ESE's works engine tuner

[Haufen]

The answer is in previous post about SwePatrick new project TZR 250cc 56/50 bore stroke engine.
"As my classrules says max 212cc i´m thinking about put thicker liners in them and run 50/50 bore/stroke and get ~196cc and a lot of material to bore if needed." until max 51.9mm bore for 212cc rules if liner wears out or damaged.

got it, thanks!

[wobbly]

My take SwePatrick would be to go square as you are planning - gives real rev potential with the already short stroke ,plus easy optimum STA values , but then fit alloy liners that are easy to port.
Weld them in at the top and bottom ( easy ) then Nicasil them.
Much better heat transfer and no wear issues with resulting overbores.

[ken seeber]

Corking crankshafts. Need to “stuff” a crankshaft. 4 holes at Ø24. Champagne corks seem to be the go as the size is ok and it’s not even a problem getting them. It’s a low speed mundane application.

So after the heating them up in hot water so they’re soft and then pressing them in, there is a question. Should they be treated in any way (eg a sealant) to prevent fuel/oil attacking the cork?

[husaberg]

Corking crankshafts. Need to “stuff” a crankshaft. 4 holes at Ø24. Champagne corks seem to be the go as the size is ok and it’s not even a problem getting them. It’s a low speed mundane application.

So after the heating them up in hot water so they’re soft and then pressing them in, there is a question. Should they be treated in any way (eg a sealant) to prevent fuel/oil attacking the cork?

Soak em in alcohol for a year...........

[wobbly]

TM MX cranks use cork and a thin layer of two pot epoxy is used to seal over the exposed surface.

[Haufen]

Happy New Year to everyone!

Anyone else going to attend the two-stroke engine conference in Paris mid February?

2-stroke engine conference

Edit: you can also download the 2018 presentations here

The presentations of this year's event are available for download now - click this text.

[Peter1962]

The presentations of this year's event are available for download now - click this text.

Thank you for the link. The presentation in session 3 about the opposed piston engine (Turner and Vorraro) whas very interesting !

[Niels Abildgaard]

The presentations of this year's event are available for download now - click this text.

Thank You for link.
The paper from Brunel university about opposed piston two stroke mentions a lapsed 2013 patent from lotus about having a generator on each crankshaft and no mechanical connection.
I made and ran such a system in ca1994.
There is a gentleman from Austria Graz who find that a side-exhaust-valved two stroke can be awfull good for range extension of electric cars.
I described it around may 2014.
It proves that being an inventor is not getting You fame and fortune but it is a nice feeling anyway.

[husaberg]

Thank You for link.
The paper from Brunel university about opposed piston two stroke mentions a lapsed 2013 patent from lotus about having a generator on each crankshaft and no mechanical connection.
I made and ran such a system in ca1994.
T.

I am confused by the mention of the lotus engine
As magnetuic drives have been around for years, my aquarium had one in the 90's.
Was it done somehow differently?

[Flettner]

Uniflow, so last century.
Three main issues as I see it.

scavenging system
combustion chamber
exhaust piston thermal loading.

Uniflow scavenge, who would have thought.

[katinas]

Thanks for winter without the snow, for the first time, it is possible to test many things on the road.

With direct to transfer intake scheme on Honda NS engine some very interesting engine reactions to some changes. Too many tests with different combination and it is very complicated transform all things in words, so I just put main things in graphs, but maybe it looks even more complicated.

Exhaust pipe and cylinder head is the same for all main tests.
In general, the biggest surprises was Type 2 mid range torque from 6000 rpm . with the exhaust pipe that mainly works from 9000 to 13000 rpm. Never feel that power at lower revs with this engine before, feels like with exhaust power valve. But Type1 with side reed petals always strongest at higher revs, especially in range from 12500 to 13000rpm. Thicker side reed petals works without any damage (0.5 mm)
From other engine reactions, looks like for midrange torque, it is very important at witch point intake tunnels is connected to transfers ports, as pressure fluctuation accumulated pressure at both transfer port ends. Maybe this explains very low Rygeriser type torque at midrange (not only because of reduced intake capacity as I think before).

Tested with two different cylinders and three different pistons.
Cylinders
1. The same as previous posted with bronze liner and side reed petals
2. Original with nicasil plating, just intake windows are fully blocked with Loctite EA3479A ( add photo), all intake flow through enlarged side boyesens tunnels. Additional carbon plate, with reed petals on it, between cylinder and crankcase, as very complicated to add side reed petals on std cylinder because of lower side cuts.
Pistons
1. Special with deep side cuts and wide exhaust side skirt for two or three exhaust windows
2. Special with deep side cuts and narrow exhaust side skirt for one exhaust window
3. Normal piston ( from CR 125 2006 big bore 57mm)

[katinas]

With additional intake widows under main A,B it is possible to use normal piston, so no needed spec custom piston with side pockets. With these widows it is possible to use wide, two or three exhaust ports.

[Norman]

With additional intake widows under main A,B it is possible to use normal piston, so no needed spec custom piston with side pockets. With these widows it is possible to use wide, two or three exhaust ports.

Very interesting. Maybe combination carb diameter, inlet length and total volume in the transfer channels are very important in your concept. Too big transfer channel volume will not create enough suction and inlet air speed to allow piston to compress air at the same time as flow continues through inlet. Too small transfer channel volume, too big carb diameter, will not keep air speed up into transfer channels when piston moving down to compress, giving less total air in. At higher rpm relatively small transfer channel volume holds back the exhaust from entering too deep into transfer channels but the exhaust pressure compresses the fresh air there. While some exhaust is occupied with compressing the transfer channels the rest is going out through exhaust port and most of the fresh air hold back and will later not have time to escape out. A three windowed exhaust port should maybe be a bit lower then? Just a thought..

[Haufen]

Thanks for winter without the snow, for the first time, it is possible to test many things on the road.

Thanks for the interstign insights, katinas!
It would be really really cool - and I guess pretty helpful for your research too - if you had a dyno!

In case you need assistance building one yourself, let me know.
You can also use a road dyno, which gives pretty accurate results if you use the same part of the road for all of your tests (numbers will be relative, but the shape and if it's better than before is what counts anyways).

click here for a link to a free road dyno, description below:

GSF Dynamometer software in combination with a commercial sound-recorder allows for making power/torque curves of a motorcycle (or car). Dyno runs are done (recorded) on the street and analysed on the PC at home. Dyno runs are essential for tuning and correct jetting of the carb. Here you found the minimum-cost dynamometer. All you need is to download the dyno software, a sound recording system and I suggest to build the voltage divider as described below.

[Frits Overmars]

... It would be really really cool - and I guess pretty helpful for your research too - if you had a dyno! ....You can also use a road dyno, which gives pretty accurate results if you use the same part of the road for all of your tests.... click here for a link to a free road dyno, description below:

I fully agree