# My 100cc V4 2-Stroke



## Johnsinski

Hello all, I ran across this forum looking for something else. But I figured you guys would appreciate my project from the "before" time, before 3D that is. I started this around 1995ish and finished it in 1997ish (sometime before graduation). Back then 3D was just coming around. Pretty much all of this was done with hand programmed "parametrics" and designed in 2D. Alot of Quickbasic programming to produce 3D G-code.

This is actually my "second" engine, the first one was a little single, to my amazement it actually ran and flew a model airplane so I decided the next step was a 100cc V4.

When I told the guys at Sundstrand that I machined the pipes to .050" thick from billet they looked at me funny.

I machined the "reed" valves from nylon or delrin or something "double-stick-taped" to the CNC table. (I got more odd looks with that maneuver too).

I also detected a "metric" Z ball lead screw in one of the CNCs during this project because of all the weird set-ups. I was getting a TLO error that just wasn't explainable.

The crank is 17 parts pressed together, with needle bearings on each rod. Each rod is "clocked" 90 degrees which fires the two inside cylinders at the same time and then fires the two outside cylinders at 180 degrees from that. It seemed like a reasonable thing to do. There are delrin seals between each double bearing to seal each crankcase volume from the next.

The cylinders have "port-cores" in them for smoother flow (unlike the standard glow engines). You can just barely see them.

When I tell people I designed and built this engine, they usually say, "that's nice". And then I have to explain, "no, I mean, I designed and BUILT this engine, from like chunks of aluminum and steel." Some people still don't get it. I like to say I built everything but the bolts and bearings.

I never really got it to run all that great, the 90cc chainsaw carb just couldn't flow enough methanol. I figured it was good enough and moved on to something else.








































































[ame]http://www.youtube.com/watch?v=X0kVLtxvKwU[/ame]


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## warranator

Awesome mate


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## Dr Jo

If this is only "good enough" I feel that I should lock up the workshop and go and take up cross stitch or something.

Jo


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## CMS

Moving on to what? 6 maybe 8 cylinders. : Nice engine.


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## lazylathe

If this is only good enough for you maybe you should send it to me.
I will look after it for you!!! ;D

That is awesome work!!!
It looks, sounds and runs like an engine, therefore it is an engine!!! :big:

Looking forward to the next "Good Enough" engine installment!

Andrew


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## Ken I

That is wonderful work - whenever a newbie shows up with something like this it makes me want to curl up under my workbench in a foetal position, suck my thumb and cry.
I dispair of ever getting to that level, but perhaps, someday....

I do have a couple of comments:

Welcome to the forum.

Post an introduction.

Post the damn drawings under the downloads section - I'm guessing a number of members are drooling over your design and might like to tackle it (I'm assuming you don't have a commercial interest in them).

Definately worth a karma point.

Ken


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## compspecial

This is an outstanding achievement,not only in the construction process, but also design-wise what with schneurle porting reed valves and tuned pipes. congratulations!
         Stew :bow:


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## mu38&Bg#

Wow, that's a very impressive engine. Sunstrand brings back memories of when I worked at Barber Colman for a few years. Being young ad dumb I left, at least I learned Solidworks there. The carb would probably work if the jets were enlarged to twice the area.


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## Niels Abildgaard

Hello Johnsinky
Awesome,but if cylinders fire two by two, two of the crank intermedia seals and two carburetors can be omitted.
I am playing wise guy because I think a 90 degree V2 two stroke with one crankcase chamber ,one carb and a one throw crank with two conrods can be the ultimate aircraft engine.
Before anyone says crankcase pumping volume is to small let me argue that crankcase pumping is not that important if You are able to make such nice tuned exhaust pipes.
So if You are finished with the engine let me take it over and rearrange parts.I have good recommendations from our animals and grandchildren.If You do not thrust me please let us have some drawing or even better 3d CAD presentations.Please?

Admirations

Niels


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## ShedBoy

Toally Freaking awesome :bow: :bow: :bow: :bow: :bow:

Brock


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## flatbelter

WoW that was enough to make a grown man cry. 

