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post #21 of 47 Old 03-11-2016
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Re: Turbo diesels

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Don't have true polishing system but do have filters in run from tanks and on return to tanks as well as the usual twin Racors and the filter on the engine.

They have portable polishing systems both down in the islands and up in the north east. Is it advisable to get this done and if so at what intervals.
An article by RichH;
As one deeply involved in filtration engineering for almost 35 years .... recirculation polishing without FIRST cleaning out the tank IS snake oil ... and will only 'temporarily' --- say again TEMPORARILY clean the oil.

Recirculation polishing prevents the 'growth' of particles into larger and large size, and removes the 'seed particles' (mostly bio-forms) from the fluid. The constant removal exponentially decreases (and removes) the amount of particles.

If you dont periodically inspect and clean the tank walls, those particles 'stuck and growing' (growing fungal filaments, etc. and agglomerating sticky gel-like particles) only become the seed particles for new and larger particle 'growth' ... AND when the matt-like 'colony' of living particles break loose (because of dead and dying micro-organisms) they rapidly 'slug' the previously cleaned up oil with an exponential amount of even more particles.
Recirculation polishing removes the particles before they can affix to the walls; but, it cant remove those particles from the walls if they have formed a 'sticky colony' (calcyx).

Recirculation polishing of a fouled tank is of NO long term benefit. You HAVE to start with a CLEAN(ED) tank.

Follow this link: Cleaning a fuel tank
and/or do search on the sailnet site for: cladosporium

The purpose of a recirculation polishing unit is keep the fuel in a pristine/uncontaminated condition by continually removing the 'seed' particles that are the source of such 'growth' - biological particles, & small 'gel-like' particles that continually agglomerate into larger and larger particles, particles that are 'excreta' of metabolism of such fungals and bacteria - asphalt-like resinous compounds. The common microorganisms found in diesel oil or all 'resin formers'.
Most filters used for 'polishing' only have about 35 to 50 grams of dirt capacity; thus, easily 'choked' if the system is already grossly contaminated; the recirculation system is used to prevent fouling - hence my caution of 'snake oil'.

A recirc. polishing should only be used in a throughly cleaned tank (+ with biostat/ disinfectant added, to help depress growth in those areas of tank that do not actively become 'pumped', such as the 'corners').
That stated, a recirc polishing system 'can' be an adjunct to tank cleaning; but if and only if - the tank is heavily dosed with suitable enzymes (chemical 'tank cleaners') that emulsify the 'goo' already adhering to the walls and which puts the particles into solution or dissolves them .... hopefully to a µM size smaller than the retention rating of the filters. The downside is that such emulsions of asphaltics dont 'burn' well; hence, you risk having such 'fuel' not completely burned in the combustion chamber and simply settle out and form thick deposits of 'coke' in the hot surfaces of the exhaust portion of the engine and downstream. Best is to bite the bullet and get inside and scrub out the tank before engaging any recirculation polisher.

Recirculation polishing systems are only to 'maintain' tank cleanliness - to prevent/retard 'growth' inside a tank.
------------------------------------------------
As I read this, don't waste your time installing your own or having someone else do fuel polishing, unless you are starting with new, perfectly clean tanks. Your filtering system should be perfectly adequate for it's job.
Now you can buy me a G&T w/a lime next time we are in the same bay somewhere, with all the money I've just saved you.
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post #22 of 47 Old 03-11-2016
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Re: Turbo diesels

I have noticed that marine turbo diesels don't take much advantage of the turbo. They basically bolt them on and that's all. No fuel supply difference, nor timing change, etc. Only small HP increases are achieved. So I say, if you burn your turbo at sea, gut it, and continue running.
A lot of sailors burn them by not allowing a cool down period for the turbo bearings, before they shut them off.
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post #23 of 47 Old 03-11-2016
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Re: Turbo diesels

"I have noticed that marine turbo diesels don't take much advantage of the turbo. They basically bolt them on and that's all. No fuel supply difference, nor timing change, etc. Only small HP increases are achieved."

Impossible. Basically bolting them on, as you say, would cause a _decrease_ in power. Remember Diesel engines are (usually) unthrottled. The amount of power obtained is determined solely by the amount of fuel injected, and the timing of that injection. Simply stuffing more air in is useless, and in fact drains power.
Without going, um, overboard, one can easily get 20% more power with a Turbo, using a bit more that 20% more fuel. With some care, 40% more power, with quite a bit more than 40% more fuel. (The Laws of Thermodynamics- you can't win, you can't break even, you can't get out of the game.)
After that point, the engine has to be designed and strengthened with Turbocharging in mind, with added Charge Cooling, Turbo Cooling, some kinds of Interlocking, and reliability... plummets.



