The new Malossi 210ccm under the microscope
After we are in ersten Teil of the post have already looked at the overflow, exhaust ports and control angles of the new Malossi 210ccm cylinders for the Vespa, today follows the cylinder head.
The new Malossi 210cc cylinder head
The cylinder head is also of crucial importance in the two-stroke engine. The design of the squeeze area and the compression can significantly influence the character of the engine.
The fact that Malossi believes the Malossi 210ccm Sport and MHR cylinders have a significantly better filling is also noticeable in the compression ratio.
The combustion chamber volume
Briefly measured and calculated using the example of the Malossi MHR with a 57mm crankshaft stroke:
The pure combustion chamber volume of the head is 26,5cm³.
The volume of the screwed-in cylindrical part in the head is deducted from this (h = 0,8mm = ~ 3cm³)
The volume of the elevation of the piston crown is 6,8 cm³
The volume of the pinch edge (0,9mm) is 3,3cm³
So we come to the following calculation:
Combustion chamber volume 23,5cm³ - piston dome volume 6,8cm³ + pinch edge volume 3,3cm³ = 20cm³
Displacement 210cm³ + combustion chamber 20cm³ / combustion chamber 20cm³ = Vc 11,5: 1
An absolutely useful value for a fast, performance-oriented engine.
The value is identical on a long stroke motor with a 60mm stroke and a pinch edge adapted to 1,3mm. Without adjustment, i.e. also here with a 0,9mm squeeze edge, you would get a value of 12: 1
We are excited about the engines that show what “the new Malossi 4ccm can do with a made-up Malossi Sport or MHR cylinder on our P210.