# Nemett 15cc 4 stroke engine.



## wheeltapper

Hi people, well I've finally bitten the bullet and started building this engine.
this won't be a blow by blow account, rather a show and tell as I (hopefully) finish a part.

It will also take me a fair amount of time as I have to save for the material and tooling required, I've already come to a stop on the head because I need a rotary table and they don't grow on trees.

first a pic of what it should look like.






parts so far, cylinder jacket





crankcase nosepiece.





part finished head.





and crankshaft.





That's it so far.
next is get a square lump of ally for the crankcase.
expensive hobby this, ain't it 

more to follow soon.


I hope :big:

cheers
Roy


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## metalmad

Hi mate
Nice start on a good looking engine 
Pete


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## Longboy

These Nemitts are little charmers. With their cylinder head and cylinder looking like one piece, it offers the illussion of a low profile, streamlined OHC design!


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## Steve_Withnell

It's a nice engine to build - my first project.  Using the excuse that it was my first engine, I built it as a glo motor and avoided all the electronic ignition and associated parts.

It does run well, but very smoky!

[ame]http://www.youtube.com/watch?v=7X2pe7BrtT8[/ame]

When it was finished there was no compression on the engine, the piston and rings were a very good fit so pretty obvious it was the valves not seating properly. I went to tremendous lengths to get the valves to seal but no joy. (Do not trying grinding them in it makes things worse!).  In frustration I used my dads old trick and put some engine oil in the cylinder put the plug back and spun it up with an electric starter. It fired a couple of times and as if by magic there was loads of compression...


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## wheeltapper

It sure does sound nice. ;D

have you considered putting wings on the workmate :big: :big:

I think I'll be going for glow ignition, the electronics isn't my cup of tea.

hopefully my one will someday sound like that, not as smoky I hope, I can see you put engine oil in it. 

Roy


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## bentprop

Nice start,Roy.I too love the sound of four strokes,they sound much more natural than a screaming 2 stroke.
This one is on my ever growing to-do list.So many projects,so little time


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## metalmad

Hi Steve
Congrats on first pop
 BTW. If the problem was with the valves mate the oil would have made no Difference
you might have a piston/ring problem. It may even just need bedding in 

My 2 cents :big:
Pete


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## Trizza

Where can you get the plans for this these days?


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## wheeltapper

Hi
back again.

A few more progress pics.

cylinder liner





part finished crankcase





and an overview of what's been done.





and a question for Steve Withnell, when you made yours, the bolts that hold the mounting angles on, did you drill right into the crankcase then seal them or are they blind holes?
I can't figure it out from the drawing.

thanks for looking.
Roy


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## Steve_Withnell

To be honest I can't remember. I don't think it matters though as I don't think there is any pressure to speak of in the crankcase.  The petrol version has a breather to the CAM shaft, and the box isn't sealed.

Steve


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## wheeltapper

Thaks anyway Steve, I found a pic of the interior with the holes showing so thats that.

Meanwhile :big: :big:

I dont usually embarrass myself in public but I had to take a pic of this.
poor mans DRO.
can I nominate it for bodge of the year? ???

I had to move the mill table an exact amount for the hole centres of the con rod for this engine.
steel bar clamped to the lathe tray, square clamped to that, digital caliper clamped to the mill vise and the other bit of the caliper clamped to the square. 

piece of wood to take out the spring. ;D ;D







am I mad or what?

Roy


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## Steve_Withnell

Necessity is the Mother of invention...The head is the one part of the engine I felt quite in awe of.  I did buy a rotary table, but afterwards did think that perhaps converting all the holes to X-Y co-ords in excel would have worked too. Need a lot of concentration to keep on top of the backlash, but I'm sure it would work.

One thing I learned from building this, was if you make a mistake, finish the part, don't scrap it and start again. That way you get to practice all the ops before starting again reducing the chance of mistakes the second time around and the other thing I discovered was sometimes as you press on, you find away of recovering the error as the work progresses. (My Nemett's head has some scars from being thrown in the scrap...)

Oh the moment when it fires the first time...