I've noticed some casual talk here about removing a blown turbocharger and soldiering on. Another impossibility, unless one has a bit of something that bolts directly into its place, otherwise the boat fills up with Diesel exhaust, and no, Duct tape will not work. And then there is the issue of the Turbo Oil lines; those need to be bypassed as well.



BTW, thank you capta, for reposting that article on "Polishing". Why the process is called such a stupid name evades me, but a company called ESI claims that they invented and patented the process in 1995. So this snakeoil is only a couple of decades old, and is just barely old enough to drink.
Three decades back there were variations on the basic concept; most involved some kind of large Funnel jammed with Toilet Paper, (unused...), for filling fuel tanks or jerry cans. They were called "Baja Filters", because of some notoriously bad Diesel available there back then. The idea was to catch the bugs before they got in the tank. They have been commercialized since.

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post #24 of 47 Old 03-11-2016 Thread Starter
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Re: Turbo diesels

Hey guys please read post # 18. This was a direct quote sent to me when I asked yanmar. Clearly it's said the without the turbo the engine will run at idle at best. To me that means it won't run if any throttle is given due to too much fuel and not enough air. Throttle just means putting in more fuel on a diesel.

At idle in gear my boat may make ~1kt. in flat water. Pragmatically that means if the turbo fails on passage I have no engine. That's the bottom line. Fini, done, the end.

I infer if I don't turn the engine off beyond leaving a cloud of smoke I'm not doing the engine any favors. Just increasing the risk the fuel rich partially burnt mix will do further damage or as the boat bounces around and parts move I will suck in detritus from the broken turbo and further ruin the engine.

So either be a pure sailboat which ain't so bad or carry a spare turbo and assorted bits to replace it. Seems running it with a broken turbo is not a good option and unless you change injectors and all the settings running without a turbo isn't either. From what I gather a engine designed with a turbo from scratch needs that turbo. It's just not practical to switch to non turbo at sea but is practical to replace a turbo.

I'm anal about warm up and especially cool down periods. Also about filter/oil changes. Only have biocide' d fuel in the tanks.

Next question- was taught to never burn the bottom 20% of a tank except in extremus. Have 4 tanks of 50 g each. Usually will burn what will be the mostly leeward tanks first for trim. Kind of like water ballast but with fuel use.
Should I discount what I was taught and periodically burn tanks dry? ( system is set up so I can do this without sucking in air so won't need to bleed the system).
Should I as part of routine maintenance empty all four tanks and clean them? If so how often?
Boat is only 2 years old. Everything works great. Just want to keep it that way.

Respectfully disagree with E. Having 200g is great for many reasons beyond windless passages. Leading that list is I can wait weeks, usually months before the gauges are down to desperate. That means I can wait until I get to some place that has good fuel and sells a lot of it. Still, I was taught to always try to keep your tanks full. The idea being less condensation. So, am I better off burning off fuel and replacing whenever good fuel is available or running the tanks down to near empty?

s/v Hippocampus
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post #25 of 47 Old 03-11-2016
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Re: Turbo diesels

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Originally Posted by outbound View Post
Hey guys please read post # 18. This was a direct quote sent to me when I asked yanmar. Clearly it's said the without the turbo the engine will run at idle at best. To me that means it won't run if any throttle is given due to too much fuel and not enough air. Throttle just means putting in more fuel on a diesel.

At idle in gear my boat may make ~1kt. in flat water. Pragmatically that means if the turbo fails on passage I have no engine. That's the bottom line. Fini, done, the end.

I infer if I don't turn the engine off beyond leaving a cloud of smoke I'm not doing the engine any favors. Just increasing the risk the fuel rich partially burnt mix will do further damage or as the boat bounces around and parts move I will suck in detritus from the broken turbo and further ruin the engine.

So either be a pure sailboat which ain't so bad or carry a spare turbo and assorted bits to replace it. Seems running it with a broken turbo is not a good option and unless you change injectors and all the settings running without a turbo isn't either. From what I gather a engine designed with a turbo from scratch needs that turbo. It's just not practical to switch to non turbo at sea but is practical to replace a turbo.

