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Old 01-29-2010, 12:40 PM   #21
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Bypass filtration report

Marin, you wrote:

"...where contaminants less than the machine tolerances of the engine are removed..." is an interesting statement.* I'm no mechanic or engine designer or lubrication engineer.* But logic would seem to indicate that if*a contaminant is*smaller than the machine tolerances of the engine, then it*isn't a contaminant.* Or do I have that wrong......?

No, you don't have it wrong if you wish to define contaminant as a foreign substance that must be causing wear or harm.* If a contaminant is something that wasn't in the original product after manufacturing, like soot from incomplete combustion generated by a diesel operating at long distance cruising revs, then yes, I guess you are wrong.* If the machine tolerances of the crankshaft are 2 microns, and you remove particles down to 1 micron, you no longer have contaminants that cause wear, although you will still have contaminants that do not.* So take your pick on your own definition of the word 'contamninant,' but the point of fine filtration is to remove particles smaller than those that cause wear, hence my comment.

You also wrote:

"If diesel and water ingress in a diesel engine's lube oil is a common problem to diesel engines in general, and one that reduces the engine's reliability and longevity, it would seem to me that it would be in the interests of Cat, Deere, Cummins, MAN, etc. to make such a device a stock accessory for every diesel they sold.* Do they?* (I don't know, I'm just asking the question.) Diesel engines have certainly been around long enough to know if this is a real, or significant problem or not."

My understanding is that really large diesels frequently come standard with bypass filtration, as do some small gensets.* I am no expert either, but my understanding on why mid sized engines don't offer bypass filtration as a standard is that most are designed for applications where running at 75% power isn't the problem it is for trawlers.* At 75% or so power, soot contamination of the oil is minimized, especially with common rail, computer controlled injection systems, which the 3306 doesn't have.* I seem to have zero soot buildup in my genset which runs at 80% rpm, but lots in the CAT.* Does that mean the CAT has a problem?* No, it is just running at trawler rpms, so it has less efficient combustion resulting in more soot.* Does this mean the engine is too big for the boat?* No, it just means it is a trawler hull, where 40 hp is required to run at 7 knots and around 2.5 gph, but requires 240 hp to run at 9 knots burning 12 gph.* If this same engine were in an earthmover or truck, a full flow OEM filter would do fine, and the engine might wear out for reasons other than the fact that the OEM filter only takes out 10 micron and larger particles, although lots and lots of companies running mid-size diesels install bypass filtration to reduce wear and extend oil change intervals.* On Delfin, we run at more or less constant power all the time and would prefer fuel economy over kicking up a bigger wake.* Under those conditions, a full flow filter doesn't do the job a bypass filter does, but for 95% of the applications this CAT would find itself in, the OEM filter does just fine.

As I noted above, the Puradyn has a feature additional to the usual function of a bypass filter, which is a heater element the oil is subjected to, and that allegedly helps with the water and diesel contamination you mentioned.* The vapor you see coming out the crankcase ventilation is, I believe, at least partly water from the moisture contained in combustion air.* Whether this water vapor causes any problems or not I am skeptical of, but it is a normal contaminant.* As I also noted about the heater element, I have no clue whether this particular feature has value or not.* I would also venture to say that if someone argues that cleaner oil has no value on a diesel, they may be arguing for the sake of arguing.* It is true that installation requires external hoses, but then again, so does my MG 509 gear (for oil cooling), so that risk is probably manageable.* It is also true that changing the oil every 50 hours would help remove soot, but who wants to do that, and regardless, won't be as effective as filtering out virtually all contaminants every 60 minutes.

I have heard lots of arguments on why such units are unnecessary, but I haven't yet heard arguments that are particularly convincing for trawlers operating at trawler rpms.

-- Edited by Delfin on Friday 29th of January 2010 02:12:07 PM
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Old 01-29-2010, 01:20 PM   #22
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RE: Bypass filtration report

Sunchaser, you wrote:

"Five years ago my brother's "big" steel vessel suffered a lubrication failure on one of its engines. A contractor was working on the ER fire supression system and inadvertently moved/disengaged an engine oil drain line near the sump."

That is really unfortunate, and I guess argues for not removing such lines before starting the engine.
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Old 01-29-2010, 01:24 PM   #23
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RE: Bypass filtration report

Delfin, the important thing is you are confident your engine is protected from contaminated oil. However, after watching many*Cat 6 cylinder engines*over the years die due to poor head and cooler design and none due to lube failures, don't overlook those greater inherent weaknesses*
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Old 01-29-2010, 01:53 PM   #24
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RE: Bypass filtration report

Quote:
Delfin wrote:

Marin, you wrote:

"...where contaminants less than the machine tolerances of the engine are removed..." is an interesting statement.* I'm no mechanic or engine designer or lubrication engineer.* But logic would seem to indicate that if*a contaminant is*smaller than the machine tolerances of the engine, then it*isn't a contaminant.* Or do I have that wrong......?

