Ducati Sporting Club

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 25-Jan-2013, 05:10 PM
dunlop0_1's Avatar
dunlop0_1 dunlop0_1 is offline
Registered Forum User
Big Twin
 
Posts: 1,564
Join Date: May 2009
Oil pressure question

Just been testing the 996's oil pressure. Now it meets the the recommended pressures both hot and cold, at idle and 4-5k.
However, there is no spec for what the pressure should be when the relief valve opens above 4-5k.
I would expect a drop but what to?
Reply With Quote
  #2  
Old 25-Jan-2013, 05:46 PM
Ghost's Avatar
DSC Member Ghost Ghost is offline
DSC Club Member
Big Twin
Bikes: Ducati 749, Phil Read Replica, DD 620
 
Posts: 1,830
Join Date: Mar 2008
Mood: 2011 DD Class 'B' Champion
Quote:
Originally Posted by dunlop0_1
Just been testing the 996's oil pressure. Now it meets the the recommended pressures both hot and cold, at idle and 4-5k.
However, there is no spec for what the pressure should be when the relief valve opens above 4-5k.
I would expect a drop but what to?

Relief valve surely is lifted by pressure and is not necessarily RPM dependent. Also viscosity will be a factor as will temperature. How hot is hot?

Also as the relief valve is opposed by spring pressure it will vary infinitely.
Just my thoughts probably bollox as usual.
Reply With Quote
  #3  
Old 25-Jan-2013, 08:01 PM
dunlop0_1's Avatar
dunlop0_1 dunlop0_1 is offline
Registered Forum User
Big Twin
 
Posts: 1,564
Join Date: May 2009
So if the pressure at hot idle is 15psi rising to 65psi max at 4-5k then when the relief valve opens creating a free flowing circuit as it where then pressure would drop back to somewhere around idle pressure? So you will only maintain the max pressure at the relief valve because after that the only resistance is from the oil galleries/crank etc. Then when the rpm decreases the valve shuts etc
Pressure is only created when resistance is met yada yada.

or is it my turn to talk bollox.

Last edited by dunlop0_1 : 25-Jan-2013 at 08:28 PM.
Reply With Quote
  #4  
Old 25-Jan-2013, 09:14 PM
batesy2 batesy2 is offline
Registered Forum User
Bevel Head
Bikes: ducati 620ss racer,aprilia rsvr mille,husqavarna 125 crosser
 
Posts: 88
Join Date: Sep 2011
Mood: easy going,love to laugh,fairly competetive
Right listen carefully,I will say this only once,(mock german accent)
The relief valve opens at a pre-set pressure dictated by the spring fitted,it will only open when that pressure is reached,
The moment the pressure reduces the valve will close but the drop only needs to be slight.
The valve will open and close rapidly but the pressure will remain at the max level at all times whilst the engine is at high revs.
Some engines never reach relief pressure due to wear in crank etc

Hope that makes sense

Batesy
Reply With Quote
  #5  
Old 25-Jan-2013, 09:21 PM
Ghost's Avatar
DSC Member Ghost Ghost is offline
DSC Club Member
Big Twin
Bikes: Ducati 749, Phil Read Replica, DD 620
 
Posts: 1,830
Join Date: Mar 2008
Mood: 2011 DD Class 'B' Champion
Quote:
Originally Posted by dunlop0_1
Pressure is only created when resistance is met.
Or is it my turn to talk bollox.

That is correct, spring pressure is constantly modulating the relief valve orifice, from a knats A**hole, to your not coming near me wi that.
Reply With Quote
  #6  
Old 26-Jan-2013, 07:20 AM
yendor yendor is offline
Registered Forum User
Montjuic
 
Posts: 76
Join Date: Sep 2011
Quote:
Originally Posted by batesy2
Right listen carefully,I will say this only once,(mock german accent)
The relief valve opens at a pre-set pressure dictated by the spring fitted,it will only open when that pressure is reached,
The moment the pressure reduces the valve will close but the drop only needs to be slight.
The valve will open and close rapidly but the pressure will remain at the max level at all times whilst the engine is at high revs.
Some engines never reach relief pressure due to wear in crank etc

Hope that makes sense

Batesy

100% correct,and very well explained.
Reply With Quote
Reply
  
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes
Postbit Selector
Switch to Vertical postbit Use Vertical Postbit

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Recent Posts - Contact Us - DSC Home - Archive - Top
Powered by vBulletin 3.5.4 - Copyright © 2000 - 2017, Jelsoft Enterprises Ltd. - © Ducati Sporting Club - All times are GMT +1. The time now is 02:41 AM.