Rochester Quadrajet! help - 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 08-17-2006, 06:54 PM
greythorn3's Avatar
Registered User
 
Last photo:
Join Date: Sep 2003
Location: arizona
Age: 43
Posts: 5
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Rochester Quadrajet! help

I am in the process of rebuilding my rochester quadrajet carb m4me or such... anyhow i took out my power piston stop and spring, and have no idea of the general ammount of turns it should be out.. anyone ever do this? or know a good setting that is emissions friendly? ive been searching the internet for over a hour and cannot find a base setting.. so im here for all the carb guru's help.. thanks in advance


RAy
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-17-2006, 07:44 PM
ChevelleSS_LS6's Avatar
Jeep XJ and a Javelin
 
Last wiki edit: Compression test
Last journal entry: August 9, part III
Last photo:
Join Date: Dec 2001
Location: Grand Rapids, Michigan
Age: 28
Posts: 1,610
Wiki Edits: 7

Thanks: 3
Thanked 0 Times in 0 Posts
I wish my uncle, or grandpa were around right now... they can tune any hesitation, any problem, out of a qjet.

Unfortunatley, I was raised in the fuel injection for the masses age, so this is unknown country for me. From experience and most service manuals, for tuning screws and otherwise it's 1.5 turns back of the seat/bottom. Hope my efforts help!
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-17-2006, 08:08 PM
Registered User
 
Join Date: Nov 2005
Location: Duffield ,Va
Age: 67
Posts: 526
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by greythorn3
I am in the process of rebuilding my rochester quadrajet carb m4me or such... anyhow i took out my power piston stop and spring, and have no idea of the general ammount of turns it should be out.. anyone ever do this? or know a good setting that is emissions friendly? ive been searching the internet for over a hour and cannot find a base setting.. so im here for all the carb guru's help.. thanks in advance


RAy
It's been a few moons ago but I used to drive the little plug out of the top part that lets you get access to the stop screw and I think I used a double D type screw driver or something to tweak it after I got it running. But I don't remember the start setting.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-17-2006, 08:24 PM
Registered User
 
Join Date: Aug 2006
Location: California
Posts: 16
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the power piston stop or APT screw is set at the factory to give the engine the correct cruise a/f mixture. a good place to start is 3 1/2 turns from the bottom, then use it to adjust the cruise mixture. the way we set the cruise mixture is with a exhaust gas analyzer, the CO reading taken in front of any catalitic convertor and with any smog pump disabled is to target a CO reading of 0.75 -1.25% CO. (any smog shop should be able to give you the readings for just a few$),you could also use a air/fuel meter such as the Innovate Motorsports LM-1 and then target a air/fuel mixture reading in the 14.2-14.5 to 1 range. i know of no easy way to do the APT screw other than those methods or trial and error spark plug readings.

henry @ oles carb
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-18-2006, 01:45 AM
Member
 
Last photo:
Join Date: May 2003
Location: Shreveport LA
Age: 64
Posts: 5,103
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
http://buickpartsdirectory.com/QJet_Tuning_Paper.doc

There's some info on power piston adjustment at the bottom of this document.
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
Rochester QuadraJet 4Mv gbowne1 Engine 10 07-28-2006 05:19 PM
rochester quadrajet low77ride Engine 12 11-04-2003 09:27 AM
Rochester Quadrajet Carb ID? bildo95 Engine 3 03-18-2003 07:28 PM
Rochester quadrajet redlineps Engine 1 01-17-2003 11:00 PM
Rochester Quadrajet 57Chevyman Engine 4 11-25-2002 12:14 AM


All times are GMT -6. The time now is 08:18 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.