Marine Diesels vs Truck Diesels - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Diesel
 Not a Member? 

Diesel This is a forum dedicated to diesel engines and their applicable accessories.


Reply
 
LinkBack Thread Tools
  #1  
Old 02-25-2011
casey1999's Avatar
Senior Member
 
Join Date: Oct 2010
Location: HI
Posts: 2,905
Thanks: 8
Thanked 21 Times in 21 Posts
Rep Power: 5
casey1999 is on a distinguished road
Marine Diesels vs Truck Diesels

Why is there so much talk of how sensative marine diesel engines are to idle and running rpm (best to run at high rpm) when diesel truck and equipment engines do not seem to have this problem? There are many semi rigs that sit idling there engines to keep the sleeper warm in the winter or idle for hours in traffic jams and these engines get many hours on them before overhaul.

Seems marine diesel are too sensative. Whats the story?
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 02-25-2011
LandLocked66c's Avatar
Sunsets and Warm Beer....
 
Join Date: Dec 2009
Location: The Bottom of a Pint Glass...
Posts: 2,111
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
LandLocked66c is on a distinguished road
I've often wondered the same thing. Diesels are generally overbuilt and very rugged engines.
__________________
1971 23' Oday Pop Top
S/V Frida

You can't steer a boat that isn't moving? Just like a life - P. Lutus
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 02-25-2011
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,155
Thanks: 0
Thanked 71 Times in 62 Posts
Rep Power: 8
mitiempo will become famous soon enough mitiempo will become famous soon enough
I think a lot has to do with how trucks are used vs boats. Trucks may idle a long time, but when driven they will be up and down through the rev range constantly. In a boat most often the engine runs at a constant rpm, sometimes for hours. I'm not an expert, but that is a big difference.
__________________
Brian
Living aboard in Victoria Harbour
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 02-25-2011
LandLocked66c's Avatar
Sunsets and Warm Beer....
 
Join Date: Dec 2009
Location: The Bottom of a Pint Glass...
Posts: 2,111
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
LandLocked66c is on a distinguished road
It appears there are different schools of thought on idling a diesel or any engine. The issues would be in-efficient cylinder/bore oiling and loads. The forces on the crank are smoother as speed increases, and oiling is more reliable.

Car and Boat diesels are generally the same class:
Quote:
High-speed (approximately 1,000 rpm and greater) engines are used to power trucks (lorries), buses, tractors, cars, yachts, compressors, pumps and small electrical generators. As of 2008, most high-speed engines have direct injection. Many modern engines, particularly in on-highway applications, have common rail direct injection, which is cleaner burning.
__________________
1971 23' Oday Pop Top
S/V Frida

You can't steer a boat that isn't moving? Just like a life - P. Lutus
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 02-25-2011
jrd22's Avatar
Courtney the Dancer
 
Join Date: Nov 2000
Location: San Juan Islands., WA, USA
Posts: 3,820
Thanks: 3
Thanked 16 Times in 16 Posts
Rep Power: 14
jrd22 will become famous soon enough
Many truck and marine engines are the same basic engine. Having owned and operated about a hundred truck and equipment diesel engines as well as several marine engines I have never subscribed to the common belief/advice that marine engines will be harmed unless they are run at 80+-% of full RPM. It is very important to have the correct size and pitch prop which allows you to reach the full operation RPM when motoring in gear. An oversized or pitched prop is just like trying to climb a hill in a truck in too low a gear. It builds excessive heat both in the cooling system and in the exhaust and is extremely hard on the engine. As far as I'm concerned you shouldn't run a marine engine MORE than 80% for extended periods, but I fail to see how any damage can be done by running at a lower speed as long as the engine develops enough heat to run at normal operating temperature. When breaking in a new diesel I have found that running it hard will lessen the chance of the rings not seating but after that I tend to baby them by running them around 60-70% and I've yet to have any of the supposed problems caused by this (fouled injectors, carbon build up). In my opinion more damage is caused by short run times where the engine never gets up to operating temp or running the wrong prop than anything else (except perhaps lack of normal maintenance). Long idle times are a waste of fuel, and with seawater cooling the engine it won't be at normal operating temp so you won't be getting complete combustion of the fuel which CAN foul injectors, etc.
__________________
John
SV Laurie Anne

1988 Brewer 40 Pilothouse

Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 02-25-2011
L02314564's Avatar
Itz That Eazy!!!
 
