Yearly Maintenance

caltexflanc said:

Could you expand on that? I am personally not familiar with transmissions that use an HX.

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Our 1973 boat with BW Velvet Drive transmissions has heat exchangers for the transmissions. This setup is illustrated in the original owners manual, so it's not an add-on by a previous owner. I believe this is a common stock setup for boats with FL120s and VD transmissions. I can't speak for later Lehman engines like the FL135, or for transmissions other than the VD.

Greetings,
Twin Lehmans here (1979 vintage) BW with HX. As from factory.

OK, thanks guys, no Lehman experience here other than having chartered a boat with them.

The Allisons have an oil cooler from the fresh water side, I guess the term "heat exchanger" threw me off.

caltexflanc said:

OK, thanks guys, no Lehman experience here other than having chartered a boat with them.

The Allisons have an oil cooler from the fresh water side, I guess the term "heat exchanger" threw me off.

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Many more brands than Lehmans use a RW HX for not only transmissions but ACs, stabilizers and hydraulic thrusters too. My transmissions operate at 40 to 50 degrees above RW temperature. With a coolant exchange system your transmissions must be in the +200 degree range?

Bow mac maintenance guide

I came across a Lehman maintenance guide some years ago from a service centre in Florida. It is pretty extensive and I think a little over board, but it provides some direction as to when to change out filters and such.

sunchaser said:

Many more brands than Lehmans use a RW HX for not only transmissions but ACs, stabilizers and hydraulic thrusters too. My transmissions operate at 40 to 50 degrees above RW temperature. With a coolant exchange system your transmissions must be in the +200 degree range?

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Specified normal range is 180-200 and my coolant runs at the lower end of that unless going flat out. putting an IR thermometer on the oil filter or sump underway was typically 190ish. Fuel is cooled by a fuel cooler in the system too. Engines are Detroit 8v92Ti.

The AC and stabilizers are RW cooled.

I stay closely in touch with all my vehicle engines and trans. To enable virtually trouble free lengthened use duration: Lubrication fluids are the single most important item for inside parts and on moving exterior portions of any engine... no matter its fuel source; for transmissions too! Coolant/cooling are the second most important fluids. IMHO there is no "correct" schedule/way to keep, or "correct" way to operate, motors or to maintain them. But there is common sense that can well tell you when fluids, filters, apparatus need service or complete change. Only reason I can see following a strict service schedule and routine is to keep factory warranted product covered. Thereafter I recommend servicing your equipment as you feel it is correct to do. That is of course... only... if you stay closely in touch with all your vehicle engines and trans!

After three years and 400 engine hours, I had the JD's original impeller replaced during the boat's recent annual maintenance/boatyard visit. While some here suggest annual replacement, the old impeller was in good shape and retained flexibility. I don't regret replacing the impeller, but don't see the need for annual replacement as recommended by others, considering the engine's level of use. The water flow at the exhaust exhibited no change.

Moonstruck said:

The frozen Chosin Reservoir in North Korea when the Chinese came across the Yalu River and over ran the US Marines. It was bitterly cold, and a bitter fight. The survivors and the ones they left were true heroes.

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True. On all counts. Just to clarify, when I did my original post of "on the way to the Frozen Chosin" I was using the term as as it was being used at that point by the people I was associated with, which was to refer to Korea generally. Not accurate, of course, but lots of things in the service were not accurate. So my post merely meant that I was on the way to Korea -- which was not until 1952. Certainly did not mean to imply that I was in any way involved in that Chosin Reservoir battle! Did most of my time in Pusan, except for a brief foray up to Seoul for the big prisoner-of-war exchange in 1953. And I was 17.

On your way is good enough for me...in harm's way on on the way there takes a notch in a man's (woman's) soul....

No one every really expects to die (hopefully) ...it's the anticipation and how you handle it that makes the soldier/sailor. When the time comes...you really never know it's gonna happen anyway for a lot of reasons.

I salute you and your brothers in arms!!! Warriors all...heroes when appropriate..but don't let that slip to that other thread....

markpierce said:

....but don't see the need for annual replacement as recommended by others, considering the engine's level of use. The water flow at the exhaust exhibited no change.

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We change the impellers in our Johnson pumps on the FL120s every four or five years. What with work and travel and all we probably put only about 100 hours on the boat every year. The impellers coming out don't look brand new, but for all intents and purposes they look pretty much like the new impellers going in.

