Back to 400sbc balancing! - 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 06-11-2004, 01:37 PM
Member
 
Last photo:
Join Date: Jun 2004
Location: parksville BC
Age: 71
Posts: 187
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Back to 400sbc balancing!

My sbc 400 external balanced has a vibration despite using the correct flexplate with the big counterweight & a brand new Summit external balance dampner. It also had a new Summit higher stall converter (1 up from stock) . I hurried getting it in so didn't do the usual tear down & pro balance. Can the flexplate be on backwards or out of rotation? Right now the weight faces the engine side not the trans side. Could the Summit converter be O.O. balance?? Coulsd someone have put a 350 internal balance crank in the 400 B4? Its in a '37 ford & no room to pull the trans back so I have to take half the front of the car off to get it out again so any thoughts B4 this would be appreciated!!

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-11-2004, 03:24 PM
Ghetto Jet's Avatar
current hot rod: CTS-V
 

Last journal entry: Lets Get Started With the Improvements
Last photo:
Join Date: Nov 2003
Location: Pennsylvania
Age: 28
Posts: 1,728
Wiki Edits: 0

Thanks: 10
Thanked 5 Times in 5 Posts
I've heard bad things about the summit dampners.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-11-2004, 04:56 PM
Member
 
Last photo:
Join Date: Jun 2004
Location: parksville BC
Age: 71
Posts: 187
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Oh also, I checked the relationship between the front balancer counterweights and the one on the flexplate. If the harmonic weights are at 2:00 the one on the flex is at 8:00 so they are 180 degrees part which should be ok?? Also, the vibration is exactly the same before and after the new balancer so likely not it!
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-12-2004, 07:44 AM
Member
 

Last journal entry: JB's 37 Pickup
Last photo:
Join Date: Oct 2002
Location: Smoky Mountains
Age: 76
Posts: 2,358
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
37, I feel your pain since I have been playing with a 36 coupe for 44 years and a 36 pu for 30 years. I finally broke down and rebuilt the x member to allow me to pull tranny without pulling the motor and can now pull motor with only removing 1/3 of the front end. My thoughts are that you may have a 385, not a 400. The 385 is a 400 block with 350 crank, which is internally balanced. Since you had an out of balance condition when you changed the harmonic balancer and flexplate, I assume you bought the car/motor with this problem. Additionally, previous builder could have converted to a internally balanced setup. And last thought, I have only ran into one torque converter that was out of balance so even that is a very remote possibility. If it were me, I would do some serious sleuth work trying to find the history on the motor before turning one wrench!!

Trees
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-12-2004, 12:20 PM
MI2600's Avatar
Member# 3287
 

Last journal entry: Vortec Heads
Last photo:
Join Date: Jul 2002
Location: N. Muskegon, MI
Posts: 2,632
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
When you said you didn't do the "normal pro balance" did you mean you didn't have the internals balanced? If so, if you changed any of the internals you probably nixed the balancing.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-12-2004, 12:59 PM
Member
 
Last photo:
Join Date: Jun 2004
Location: parksville BC
Age: 71
Posts: 187
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
No, I didn't have it balanced & didn't even pull the pan as I heard it running B4 I bought it & it was smoke free & solid. It was in a Blazer which had been crashed though so couldn't drive it & didn't notice the vibration. All I did was drop the front of the pan a bit so I could install a Summit cam, chain & gears. & a built th350 trans & Summit converter out back. No history available so I guess I'll have to pull it anyhow though sure would like to wait until the summers over. Also, can a converter be balanced properly after it has been running in a car?? I ask as I know its near impossible to comletely drain out the fluid so a static balance would seem impossible!.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-12-2004, 03:42 PM
MI2600's Avatar
Member# 3287
 

Last journal entry: Vortec Heads
Last photo:
Join Date: Jul 2002
Location: N. Muskegon, MI
Posts: 2,632
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sounds like you've got the flexplate on correctly (weight toward the block) and if I read correctly the vibration occurs with two different balancers.
Could the crank have been bent in the Blazer's accident?

I had a vibration in my 406 when I was using one of those balancer plates with a 350 flywheel. After I put a 400 flywheel on it, it stopped.
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



All times are GMT -6. The time now is 10:30 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.