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Old 02-05-2014, 03:48 PM   #21
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Pretty sure it's because of construction and compression...the Ford Lehman is 16.1 to 1 compression...almost the bottom of the scale for diesel compression ratios. Don't misinterpret that ALL marine diesels can get by with low tech coolant...I was just talking Lehmans which is what the OP was discussing.

Cavitation Article

Cavitation is a direct result of an engine having an extreme compression ratio. Standard diesel engines compression ratios usually range from 16:1 to 22:1. A standard gas engine has a ratio of about 7:1 or 8:1, therefore they do not suffer from cavitation. Some high performance gas engines range up to about 14:1, and seeing this is a relatively high ratio they do suffer from cavitation like diesels.

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Old 02-05-2014, 09:09 PM   #22
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A user built and screened on line manual like Wikipedia only for Lehmans?
Umm, my wife suggested the same thing, only that it shells be fur the entire boat and that I should do it.

I can't even post pictures.

Good idea though for someone.
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Old 02-05-2014, 09:43 PM   #23
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"Shells be fur..." Good thing I use an iPad too so I know what the stupid thing does to writing.
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Old 02-05-2014, 09:56 PM   #24
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Umm, now I just read that whole article. Two thirds down they mention the real issue, if your engine was not designed to be a real diesel or your cylinder walls are too thin, then you will have these issues and need to mitigate then by buying special stuff.

Which reminded me that a jeep engineer ten years ago told me that the reason I had to get the special friction modifier for my transfer case, was because that's how they dealt with design/manufacturing problems.

I did like the above article did explain why diesels are built sui robustly.
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Old 02-06-2014, 05:41 AM   #25
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Many true high performance diesels will have a lower compression ratio BUT require SCA .
Tiubos putting out 30-40 PSI of boost underway create enough combustion pressure to really ring the cylinder walls.

Its the in operation loads that count , not the paper compression ratio.
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Old 12-16-2015, 06:27 PM   #26
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Umm, now I just read that whole article. Two thirds down they mention the real issue, if your engine was not designed to be a real diesel or your cylinder walls are too thin, then you will have these issues and need to mitigate then by buying special stuff.
I'm pretty sure the 8.3L cummins in my rv was designed to be a "real" diesel. It requires sca's to prevent cavitation.
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