Join Date: Jul 2007
Location: NW Louisiana
Posts: 82
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
L02314564 is on a distinguished road
This is from "Gas Versus Diesel" by David Pascoe. "In pleasure craft use, diesels not only don't run continuously, but they are often rarely run. And in this case, it is the disuse that leads to their early demise. The reason for this is due to corrosion. An engine that is not running, especially for extended period of time like weeks, yet alone months, develops internal corrosion in all parts of the systems so that wear is greatly accelerated. An engine that is running all the time precludes most of this corrosion from occurring. Diesel engines in pleasure craft almost never wear out; they break down due to corrosion damage and other maintenance deficiencies."

It sounds right. Hope it helps.
__________________
Edward
U.S.A.F. Retired
S/V Itz That Eazy!!!
1976 Catalina 27 #2684
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 02-25-2011
SlowButSteady's Avatar
Senior Slacker
 
Join Date: Feb 2010
Location: SoCal
Posts: 4,223
Thanks: 0
Thanked 17 Times in 15 Posts
Rep Power: 5
SlowButSteady is on a distinguished road
For what it's worth, the manual for my Yanmar 2gm20 (see attached) advises one to "race" the engine every couple of hours when idling for extended periods.
Attached Thumbnails
Marine Diesels vs Truck Diesels-untitled.jpg  
__________________
Never forget them. Do something to prevent it from happening again.
Charlotte Bacon, Daniel Barden, Rachel Davino, Olivia Josephine Gay, Ana M. Marquez-Greene, Dylan Hockley, Dawn Hochsprung, Madeleine F. Hsu, Catherine V. Hubbard, Chase Kowalski, Jesse Lewis, James Mattioli , Grace McDonnell, Anne Marie Murphy, Emilie Parker, Jack Pinto, Noah Pozner, Caroline Previdi, Jessica Rekos, Avielle Richman, Lauren Rousseau, Mary Sherlach, Victoria Soto, Benjamin Wheeler, Allison N. Wyatt
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 02-26-2011
CrazyRu's Avatar
Senior Member
 
Join Date: May 2007
Posts: 452
Thanks: 2
Thanked 0 Times in 0 Posts
Rep Power: 8
CrazyRu is on a distinguished road
Being truck driver and former owner of a few highway semi's I should say that idling of modern truck engine is a bad thing. Engines don't take it well and manuals say to bring RPM's up from 600 to about 1200 if engine is left idling overnight. Most trucks you see idling actually running at higher RPM than idle.
__________________
CR
s/v NEMO - Freedom 28 Cat Ketch, centerboard
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 02-26-2011
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
I think the real issue isn't idling the engine, but that has to be balanced off by running the engine hard enough to blow out the carbon deposits occasionally. If that isn't done, then idling is going to be a bad thing.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 02-26-2011
Senior Member
 
Join Date: May 2006
Posts: 201
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
r.furborough is on a distinguished road
It's also a heat issue, a diesel needs to be run fairly hard to get it up to normal operating temperature for complete combustion, idling a diesel, particulary straight after an initial start to charge batteries does not allow this. Further, some makes of engine are more susceptible to cylinder glazing under these conditions due to poor oil control on the cylinder walls by the oil control rings of the piston. This is where the thoughts of running hard at at least 80% is required to achieve cylinder pressures that allow the piston and oil control rings to do their job properly whereas in actual fact it's probably just a way of overcoming bad design, manufacturing and materials.
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Turbo Diesels tdw Gear & Maintenance 26 02-26-2010 09:30 PM
Beta marine Diesels engines Tequiza Terri Gear & Maintenance 2 01-17-2005 12:13 PM
Need new diesels - NOW! bvicaptn General Discussion (sailing related) 0 07-09-2002 06:25 AM
Question about marine diesels bdkorth Learning to Sail 9 07-03-2002 10:52 AM
diesels anneminix Gear & Maintenance 1 10-26-2001 07:51 AM


All times are GMT -4. The time now is 01:19 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.