ESE's works engine tuner

**Flettner** · 16th July 2019, 15:17

Here is a 60.5mm piston, not finished outside. Thats why there is a lump on its head, to hold on to, to do the cut aways and piston ring groove. Material? magic.
https://youtu.be/MxyTBXiaFQw

**Flettner** · 16th July 2019, 15:25

https://youtu.be/MxyTBXiaFQw
60.5 mm piston, clearly not outside finished yet.

**TZ350** · 16th July 2019, 15:49

What sorcery is hiding in here?......

**Flettner** · 16th July 2019, 17:52

tried to put up a video but won't take.
So here is a picture instead, my new 175 piston, 60.5mm

**katinas** · 16th July 2019, 19:02

Thanks Wob very much about this info, maybe we must to rise C before Europian final round
You are right, for accurate comparison test we must found right cylinder height for std piston and from this point start to test with rounded. But its even more pain.

Usual modification route is-
Work with bottom end (crank, crankase) then testing
Work with cylinder, then testing
Rounded piston, then testing

Add photo with another modification on C, crankcase step, its mimic to hydrodiode , we do this on SX50 and World Cup SX65, but still blind zone.
Maybe this coud help with full rounded piston, but we not tested.
I think for all of us would be very interesting to see your work results with sharp edge at C on much higher revs and power output engines than MX.

**jonny quest** · 17th July 2019, 01:09

Originally Posted by katinas

Thanks Wob very much about this info, maybe we must to rise C before Europian final round
You are right, for accurate comparison test we must found right cylinder height for std piston and from this point start to test with rounded. But its even more pain.

Usual modification route is-
Work with bottom end (crank, crankase) then testing
Work with cylinder, then testing
Rounded piston, then testing

Add photo with another modification on C, crankcase step, its mimic to hydrodiode , we do this on SX50 and World Cup SX65, but still blind zone.
Maybe this coud help with full rounded piston, but we not tested.
I think for all of us would be very interesting to see your work results with sharp edge at C on much higher revs and power output engines than MX.

I have lowered C port openings with epoxy. Maybe fully Radius piston and epoxy lowered C.

Entrance of C wider than cases works good. Any benefit from A and B entrance wider than cases?

**shnaggs** · 17th July 2019, 01:32

Originally Posted by jonny quest

I have lowered C port openings with epoxy. Maybe fully Radius piston and epoxy lowered C.

Entrance of C wider than cases works good. Any benefit from A and B entrance wider than cases?

Have wondered this myself...

**katinas** · 17th July 2019, 06:51

Originally Posted by jbiplane

Thanks for responce. The more information is on producer site.
http://sibaero.ru/%d0%b4%d0%b2%d0%b8...-sibaero-2r-i/
I nether see this engine working, only read information on Russian amateur aviation forum. Both cylinders are working (have the same themperature).

Hi,
On parallel two cylinders air cooled engines, aviators use isolation plate between cylinders to lower and maybe equalized cylinders temperature for both transfers sides. Without plate engine lost power.
Maybe this help.

**katinas** · 17th July 2019, 08:11

Originally Posted by jonny quest

I have lowered C port openings with epoxy. Maybe fully Radius piston and epoxy lowered C.

Entrance of C wider than cases works good. Any benefit from A and B entrance wider than cases?

Yes, on dyno entrance of C wider than cases add something on reed engine, but with rotary or piston ported maybe all goes in different way.

Minarelli scooter engines made with big step, aprox 3mm at A ex side wall and case.

**Mental Trousers** · 17th July 2019, 10:28

DB Errors have been fixed. You can now view the thread images again.

**wobbly** · 17th July 2019, 10:51

Katinas , I am tuning for a team in OZ champs till next week , but as soon as I am back I will try C duct step ( sides only first , then all 3 edges ).
Its a test I can do back to back on the dyno in probably 1/2 an hour , so really worthwhile if a sucess , no drama if its no use.
I have a new piston from Vertex to test with angled squish only - then flat top.
Once I have done this is I will CNC that piston with radius to test again , but with a sharp C edge and test C height as well.
As I said , with full radius the front side power was very good - exactly what you want in MX.
But using a radius with sharp C and dropping the cylinder essentially makes the C lower in timing - again good for front side power.
I am hoping that dropping the cylinder and grinding up the C with the sharp edge will give more everywhere - including into the overev.
Bastard 2T will make a fool of me im sure , but I have to try it.
I think if you add big ball nose radius on the duct entry wall you will see a gain - worth over 1/2 Hp in the kart engine.

**katinas** · 18th July 2019, 01:49

Thanks you Wob for your clear reference.

Actually for World Cup we send boy with two reverse restrictions in C port (add sketch blue color where was grinded) because KTM 65 cylinder is relatively high. With shorter cylinder, shorter Lc, and just one step on case is enough. On dyno with 65 this add 0,3 hp with better midrange. We use grinded spark plug that Jan and Frits recommended and this again add mid range. But very interesting, it looks like plug works one number cooler that before grinding, maybe better flush..
At World Cup boy was only one, in the whole group, with std. KTM exhaust pipe, but for us it works very well.

But Lotte van Drunen, what a ride !!! She won both starts, amazing.

**jfn2** · 18th July 2019, 04:14

Katinas
Did you test with just the overhang and then test with just the hydro diode. I wonder why the use of hydro diodes are not used on all the transfer passages for reversion? I also wonder if the placement of the diode makes a difference?