Buick V6 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> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-20-2011, 10:12 AM
Registered User
 
Join Date: Aug 2011
Location: Springville Ca
Posts: 4
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Buick V6 backfire

I am working on a sand rail with a friend. The problem is that it wants to backfire at idle real loud just on the right side. The engine is a 78 231 V6 w/HEI. owner claims he did a compression check. I think it is a valve issue. What is your take on this problem.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-20-2011, 06:22 PM
Registered User
 
Last wiki edit: General Motors transmissions Last photo:
Join Date: Mar 2006
Location: near Yellowstone park
Posts: 4,203
Wiki Edits: 27

Thanks: 11
Thanked 233 Times in 219 Posts
odd or even fire ?

some of the GM v 6's have odd crank and cam, fire not 120* apart...The spark plug wires and distributor have to be in the right position per the shop manual or you can have 3 cylinders right on and 3 mistimed.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-20-2011, 09:23 PM
Registered User
 
Join Date: Aug 2011
Location: Springville Ca
Posts: 4
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Backfire

All my shop manuals don't even show HEI and this engine has #1 on the right side unlike anything I ever seen and Distributor in the front. Do you have a pic?
Thanks for your response.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-21-2011, 07:49 AM
Registered User
 
Last wiki edit: General Motors transmissions Last photo:
Join Date: Mar 2006
Location: near Yellowstone park
Posts: 4,203
Wiki Edits: 27

Thanks: 11
Thanked 233 Times in 219 Posts
info needed

I tried an on line search and didn't find anything. I have a T bucket project, donor was a V6 Vega that I had repaired a couple of times and was still owed for some of the work. after the 3rd crash the kid had it towed to my place and handed me the title. He only owed me $ 300 but had recently spent $ 2k on the engine-5 speed. bored, hotter cam, holly 4 bbl aluminum manifold. headers. When they first put it together, the kid looked at the rotor and stuck in the plug wires. It ran poorly. He took it to a shop and the mechanic Knew about correct dist position and wires, a simple fix. We arae still up north, won't go south this year until after christmas. I have a shelf in the south shop with about 6 ft of shop manuals. there should be one for that engine. I have gone to bigger public libraries that have an automotive reference section and coppied the pages I needed. The V6 engines were factory installed in Jeeps and a popular swap to early ones You might get some info from one of the jeep forums
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-21-2011, 10:46 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by 66coupe
I am working on a sand rail with a friend. The problem is that it wants to backfire at idle real loud just on the right side. The engine is a 78 231 V6 w/HEI. owner claims he did a compression check. I think it is a valve issue. What is your take on this problem.
Be sure the firing order is correct at the cap and at the plugs. The firing order was different between odd and even firing engines, IIRC (odd fire is 1-6-5-4-3-2, the even fire is 1-4-5-6-3-2). Be sure #1 is really on the side you think it's on. I'm not a Buick V6 expert, but I had thought it was on the driver side. Both positions (driver and passenger side) are shown on various websites.

Often if the problem is distributor (not firing order) related it's due to a "odd" or "even" fire distributor mismatch.

The first 231V6 Buick engine was an "odd fire" (firing at 90-150-90-etc.). Mid-'77- up engines- like yours- were changed to an "even fire" (firing every 120) configuration by splitting the rod journals to allow those rods to be offset from one another. This required a different crankshaft, camshaft, distributor and flexplate/flywheel. So be sure the engine matches the distributor, whether it's odd or even fire. I'd double check the block casting number and date code to be sure it's the year and type you think it is. .

HERE is an article explaining how to convert an even fire distributor to odd fire. Obviously the opposite can be done by using the right pick up coil assembly.

Other things to check:

Also see that there is no crossfiring between the plug wires going on. Check the distributor cap for any signs of carbon tracking or cracks.

If you have a net lash valve train and the block and/or heads were milled an/or the head gasket thickness is different than stock, this can cause problems w/the valves being too tight. Or if the valve train is adjustable, if they're too tight they can be the cause of the backfiring.

Last edited by cobalt327; 11-21-2011 at 11:13 AM.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 11-22-2011, 10:01 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
The firing order was different between odd and even firing engines, IIRC (odd fire is 1-6-5-4-3-2, the even fire is 1-4-5-6-3-2).
Be sure to check the firing order info above. I have reason to believe this is incorrect and should read:

(even fire is 1-6-5-4-3-2, the odd fire is 1-4-5-6-3-2). Again- be sure to verify what you have and to use the applicable firing order.

As for you thinking the passender front cylinder being #1, there are various diagrams that may be confusing, like:



The small diagram to the front left of the bigger diagram looks something like a firing order diagram, but it is how the coil packs are configured- not how the cylinders are located on the engine itself.

Last edited by cobalt327; 11-22-2011 at 10:25 AM.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 11-22-2011, 11:32 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
What I'm seeing is ALL the Buick V6 321/3.8L/3800 engines share the same 1-6-5-4-3-2 firing order, regardless if odd or even. It is amazing the amount of BS that is out there.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-22-2011, 05:08 PM
Registered User
 
Join Date: Dec 2011
Location: Marceline Missouri
Posts: 1
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
odd ver even firing order on buick 231

The Buick 231 odd-fire has a firing order 1-6-5-4-3-2. As the crankshaft is rotated through the 720 required for all cylinders to fire, the following events occur on 30 boundaries:
Angle 0 90 180 270 360 450 540 630
Odd firing 1 6 5 4 3 2
Even firing 1 4 5 6 3 2

More modern 90 V6 engines avoid this problem by using split crank pins, with adjacent crank pins offset by 15 in opposite directions to achieve an even 120 ignition pattern. Such a 'split' crank pin is weaker than a straight one, but modern metallurgical techniques can produce a crankshaft that is adequately strong.

In 1977, Buick introduced the new "split-pin crankshaft" in the 231. Using a crank pin that is 'split' and offset by 30 of rotation resulted in smooth, even firing every 120.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-22-2011, 06:55 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by wade braaten
odd ver even firing order on buick 231
With due respect, posting an excerpt from a Wikipedia article- errors and all- is not really too helpful here.
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
1958 buick onto 1993 buick frame/floor flatlandlowrider General Rodding Tech 5 03-27-2011 07:17 PM
Backfire !!!!! roundman101 Engine 11 10-13-2006 11:56 AM
backfire!!!! Old School Nut Hotrodding Basics 2 08-23-2004 10:23 PM
Buick Century or Buick Skylark 2 7skylark6 Engine 4 12-26-2003 10:05 PM
backfire mikeh Engine 1 12-10-2002 02:37 AM


All times are GMT -6. The time now is 03:30 AM.


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.