basic timing question - 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> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-25-2012, 11:52 AM
Registered User
 
Last photo:
Join Date: Apr 2005
Location: ramona, calif.
Posts: 305
Wiki Edits: 0

Thanks: 2
Thanked 3 Times in 3 Posts
basic timing question

I have an 84 chevy blazer with a 350 motor. The data sticker under the hood is long gone. It is a federal emission packge. I can not remember if you plug the vaccuum line on that motor to set timing. Also has the timing marks that are ntches under the water pump with the large notch being tdc. Does anybody know how many degrees each notch represents. My old eyes cant quite make out the marks......Steve

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-25-2012, 12:33 PM
Registered User
 
Last photo:
Join Date: Jan 2012
Posts: 136
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
For initial timing the Vacuum advance line needs to be plugged.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-25-2012, 05:31 PM
Registered User
 
Join Date: Jun 2010
Location: TX
Posts: 1,259
Wiki Edits: 0

Thanks: 0
Thanked 110 Times in 101 Posts
Each notch is usually 2 degrees but don't go by those.

Set the initial timing advance where the engine starts and run best. That is usually about 16 to 20 degrees BTDC on a 1971 and later low compression engine with dished pistons. The 1970 and earlier high compression engines with flat top pistons can only tolerate about 12 degrees BTDC initial timing advance before the engine tries to compress the ignited mixture.

As was mentioned above, the initial timing should be set with the vacuum advance disconnected and the vacuum source plugged. I will add that the idle speed should be turned down as low as possible (600 RPM) while the intitial timing advance is set in order to prevent the centrifugal (mechanical) advance from working . All you are setting at the harmonic damper is the timing at the crank. After the timing at the harmonic damper is set, re-connect the vacuum hose to the distributor vacuum canister and turn up the idle to specification.

It is difficult to set the timing in this manner if the engine is equipped with a radical camshaft that causes the engine to have low vacuum. In that case, the engine will not idle low enough to prevent the mechanical advance from working and a different method must be used.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-25-2012, 09:18 PM
Registered User
 
Last photo:
Join Date: Apr 2005
Location: ramona, calif.
Posts: 305
Wiki Edits: 0

Thanks: 2
Thanked 3 Times in 3 Posts
thanks guys
Reply With Quote Quick reply to this message

Recent Hotrodding Basics 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:
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
help with basic question GMR Electrical 8 01-20-2010 09:22 PM
Basic Nitrous question renfroe453 Engine 7 10-13-2009 07:52 PM
Basic Q-jet question(s) N/A Hotrodding Basics 24 03-24-2009 01:36 AM
Basic A/C Question MI2600 General Rodding Tech 3 06-14-2005 07:42 AM
basic welding question montea Body - Exterior 8 02-04-2005 02:01 PM


All times are GMT -6. The time now is 11:02 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.