The impellers coming out don't look brand new, but for all intents and purposes they look pretty much like the new impellers going in.

I guess you do not spend much time in shallow , silty water.

George, We have 6V92s in our Jefferson 52. What oil analysis kit do you buy from JG? Does the basic cover everything we would be concerned with? This fall I will be getting sample program started. Thanks

Rogerh said:

George, We have 6V92s in our Jefferson 52. What oil analysis kit do you buy from JG? Does the basic cover everything we would be concerned with? This fall I will be getting sample program started. Thanks

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Replied to your PM.

George,
The oil analysis kit is the one that you had in one of your previous links.
http://www.jglubricantservices.com/d...0Procedure.pdf

I went to their website and they had a bunch of options for the kind of kit you get. Is this the one that you use. If so which kit would be appropriate to order? If it is not the one you use could you provide the website for them.
Thanks
Roger

FF said:

The impellers coming out don't look brand new, but for all intents and purposes they look pretty much like the new impellers going in.

I guess you do not spend much time in shallow , silty water.

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No, we don't. There isn't much of that out here. Up the rivers like the Fraser and Columbia there would be, but we don't boat there. Other than when we're at anchor there is rarely less than 100 feet under the keel. Typical depths we cruise in are 200 to 1,000 feet and the water is almost always clean.

At the time this photo was taken the depth sounder was reading about 1,100 feet.

Astral Blue said:

Contrary to most people's beliefs, frequent oil changes are not necessary. ............

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So in your opinion the manufacturer does not understand the best maintenance practices for the engine they designed and built?

Rogerh said:

George,
The oil analysis kit is the one that you had in one of your previous links.
http://www.jglubricantservices.com/d...0Procedure.pdf

I went to their website and they had a bunch of options for the kind of kit you get. Is this the one that you use. If so which kit would be appropriate to order? If it is not the one you use could you provide the website for them.
Thanks
Roger

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No. Sorry for the confusion, I only posted that as an example of the pumps that many people use to draw these. As noted in my PM, I used the Detroit accordion squeeze bottles when drawing them myself. The pumps appear easier ( a lot of mechanics use them) as long as you keep them clean and use new tubing for each individual sample. . I just never got around to getting one.

The only medals I got was a KFS, (Knife Fork And Spoon) for being first in the Naafi (PX) queue, with VD and scar ! !
Oil changes vary in trucks because of the work they do, short range stop/start are changed more frequently due to the acid accumulation from frequent warm ups. Long distance much less frequently.
Many police cars in America are never shut down and for this reason as results have shown that exhaust pipes and mufflers rarely need changed as there's no rotting of mild steel by acidic gasses.
All engines produce acid during the warm up phase, once the engine is up to working temperature some of this acid will evaporate but trace elements will remain in the oil, this is one of the reasons for not running it at a fast idle for long periods, the second reason is that in the older non electronic engines is if the engine is not up to full working temperature it will not burn all the diesel injected into the cylinders and unburnt fuel will dilute the lubricating oil on the cylinder walls causing excessive wear leading to premature overhaul.
The kindest way to treat your engine is to start at idling speed, as soon as the oil pressure is up to normal cast off and bring the engine up to temp by moving out of the dock and as soon as it's practically possible increase the load gently until it's up to normal working temps, then you can thrash the daylights out of it you won't do it any harm diesels will take a colossal amount of punishment but common sense says to run it up to your normal cruising speed sensibly.
A very important factor in prolonging engine life is to bring your boat into your dock and allow the engine to idle for around 4/5 minutes to allow the engine to cool down gently and even out the thermal stresses, this is particularly important for turbo charged engines.
A quick acid test to try with some fresh oil is put a drop on the end of your finger and taste it, now take out the dipstick and dip a little on your finger and taste it, you can taste the difference if the oil is acidic, it won't kill you or poison so go on and try it.

A very important factor in prolonging engine life is to bring your boat into your dock and allow the engine to idle for around 4/5 minutes to allow the engine to cool down gently and even out the thermal stresses, this is particularly important for turbo charged engines.

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For the mains, this is usually accomplished in the docking and line securing process.
Its a good idea on generators too, to run them just for a minute or two with no load before shutting them down.

caltexflanc said:

For the mains, this is usually accomplished in the docking and line securing process. ...

