank together. I`ve done very little soldering and it didn`t go too well. I didn`t get the part hot enough and so the solder clumped on the metal rather than flowing in the joints. I got there in the end but there was more tidying up of the part than should really have been needed.

Here are the parts assembled along with the base and con rod. At all joints which require bushings on the plans, I`ve used bearings. My intention is to use a bushing on the piston wristpin.

And finally the parts "posed" together! The gear under the cylinder is proping it up as it isn`t bolted down just yet.

sbwhart · « **Reply #101 on:** March 21, 2011, 02:52:52 AM »

Comming together nicely Chris

Stew

Stilldrillin · « **Reply #102 on:** March 21, 2011, 03:06:13 AM »

That's looking good Chris!

David D

raynerd · « **Reply #103 on:** March 21, 2011, 04:26:53 AM »

Thank you for your comments... I`m getting there. Whether it will run or not is a different story!

NickG · « **Reply #104 on:** March 21, 2011, 04:43:11 AM »

Chris, looking great that. The base looks easily thick enough to me too.

Nick

Bogstandard · « **Reply #105 on:** March 21, 2011, 05:09:08 AM »

Chris,

Now you are starting to slow down a bit and take your time, it is very noticeable in your work.

Compared to your earlier builds, this one is exceptional. Keep it up.

Bogs

raynerd · « **Reply #106 on:** March 21, 2011, 07:55:23 AM »

Thanks John!

I`m still struggling to find data for the groove width and depth on this piston for the piston ring! The table that was posted would have been perfect only it doesn`t include a 3/32" cross section! I`ll have to try and work it out based on that data unless anyone can lend me a hand!

Chris

NickG · « **Reply #107 on:** March 21, 2011, 08:43:38 AM »

Chris,

As Doug said, I believe the ring is technically supposed to roll slightly in the groove so it pushes against the groove wall and seals. This is maybe to get the lowest friction. I don't know whether the groove dia is supposed to be size for size or slightly larger than the id of the o ring. I would think, like you it's supposed to be marginally larger.

Might be worth checking if Marv has a program for this?

Nick

Bogstandard · « **Reply #108 on:** March 21, 2011, 08:52:10 AM »

Chris,

Whenever I fitted o-rings as piston rings I looked at them in a slightly different way, in that I didn't want them rolling up and down in a wide slot. To me that stinks of maybe getting twisted up and uneven wear.

My way for a 3/32" (0.094") cross section ring would be to just cut a square section slot a couple of thou wider and the same shallower.

So 0.096/7" wide by 0.091/2" deep.

That way, the ring, by being pushed into the groove, would take up an oval shape, giving a nice side pressure to form the seal. As the ring wore away, it would slowly form a flat where it rubs on the cylinder wall and gradually return to it's original round shape.

Your bore does need to be rather smooth, otherwise it will wear away an o-ring fairly quickly.

I am sure that other people have different views on the subject, I just told you mine that worked for me.

John

dbvandy · « **Reply #109 on:** March 21, 2011, 10:31:51 AM »

I agree with Bogs... The fitment of the o-ring is important, but not critical.... from all the information I read on the subject, the important thing is that you have pressure on the dynamic surface (cylinder) at all times. The engine is very low compression, about 4 to 1 where a car is about 10 to 1, so you are not going to get much blow-by either way. Jan Ridder does not even use o-rings in his engines, just a tight fit.

It is starting to look like something now! I love that feeling!

Have you decided on ignition? If I had seen this, I would have done it without a doubt...

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=13767

This CDI unit will make for a really clean install. You still have to lug around a battery, but it will make a reliable spark. Or you can go the route I did with the trimmer coil as it works beautifully and does not need anything else to run. On the Otto, I used some neo magnets on the flywheel, so you don't have to use the finned flywheel from the trimmer.

Just some food for thought....

Doug.

raynerd · « **Reply #110 on:** March 21, 2011, 12:45:46 PM »

Thanks for all the info regarding the piston o-ring. I`ll let you know how I get on.

dbvandy - I`m really not sure what I`m doing about ignition yet. A lot of it falls down to cost, what you showed me seems an excellent price. I`d quite like to use my smaller 10mm spark plug so I`m not sure if it`ll fit in place of the 14mm plug that comes with it. I`ve finally got my head around the points/contacts system that the original plans suggest but they look clunky and I believe I could do without them if I used the item you linked to?

Where or what is the hall sensor in this bundle and how will it be fitted?

I believe this is the sort of thing:

REMOVEhttp://www.youtube.com/watch?v=jeRE8SoxStU&feature=mfu_in_order&list=UL

...but it worked out about £90+ when I priced it up. Is it the same sort of thing in the link that you have suggested?

saw · « **Reply #111 on:** March 21, 2011, 03:14:27 PM »

Nice thanks for showing

dbvandy · « **Reply #112 on:** March 21, 2011, 09:21:09 PM »

Quote from: craynerd on March 21, 2011, 12:45:46 PM

Thanks for all the info regarding the piston o-ring. I`ll let you know how I get on.

dbvandy - I`m really not sure what I`m doing about ignition yet. A lot of it falls down to cost, what you showed me seems an excellent price. I`d quite like to use my smaller 10mm spark plug so I`m not sure if it`ll fit in place of the 14mm plug that comes with it. I`ve finally got my head around the points/contacts system that the original plans suggest but they look clunky and I believe I could do without them if I used the item you linked to?