Steve


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## wheeltapper

Hi all.
Just a couple of pics of the finished crankcase.

Or
how to turn an expensive lump of aluminium into a hole  8)











cheers
Roy


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## wheeltapper

Hi
more progress.

piston









and from these





to this

















thanks for looking.
Roy


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## ShedBoy

Nice work. Love these Nemetts engines. That carby looks great Roy like the rest :bow:

Brock


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## wheeltapper

Thanks. ;D

Roy


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## metalmad

going great Roy 
Pete
Keep it coming !


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## Swede

I like the carburetor especially... lots of fiddly parts that have to be well-made for proper function.

Very nice! ;D


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## wheeltapper

Hi
another landmark reached,
the cylinder head.
top




underside




and with carb and exhaust





cheers
Roy


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## kustomkb

Your parts are looking great!

Keep up the nice work.


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## agmachado

That's true!!!

The look is great!!! Very cool!!!

Alexandre


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## wheeltapper

thanks for the kind words :bow:

I temporarily assembled the beast, and here it is.










so far so good.

cheers
Roy


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## wheeltapper

THE BEAST LIVES    

It only works.

here are some pics of it ready to run,

















and a couple of videos,








and some pics after stripping, cleaning and shining up a bit,

















Am I chuffed or what?

hope you guys enjoy .

cheers
Roy


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## EL-CORAZON

Very nice-
Are you planing to use it in a plane ?


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## danstir

Great engine. It looks like you paid a lot of attention to detail. Thanks for sharing!


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## wheeltapper

Hi if any of you had trouble with the Photobucket link here is a youtube one.
[ame]http://www.youtube.com/watch?v=NoBvCvlGmqU[/ame]

one more to follow .

Roy


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## wheeltapper

Hi
second video.
[ame]http://www.youtube.com/watch?v=WYW1gqZjuV8[/ame]

Roy


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## Catminer

Splendid Roy,I really like the boxy look of the ohc housing.
 Peter


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## wheeltapper

EL-CORAZON  said:
			
		

> Very nice-
> Are you planing to use it in a plane ?




Hi
No, I only built it to see if I could build it. 
I tried flying planes when I was younger and they flew quite well ......................as long as it was downwards. 

So it will go onto a nice stand and sit on a shelf.

Roy.



PS
 I suppose this means I have to put up a bloody shelf now. :


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## metalmad

real nice Roy :bow:
Pete


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## Blue_Rock

Love the chunky look of the Nemett, well done!


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## pcw

wheeltapper  said:
			
		

> I tried flying planes when I was younger and they flew quite well ......................as long as it was downwards.



hehe know the feeling, spend two years af building a ME109. 4 metre wingspan, retractable running gear, in short all you want to see on nice model and seeing it dig a nice hole in the ground cause some idiot didnt look on board wich frequencies where being used and switching on his remote..............


back to your engine. nice build good runner!
pascal


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## EL-CORAZON

wheeltapper  said:
			
		

> Hi
> No, I only built it to see if I could build it.
> I tried flying planes when I was younger and they flew quite well ......................as long as it was downwards.
> 
> So it will go onto a nice stand and sit on a shelf.
> 
> Roy.
> 
> 
> 
> PS
> I suppose this means I have to put up a bloody shelf now. :
> he he...yes I see. fore the moment I am better in assembly things out of wood then metal  I could help you whit shelf thou :bow:


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## kustomkb

Congratulations Roy!!

That is a beauty, and a beast too.


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## wheeltapper

Hi guys
one more pic then I'll stop boring you with it.
I had a free afternoon and a lump of ali 

so I made a spinner.





thats all folks.

cheers
Roy


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## flatbelter

Awesome engine build. What size prop is that and what did the RPMS peak at?

Where did you find a gilmer timing belt for that? 

Thanks for sharing, what a terrific engine. Love the polish job too.


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## wheeltapper

Hi
thanks for the kind words.
the prop is a 14 x 6, the max revs were 6500 but that would probably increase if I ran it in and tweaked the settings.

the timing pulleys and belt came from here http://www.hpcgears.com/

cheers
Roy


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