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Go Back   SailNet Community > On Board > Gear & Maintenance
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  #21  
Old 02-23-2008
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Jody—

This statement shows you really don't understand what I am saying at all. The catalytic converter is the REASON that we don't use leaded fuels any more. The catalytic converter has nothing to do with octane boosting, and a lot to to with the content of the exhaust coming out of the tail pipe. It is one of the major components of a emissions control system on a modern gasoline engine. If you were to put leaded gasoline through a car equipped with a catalytic converter, the engine would burn it just fine... but the tetraethyl lead would destroy the catalyst in the catalytic converter—requiring you to replace it.
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Ironically with lead almost minimal in fuels a catalytic converter is still required... ironic?
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  #22  
Old 02-23-2008
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Around the same time that folks were trying to clean up emissions and someone decided the catalytic converter was a good idea...Remember that we also got rid of leaded gasoline because LEAD IS AN ENVIRONMENTAL TOXIN and heavy lead levels were found in the blood of people living in heavy exhaust areas--as well as on/in the ground. Same thing for asbestos from brake pads, on ground.

We didn't just get rid of lead to make the catalysts happy, we switched to catalysts because getting rid of the lead was necessary, and synchronicitous (ouch) on the timing.

Of course, glomming onto MTBE and spreading that all over the ground water supply wasn't exactly a smart move, but it made so many ecofreaks SO very happy because it wasn't "ethyl". (sigh.) Now I'd just like to find someone who sells GASOLINE without the booze in it, in the car I'm sure I see a 10% mpg loss thanks to the booze, and even the EPA reluctantly confirms that. Let's see now...it burns 10% cleaner, but I need to burn 10% more of it....And that accomplishes, uh, what? Duh?

Short engine runs also contribute to engine wear because the oil has not been heated up high enough and long enough to "cook off" the condensates and the fuel that normally dilute the oil. If the typical auto engine isn't run for at least a 1/2 hour every time the car is used--the oil builds up excess levels of fuel and water (condensate) and the engine wears because the oil has been contaminated. Frequent oil changes don't really help that, because the contaminants build up so fast. A half hour at "operating temperatures" generally is enough to cook them off though. I caught on to this after some oil analysis left me asking "Why is my oil contaminated?" and I'm just mule-stubborn now about not hitting any ignition key without a Real Good Reason. Diesel, auto, no matter, same oiling system same problem. There's just more condensation in typical marine installations, so even more need to cook it off.

Last edited by hellosailor; 02-23-2008 at 10:44 AM.
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Old 02-23-2008
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Two things black smoke is unburt fuel , and engine idling by trucks is not as it states, all trucks at idle have their rpms boosted to a higher rev to clean burn. Idling per say for highway rigs today is constanlty monitor by base stations company owned, for such reason as speeding over revs and idle time.
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Old 02-23-2008
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Well said... BTW, if the auto industry hadn't been pushing the oil industry to remove the lead, we'd probably still be using leaded gasoline... I know, since I've seen some of the oil and auto industry memos on the issue.
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  #25  
Old 02-23-2008
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Originally Posted by theartfuldodger View Post
Two things black smoke is unburt fuel , and engine idling by trucks is not as it states, all trucks at idle have their rpms boosted to a higher rev to clean burn.
Black soot expelled while accellerating is not necessarily unburned fuel. I know this because my Perkins 4-108 was carboned up when I bought the boat. A few acceleration runs up to hull speed/3500 RPM expelled the crud. Now if I accelerate the boat I get nothing but normal exhaust. The engine did not have a problem starting beforehand. Diesels need to be put under a load and revved now and then to clear the combustion chamber; just as gasoline engines do.

If I am sitting idle or motorsailing to charge the batteries; I run at around 1100 RPM; base idle is 700 or so. At low RPM the alternator does not kick on; 100RPM is where it starts charging batteries. So if that's true regarding high idle to burn cleanly; I'm already doing that. I still don't think you are going to glaze your cylinders while warming up the engine for 15-20 minutes. If dockside I engage reverse to help warm up the gearbox for 5 minutes or so before exiting the slip.
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Old 02-23-2008
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I would add to my original posts, that Valente and keelhauling both make good points to consider. You need to check how much other stuff may have to be moved or replaced to upgrade. If you have to have a new fuel tank custom made or a custom wet exaust it might be cost prohibative. Also if your able to do alot of the stuff your self, the cost of rebuilding will go down. One warning to remember. Any thing that wasn't suposed to go to the machine shop that was still attched. Will be handed back to you all in the same box with out any notes on where it came off.