Where or what is the hall sensor in this bundle and how will it be fitted?

I believe this is the sort of thing:

REMOVEhttp://www.youtube.com/watch?v=jeRE8SoxStU&feature=mfu_in_order&list=UL

...but it worked out about £90+ when I priced it up. Is it the same sort of thing in the link that you have suggested?

This has the CM6 plug boot as well...

Includes:
Ignition Unit
Hall Sensor, Lead & Bracket
CM6 & 14mm style Plug Cap
Ignition Power Lead
Snake Wrap
Servo Lead Locks

The hall sensor is in the lower right with the red black and white wires.

raynerd · « **Reply #113 on:** March 22, 2011, 02:46:01 AM »

So what actually spins and triggers the hall sensor? I appreciate your advice, this is all new to me!

Bogstandard · « **Reply #114 on:** March 22, 2011, 03:43:58 AM »

Chris,

If you are looking to keep the price down, you can actually make your own.

I used to make the TIM 6 units, for less that around a fiver each.

It isn't the switchgear part that is the expensive bit, it is the coil. That is why these modules are rather expensive, they have it all built in.

If you can hide a car or motorcycle coil somewhere, then the TIM 6 version on here will be fine.

http://www.5bears.com/tim4.htm

Basically, you embed a small neo magnet in the flywheel or camshaft end, and as it passes the close mounted hall sensor, the sensor sends a signal to circuit which then fires the coil, et voila, spark at the plug (any size).

On the TIM 6 shown, it doesn't need to be a hall sensor, it could be contact breakers or even a microswitch.

Bogs

HS93 · « **Reply #115 on:** March 22, 2011, 04:09:22 AM »

Quote from: craynerd on March 21, 2011, 12:45:46 PM

Thanks for all the info regarding the piston o-ring. I`ll let you know how I get on.

dbvandy - I`m really not sure what I`m doing about ignition yet. A lot of it falls down to cost, what you showed me seems an excellent price. I`d quite like to use my smaller 10mm spark plug so I`m not sure if it`ll fit in place of the 14mm plug that comes with it. I`ve finally got my head around the points/contacts system that the original plans suggest but they look clunky and I believe I could do without them if I used the item you linked to?

Where or what is the hall sensor in this bundle and how will it be fitted?

I believe this is the sort of thing:

REMOVEhttp://www.youtube.com/watch?v=jeRE8SoxStU&feature=mfu_in_order&list=UL

...but it worked out about £90+ when I priced it up. Is it the same sort of thing in the link that you have suggested?

Why is it £90 + when it is only $29 in the advert postage is not that bad from hobbyking I get stuff all the time ?

peter

raynerd · « **Reply #116 on:** March 22, 2011, 04:40:00 AM »

John, many thanks for your explanation. I`ll have a good read of the link you posted.

Peter - I`m sorry, I didn`t make myself clear. I`m not sure myself what I would need for this sort of setup and so from a UK supplier (who will remain nameless because they gave me copious amounts of advice and info) all the parts came to £90+ !! This is why I questioned this price at $29 - I didn`t think it would surely include everything I needed!

Chris

NickG · « **Reply #117 on:** March 22, 2011, 05:04:33 AM »

Chris,

I think the one you're talking about will have been specifically designed for model engines such as yours, while the one pictured is a commercial thing for replacing ignition on lawn mower engines and the like? It's not exactly compact by the looks of it.

As Bogs said, it's the coil that costs the money, you're into electronics so could easily make the circuit up and microswitches can last a long time, are compact, cheap and easy to replace. The other way is to completely use the setup the original webster had, car / motorbike coil, battery and contact breakers. You'd need a big base to hide all that in though!

Have you thought about piezo like Jan ridders uses on some of his? I think they sap a lot of power though.

Nick

raynerd · « **Reply #118 on:** March 22, 2011, 05:14:28 AM »

I`m just looking over this and your right, this really is a bargain as it works out at £20 including postage providing it doesn`t get caught up in customs. I have been stupid and didn`t see that it is fitted with a CM6 plug which is what I wanted to use anyway!! The link you sent John looks excellent and once I`ve got it running it might be something I experiment with for fun so that I can say it is truely all built including ignition but I expect I`ll have enough issues getting it running than worrying about building the ignition system as well. I think I`ll go ahead and order one of these for £20.

I hope it becomes obvious how to wire this up when it arrives! Will I need to use a car battery or could I use a battery pack to reduce size?

Also, looking at the video I posted, I noticed the hall sensor is attached to a modified axle of the second gear which is actually reducing the spark ignition to just spark once per two revolutions as per a normal 4 stroke right? I have been thinking, using the contacts (or the hall sensor) on the main crank shaft you`ll have a spark per revolution so does this mean one is redundant - does this matter?

