Volvo Penta Running Rich - Page 3 - 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
 Not a Member? 
  #21  
Old 11-18-2007
Senior Member
 
Join Date: Jun 2004
Location: Malaysia
Posts: 314
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
haffiman37 is on a distinguished road
Most of You seemes to be locked up in 'air volume'.
A diesel is calibrated in wheight units. If You go by mixture rate 15:1 it will mean 15 kg of air to 1 kg diesel at a given temp. The temp of diesel will normally not vary to much, usually similar to sea temp, but air temp and thereby density of air might be a different story.Not only the outside air temp but as much engine room temp is a big factor. Run on a cold day with engine room 'open' versus a hot day with engine room closed and the difference will be rather noticable.

The volume the engine sucks per stroke is 'constant' but the wheight of the volume sucked in varies a lot!
I keep out prop overload, dirty filters etc as they are not conciddered daily variables.
Reply With Quote Share with Facebook
  #22  
Old 11-18-2007
Senior Member
 
Join Date: Jul 2007
Location: Philadelphia
Posts: 828
Thanks: 0
Thanked 5 Times in 5 Posts
Rep Power: 8
Ulladh is on a distinguished road
Another possibility for oil in the exhaust stream may be a faulty or stuck open water jacket thermostat, preventing the engine achieving the optimal operating temperature, resulting in incomplete combustion.
Reply With Quote Share with Facebook
  #23  
Old 11-18-2007
Senior Member
 
Join Date: Sep 2006
Posts: 2,207
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 9
Rockter will become famous soon enough
Haffman...

It's breathing the same stuff... air.
Reply With Quote Share with Facebook
  #24  
Old 11-18-2007
Senior Member
 
Join Date: Jun 2004
Location: Malaysia
Posts: 314
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
haffiman37 is on a distinguished road
Quote:
Originally Posted by Rockter View Post
Haffman...

It's breathing the same stuff... air.
1 cubic air at 50C is lighter than 1 cubic air at 10C, this gives less oxygen/cubic. Engine runs rich. The engine sucks air in 'cubic' units/stroke, is injected with 'cubic units' of fuel, but variations due to temp makes a huge difference. No rocket sience, basic diesel knowledge.
Reply With Quote Share with Facebook
  #25  
Old 11-19-2007
Omatako's Avatar
Senior Member
 
Join Date: Sep 2003
Location: Auckland New Zealand
Posts: 2,409
Thanks: 0
Thanked 27 Times in 24 Posts
Rep Power: 12
Omatako will become famous soon enough
"1 cubic air at 50C is lighter than 1 cubic air at 10C"

Just for my interest, how much lighter?

If thus was such a noticeable factor then trucking companies who use hundreds of thousands of gallons of diesel would have to modify their operating budgets from summer to winter. I have for many years worked for such companies where fuel is a MAJOR cost consideration and have never heard of such budget considerations.

Interesting concept . . . . . .

Andre
Reply With Quote Share with Facebook
  #26  
Old 11-19-2007
Senior Member
 
Join Date: Jun 2004
Location: Malaysia
Posts: 314
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
haffiman37 is on a distinguished road
How much lighter depends, but why do 'hot air baloons' fly?
Reply With Quote Share with Facebook
  #27  
Old 11-19-2007
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,153
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
Quote:
3, any exact same sized gas engine will use the same air volume as a Diesel as long as both are w/o a turbo or blower (naturally aspirated).
Not trying to beat a dead horse but just breaking it down a bit so I can understand it....

Take two mason jars, each the same size, and put the lids on them. Apply a vacuum of 20" on one of the jars. Which one has more air in it? (20" is the vacuum a gas motor pulls at idle) I don't think the restricted air intake on a gasoline motor can be discounted.
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


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


Boating for over 25 years, some of them successfully.
Reply With Quote Share with Facebook
  #28  
Old 11-19-2007
Senior Member
 
Join Date: Sep 2006
Posts: 2,207
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 9
Rockter will become famous soon enough
Here is the relation...

P1*V1/T1 = P2*V2/T2

If the pressures are the same, it becomes...

V1/T1 = V2/T2

Make the volume ratio the subject...

V2/V1 = T2/T1

Since density (rho) and volume (V) are inversely proportional, you can write as...

rho1/rho2 = T2/T1

So, if the temperatures are 10 degC and 50 degC respectively, convert both to the absolute temperature scale (just add 273 to both) and write as...

rho1/rho2 = (50+273)/(10+273) = 323/283 = 1.1413

...or about 14 percent more dense.

The motor would rather breathe the denser air.
Reply With Quote Share with Facebook
  #29  
Old 11-19-2007
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,153
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
Quote:
P1*V1/T1 = P2*V2/T2

If the pressures are the same, it becomes...

V1/T1 = V2/T2

Make the volume ratio the subject...

V2/V1 = T2/T1
Well...., yeah, when you put it that way...
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


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


Boating for over 25 years, some of them successfully.
Reply With Quote Share with Facebook
  #30  
Old 11-19-2007
Junior Member
 
Join Date: Aug 2007
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
doffe is on a distinguished road


Thanks ERPS for your input. I think that you are right (blow back). I will see if I can capture some of the oil before kicking it back in for combustion.

As for the Diesel v. Gas air use, I think the answer is that a gas engine at full throttle uses that same amount of air as does an equivalent volume diesel (naturally aspirated in each case). However, the gas engine is using less when throttled back. Eg. you can adjust the air flow and then match gas flow as appropriate.
Reply With Quote Share with Facebook
Reply


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
Volvo Penta Outboard? rhbroehl Gear & Maintenance 9 07-23-2011 01:40 PM
Volvo Penta not buzzing stack Jeanneau 17 10-14-2010 09:44 AM
Volvo Penta Marine Diesel MD11C Parts Source? ntheyer General Discussion (sailing related) 35 04-07-2010 02:33 PM
Volvo Penta engine rondezvous Gear & Maintenance 1 09-24-2006 12:24 PM
Running Backstays Dan Dickison Gear and Maintenance Articles 0 05-14-2002 08:00 PM


All times are GMT -4. The time now is 02:30 AM.

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.