I'm anal about warm up and especially cool down periods. Also about filter/oil changes. Only have biocide' d fuel in the tanks.

Next question- was taught to never burn the bottom 20% of a tank except in extremus. Have 4 tanks of 50 g each. Usually will burn what will be the mostly leeward tanks first for trim. Kind of like water ballast but with fuel use.
Should I discount what I was taught and periodically burn tanks dry? ( system is set up so I can do this without sucking in air so won't need to bleed the system).
Should I as part of routine maintenance empty all four tanks and clean them? If so how often?
Boat is only 2 years old. Everything works great. Just want to keep it that way.

Respectfully disagree with E. Having 200g is great for many reasons beyond windless passages. Leading that list is I can wait weeks, usually months before the gauges are down to desperate. That means I can wait until I get to some place that has good fuel and sells a lot of it. Still, I was taught to always try to keep your tanks full. The idea being less condensation. So, am I better off burning off fuel and replacing whenever good fuel is available or running the tanks down to near empty?
All the turbo stuff has been covered. I'm not sure what the last 20% will hurt by using it, you pull from the bottom of the Tank so what does it matter. I don't think it matters burning all the way down or not, What I think does matter to a point in humid conditions keeping the Tanks full but you just don't exchange that much air so even this has minimal value. With your capacity I would use it to seek out clean fuel. The horror stories you hear are from leaving old fuel in old tanks on Boats that aren't used a lot.
I think your filters tell you all you need to know about fuel quality, some of the really nice setups will have Vacuum gauges or differential monitors but the clear bowls tell all.
Finally Polishing has been developed around Mission critical generator design where the Emergency seldom uses the available fuel. Most are only run for exercise. If you've seen any of these NSA or GOOGLE sites you will know what I mean. Crazy kilowatt's in wait.
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post #26 of 47 Old 03-12-2016
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Re: Turbo diesels

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Still, I was taught to always try to keep your tanks full. The idea being less condensation. So, am I better off burning off fuel and replacing whenever good fuel is available or running the tanks down to near empty?
Yeah, I went with this old bunch of hogwash for something like 50 years, too. Like an idiot! When RichH pointed it out in a post, I really felt STUPID!
If we could get water into a tank by condensation, we wouldn't need watermakers would we? Everybody would have clean drinking water whenever they wanted.
I don't care how long you leave a tank empty, it ain't going to fill itself up with water. Face palm!

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Re: Turbo diesels

we do pre filter our water even with a whole boat filter system when cruising. Never been impressed with baja filters. Never been given the time to sit at a fuel dock and fill a clear jug and wait for it to settle. See filters on the hoses at car/truck fuel stations.

Are there any pre filters worth the money to use when filling diesel into a boat? Would think if you decrease the crap going in less crap would come out. GIGO

s/v Hippocampus
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post #28 of 47 Old 03-12-2016
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Re: Turbo diesels

This would be a good time for someone to try smaller injectors on their turbo diesel, open the wastegate, and note how the engine runs.
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post #29 of 47 Old 03-12-2016
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Re: Turbo diesels

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Originally Posted by outbound View Post
we do pre filter our water even with a whole boat filter system when cruising. Never been impressed with baja filters. Never been given the time to sit at a fuel dock and fill a clear jug and wait for it to settle. See filters on the hoses at car/truck fuel stations.

Are there any pre filters worth the money to use when filling diesel into a boat? Would think if you decrease the crap going in less crap would come out. GIGO
Ive never seen one it would need to be something built into a funnel, cumbersome when not in use and another service item. I would look for external spin on filters on their system, they are easy to spot and avoid any site without this final filtration.
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post #30 of 47 Old 03-12-2016
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Re: Turbo diesels

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Originally Posted by outbound View Post
we do pre filter our water even with a whole boat filter system when cruising. Never been impressed with baja filters. Never been given the time to sit at a fuel dock and fill a clear jug and wait for it to settle. See filters on the hoses at car/truck fuel stations.

Are there any pre filters worth the money to use when filling diesel into a boat? Would think if you decrease the crap going in less crap would come out. GIGO
SORRY but you are mistaken about Baja filters. They do work and work well. They enable a purchaser to identify if the fuel being purchased has water or sediment in it.

If I have ANY doubts about the fuel being supplied I use the Baja filter on the first gallon or two.

I have also found myself with water in my my dinghy tank and been able to use Baja to separate the water out.
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