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I agree. Still, my engine compartment remains significantly above the ambient temperature 24 hours after the engine is shut down. And regardless, my engine manufacturer warns not to run the engine at idle for more than five minutes (yes, about the time it takes to transit the marina to the berth and to begin securing the boat.) If you think I'm concerned about a rapid cool-down of engine, I'm not. The 4-cylinder engine has sufficient mass to retain heat for quite a while.

>If you think I'm concerned about a rapid cool-down of engine<

The folks that worry about a rapid cool down are folks with hard working turbos.

When the unit is run hard , then simply shut down the lube oil can cook in the turbo causing carbon deposits.

These folks need a couple of min at idle before a shutdown , or an aftercooler system that pumps lube oil for 5 min or so.

FF said:

>If you think I'm concerned about a rapid cool-down of engine<

The folks that worry about a rapid cool down are folks with hard working turbos.

When the unit is run hard , then simply shut down the lube oil can cook in the turbo causing carbon deposits.

These folks need a couple of min at idle before a shutdown , or an aftercooler system that pumps lube oil for 5 min or so.

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That's been my understanding too Fred. Have never heard of 5 minute cool down periods on non turbo diesels before.

On impellers, I don't particularly worry about them inside of about two years. I worry more if the boat has sat for many months as taking a set can cause cracks, if they ran dry for some reason or a thru hull was inadvertently left closed and the engine started for a moment, or some other event that would be hard on them. But more than two years, while the impeller might well go much more, I've seen them fail. Sometimes because the replacement sat who knows where before getting put in. But most importantly, because when an impeller fails the job of changing it goes from just a few dollars and 20 minutes to something much much more. I have to then spend 20 minutes looking up the right part numbers for gaskets on my heat exchanger, 20 minutes on the phone ordering them, then I have to pick them up. Another 30 minutes getting the end caps off. I glue the gaskets with cat gasket cement on one side. If everything comes right apart, then hurray. If not, then its probably a good hour work to remove the gasket, get it scraped nice and flat and get a new one ready, per end cap and there is two. Since the end caps are off, I might as well get the rod and brush out and have a go at the heat exchanger tubes, + 1 hour. No charge at this point for the 2 seconds to pluck out the minor missing pieces of the impeller, so we have that going for us. At another 30-45 minutes to put everything back together, plus the 20 minutes it would have taken to just swap out the impeller as per usual.

Sooooo, being naturally time selfish, while I'm not a zealot for having impellers replaced every 12 months like clockwork, lets just say that I find letting them go for years and years to be a bit stress causing. Cracking the H/E open is best done at my convenience, not on unexpected discovery!

ghost said:

Sooooo, being naturally time selfish, while I'm not a zealot for having impellers replaced every 12 months like clockwork, lets just say that I find letting them go for years and years to be a bit stress causing. Cracking the H/E open is best done at my convenience, not on unexpected discovery!

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Scheduled maintenance is so much less costly and less stressful than waiting until something goes wrong. We replace by the manufacturer's recommendations and our maintenance schedules. If that means too often, then fine. But if that means we eliminate one adverse event then it's worth it.

More than once I've taken a quote from one thread to start another. I should do it more often.

I think an impeller change interval is dependent upon two things: the length of time the impeller has been in the pump and the frequency of the pump's being used. I believe more frequent use, or at least regular use, permits a longer change interval because the impeller is less likely to harden up and take a set.

Marin said:

I think an impeller change interval is dependent upon two things: the length of time the impeller has been in the pump and the frequency of the pump's being used. I believe more frequent use, or at least regular use, permits a longer change interval because the impeller is less likely to harden up and take a set.

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I think you're right but we still stick to our schedule. The one thing too that people need to be cautious of is impellers in their spare parts. Not accomplishing much if you replace a two year old impeller with a four year old one. Even if you have to discard some, make sure the one you're putting in is in good condition.

BandB said:

I think you're right but we still stick to our schedule.

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I've never had an experienced engine expert tell me that fresh oil is bad for an engine, and your comment reminds me that I've never had one tell me that a new impeller is bad for a pump.

Another 30 minutes getting the end caps off.

Change the little screws for Allen head machine screws , the wrench can easily be inserted bt feel.