From billet no less, with tuned pipes. 

What happened to the fuel injection?  (I wonder if anyone has a thread on gas to methanol carb conversions? I'll have to look )

 Thanks for sharing! That was fantastic!

 :bow: :bow: :bow: :bow:


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## metalmad

Fantastic job Mate 
wonderful engine :bow: :bow:


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## Ramon

Truly awe inspiring - superb workmanship - fantastic design. 
What else needs - can - be said
Absolutely totally bloody superb :bow: :bow: :bow:

Should inspire us all to 'must try harder' 
Thanks for sharing it

Ramon


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## V. Lehtonen

It's difficult to find words for that  , it's unbelievable and awesome :bow: :bow:


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## Johnsinski

Yikes! Thanks for all the compliments.

Somewhere along the line the 2D cad files went missing, but I've been meaning to draw it back up in 3D anyways and design it the way it should have been. I'd be honored to have somebody else build it.

I also had a scare a while back and thought I'd lost all the spare parts for it too, but they were in a mismarked box, whew!


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## Admiral_dk

I'm very impressed with your design and build.

Regarding the carb - it's for a gasoline engine and therefor the jets are way to small when you run it on methanol !

Personally I would run it on gasoline - cheaper and more powerful (unless you really tune it to a much higher power level, where the methanol might work better).

If you run it at much higher revs, you should put stops on the reeds, to prevent them from breaking - they will close faster too if the stop is correct made and adjusted


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## agmachado

Very nice work!!!

The design is very cool too!!!

Cheers,

Alexandre


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## Johnsinski

I had this sitting in my pits once. Just by dumb luck it fits right between the diffs. I wish I would have had a candid camera going. Direct drive to 3:1 diffs puts it at about 70MPH, that should work right? (actually that probably would work, the clutches would be a problem though)


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## litoweapon619

dam super nice  ;D


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## dsquire

Johnsinski  said:
			
		

> Yikes! Thanks for all the compliments.
> 
> Somewhere along the line the 2D cad files went missing, but I've been meaning to draw it back up in 3D anyways and design it the way it should have been. I'd be honored to have somebody else build it.
> 
> I also had a scare a while back and thought I'd lost all the spare parts for it too, but they were in a mismarked box, whew!



Johnsinski 

I hate to be the one to tell you this but some a55 w1p3 has stolen your work and posted it as his own on this Chinese site. 
http://tech-domain.com/thread-40019-1-2.html

There are many other HMEM members that have had there work stolen as well. Here is a link to another post about that. http://www.homemodelenginemachinist.com/index.php?topic=16479.msg168008#msg168008

I really liked the way you built this engine and it really ticks me off that some low life would do this.

Cheers 

Don


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## Johnsinski

If they can reproduce it based on the pics, good for them. But yea, I agree, douchbags.

I also just read they (China) copied an entire city from Europe.


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## AussieJimG

Bloody awesome. Thanks for sharing and welcome to the collective.
Jim


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## mklotz

I think it's fascinating that the lowlife who stole your pictures had the balls to watermark them to prevent anyone from stealing them from him!


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## kutzdibutz

lessons learned for myself- watermark the pictures before posting... 
(its a pain that one has to do such things, but an easy measure as well)

Nice engine! 

Cheers, Karsten


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## mu38&Bg#

mklotz  said:
			
		

> I think it's fascinating that the lowlife who stole your pictures had the balls to watermark them to prevent anyone from stealing them from him!



If you look at the site, every uploaded photo has the website's watermark.


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## hdwrench1

The talent on this forum is amazing!!
Well done

Cheers
Wayne
 :bow:


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## Johnsinski

Ooops, I just realize when I reorganized my Photobucket, it broke all the links the the pictures. I didn't see an edit button otherwise I would have changed the original post. New links:


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## Till

Johnsinski said:


> If they can reproduce it based on the pics, good for them. But yea, I agree, douchbags.



It has nothing to do with reproduction or claiming ownership. This guy is most likely getting paid.  They are skimming the web for content to increase the rank in web searches and to attract visitors. It's all about money.


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