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Old 10-08-2008, 12:56 PM   #12
Marin
Scraping Paint
 
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Join Date: Oct 2007
Posts: 13,745
RE: Oil-Bypass-System

Quote:
Forkliftt wrote:

Question is- I read somewhere that Bob Smith suggests a single weight oil for the Lehmans.
The Lehman operator's manual contains recomendations for the types of oil to be used. All are single-weight although the weights vary by ambient operating temperatures.* The recommended weight for the normal temperature range in the PNW is 30 wt.

When we bought our boat I asked a good friend who's been in the engineering department at Alaska Diesel Electric (now Northern Lights/Lugger) for thirty-something years what sort of oil to use in our two FL120s. At the time they were relatively low-time engines. Without hesitation he said "Delo 400 30 weight, don't use multi-viscocity and don't use synthetic." We got the same answer from the very experienced diesel shop in our marina.

So that's what we've been using for the last 10 years. Now I have heard of people using multi-viscocity oil in their FL120s and according to them they've not had any problems. I have also heard of a few people who have switched their Lehmans to synthetic oil, and they say they've had no problems.

So I cannot offer any definitive reasons why single weight oil is better for these engines than anything else other than that's the kind of oil they were originally designed to use. But the people who have told me to use single-weight oil have all been very experienced in the marine diesel field so we have chosen to adhere to their advice.* I have seen fairly scientific explanations of why single-weight oil is advantageous over multi-vis in certain applications.* I recall it had something to do with the single-weight retaining higher lubricity across the operating temperature range but I could be completely misremembering this.* It was on the T&T list so a search of their archives might turn these explanations up but the T&T archives is not very user-friendly with regard to searches.



-- Edited by Marin at 15:11, 2008-10-08
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