engine backfire! - 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 12-06-2011, 01:59 PM
Registered User
 
Join Date: Oct 2010
Location: united kingdom
Posts: 237
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
engine backfire!

Hi, I ran my car down the strip a couple of times this summer,my chevy small block is mounted up to a T5 manual box. What I did notice when I went through the gears I had a loud backfire through the exhaust when i stuck the clutch in to get another gear,is this a leaning out symptom!
the backfire didnt happen when I changed up the gears at 4000 rpm but it did at 5500rpm
Thanks in advance!

    Advertisement

Last edited by dave350v8; 12-06-2011 at 02:07 PM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-06-2011, 03:03 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 7,091
Wiki Edits: 0

Thanks: 4
Thanked 540 Times in 456 Posts
Quote:
Originally Posted by dave350v8
Hi, I ran my car down the strip a couple of times this summer,my chevy small block is mounted up to a T5 manual box. What I did notice when I went through the gears I had a loud backfire through the exhaust when i stuck the clutch in to get another gear,is this a leaning out symptom!
the backfire didnt happen when I changed up the gears at 4000 rpm but it did at 5500rpm
Thanks in advance!
It's throwing some unburnt fuel out the cylinders on the shift which ignites somewhere inside the exhaust system, not uncommon. The causes can be an over-rich from the carb, or a cylinder being interrupted during its burn by a sudden change in power take off from the crank or a change in RPMs, or it could be at 5500 you're hitting some valve float and an exhaust isn't getting onto or perhaps bouncing off its seat. This condition is usually the spring loosing control thus either allowing the lifter to loft as it goes over the top of the lobe and/or allows the valve bounce when it hits its seat.

Bogie
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-06-2011, 05:27 PM
Registered User
 
Join Date: Oct 2010
Location: united kingdom
Posts: 237
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
Thanks for the reply,thinking back I was running a mallory dualpoint,the points gap was not perfect so perhaps it was that! the condensor was the original one as well,I really need to try it now I have put a unilite on it now.
Dont think it was valve bounce,the cam has matching valve springs which have done 600 miles!
Thanks again for your input
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-06-2011, 10:57 PM
sqzbox's Avatar
My pipes are my music
 
Last photo:
Join Date: Sep 2009
Location: indiana
Age: 64
Posts: 2,938
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Maybe a rev limiter tach is in your future. Check under the tree on Christmas.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-07-2011, 01:00 AM
Registered User
 
Join Date: Oct 2010
Location: united kingdom
Posts: 237
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
Will do, Seems the summer is a long time away!
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
Engine Backfire byron74 Engine 2 02-09-2009 10:41 AM
engine backfire jum Engine 3 06-04-2006 05:29 PM
Engine Backfire rosebud48001 Engine 3 03-12-2006 09:10 AM
engine backfire rick6160 Engine 3 03-01-2006 10:44 PM
Engine backfire mychevystang Engine 12 05-02-2005 05:39 PM


All times are GMT -6. The time now is 04:51 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.