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Old 07-08-2007, 02:25   #1
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Alan

Excellent post!!! But it brings to mind at least one question this morning. Just how does one check a water trap? Mine is a sealed unit with a hose in and a hose out.

http://www.merlinmortgage.biz/catalp...water_trap.jpg
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Old 07-08-2007, 05:43   #2
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Thanks for that Alan, very informative.

In relation to oil changes, you say

Every 100-150hrs or 6 months.
Drain and replace Engine Oil.

Is that most manufacturers recomendation's, or just sensible practice.

Reason I ask is on mine the suggestion is


Simple Servicing. Servicing this engine is a snap. Filters, fill caps and maintenance items can all be accessed on one side of the engine, if that's important to your customers. You can expect the naturally aspirated version of the B3.3 to run 500 hours between oil and filter changes. The turbocharged version has service intervals of 250 hours

http://www.cummins.com/jp/pages/en/p...uction/b33.cfm

Is this unrealistic, or are some engines just tougher than others.?

Dave
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Old 07-08-2007, 08:18   #3
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I change the oil and filter each 75 hrs on my volvo md17d.
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Old 07-08-2007, 08:58   #4
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Excellent Post!!
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Old 07-08-2007, 09:09   #5
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quick question, I have sail drives with no raw water intake filter. Should I check every 6 months the raw water heat exchanger?
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Old 07-08-2007, 14:15   #6
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Hi all, firstly, if any questions arrisign from "study hall" articles could be started in a new thread for now, ti would be great.
Oil changes are normaly done at a 6 month interval for only one reason. (This is 6 months, not hrs) Moisture build up from condensation within the engine. This issue varies from place to place. It depends on the severity of the winter you have. So for many it is a non issue. The "common" view of a 6 monthly change is so as manufacturers are covered. All the points in the Study Hall are generic and are an average across the board of manufacturers (based on my experiance as a tutor). So each boat owner can slide the rulings eitehr way to suit there needs. Realise that the engine is not going to sieze at 7months of 501hrs just because you didn't religously change the oil or whatever. All maintenance should be done as a pre-season check over and "wake up" for the vessel anyway, and this tends to be 6 monthly.
As I also stated in the article, it is an average on engine size. And if your engine is under a warranty, follow the advice of the manufacturer. If you ever have an engine problem, saying that "wheels" said so, will not wash with them, even though you'd think eh? ;-) :-)
Just for a little side stroy. I am trying a full synthetic this season. The reason is that there is a lot of oil to change in my engine and it is like most, an impossible job to do without oil getting everywhere. I am hoping to extend my changes out to a couiple of years. But I need to monitor for moisture. If moisture becomes an issue, it is back to regular oil and frequant changes.
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Old 07-08-2007, 14:22   #7
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Wheels, shouldn't cleaning the heat exchanger be on this list?

As soon as I get a new gasket for the heat exchanger cleanout cap, I'm going to do this on my Universal M18. Does anyone have any pointers for doing this? I'm planning to use a small wire brush and have at it...
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Old 07-08-2007, 14:42   #8
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Wheels, I look forward to your experiences with synthetic oil. I switched to Mobil1 in my car back in 1985, when it was a brand new concept (the oil, not the car<G>) and a friend happened to work in the Mobil HQ PR offices.

"Dino" oils back then were nowhere near as good as they are today, that needs to be said up front. But in the packet I was given, were teardown photos from taxi and police fleets (V8 engines) showing the tar/coke buildup inside the valve covers with premium dino oil used, versus covers that had no build-up at all when Mobil1 was used.

The point they were demonstrating, was that the syn oil just doesn't break down and form tars in heat, when dino oil does. Equally important but harder to "show" is that the syn oils are supposed to have radically different behavior under high compression and thin film conditions, i.e. when there is just a thin film left on the main bearings "from yesterday" or last week, and the engine is being started up. I was taught that during the first three revs of a cold engine, the bearings essentially are slamming on dry metal with no lubrication, taking extreme wear compared to just a few seconds later when there is oil pressure and an oil film surrounding them. Supposedly, syn oils will provide much better protection to the bearings during this "dry" startup period because they stay on the metal longer, and function better in the thin layer.

Then again, since they are usually sold as a premium product, the makers are more generous about all kinds of additives. I was surprised to find molybdium disulphide (the black dry "moly powder" lube) in my first oil analysis, apparently that was also in the bottle and simply not mentioned on the label.