No, you don't have it wrong if you wish to define contaminant as a foreign substance that must be causing wear or harm.

I would also venture to say that if someone argues that cleaner oil has no value on a diesel, they may be arguing for the sake of arguing.*
Plus I suppose you can have chemical contaminants to the lube oil that no mechanical filter could remove, yet they could reduce the lubricating qualities of the oil.* This is the case with the Simms/Cav injection pump used on the old Ford Lehman 120.* This pump has its own oil sump and the oil in it can become diluted with diesel fuel that leaks down past the injection plungers, a leak that gets worse with time as the plungers and bore walls wear with use.* There is no cure for this--- wear can be held to a minimum by ensuring good lubricity in the diesel fuel since that's what lubricates the plungers in their bores--- hence the required 50-hour oil change for the pump.

And you're correct, I've never heard a mechanic--- automotive, aircraft, or marine-- say that clean oil is bad for an engine.

I just wonder, though, with an engine like he FL120 that supposedly can be a 12,000 to 14,000 hour engine in recreational use (they have gone over 25,000 hours between overhauls in constant use on ferryboats), all these hours racked up without the benefit of a diesel fuel/water "boil off" system for the lube oil or even a bypass-type oil filter, how much such a system would really add to the longevity of the engine.

These are engines that are supposed to be operated in the 1500 to 1800 rpm band, which in marine use is considerably below the theoretical loading figures you hear bandied about.* They achieve the proper temperature at these relatively low power settings and, assuming proper maintenance and service and little or no abuse, they seem to run "forever."

It's probably apples and oranges to compare the operating characteristics of an antique engine like the FL120 and a modern engine, so perhaps the need for additional contaminant removers is much greater with today's engines.

*
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Old 01-29-2010, 10:51 PM   #25
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RE: Bypass filtration report

Marin,
A 3306 is not a modern engine.
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Old 01-30-2010, 12:43 AM   #26
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Bypass filtration report

True, but I suppose it depends on what you're comparing it to. The 3306 was introduced, I believe, in the 1970s and manufactured through the 1990s or so. Compared to some of the 1950s or earlier antique designs*still powering some boats, that's pretty modern.

But when I said "modern" in my post I was referring to the current generation of diesels.

-- Edited by Marin on Saturday 30th of January 2010 01:44:53 AM
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Old 01-30-2010, 06:06 AM   #27
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RE: Bypass filtration report

current generation of diesels.

Is all turbo charged and includes high pressure rail + electronic injection.

3 or 4 little squirts per cylinder firing.
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Old 01-30-2010, 10:45 AM   #28
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RE: Bypass filtration report

Quote:
sunchaser wrote:

Delfin, the important thing is you are confident your engine is protected from contaminated oil. However, after watching many*Cat 6 cylinder engines*over the years die due to poor head and cooler design and none due to lube failures, don't overlook those greater inherent weaknesses
LOL, thanks for the happy thoughts, Sunchaser.* Actually, CAT makes quite a few different engines, and I'm not sure you would find a lot of support for the idea that they all die from "poor head and cooler design."* The 3306 was designed for broad applications on the North Slope and I have personally seen individual engines with over 50,000 hours on them.* So perhaps I'll be lucky, remember to check the engine before starting it to make sure the bilge isn't full of oil, and go a few miles before poor head and cooler designs catch up with me.

*
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Old 01-30-2010, 02:46 PM   #29
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RE: Bypass filtration report

Delfin - Look, you have a gorgeous boat and have done a ton of first class work to get it near perfect. I'm envious. Your zeal, enthusiasm and dedication is to be commended. Keep up the posts. Will you be on the Inside Passage this summer?
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Old 01-31-2010, 06:47 PM   #30
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RE: Bypass filtration report

Sunchaser, I sure hope so.* I am trying to get retired so we can head to NZ and Oz, where we used to live.* That is probably still a couple of years away, but hopefully this summer we will get back up Alaska way, at least for a month or so.* Let's rendezvous in Ocean Falls, and debate the complexities of diesel management on a trawler!
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Old 02-02-2010, 05:37 AM   #31
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RE: Bypass filtration report

I have heard lots of arguments on why such units are unnecessary, but I haven't yet heard arguments that are particularly convincing for trawlers operating at trawler rpms.

it is just running at trawler rpms, so it has less efficient combustion resulting in more soot. Does this mean the engine is too big for the boat? No, it just means it is a trawler hull, where 40 hp is required to run at 7 knots and around 2.5 gph, but requires 240 hp to run at 9 knots burning 12 gph.

You answered your own queery , constant or long term underloading will load the oil with soot , combustion by products and increased cylinder damage.

Clean oil , weather from better filtration will help , but more frequent oil changes will still be required to remove the chemical contaminants.

Weather the rings will break free from soot lock and wear away the burnishing from the cylinder is doubtful , and even then,the oil holding hone scratches can not be restored without a partial overhaul.

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