ForumsBasic TrainingOnline Maintenance ManualsThe M715 Zone Vin RegistryVPW's M715 Parts ListGalleriesLinks

Go Back   M715 Zone > General Tech > Stock Tech > Stock Tech Archives

Stock Tech Archives Look here first for all archived messages

 
 
Thread Tools Display Modes
  #1  
Old January 11th, 2004, 12:10 PM
AVL Jeeper AVL Jeeper is offline
Basic Trainee
 
Join Date: Jan 2004
Location: Seattle, WA
Posts: 38
AVL Jeeper is a Soldier
Default

Hi! Just registered here, I guess this is where the action is now. I kind of miss the old board layout. Anyway,

I think I may need a new PCV valve. The plunger is loose in the housing. I can see it fall up and down if I flip the valve assembly up and down. I was under the impression that the spring in there is supposed to keep the valve closed untill the manifold vaccum opens it up. Is that true?

My truck is not idling very smoothly, so that is what led me to remove the PCV valve in the first place.

If I need a new valve, can I get one @ NAPA or Advance Auto? If not I will contact AB linn or Memphis Equip.

THanks for the help,
Karl
Asheville, NC
1967 M715 all stock except winch from M35A2 6x6, custom front bumper and British black and green camo.
  #2  
Old January 11th, 2004, 05:21 PM
Barrman's Avatar
Barrman Barrman is offline
Chief 9-flats

 
Join Date: Dec 2003
Location: Giddings, Texas
Posts: 7,747
Barrman is a Soldier
Default

Karl,
Welcome. The PCV valve is a check valve. It allows the gases inside the engine to be recycled through the combustion cycle. A straight hose would do the exact same thing. The PCV is installed to prevent the gases from going the other way. Such as in a backfire. To answer your question. Some are spring loaded and some not. As long as it opens and closes to the proper pressure it will work. Mine is also loose and rattles when shaken. I don't know if the specified one is spring loaded or not.

I would suggest a check of timing and carb cleanlyness for your idle problems. Also make sure that 1-5-3-6-2-4 is your firing order. The timing is supposed to be 5*BTDC. The balancer is graduated so getting right on 5 is very straight forward. Good luck
__________________
Remember if you didn't build it you can't call it yours.

6.2 powered M715, 5 M1009's, M416, 2 M101's, 2 M105's, 3 M35's, M1007 6.5 turbo Suburban project called Cowdog.
  #3  
Old January 11th, 2004, 05:28 PM
LuckyPabst's Avatar
LuckyPabst LuckyPabst is offline
Private 1st Class
 
Join Date: Dec 2003
Location: Lone Pine, CA
Posts: 451
LuckyPabst is a Soldier
Default

Tim's kinda right. They do rattle when new. But a good rule of thumb is if in doubt, replace it. They aren't expensive.

The PCV valve is designed to be open during high vacuum like at cruise or when decelerating. It will close when the vacuum drops below a certain point so you still have sufficient vacuum for the carb to operate.

Direct vacuum to the crankcase is bad and will give the same symptoms of a huge vacuum leak when you accelerate or at other low vacuum times.

Chris
  #4  
Old January 12th, 2004, 01:43 PM
bump_r's Avatar
bump_r bump_r is offline
Administrator

 
Join Date: Dec 2003
Location: West-central Ohio
Posts: 691
bump_r is a Soldier
Default

Oh, yeah, about the timing - these engines will run (crappy, but run) with gross out-of timing conditions. A performance mod: These trucks were spec'ed to run of crap gas - 85 octane, I think. This is probably why the timing is so conservative. With modern commercially-available gasoline 87 R+M/2 octane), you can probably advance your timing to 8~12 BTD for a bit better performance. Just Doug, er, I mean retard it if you get any detonation.

Any thoughts on this matter?
__________________
"other peoples junk, is something or other" - Militarypotts 02/07/2011
 

Thread Tools
Display Modes

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 On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Valve spring compressor 77hiboy Stock Tech 8 November 12th, 2009 05:53 PM
Crazy Valve lash! Maingear Stock Tech 15 November 9th, 2009 12:50 PM
PVC valve old1k Stock Tech 1 August 12th, 2008 09:56 PM
Valve Seals dhood Stock Tech 7 March 15th, 2007 11:04 PM
230 valve adjustment Bean101 Stock Tech Archives 5 February 29th, 2004 12:33 PM


All times are GMT -7. The time now is 12:02 PM.

 

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
1998 - 2019


This site is owned and operated by:
M715 Zone, LLC
President: Jon Schmidt, User ID=brute4c
If you have any suggestions, comments, problems or questions, contact:  brute4c@m715zone.com

Use of this site means you understand and agree to our TERMS OF USE

Copyright Notice:
This web site is subject to the protection of the copyright laws of the United States and other countries. Except for Personal Use Only, you may not modify, copy, distribute, transmit, display, perform, reproduce, publish, license, create derivative works from, transfer, or sell any information obtained from any part of the M715 Zone website without the prior written permission of M715 Zone, LLC.

Written permission can only be obtained by contacting
brute4c@m715zone.com

Copyright 1998-2019