Chris

EDIT: Nick, you posted while I was replying. To be fair, the size of this unit looks about the same size (infact looks the same thing) as what was quoted at £90 for but maybe I`m wrong. I wouldn`t say I`m into electronics, I can get by but I`m not always confident in what I`ve made. I`ve been considering the coil and points method but I don`t mean to offend anyone, but it does look a little clunky!! I`ve not looked into a piezo ignition so I`ll have to have a google of that! Working out the price of the unit that was suggested, I am still very much interested in that!
I do appreciate everyones advice... it would be much easier if there wasn`t all these options

HS93 · « **Reply #119 on:** March 22, 2011, 05:20:56 AM »

I think you will find it it is small sa it is for a model plane or boat or car. the box is less than 2" long by about 3/4 high mesuring it against the rc plugs in the pictute.

peter

raynerd · « **Reply #120 on:** March 22, 2011, 05:45:10 AM »

Well I`ve gone for it and ordered one. I`ve just found a couple of almost identical packages, in fact on one, the photo was identical just a different sticker on the electronics box and that was £60. I`ll let you know when it arrives.

NickG · « **Reply #121 on:** March 22, 2011, 06:07:34 AM »

Sounds a good deal that then Chris. Will be interesting to see what it's like.

You're right, if you ran it off the large gear it would fire at the right times. If you ran from the crank it'd fire 2 x as much as it needs to but lots of ignition systems are apparently 'wasted spark'. Guess you're wearing the plug twice as much - can't see this being a problem as you don't generally change car spark plugs for about 40,000 miles these days. That's a lot of sparks! If you're using a hall sensor there's nothign to wear there so shouldn't be an issue.

Nick

lordedmond · « **Reply #122 on:** March 22, 2011, 07:09:39 AM »

Quote from: craynerd on March 22, 2011, 05:14:28 AM

I`m just looking over this and your right, this really is a bargain as it works out at £20 including postage providing it doesn`t get caught up in customs. I have been stupid and didn`t see that it is fitted with a CM6 plug which is what I wanted to use anyway!! The link you sent John looks excellent and once I`ve got it running it might be something I experiment with for fun so that I can say it is truely all built including ignition but I expect I`ll have enough issues getting it running than worrying about building the ignition system as well. I think I`ll go ahead and order one of these for £20.

Part quote

a box and a load of wires sticking out of it

,coming through customs

they are going to love the look of that when they X-ray it

call the Army quick

Just joking

I hope it does what it says on the tin because its a good cheap way to get some sparks , much cheaper that the sum of the parts purchased elsewhere

I have had some electronic bits torn apart before coming from the US but it was just after 9/11

Stuart

raynerd · « **Reply #123 on:** March 22, 2011, 07:28:33 AM »

...and to be fair, the function of the electronics parts is to mark a spark!!!

Humm, never considered that when I ordered!

Chrius

madjackghengis · « **Reply #124 on:** March 23, 2011, 08:50:25 AM »

Quote from: Da_Kengineer_Meister on March 22, 2011, 05:58:08 AM

This looks like you are coming right down to the last little bits... Question and please forgive my ignorance since I'm not an engine guy... Are the basic differences between the different spark plugs defined by the following three items...? The dielectric resistance, the operating voltage to strike a spark and the sustained current?

As a life long engine mech, the primary differences in plugs are thread size, the length of heat path from center electrode to cooling, and the size of the plug its self. Resistor plugs are the common thing because they don't cause radio interferance with modern electronics, so their resistance is pretty common, and the plug size has gotten smaller because engines are so much smaller in weedeater applications, but other than that, plugs are pretty much the same, with the ignition units making most of the difference. Almost any form of ignition will fire across a .020 in gap, and with model engines, this means we can use very small coils and low voltages, if we wish to. I just pulled a champion plug from a weedeater engine which is ten mm thread, the smallest plug I've ever seen, and I believe it is the same as the cm-6, although I haven't seen on of those except in pictures. In general, the higher the number, compared to other plugs of same manufacture, the longer the heat path, and the hotter the plug runs. In an engine which is run continuously and for long periods, this is critical, as a too hot plug can cause a hole in the piston. For model engines, this is not normally even an issue at all, and hot plugs don't foul as easily. If you find your plugs getting fouled from messing around with timing, mixture and oil, the easiest way to "clean" it, so it will reliably fire is to hold it in a vise on the wire end, and aim a torch flame down between the center electrode and the casing with the threads, trying to get the blue tip of the flame on the center electrode. Any oil down deep with show up as a pale blue flame around the opposite side of the ground electrode, as opposed to the reddish spread flame of the torch impinging on the steel, giving it the reddish hue, and aiming between the center electrode and ground from both sides, hits the hardest part to get up to temperature, and once there is no more light of "phantom" blue flame on the opposite side from both sides, you will fine pristine ceramic on the center electrode when it is cooled off.

Cheers, Jack

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Author Topic: Webster IC Engine build log. (Read 244001 times)

lordedmond