The head is different, the crankcase looks 35+/35WC like so probably a normal long stroke model but what really has changed I do not know.

The main thing of interest in the car is the new as yet unnamed prototype Novarossi engine. Having worked on the new engine for the last month & a half testing mostly in Italy, he said ‘we are really on a good way with this engine’. In terms of a release, Simon has no specific details but expects it to go on sale ‘soon’.

Euro Nitro Series » Chassis Focus ? Simon Kurzbuch

At least they all had the same tyres to make things 'equal' !!!!!

Are the engine cooling heads interchangeable? Have an Nova .12 whose cooling head is too tall that it hits the roof of the body.

Iooks like the new .21 will be named "mephisto"
17.6mm stroke
14.5mm crank
update conrod

And there it is
Novarossi Mephisto .21 On Road Ceramic DLC

Hey Roelof are there any *real* pictures out yet ?

Look a view posts back, the Kurzbuch engine.

Interesting to see on the exploded view is that on the rear and front normal old style bearings are used like a 6mm wide front (no 5mm) and a simple 14.5x26x6 bearing on the rear (no stupid extra dimensions)

And as it is an extra long stroke version it seems Novarossi did get it finally right. Kurzbuch was flying on the ENS

The course of this new novarossi is enormous
Much more extra long course than its rivals.

The course..???...Whats the course of an engine?.....anyways.....I just ran in my Nova Ison in the C803 at the Mach in Heemstede. Ambient temps of around 20 to 25 degrees, relatively dry air for the Netherlands. It now has about 4,5 liter of runnertime through the chambers and I just changed the conrod.....By the looks of the piston it has been run pretty rich....care for any comments in this?

Stroke was what I wanted to say ... I use Google Translator sometimes the translations are not the best.

Dam what did you do to that piston!! Lol

My piston and head after 5.5 liter:
Novarossi Ielasi Tuned Engines - Official Thread

Runnertime is a fuel with a high content castor oil, it just burns brown/black. And the stock ISON21 is not the highest performing engine so it does not burn cleaner as well, as long the temperature, smoke tail, sound and speed looks right is must be OK.

pedro look at his pic that's how it should be! when shimmed right, you got some funky looking burn pattern going on is it shimmed right? in your post you put temperature 25-30 degrees is that correct degrees? If so, thats way to cold to break in a motor