T&T: Multi Grade Oil in Lehman Engines

[Mike Maurice]

I have had a couple of talks by phone within the last couple of weeks 
with the Smith's at American Diesel. Bob is adamant about NOT using 
multi weight oil in Lehman engines. His technical reason is that to make 
the oil they start with a 10 weight and add the plastic enhancer that 
spreads the viscosity out from 15-40.  This does nothing to help the 
lubricity.

This question came about because someone used 15-40 in a 225hp turbo 
charged Lehman and I wanted to know how Bob felt about running it that 
way till the next change. He had no problem with it as long as the 
engine was not run hard. We were running at 1250 rpm for about 150 hours 
with short bursts to WOT for periods of a couple of minutes every day or so.

Do not interpret this to apply to synthetic oils or to engines other 
than Lehman.

However, I am suspicious that if an engine is accidentally over heated 
due to the internal water pump failing without warning, that some 
engines that have seized up would not have if they had been running a 
single weight oil.

Bob does not think that anything he says will change the minds of those 
who are inclined to disregard his advice and I agree with him about this 
last point.

Regards,
Mike

_____________________________________
Capt. Mike Maurice
Tigard Oregon(Near Portland)