Author Topic: Another version of how not to build a model engine  (Read 89667 times)

Offline NickG

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Re: Another version of how not to build a model engine
« Reply #125 on: December 19, 2009, 09:32:35 AM »
S, the cylinder wall looks extremely thin! Is there any particular reason for that?

Nick
Location: County Durham (North East England)

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #126 on: December 19, 2009, 11:45:54 AM »
Nick, when looking it afterwards, I have no idea why I made it so thin. Must have been some brainstorm .

But in any event, new cylinder wall is about five times thicker (1.2mm(~0.047")), than on the previous one (0.2mm(~0.0078")).

Brackets are now filed, and ready for silver soldering:


If all goes well, after soldering, I'll continue the lapping session.

Offline NickG

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Re: Another version of how not to build a model engine
« Reply #127 on: December 19, 2009, 11:53:45 AM »
The new one looks much more substantial, good luck.
Location: County Durham (North East England)

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #128 on: December 19, 2009, 01:58:03 PM »
Soldering session went ok. Parts soldered together, after some lathe treatment, and cleaning:
« Last Edit: December 19, 2009, 02:01:15 PM by sorveltaja »

Offline chuck foster

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Re: Another version of how not to build a model engine
« Reply #129 on: December 19, 2009, 10:24:07 PM »
looking good sorveltaja  :thumbup: ............... i know the feeling about making part's over and over again.  :dremel:

the new cylinder looks allot better, more solid. good luck with the lapping.
looking forward to the next write up.  :ddb:

chuck  :wave:
hitting and missing all the way :)

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Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #130 on: December 21, 2009, 05:34:46 PM »
Thanks for the replies :thumbup:.

Piston/cylinder fitting is in progress. Although 3/4 is done, it's quite tedious job to do, as I have to do it manually. I tried using lathe for that, but piston gets too easily stuck in the cylinder. So tight, that it has to be hammered out.

I really don't prefer to do that. That's the reason, why I do the job manually.

One may ask: "why don't you use o-rings?". During the process, I have indeed looked for an easier way to make tight cylinder/piston fitting.

I have read about successful use of Viton as piston ring(s). Viton is available here, but it's rather expensive.

Anyway, I have enough ptfe(teflon) to make o-rings, as an alternative, as it stands heat, and doesn't require lubrication. 

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #131 on: December 22, 2009, 09:01:26 AM »
Piston fitting is now done. After short run-in in lathe with plenty of oil, piston moves smoothly in cylinder:
   

Compression feels good, and it's again about the time to restore the engine to its glory running condition :ddb:.

Offline Bernd

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Re: Another version of how not to build a model engine
« Reply #132 on: December 22, 2009, 09:45:41 AM »
S,

Can't believe the dedication you have put into this engine. Your perseverance has been unbelievable. I hope this engine turns out to be a good runner after putting that much effort into it. I know I wouln't have had the patients to carry on as far as you have on one project.  :clap:  :thumbup:

This thread will hopefuly inspire others to carry through to the end on their project.

Bernd
You can't fix "STUPID".

Offline NickG

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Re: Another version of how not to build a model engine
« Reply #133 on: December 22, 2009, 11:20:38 AM »
Very true Bernd. Today I've been looking at the poppin plans (another flame licker) incase I can't get mine going  - even down to what materials to buy! But that is pretty negative so am going to follow in S's footsteps and concentrate on trying to get mine running for a bit first!

Nick
Location: County Durham (North East England)

Offline Stilldrillin

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Re: Another version of how not to build a model engine
« Reply #134 on: December 22, 2009, 12:15:51 PM »
S,

Can't believe the dedication you have put into this engine. Your perseverance has been unbelievable. I hope this engine turns out to be a good runner after putting that much effort into it. I know I wouln't have had the patients to carry on as far as you have on one project.  :clap:  :thumbup:

This thread will hopefuly inspire others to carry through to the end on their project.

Bernd

S`s avatar prompts me to say , he`s certainly showing "dogged determination".......  :lol:


Sorry.....  ::)

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #135 on: December 22, 2009, 05:02:54 PM »
Thanks again, guys :wave:.

Hopefully this thread shows the pitfalls, that are to be avoided, when designing/building a test engine. And also, how to make the construction more durable.

