Hello to all,

I´m just on with rebuilding my OM603A. It was already running with a 7mm pump and HX40 as a daily Driver for several years. So now normal things are to do, like a new head gasket, new Pistons rings, honing cylinders, changing to Manual tranny and so on. In this way, I consider about to drill the prechamber holes a bit wider, except of the bottom one spraying direct onto the Piston. Is there anybody with experience in that? Are there any noticeable benefits? I can´t find some really clear Statement on that. I´m going to build another pump with 7,5 or 8mm elements. Max. Power Output was appr. 350 HP and I will try to reach 400 HP in the next step.

Many many greetings from Germany!

Yours Konstantin

You want air in the combustion chamber where it will make power to push on the piston, not in the prechamber will it will push against the chamber wall.