positive crank case pressure? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 08-08-2009, 05:19 PM
slate84's Avatar
Registered User
 
Last photo:
Join Date: Jan 2009
Location: brookings south dakota
Posts: 127
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
positive crank case pressure?

i just got done with my built motor about two hundered miles ago. the first fifty miles or so i didn't have pvc valves in the valve covers and i noticed that there would be like a oilly smog coming out from both of them, (factory vortec covers) so i went and got two of the correct pvc valves for the year motor (98 vortec 350) and plugged those in and some cheap APC breather filters from the ricer section. worked fine, i thought. i'm driving the car down to the range and i see a white cloud behind me so i shut it down and checked under the hood, oil spurting onto the header from the dipstick tube, given the stick doesn't fit right to make a great seal, i dont think it should be coming up like that. i checked compression hot and it was 165 +-3psi across the board so i dont think its rings, i'm guessing the filters got saturated with oil and built up the pressure. but how should i correct this problem?

motor is a 10.5-1 vortec 350, hr282xr comp cam, air gap, holley 650 dp. 15* initial, 13* vac, 21* mech.

(ps i would like to thank you all for helping me build a car that scares the **** out of me.) '84rx7, 420ish hp, 460ish trq t-5.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-08-2009, 05:37 PM
slate84's Avatar
Registered User
 
Last photo:
Join Date: Jan 2009
Location: brookings south dakota
Posts: 127
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
i'd also add, there is a small amount of pressure coming from the pvc ports at idle, it'll lift a sheet of paper, and more at higher engine speeds, i was down almost a quart after my first 50mile oil change, remembering that some of which is now coating the engine. plugs all look perfect too.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-08-2009, 05:57 PM
motorhead454's Avatar
Registered User
 
Join Date: Mar 2008
Location: washington
Posts: 167
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I am having the same issue on my 305 but have not put my pcv in it yet. be interesting to see what we come up with.you have two pcv's? I was told to do one on one side and a strait breather on the other. havent done it yet but will try it.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-08-2009, 06:09 PM
slate84's Avatar
Registered User
 
Last photo:
Join Date: Jan 2009
Location: brookings south dakota
Posts: 127
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
well, there was a rubber port that fit it on each one. one valve cover with a pvc size rubber bung, other with oil cap and pvc rubber bung.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-08-2009, 06:26 PM
motorhead454's Avatar
Registered User
 
Join Date: Mar 2008
Location: washington
Posts: 167
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by slate84
well, there was a rubber port that fit it on each one. one valve cover with a pvc size rubber bung, other with oil cap and pvc rubber bung.
aww well what I do is just run a breather as my fill cap. so it will get good ventilation. when I first put the motor together I ran a fill cap and when I drove down the street it would blow the cap right off with all the pressure. try that and see if it helps.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-08-2009, 08:46 PM
Registered User
 
Join Date: Oct 2007
Location: Michigan
Posts: 106
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The PCV valve draws air through the crankcase like it's name. If you run a pcv and breather on each valve cover the air for the pcv will come from that valve cover not through the crankcase. If you have two holes on each cover put pcv in one other hole plug or put in filler cap and on other valve cover put one or two breathers. Pressure builds up in the crankcase, more rpm more pressure. It needs to be vented or will vent and spill oil out the easiest place.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-08-2009, 09:21 PM
motorhead454's Avatar
Registered User
 
Join Date: Mar 2008
Location: washington
Posts: 167
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Henry the 32nd
The PCV valve draws air through the crankcase like it's name. If you run a pcv and breather on each valve cover the air for the pcv will come from that valve cover not through the crankcase. If you have two holes on each cover put pcv in one other hole plug or put in filler cap and on other valve cover put one or two breathers. Pressure builds up in the crankcase, more rpm more pressure. It needs to be vented or will vent and spill oil out the easiest place.
ya I have 1 hole each cover so I run breather 1 and pcv other. no fill cap.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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 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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Should I get my engine balanced? maxpower_454 Engine 21 03-20-2009 09:13 PM
crank case evacuation with m/t valve covers cope Engine 4 06-04-2008 04:43 AM
Is it no good to have a High volume oil pump? Calderone Engine 17 01-31-2008 05:26 PM
Crankcase pressure effect on oil pressure? cboy Engine 8 06-12-2005 08:04 AM
Oil pressure drop under load knizet Engine 9 01-13-2004 02:26 PM


All times are GMT -6. The time now is 08:56 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.