David D, that saying isn't familiar to me, but I'm quite sure, that it fits for me, as I'm too stubborn to give up on this project.

Anyways, the engine is almost assembled, and the valves and camshaft are adjusted.

Tomorrow it's time to test, if how the engine runs.

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #136 on: December 23, 2009, 03:47:52 PM »
Engine was bit stiff at first, but now it runs again :beer:.

But the recently made spark plug (on the left) failed, and started to leak :


It is now replaced with the older plug (on the right side).

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #137 on: December 23, 2009, 06:06:20 PM »
At this time, the engine takes more persuasion to get it to run, than before.

But when it finally gets going, it runs more stable than ever. And even longer time than before.   

Crappy video:
&feature=channel

Offline Darren

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Re: Another version of how not to build a model engine
« Reply #138 on: December 23, 2009, 06:08:52 PM »
Sounds like you have it under control now  :clap: :clap: :clap:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline sbwhart

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Re: Another version of how not to build a model engine
« Reply #139 on: December 24, 2009, 02:25:43 AM »
Great work sounds real well  :clap: :clap: :clap: :clap: :clap: :clap:


Cheers

Stew
A little bit of clearance never got in the road
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Location:- Crewe Cheshire

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #140 on: December 24, 2009, 08:40:32 AM »
When testing, I've noticed that the spark plug has to be cleaned throughly between runs.

Reason might be that the gasoline has still too much oil in it. Even when running the engine on ethanol without oil, the spark plug had to be cleaned before next run, or engine fails to start.

After all, there is still some run-in to do, to find out how well the new piston/cylinder -combo keeps its tightness. 


Offline Bernd

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Re: Another version of how not to build a model engine
« Reply #141 on: December 24, 2009, 11:07:54 AM »
Sounds like a fine ticking watch running.

Bernd
You can't fix "STUPID".

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #142 on: December 24, 2009, 04:27:01 PM »
Today was the longest running session so far (~30 minutes), at a wonderfully low speed (1200-1400 rpm) :nrocks:.

I'm not sure if it's possible for an engine that small to run any slower, but I'll try it anyway :wave:.


Offline jim

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Re: Another version of how not to build a model engine
« Reply #143 on: December 24, 2009, 05:43:08 PM »
 :clap: :clap: :clap:

well done!

its reading posts like this that keeps us all going :thumbup:
if i'd thought it through, i'd have never tried it

Offline NickG

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Re: Another version of how not to build a model engine
« Reply #144 on: December 25, 2009, 05:51:35 AM »
Well done, looks like it's running superbly. Might cooling be an issue running it any longer than that?

Nick
Location: County Durham (North East England)

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #145 on: December 25, 2009, 10:43:32 AM »
Nick, the engine ran out of gas, after that 30 minutes ::).

It seems that the engine speed is low enough, so that it doesn't cause an overheating.

Adding some cooling element(s) would be cool, but not quite yet...

Offline sorveltaja

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Re: Another version of how not to build a model engine
« Reply #146 on: December 26, 2009, 12:13:01 PM »
To lower the idle speed, I increased the weight of the flywheel by adding smaller brass flywheel to it.

Also a bit of fiddling was done with crankshaft camshaft timing.

Result:


Anyways, I consider that as a giant leap for mankind in this project, closer to goal :ddb:.

« Last Edit: December 27, 2009, 12:31:19 PM by sorveltaja »

Offline chuck foster

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Re: Another version of how not to build a model engine
« Reply #147 on: December 26, 2009, 01:47:51 PM »
now that's a big improvement  :thumbup: :thumbup: 


chuck  :wave:
hitting and missing all the way :)

skype:  aermotor8

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Offline NickG

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Re: Another version of how not to build a model engine
« Reply #148 on: December 26, 2009, 04:39:24 PM »
It's spot on now! Were you timing it with a strobe light or something there?

What are your overall plans for this then S? Is it to dress this one up a bit or now you have the baseline are you going to start a new version?

Well done  :bow:  :thumbup:

Nick
Location: County Durham (North East England)

Offline John Hill

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Re: Another version of how not to build a model engine
« Reply #149 on: December 26, 2009, 05:42:19 PM »
Really nice result and it runs so well too! :thumbup:
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