Cruisers Forum
 


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 19-05-2019, 17:09   #166
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,473
Why do people replace diesel engines in a sailboat?

There are a few reasons for a cylinder wall to become smooth so that oil isnít contained in the cross hatching and blowby goes up, oil temp goes up, oil gets black quickly and oil consumption increases.
First is cylinder wall glazing, that is actually unburned fuel deposits coat the cylinder walls and eventually turn into something like a varnish.
Itís from low temp operation, if the engine is allowed to run at design temp this wonít happen, it takes very little load to get up to operating temp, but loads just from an alternator if using the engine to charge batteries is often not enough load.
Often unless allowed to get really excessive glazing can be recovered from, by a good detergent in the oil and an Italian tune up.
Iíve never seen it so bad that the engine has to be honed myself, heard of it, but never seen it.

Second is bore polishing, something that airplanes that are infrequently used and our boats suffer from as they age. An engine that sits for a decent long interval, say weeks can and will form a light coat of rust on the cylinders, especially if it has water in the exhaust as that is a humid environment.
When the engine is started of course this rust is very quickly cleaned off by the piston rings, but it causes wear of the cross hatching, repeat dozens or hundreds of times and eventually you have polished your bores.
Bore polishing the only cure is either honing, or usually bore it out to oversize as likely the engine is decades old anyway.

However these engines can have excellent crankshafts and cams, lifters etc. that exhibit very little wear, they are mostly victims of just not being used, and are often excellent candidates for an overhaul

I plan on keeping my old 4JH(B)E until lack of parts force me to replace it, I think your crazy to not overhaul an engine that still has good parts availability, a good overhaul is Better than new, cause you determine the tolerances in an overhaul, the engine can be as perfect as you can make it if you desire.
a64pilot is offline   Reply With Quote
Old 19-05-2019, 17:27   #167
Registered User

Join Date: Jun 2010
Posts: 723
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by a64pilot View Post
All internal combustion engines I am aware of have some form of crankcase vent.
However PCV stands for positive crankcase ventilation, a Diesel has no vacuum so unless a pump has been fitted for this purpose it canít be a positive crankcase vent, that is on gas engines that have vacuum, the vacuum in the intake manifold is what makes it a positive crankcase vent.
Trivia really the result is the same, but hopefully the manual doesnít refer to it as a PCV system does it?
No, itís just a crankcase vent, it is built inside the rocker cover and goes to an inlet port opening into the rocker area.
There is apparently some some wire mesh filter as well, I will check it out when I do the valve clearances.
olaf hart is offline   Reply With Quote
Old 19-05-2019, 18:18   #168
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,473
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by olaf hart View Post
No, itís just a crankcase vent, it is built inside the rocker cover and goes to an inlet port opening into the rocker area.

There is apparently some some wire mesh filter as well, I will check it out when I do the valve clearances.


What you describe is extremely common, even among automobiles.
The mesh serves as an air oil separator, and sometimes if oil changes are neglected and or cheap oil used the valve cover being cooler than the rest of the engine the oil fumes will condense to a wax like substance and can clog that mesh, then you build crankcase pressure and start blowing seals or maybe leaks.
When the valve cover is off, look for this issue, usually mineral spirits will clean it out pretty well.
a64pilot is offline   Reply With Quote
Old 20-05-2019, 10:34   #169
Registered User
 
u4ea32's Avatar

Join Date: Nov 2009
Location: Los Angeles and Maine
Boat: Olson 40
Posts: 320
Re: Why do people replace diesel engines in a sailboat?

I spent a lot of money and time refurbishing a low hour Yanmar 3GM30F. The result was rude: noise, vibration, smell, complexity, expense, maintenance, and an absurdly low level of reliability. I did not want to continue to be abused by something that is essentially unnecessary.

So I pulled it all out, and went electric. A Tesla of the Seas.

ElectricYacht 10KW air cooled (more than twice the power I need), with a 5KW bank of LiFePO4 GC2 batteries by Battle Born in Reno.

It is not a little better. It is enormously better in every single way.
u4ea32 is offline   Reply With Quote
Old 20-05-2019, 18:35   #170
Registered User

Join Date: Jul 2018
Posts: 16
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by u4ea32 View Post
I spent a lot of money and time refurbishing a low hour Yanmar 3GM30F. The result was rude: noise, vibration, smell, complexity, expense, maintenance, and an absurdly low level of reliability. I did not want to continue to be abused by something that is essentially unnecessary.

So I pulled it all out, and went electric. A Tesla of the Seas.

ElectricYacht 10KW air cooled (more than twice the power I need), with a 5KW bank of LiFePO4 GC2 batteries by Battle Born in Reno.

It is not a little better. It is enormously better in every single way.
Until you need more than a very modest range motoring. Otherwise I'm with you. But we're still at least a decade (probably closer to 2) from seeing battery/electric tech replacing diesel for the average consumer.
BoatandBeach is offline   Reply With Quote
Old 20-05-2019, 19:03   #171
Senior Cruiser
 
newhaul's Avatar

Cruisers Forum Supporter

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 9,841
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by BoatandBeach View Post
Until you need more than a very modest range motoring. Otherwise I'm with you. But we're still at least a decade (probably closer to 2) from seeing battery/electric tech replacing diesel for the average consumer.
you mean like the run thru the red sea after the Suez canal as recommended to avoid possible piracy issues for 24 to 36 hours straight on a circumnavigation or just a transit from the med to the Indian.

Or bashing north to san Diego from Mexico
__________________
Non illigitamus carborundum
newhaul is offline   Reply With Quote
Old 21-05-2019, 03:19   #172
Registered User
 
malbert73's Avatar

Join Date: Jun 2008
Boat: Tartan 40
Posts: 1,841
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by newhaul View Post
you mean like the run thru the red sea after the Suez canal as recommended to avoid possible piracy issues for 24 to 36 hours straight on a circumnavigation or just a transit from the med to the Indian.