On water absorbtion...I don't think you'll find they are a lot better, if any though. Water is still water and it is simply better to get it out of the oil. The water does literally COOK OFF if the engine is run long enough to heat the oil and get the water back into vapor state, above 100C.

Or, if you are running enough oil, it may pay to drain it, let it stand in a "column", and scoop the water layer off the top, rather than throwing out dozens or hundreds (?) of liters of perfectly good oil, just to get the water out. (Or heating the oil and letting it cook out.)

I know the dino oils have improved, and of course Mobil is only one of many suppliers in a huge field today. And now marketing all sorts of synthetic blends just to really confuse the customers.<G> But I sitll believe in synthetic oil, and would urg you to do an oil analysis on the old stuff, and then on the new stuff, to see real numbers on how different it can be. Viscosity breakdown? Way less. You can see real differences.
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Old 07-08-2007, 18:16   #9
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Quote:
Originally Posted by Alan Wheeler
Moisture build up from condensation within the engine. This issue varies from place to place. It depends on the severity of the winter you have.
Your winter doesn't have much to do with this. Moisture is in the air, the engine is hot. Warm air holds more moisture. As the metal cools the air in suspension condensates out onto the metal and eventually drips into the sump.

Hot days and cool nights will have a similar effect even if the engine is not run. The engine cooling at night will lower the air temps and moisture will condensate.

Fuel tanks will do the same thing. That's why it is better overall to keep the tanks full as there is less "exposed" metal to form water condensation.

Having said that, no one has ever destroyed an engine by changing the oil or filters too much. I err on the conservative side. 100 hrs or 3 months.
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Old 07-08-2007, 19:57   #10
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"Your winter doesn't have much to do with this."
Actually winter could result in LESS condensation, if you are someplace where "Winter" means nasty cold dry air that is so cold the moisture has long fallen out of it. And if the metal parts of the engine stay below freezing ALL DAY AND ALL NIGHT long, there's no heat cycling and no condensation forming on the cold metal every evening to fall into the oil.
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Old 07-08-2007, 23:22   #11
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That is quite possible. If you read my point, you will note it wasn't a "hard and fast" point. Here were I live, our winters are extremely damp and condensation can be a big issue. We can have very damp evenings, a good cold hard frost and a lovely warm day. So for me here, it is a big problem. But it varies from place to place. As I said in that statement, it's something you need to judge for yourself. It is an average across the board advice.
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Old 08-08-2007, 12:12   #12
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Wheels, do you take any steps to "seal" your engine for the winter?

Since condensation is limited to the moisture in the engine, in theory if you were to plug the air intake and exhaust, and then seal any other breathers, etc., you would be able to STOP condensation by preventing the ingress of any fresh moist air during the normal daily thermal cycling. (I suppose you could take a bug rubber glove over the air intake to allow for expansion, and film a horror movie in your spare time.<G>)

Going one step further, if you placed a large package of dessicant in the intake and exhaust before you sealed them, and kept some heat (even a large bulb) under the engine to keep it warm and keep the moisture in the air for a couple of days, mightn't that suck the moisture out and trap it before it had a chance to condense into the works??

I wonder if there's some clever way to slip a tube of "dessicant that steals water from engine oil" right down the dipstick tube??
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Old 08-08-2007, 13:20   #13
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For me, nah. I run the engine too much. I am at the boat more than I am at home in the winter. I use the winter to do major projects, so I spend 4 days per week at the boat. I try to run the engine weekly in the real cold period.
In saying all this about condensation though. Personaly, I don't think it is a major issue. I am only parroting what most manufacturers prescribe as a good maintenance principle. AS I said, it will vary from apllication to apllication adn it is upto the individual to find the best course of procedure for there own boat. The guidline is a guidline.
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Old 08-08-2007, 14:13   #14
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"I try to run the engine weekly in the real cold period. "
You need it to power up the batteries? Or...? Just to encourage condensation?<G> Personally, I was taught never to hit the starter on an engine unless I was going to run it for a while, because "starting" is what really kills everything. Camshaft, bearings, all the unlubed parts, the starter and alernator throwing spikes, all sorts of nasty stuff.
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Old 08-08-2007, 18:12   #15
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Condensation effects are minimized by running the engine long enough and frequently enough to "boil" out the water and changing the oil frequently.

Moisture is the primary reason I change the oil.
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