For my money I would rebuild the engine, but that comes with a caviat. I would not only remove the engine myself, but other then having the block and head magnafluxed or pressure tested, plus maybe the cam or crank shafts milled, I would do most of the rebuild my self. So for me it would be a couple hundreds or so in parts, and taking the time to grind or sandblast and repaint the motor mounts, manifolds, and other bits.

In the end, before you make any firm decisions, have a couple estimates writen up for each option. Don't worry about wasting other people's time. I'm a home remodler now and it never bothers me to give estimates to people who really are considering hiring me. It only bugs me when there just fishing for lower prices then they've already been quoted or already plan to give the work to someone else and are just getting quotes for insurance.
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Old 02-24-2008
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Thanks for all the posts.

some got a bit off topic but hey thats how the discussion goes.

Hellosailor, hard or soft hours? Proper maintenance? Bit hard to tell as I've only owned the boat 2 years out of the last 29. Probably a mixed bag; the last owner kept detailed records & probably did a better job than me. The guy before him let the boat go downhill, which probably included the engine.

Valiente, my engine sounds similar to yours, low engine hours, no real problems but an elderly engine. I'm leaning towards your solution however I'm in no rush; I've got 2-3 years to see how the engine runs and make up my mind.

Sailingdog / artbyjody, understand your points about fuel problems. The previous owner had a theory that you never had to change the fuel filter until it clogged up as their are two inline and you switch to the 2nd one when necessary. When I checked the filter the main one was absolutely clogged with gunk and the taps were stuffed so fuel had always been run through both filters regardless whether the taps were opened or closed!

KeelHaulin, I normally run the engine at maximum revs of around 2,100RPM as thats pushing the boat around six knots and thats generally fast enough. The engine specs state maximum revs of 4,000rpm and continous maximum revs of 3,200RPM. I'll try your suggestion and take it up to 3,200 and see whether I get any black smoke.

Danjarch, should of mentioned that some things have already been repaired / replaced. For example, rebuilt starter motor by the previous owner, rebuilt saltwater pump & exhaust manifold by me, etc.

Probably should of also mentioned my plans are to coastal cruise for the next 3-5 years and then look at longer trips after that. Therefore I have the luxury of seeing how the engine performs whilst still fairly close to home. The rebuild / replace decision would be part of the preparation for the longer trips. So far the engine has performed faultlessly, starts no problem and chugs along no worries. Have always warmed up / cooled down, regularly changed oil, etc, etc.
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Old 02-24-2008
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Originally Posted by Ilenart View Post

Valiente, my engine sounds similar to yours, low engine hours, no real problems but an elderly engine. I'm leaning towards your solution however I'm in no rush; I've got 2-3 years to see how the engine runs and make up my mind.
Fair enough. If I wasn't going offshore, I wouldn't be doing a damn thing...but recreational use in Lake Ontario in which it's hard to be more than one day's sailing time from a rebuilder...is a different thing from even "coastal".

One thing you might consider now is to purchase the full set of rebuild parts now, as they will only be scarcer in three years when your engine is 32 years old. These days, if you discover after a diagnostic tear-down that your engine is still in great shape, you should have no problem flogging the parts on eBay or to some other rebuilder.

It's not that none of the parts will be available in three more years; it's that the one part you need won't be.

Having rebuilt an Atomic 4, a very popular engine that is frequently rebuilt, and yet having a few problems finding certain parts, I can imagine that for a rarer engine it would be significantly more problematic.
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Old 02-25-2008
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Another option is to exchange for a rebuilt engine of the same type, particularly if it is a common motor. I purchased a boat last year with a very tired MD11C and went through the same trade-off assessment. Replacing with a newer engine would provide more HP and lower weight, as well as piece of mind for $10k+. There are smaller shops offering rebuilt motors, generally ones they refurbished after taking out during a replacement. I ended up exchanging my MD11C for a rebuilt MD11C, helping with the work (a full day as there was no need to change mounts as when you re-engine), and now have a well-running motor for a bit over $3k. I would only do this with a reasonably local and reputable mechanic.

Chris
Baltic 37 Brut
Volendam, NL
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Old 02-25-2008
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Guys...

I will never understand this.
The original posting has a 20 year old motor with 2700 hours on it and there is nothing wrong with it.
It starts, it runs, and the 'box is ok.
Some clash head says that 20 years means trouble when there is none and wants to sell a new motor that will not last 20 years because 20 years means trouble.

Get out of here.

Maintain it, and leave it there.

My old motor is 31 years old, and though it's not without trouble, at last count, it took me about 200 miles, used little oil, and started fine. I let it freeze a while back, and cracked the block. It weeps (out) a little, but it's raw cooled, so coolant supply is not a problem.

If it blows up I will change it, but the idea of tearing it out of there when I don't need to, I get from others wanting to sell me another one.



Rockter.
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