I have a pair of TAMD41P-A's that I normally operate at 15 -1800 rpm to obtain the best fuel economy, Once an hour I do operate it at 3000 for 5 minutes. However I have heard that operating at low rpm causes the cylinder walls to glaze over as the internal temps do not rise high enough. However my understanding is cylinder wall glazing is caused by running at high rpm without any or enough load on the engine. Has anyone got any comments?