Motorboy

Hi folks!

Now i am ready with the high tensile steel sleeve with extra height above sleeve for contrapiston. The old sleeve was an peeled ABN sleeve. You can see there are difference in these porting windows, they are to preventing the piston ring to come out of piston groove.
The sleeve are made to get light press fit in the crankcase and make better heat transfer from sleeve to crankcase.

I am planning to use ringed piston and contrapiston in the sleeve.

Jens Eirik

Hobbsy

My Feedback: (102)

Looking good Jens, keep us posted on your progress.

Motorboy

Today in evening i has maked the new piston with 2 ring groove for better compression and less leakage. I melted old piston and poured in the steel tupe to make a solid bar ready to make a new piston. The important tools are micrometer (better digital micrometer), deept micrometer (my deept micrometer are homemade of old micrometer), blade seeker for ring groove, watch maker magnifying glass to control the surface are smooth in ring groove to prevent leakage. My tools are a chinese made lathe 250x550 and i am very satisfied to use the lathe.

Do not use abrasive paper or grinding tool at piston in case the grinding grain will fasten in the piston surface and make rubbing marks in the sleeve.

In next time are drilling the hole for wrist pin and milling in the piston to make room for connecting rod. The drill for wrist pin are the D-bit drill of silver steel and give smoothed surface and true hole.

The picture tell more than i am writing here..

Jens Eirik

chevy43

Whay did you make a new pistion? Did you make a new piston because you need more strenght? Do you put rings in the pistong groves? If so are you making new ones or using the old ones?

Why didn't you just make a contra pistong head like your other engines? Sorry for all the questions but I like your projects and want to undertand what you are doing.

Treven.

Motorboy

The old piston are made for ABC/ABN sleeve and can not use in steel sleeve and there are not enough material to make ring groove in old piston. Therefore i am making the new piston. Yes, put the two rings in grooves. As you see the sleeve has extra height above sleeve, this is a place for contrapiston same i did for the OS 10FP as pure diesel engine in this link http://www.rcuniverse.com/forum/m_40...tm.htm#4325493 Also nothing to have leaky cylinderhead gasked

Jens Eirik

chevy43

I see now. Do you make your own rings or what?

Motorboy

Yes, i am making own pistonrings of cast iron.

Jens Eirik

chevy43

So I guess you would turn a tube out of cast iron slightly bigger than the pistion then part off the rings to the right width? Then cut a gap in them? Maybe finish them on a surface plate with some fine sandpaper? I've got to join the model engine club!

Motorboy

chevy43
It is a bad idea to make piston ring bigger than bore then part off. If the ring was mounted in bore, you can see there are not full contact between piston ring and bore.

The ring formula: Bore/30 or Bore/25= ring tickness, Ring tickness = ring height, Tickness x 4 = ring gap

1. Turn to tupe are 0.1-0.15 mm bigger than bore.
2. lap the tupe to the tupe fit very very light press fit in bore. (Break-in the engine will make pistonring fit to bore and keep tight.)
3. Part off the rings where the thickness are a bit bigger than ring groove.
4. Grind the rings to fit the groove with plain fine hone stone + oil. Do not grind in one way or rotate, grind as in "8". The ring must rotate free in groove without play.
5. Break off the ring and add the spacer between ring gap who are measured ring thickness x 4 = ring gap.
6. Hold the ring between the two disc who are bigger than ring and thicker than 6 mm with bolt and nut in mid of disc.
7. Heat up the disc with ring inside to 500-600 degree celsius.
8. Let it cool down and dismandle disc and ring gap spacer, now you has a ring who are bigger than bore and can mount in bore. The ring will be elastic.
9. Adjust the ring gap with needle file.
10. The ring are ready to use. Mount piston ring careful in ring groove. The ring are brittle.

Ring can be made of cam shaft or brake disc, both are made of cast iron.

You undestand?

Jens Eirik

chevy43

Yes Jens, I understan very well. Than you again!

Motorboy

Today i done ready with contrapiston and in last week i done ready with piston ring, drilled wrist pin hole in piston with D-bit drill and maked groove for lock ring for wrist pin with special tool.

Tested compression, very well compression and very little leakage

The last work are the new cylinderhead and compression screw.

Jens Eirik

DerFly

det ser ut som skit fin!

mylamo

My Feedback: (1)

Si

Motorboy

Now i am ready with the cylinderhead and i has tried to start, the engine are easy to start and works well. I shall find the carburator to my engine + make a adapter between carburator and fronthouse.

I maked the beam type torque wrench of 4 mm pianowire and the torque are adjusted and marked up at scale from 0 to 3 cm/kp ( 2.94 Nm/ 34.71 oz/ft) in both ways. I used this torque wrench to screw all screws at the engine. It is not difficult to make torque wrench, use the formula: Force x length = Torque before you are marking in the scale
http://en.wikipedia.org/wiki/Torque_wrench

Jens Eirik

gkamysz

My Feedback: (19)

Good idea on the torque wrench. I might make one myself. The head looks nice.

Motorboy

In evening (norwegian time) i had maked the new carburator body with 7 mm venturi, next parts are the airbleed screw and barrel stop screw, barrel , jet and main needle.

Jens Eirik

Motorboy

Yesterday i maked the barrel with main needle and jet. There are not possible to get air leakage, only direct from tank to jet via rubber hose.

And today i ran the engine under break-in, the engine are nice to run and trottling are smooth and nice. Easy to start after little priming with finger at carburator intake + 2 turns of propeller then start the engine after 2-3 flip. I am using running in fuel for diesel engine. The propeller are 15x6 APC

See at the movie of the engine here: http://www.youtube.com/watch?v=6jwH6Wc1StY

Jens Eirik

gkamysz

My Feedback: (19)

Nice job on th carb. When I saw your last post I thought it was an Enya carb. The design is similar to PAW.

Motorboy

The carburator are of my own idea when i maked the carburator too simple and few loose parts.

Jens Eirik

David Owen

Congratulations, Jens. Very nice job on the OS Diesel.

regards
David

gkamysz

My Feedback: (19)

Have you flown this engine,yet? How does it do? Does carbon collect between the rings?

Motorboy

Here in Bergen was weather bad in winter therefore i not has tried to fly the plane with the engine. I am planning to mount the engine at "Maricardo" airplane. I ran the engine at break-in in some hour to be sure the rings are adapted in sleeve. After the engine was adjusted to normal running and ran 2-3 tank. There are not problem with carbon build up in the rings and compression are good.

I has maked a new carburator with "automatic" mixture from idling to before full trottle. In full trottle are the fuel adjusted to right mixture by main needle. Nice trottling

Jens Eirik

martenson

Motorboy: I'm speachless, I wonder why Norway don't make engines and cars.
With your knowledge you could be making big engines.
Real good work, I buy my ether from Norway, we can't buy it here in Sweden.
Keep up the good work.
Any engines for sale??

Motorboy

Martenson...
Thanks

But are you sure Norway don't make cars and engine???
Here are the links: http://www.semidiesel.no/, http://www.sabb.no/ , http://www.think.no/, http://www.moxy.no/
And there are not in webside: Bergen Diesel (Now.. Rolls Royce Marine A/S)

No, i has not some engines to sale... sorry.

Jens Eirik

robot797

could you convert any engine to diesel

if so what does it cost to get a kyosho gx-12 to run on diesel