Firing Order Question - Hot Rod Forum : Hotrodders Bulletin Board -- 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
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 10-15-2004, 12:04 PM
airman_turtle's Avatar
Last photo:
Join Date: Nov 2003
Location: Louisa, VA
Age: 33
Posts: 180
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Firing Order Question

I was having one of my random thoughts, and i wondered why vehicle firing orders are the way they are.

for example

GM has 1-8-4-3-6-5-7-2

1 2
3 4
5 6
7 8

that just bounces around the motor. It would seem more symetric and balanced if it was something like




why are they set up the way they are. I know there are cams out now that change the firing order so 5 & 7 dont fire in sequence.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 10-15-2004, 02:54 PM
docvette's Avatar
Registered User
Last wiki edit: Rebuild an alternator Last photo:
Join Date: Mar 2004
Location: Lafayette, california
Age: 65
Posts: 7,360
Wiki Edits: 12

Thanks: 0
Thanked 7 Times in 4 Posts
Crank throws

Doc here

If I understand your question properly, The reason is because the rotating assembly is balanced in the LEAST objectionable amount of vibration and wear by weight, and F.O. So that the firing pulses are offset by each other. For each action, there should be an equal and opposite to speak.

Heat is another factor to...

To point out an example , the 80's Buick had 2 flavors of 231 v6's, Even-fire and ran like a V6, and was smooth, the other developed a bit more punch but was a "Vibrator"...and a parts wearer...

I suppose in theory, you could set up the engine in ANY fire order you wanted, provided your rotating assembly was weighted accordingly, the cam followed suit,and the pulses were all balanced..but it would probably be costly...

Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


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

All times are GMT -6. The time now is 04:18 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.