Or bashing north to san Diego from Mexico


Or even like trying to get to a reasonable destination on the Chesapeake in the summer when the breeze doesnít materialize? 30nm at 7 kts canít be done with any reasonable array

Mike
malbert73 is online now   Reply With Quote
Old 21-05-2019, 03:24   #173
Registered User

Join Date: Aug 2016
Location: ABC's
Boat: Prout Snowgoose 35
Posts: 1,760
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by malbert73 View Post
Or even like trying to get to a reasonable destination on the Chesapeake in the summer when the breeze doesnít materialize? 30nm at 7 kts canít be done with any reasonable array

Mike
All this might be true but why do people even bother with the argument when they know damn well that some people sail in their local areas, or even around the world without an engine. Rather than trying to educate it instead reads as pushing an agenda.

---

Now on the subject of repowering. It's a strange one. How many people repower their cars, motorcycles, campervans? I don't imagine many. That being said, I can certainly understand it. Especially if you are buying an old boat. The engine installed might have an unknown installation date, unknown hours, unknown service histroy, and you've got no idea what the mods and bodges the previous owner(s) have done. In such cases often it's not even worth time to figure it out. It usually takes much longer to deconstruct something and rebuild, than to just build or start from a clean slate.
mikedefieslife is offline   Reply With Quote
Old 03-06-2019, 19:56   #174
Registered User

Join Date: Dec 2015
Posts: 522
Images: 1
Re: Why do people replace diesel engines in a sailboat?

Here's another reason. I just pulled my Atomic 4 Gas engine out and dropped a diesel right into the same spot. I got the boat for nothing because the gas engine wouldn't run and I don't like the constant danger gasoline brings to the table. The boat was well worth the new diesel.
Rorzech is offline   Reply With Quote
Old 03-06-2019, 20:01   #175
Senior Cruiser
 
newhaul's Avatar

Cruisers Forum Supporter

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 9,841
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by Rorzech View Post
Here's another reason. I just pulled my Atomic 4 Gas engine out and dropped a diesel right into the same spot. I got the boat for nothing because the gas engine wouldn't run and I don't like the constant danger gasoline brings to the table. The boat was well worth the new diesel.
where are you located? I could use that a4 as a parts motor
__________________
Non illigitamus carborundum
newhaul is offline   Reply With Quote
Old 03-06-2019, 20:51   #176
Registered User

Join Date: Dec 2015
Posts: 522
Images: 1
Re: Why do people replace diesel engines in a sailboat?

Yes reliability and piece of mind is valuable. A couple of days ago a giant cruise ship in Venice came crashing into the dock and smashed a tour boat and injured some people, all because he developed a problem with his engine. The captain was on the bridge watching the slomotion disaster helplessly. Yes reliability is paramount !
Rorzech is offline   Reply With Quote
Old 03-06-2019, 21:35   #177
Registered User

Join Date: Dec 2015
Posts: 522
Images: 1
Re: Why do people replace diesel engines in a sailboat?

Thunder Bay Canada. rjzech@gmail.com
Rorzech is offline   Reply With Quote
Old 03-06-2019, 21:44   #178
Registered User
 
Island Time O25's Avatar

Join Date: Sep 2014
Posts: 2,722
Re: Why do people replace diesel engines in a sailboat?

A good buddy who happens to be a diesel mechanic for past 45+ years swears by keeping old school heavy and slow turning diesels over shiny new electronics ladden thin walled ones. Says old Yanmars way more reliable then the latest generation. Same for Kubota based Universals. Also he's very down on modern Volvo diesels, especially their overpriced parts and often less then competent service departments.

Also the old school engines are easier to service in out of the way places, having no or little electronic parts, etc. If you're repowering a day sailer in New England or PNW it's not an issue but if you're far from civilization on RTW chances are that a local mcgyver can bring an old Perkins or Universal to life more easily with cannibalized parts and whatnot than a commonrail latest turbo engine.
Island Time O25 is offline   Reply With Quote
Old 03-06-2019, 22:06   #179
Senior Cruiser
 
newhaul's Avatar

Cruisers Forum Supporter

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 9,841
Re: Why do people replace diesel engines in a sailboat?

Quote:
Originally Posted by Rorzech View Post
wrong coast darn it . Not worth the cost of shipping
__________________
Non illigitamus carborundum
newhaul is offline   Reply With Quote
Old 05-06-2019, 22:19   #180
Registered User

Join Date: Aug 2014
Location: Whitianga, New Zealand
Boat: Cal 2-46
Posts: 169
Re: Why do people replace diesel engines in a sailboat?

Love my Perkins 4-236. 5000 hours, 43 years old. Purrs. and powerful.

I bought a "spare" one ($NZ3.000) just in case as my partner was worried about the old one. Still got in in the garage under covers.

Had to motor back from Tonga last year, no wind. Six days on motor.

Pete
Jimmyhenry is offline   Reply With Quote
Reply

Tags
boat, diesel, engine, sail, sailboat

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need to Replace Engines Want advise Stargazerroatan Engines and Propulsion Systems 6 21-05-2019 22:00
Which engines can replace a Volvo Penta MD11C Popeye2 Engines and Propulsion Systems 15 23-10-2018 06:27
Lines - To replace, or not to replace? TooCoys General Sailing Forum 31 25-04-2017 13:32
How often do people really replace their rigging holding mast videorov General Sailing Forum 40 22-05-2013 13:24
Why So Many Boats with Rebuilt / New Engines ? headhertz Engines and Propulsion Systems 42 29-09-2011 13:19

Advertise Here


All times are GMT -7. The time now is 04:30.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.