406 sbc knocking noise at idle - 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 03-21-2011, 07:39 PM
rotnrobbie's Avatar
in memory of roy taft
 
Last photo:
Join Date: Jan 2010
Location: antelope california
Age: 26
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
406 sbc knocking noise at idle

Hello I have a 7o nova with a 406 small block. A couple days ago I noticed this intermittant knocking noise. Its only when its idling once I give it some gas it goes away until I let off again and it slowly returns. Any ideas?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-21-2011, 08:04 PM
tnovot's Avatar
Registered User
 
Join Date: Oct 2008
Location: North Central Illinois
Age: 71
Posts: 137
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
You don't say what your oil pressure is at idle but SBC's typicaly do not need alot at idle.
Could be a rod bearing, crank damper, any belt driven accesory, piston slap if it occurs when cold but goes away when warm.
Is the noise coming from bottom end? Front of engine? from trans or converter area if A/T. You can use a hose or long handled screwdriver as a stethescope to help locate the noise. You will get more opinions and advice if you provide more info. Need to know more about symptoms, conditions, etc.
Terry
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-21-2011, 08:16 PM
Registered User
 
Last photo:
Join Date: Dec 2010
Location: williamston sc
Posts: 319
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The first time I had a bad cam it knocked at idle,wouldn't when reved or driving.At idle the knock would come and go.I had convinced myself that it must be a wrist pin but when I tore it down a lobe on the cam was wiped out.Strange thing though it ran pretty good.It sounded like tapping on a valve cover with a screw driver handle.A low pitch clunk.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-21-2011, 10:00 PM
rotnrobbie's Avatar
in memory of roy taft
 
Last photo:
Join Date: Jan 2010
Location: antelope california
Age: 26
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The oil pressure at idle when its worm is about 20 on my gauge thats how its always been im not seeing a drop or change in anything. I just swapped my carb from a qjet to a holley 750 double pumper about three weeks ago. I have a 700r4 trans runnin 4 10s in the rear. I drive it about 3 to 4 times a week just around town some freeway. The noise sounds like its coming from under the intake manifold or the carb. ive checked my valves and everything for noise but I cant pinpoint it. My starter went out right after I got the carb installed so I changed that. I drove it today after I checked my valves and rods and all that and when I get on the throttle real good for like 2 seconds the engine gets real loud (more so than it should) but than seems to quite down and everything is normal. Could I maybe have a torque convertor issue? Or my fly wheel? I really dont think its a rod cause than wouldnt it just make the noise all the time? it only in idle worm or cold it doesnt matter. Maybe something is loose im going to dig into it more tomorrow I was just looking for ideas. Thank you
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
Knocking Noise RenoValron Engine 5 09-28-2005 07:34 PM
Knocking noise RetroJoe Engine 15 08-17-2004 07:01 PM
Knocking noise, HELP! Please!! fireforsin Engine 4 01-04-2004 11:31 AM
knocking noise during idle and full throttle 89camaroman Engine 8 10-18-2003 09:01 PM
Knocking noise? MichaelB Transmission - Rearend 7 08-19-2003 07:03 AM


All times are GMT -6. The time now is 04:28 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.