the unknown noise - 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 04-16-2007, 02:18 PM
Registered User
 
Join Date: Apr 2007
Location: East Berlin, PA
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the unknown noise

my 400 small block make a strange when driving down the road when i go to accelerate. it's not a knock but more of a chain dragging noise it sounds like it is coming from under the valve cover. the noise only happens when driving not when it's in park. it has plenty of oil it just sounds like somethings loose. if anyone has any info let me know.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-16-2007, 02:27 PM
Bench racer
 
Last photo:
Join Date: Jun 2004
Location: Southern Indiana
Age: 43
Posts: 141
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Is this something that just started or has it always done this? Sounds like detonation, which is BAD!
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-16-2007, 02:27 PM
Registered User
 
Last photo:
Join Date: Jan 2006
Location: Louisiana
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
check your rocker arms to see if any are loose. if they are you may wanna look at a lifter to see if its whiped a loab off the cam. but I would just try to see if one is loose. Id try to re-adjust it if it is first. if it starts doin it again look to see if the stud is coming out of the head. It happens sometimes especially on performance engines with press-in studs.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-16-2007, 02:31 PM
Registered User
 
Join Date: Apr 2007
Location: East Berlin, PA
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by SlowGTA
Is this something that just started or has it always done this? Sounds like detonation, which is BAD!
it's been like that for a while.someone told me it was spark knock so i adusted the timing and that didn't seem to help.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-16-2007, 02:49 PM
Bench racer
 
Last photo:
Join Date: Jun 2004
Location: Southern Indiana
Age: 43
Posts: 141
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
IF it's detonation or "spark knock" it will destroy the engine!

What is your timming set at and what are the specifics of the car and engine. Compression, heads, cam, intake, transmission, weight, the more info the better.

Also what changes, if any, were made right before it started doing this (new carb, cam, ANYTHING)
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-16-2007, 07:46 PM
T-bucket23's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Engine basic condition - how to check Last photo:
Join Date: Aug 2005
Location: Massachusetts
Age: 57
Posts: 5,362
Wiki Edits: 26

Thanks: 9
Thanked 145 Times in 128 Posts
Heat Riser valve ??
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-17-2007, 04:50 PM
Registered User
 
Join Date: Apr 2007
Location: East Berlin, PA
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by SlowGTA
IF it's detonation or "spark knock" it will destroy the engine!

What is your timming set at and what are the specifics of the car and engine. Compression, heads, cam, intake, transmission, weight, the more info the better.

Also what changes, if any, were made right before it started doing this (new carb, cam, ANYTHING)
i don't know what the timing is set at. i turned it this morning and the noise whent away. i had a timing gun one time and i thought i knew how to use it but i guess i was wrong. the motor is a 1973 400 bored 0.60 over 4 bolt main, flat top pistons, edelbrock performer rpm intake, edelbrock carb 600cfm. lunati high performance cam. i don't know the specs of any of it because it was all in the car when i bought it. some days it runs good some days it run like crap. another question i have is when driving uphills it seems like the carb is bogging out what would be the cause of that? i haven't made any changes to the car other then changing spark plugs and stuff like that
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 04-18-2007, 08:34 AM
Registered User
 
Last photo:
Join Date: Jan 2006
Location: Louisiana
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
if its bogging and making a rocking and jaring sound and it sounds like a chain is ratteling under the hood you had better check the timing. if you have a timing light hook your positive and negative to the battery and your plug wire leed to the #1 plug wire and see what it is set on. I would say its too high so try backing it down to see if you can ever see the mark. also try to keep your Idle RPMs around 650/850 rpm. anymore and mechanical advance will kick in.You will have to adjust the idle on the carb to get it to where it needs to be each time you adjust it. probably even the A/F mixture screws.

Either that or the carb is way too lean, and needs to be jetted. but I would go with timing 1st I would say to get you running set it anywhere between 10-14 degrees at idle. after that you will just have to try different settings to see which does the best. you dont really want much more at idle because It may kick back and tear your starter to pieces.

let us know what your base timing is.
hope I was some help
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:
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
ford toploader noise mustang302 Transmission - Rearend 43 11-20-2006 02:24 AM
Help track down a weird noise curtis73 General Rodding Tech 10 05-02-2006 12:38 AM
Overefficient cooling system and popping noise. TVR383 Engine 8 11-09-2005 09:17 PM
Knocking noise, HELP! Please!! fireforsin Engine 4 01-04-2004 12:31 PM
valvetrain gurus: need help identifying mysterious valve noise blndweasel Engine 10 03-04-2003 08:59 PM


All times are GMT -6. The time now is 09:47 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.