Thread: Porting M110
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Old 01-19-2009, 05:00 AM
Dlespera Dlespera is offline
Mein Schöne Stern
 
Join Date: Nov 2008
Location: Lion sur Mer, Normandy, France
Posts: 19
M110 port and combustion chamber design (Euro)

Hi folks,

I can sort of provide an answer to my own question but also question some assumptions about this head.

Many people will point out that domed pistons and traditional hemi designs are not very good in terms of combustion and detonation resistance.

Well, MBZ did not do the usual "hemi" things in this engine. The Euro piston is domed but only under the exhaust valve. The combustion chamber is actually a pocket with the spark plug oriented towards its center. The combustion chamber area near the intake valve is lightly carved to improve flow. The intake ports are relatively small but very uniform and designed to maintain strong gas velocity at low engine speeds. All ports are actually divided by small humps before and after the valve guides - this is designed to maintain best velocity. American hot rodders would remove the humps but that would be a mistake with stock camshafts.

The exhaust could use a bit of porting. The intake side needs to have its area just above the valve seats make smoother - mass production machining artefacts do not make this as uniform as it could be. That is about all that needs to be done - small mods and cleanup.

This design with its very, very conservative camshafts seems to ensure that the relatively heavy cars it must propel will move swiftly at low road speeds. So "real" porting would only make sense if the cams were changed and the engine were fitted to a light car like say a W201.

Looking at the DOHC head one notices that it was designed to be as compact as possible and therefore has combustion chambers that are not heavily surrounded by water passages - hence the noisy character of this engine.

Voilà !

Denis

Lion sur mer
France
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