Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - 700R4 line bias valve and pressure regulator.
View Single Post
  #3 (permalink)  
Old 11-21-2012, 10:38 AM
Crosley's Avatar
Crosley Crosley is offline
Global Moderator
 
Last wiki edit: T-350 rebuild tech
Last journal entry: Morris update 03-22-2015
Last photo:
Join Date: Nov 2002
Location: ... USA
Posts: 8,607
Wiki Edits: 1659

Thanks: 619
Thanked 177 Times in 161 Posts
Quote:
Originally Posted by ASE Doc View Post
Hi Guys, I've been doing a lot of research as I prepare to put my 700R4 back together. I read Tony's 700R4 pages and found some interesting points. One thing that Tony talks about is blocking the line bias valve. Apparently, the line bias valve bleeds off line pressure above 1/2 throttle. Blocking it prevents the bleed off and maintains higher line pressure which I would imagine produces faster firmer shifts. I am very interested in this since making sure that the 3-4 clutches don't slip and burn is of great importance to me. My question is, why did GM design this valve into the system to begin with? Is there any down side to disabling it?

One more question I have concerns the pressure regulator valve. My trans had the .500 boost valve already installed. It also had the regulator valve modified by grinding down the valve between line pressure and converter feed. This would create constant flow to the converter(clutch maybe) when it would have normally been closed off. What is the purpose of this? Does it increase flow through the cooler? Thanks in advance for any input.
Line bias valve operates as you mention. Why GM designed it that way? Ask GM engineers. You can block the line bias valve fully or install a stronger spring so main line pressure ramps up quicker & higher. A .471 main boost valve with .282 or .296 secondary boost valve with a blocked line bias valve works well on the street for main line pressure and proper TV linkage operation.

The mod to the main PR valve does increase flow. GM cut notches on the PR valve in later design changes

__________________
Dont worry how old you are... it is the mileage on your body that adds up.
Reply With Quote