The paper divides into two parts. First the investigation of the noise of an unconventional design of two cycle diesel engine, including the results of applying known noise reducing features to it. Then taking one component of that engine, the scavenge blower, and re-designing it from first principles to produce a low noise machine suitable for the low noise engine. The final assembly of engine and blower demonstrated that the noise that has been regarded the characteristic of the two cycle engine is in fact that of the Roots type blower and when eliminated the noise level can be quite low. The present test bed noise level of 97/98 dBA at 1 metre shows promise of this type of engine meeting the legislative requirements of the 1980's.