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Diesel fitter


Chambo

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Back to vacuum and the suggestion of it being related to oil mist down the crankcase breathers. Pondering last night I think this is very unlikely.   In effect a high inlet vacuum the more it will "suck" on the breather so it will be similar to a higher crankcase pressure and would be likely to make an oil mist ingestion problem worse - just like a higher case pressure.  I that case a low vacuum might have an effect on oil leaks but not oil mist going down the breather.

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3 hours ago, Steve56 said:

As you say this could be a problem. The LPWS range of engines had a bit of a name for bore glazing. In fact at one point lister would actually supply the engine pre filled with running in oil which was used until the first oil change. If I can put my hands on the technical bulletin about oils I will post here.

I use Premier Lubricants  "Marine Oil" SAE 10W40 API-CC formulated to prevent bore glazing as I was told it could be a problem. I change oil and filter every 125 hours rather than 250 as I'm sure I don't get quite a bit of oil out. I use a Pela through the dip stick. I have the larger oil filter not the older small one

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3 hours ago, Tony Brooks said:

Back to vacuum and the suggestion of it being related to oil mist down the crankcase breathers. Pondering last night I think this is very unlikely.   In effect a high inlet vacuum the more it will "suck" on the breather so it will be similar to a higher crankcase pressure and would be likely to make an oil mist ingestion problem worse - just like a higher case pressure.  I that case a low vacuum might have an effect on oil leaks but not oil mist going down the breather

My reasoning there. Probably wrongly. Was that at low speeds you have maximum oil mist up the breather from crankcase pressure and minimum air flow into the engine. Although the suck from the inlet manifold will be lower could it be that the ratio of oil to air and diesel will be higher at low rpm than at high rpm when there will be a lot more air and diesel going into the engine diluting the effect of the oil. Thus smoke at low speeds clearing at high speeds.

A little knowledge may well be dangerous so please don't shoot me down.

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1 minute ago, Peugeot 106 said:

My reasoning there. Probably wrongly. Was that at low speeds you have maximum oil mist up the breather from crankcase pressure and minimum air flow into the engine. Although the suck from the inlet manifold will be lower could it be that the ratio of oil to air and diesel will be higher at low rpm than at high rpm when there will be a lot more air and diesel going into the engine diluting the effect of the oil. Thus smoke at low speeds clearing at high speeds.

A little knowledge may well be dangerous so please don't shoot me down.

 

This problem seem an odd one to me so all thoughts and contributions should be welcome. personally I can't see why low seed would create more oil mist that high seed. If anything I would expect a crankshaft at high speed to produce more smaller oil droplets flung further than at low speed. However I have never needed to find out or measure crank case pressure in a scientific way. Hand over an open ail filler is the closest I have got and that was always off load.

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funnily enough I’ve never heard of anyone other than me carrying out the vacuum test. I only did it as part of my quest to find an oil leak and it makes such a deal of it in the manual. The figures are there and once you’ve got a bit of clear tube it’s very easy to do you just seal it to the dipstick.

what did it achieve? Confirmation that blowback isn’t a problem after i’d found that the pressure/vacuum in the manual were the wrong way round. It didn’t solve the leak! But if Chambo did do the test it could indicate blowby and could help. As long as he doesn’t let water into the engine it is very easy and you don’t need any tools other than scissors to cut the tube. He’s got the manual.

Thank you Tony

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5 hours ago, Peugeot 106 said:

I use Premier Lubricants  "Marine Oil" SAE 10W40 API-CC formulated to prevent bore glazing as I was told it could be a problem. I change oil and filter every 125 hours rather than 250 as I'm sure I don't get quite a bit of oil out. I use a Pela through the dip stick. I have the larger oil filter not the older small one

As mentioned earlier. Here's the Tecnical Bulletin that Lister Petter put out.

20211210_153740.jpg

20211210_153854.jpg

20211210_153938.jpg

This is the final page. Apparently to big a file to put into one post. May be of interest to some of you.

20211210_154017.jpg

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Steve that’s good. The handbook repeats what you said about running in oil

 

You had me worried there. I’ve checked the handbook it looks like mine 10W40 is fine from -15 to +50 deg C ambient. I was told to always go for a CC oil.

CB is mild to moderate duty lower quality fuel

CC is moderate to severe duty

 

if anybody knows any different please shout. It’s easy enough to carry a gallon on board for oil changes

 

Included in the handbook seems a pile of all they know about lub oils including petrol, turbocharged ,supercharged eg al. Since it’s the Alpha operators hand book it’s beyond me why they couldn’t just stick to advising what oil to use in an Alpha.

 

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The 10W/40 is absolutely fine and API CC is the correct spec. The problem with the manuals is they that cover the whole range and uses of the engine. For instance if the engine was being used on a generating set running at a much faster speed and at close to full load it would be a lot more forgiving to whatever oil was used. Really in a narrowboat they very rarely work hard so much more of a problem.

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