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48kenworth

new 40w ashless oil in fuel???

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I have obtained a large quantity of new 40w ashless oil and was wandering what diesel to oil mix ratio would be safe to run in a 1st gen?

Thanks

Jon

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Hmmm... 40 weight... I would start out at 200:1 and work your way towards 128:1 then you can figure out your happy spot. But you won't need to go below 128:1 ratio and you shouldn't need to be above 200:1 ratio.

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Yea the oil is free to me and I was hoping to use it to cut my fuel cost. This is engine oil used in large natural gas engines. I was really hoping to be able to run the oil much heavier.

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Remember the VP44 pump is designed for 3-5 cSt (centiStoke) fuel not 50 cSt @ 100*F its just way to thick. The only way you could burn large amounts of this oil is to heat it to 210*F then it drops to 9 cSt. So what happen is you put way more stress on the VP44 pump trying to push this thick cold oil in the cool mornings. Then the oil is so thick it doesn't atomize so it doesn't burn good either. Any oil is a cetane reducer so if you add too much oil the burn rate is so slow that you'll actually degrade your MPG number trying to save a few pennys... Once you drop below 100:1 ratio most people report back they lose performance and MPG. The exhaust smoke turns more white. 5% volume is 1.75 Gallons of oil which is cummins designed max... Which is 20:1 ratio. My biggest worry is the the oil viscosity more so that anything else that little VP44 has to pump up that oil to over 4,500 PSI just for a idle. Thicker the material the harder to compress...

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does anyone have the original cummin's report on mixing motor oil and diesel, I've heard from some people 20% which sounds like way too much and others say you can't add any at all of which is a lie. I'd really like to read the original cummin's write up on this subject

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I am not sure a VE would like it. I have run straight motor oil and it was fine, though I was just sitting there testing out different "fuels". The stuff doesn't burn clean, I could barely walk past the exhaust without wondering if the wiff I got was going to take off 5 years of my already short life. The stuff also has metal in it. You know, all that crap that is on the magnet of the oil pan...and that's just the magnetic stuff. You have fine grit sandpaper running through the fuel system because the stock fuel filter will not get that out, maybe some but not all. The only way to do it, which is still leary with me, is to run it through a centrifuge filter first. If you don't do that and run it just through the stock fuel filter, well let me calculate. I think the plunger in a ppump moves from TDC to BDC about 12mm. At 1700 Engine RPM, the plunger itself will have gone a total distance of 66ft in just 1 minute, so 10 minutes is of course 660ft. So drag the plunger down 5000grit sandpaper for that long... Now the plunger is perfectly fit so maaaybbeee it won't get into the sides of it. Wellll, it still goes through the injector, the delivery valves, everything. You won't notice it, but over time everything will start to show the effects, and it will cost big money in replacement parts. Of course you could just not replace them and live with it running weird and getting crappy mileage. It won't blow up or anything. But remember, it is lowww cetane oil, it burns a lot slower than the engines are made to run. I found the owners manual of those huge 2 stroke diesels, it's like 1000 pages long, anyways, those things run that kind of oil, why? Because they are slow. You're talking a few hundred RPM, the fuel has all the time in the world to burn. Low cetane oil has the most BTU's of any fuel also. That big diesel was said to be 54% efficient. To make a long story short, you don't run that 85 octane crap that I saw in colorado (only goes to 87 here) in a nascar, it's not for nascars and they won't like it, same with WMO in a cummins..

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I think the oil may be better off in the crank case than in the fuel. Is this oil rated for compression ignition engines?

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