BBC valvetrain issues - 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 07-14-2008, 09:29 AM
Registered User
 
Join Date: Jul 2008
Location: central nj
Posts: 2
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
BBC valvetrain issues

I bought an unfinished project which included a Gen VI 454. It's a marine block, .30 over and has rectangle port heads. I don't know if the heads are original to the engine. It has a Crane flat tappet hydraulic cam with .533 lift on intake & exhaust. It runs strong but has broken 2 exhaust pushrods. When the first happened I thought the adjusting crimp nut came loose. ( It was converted to adjustable rockers). When the second one broke (different cylinder) I pulled everything off and saw that the rockers were contacting the studs at full lift. So I ordered a set of rockers from Summit with extra long slots for high lift cams. When they arrived I compared them to the rockers on the car and the slot is the same length!! I double checked the the part # in the catalog and it's correct. WHAT THE HECK IS GOING ON???
I measured my pushrods and they are standard length. Because of the mix parts could the standard pushrods be to long for this application?? Any thoughts would be appreciated.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-14-2008, 09:44 PM
Registered User
 
Join Date: Oct 2007
Location: rio de janeiro
Posts: 50
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If the heads were converted from positive stop to adjustable.it means drilling,taping and installation of new studs.Maybe the studs are misaligned and causing the interference... Or maybe there is a mix of MK Vl block with MK lV heads that use different lenght pushrods...
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-14-2008, 10:03 PM
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Kemah TX
Posts: 425
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by paulo1
If the heads were converted from positive stop to adjustable.it means drilling,taping and installation of new studs.Maybe the studs are misaligned and causing the interference... Or maybe there is a mix of MK Vl block with MK lV heads that use different lenght pushrods...
The rocker stud conversion is a bolt on the rocker studs are 3/8 on the bottom and 7/16 on the top. No drilling required. I am with Fbird grind the rocker to get the clearance you need I used to do it on SBC stuff when I was in high school when I could not afford anything else.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-15-2008, 06:04 AM
Hotrodders.com Moderator
 

Last journal entry: PICTURE TEST
Last photo:
Join Date: Jan 2004
Location: york pa
Age: 52
Posts: 2,795
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
valve train

I wouldn't grind on any thing until you figure out the problem..

Have you checked the pushrod geometry????

Keith
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
bbc what gears to run.? chevelle4542speed Engine 5 12-07-2006 06:47 PM
Lowering - Camber issues 49lincoln Suspension - Brakes - Steering 1 05-25-2006 01:24 AM
96 to 00 BBC Question Mustangsaly Engine 6 02-20-2006 08:03 PM
BBC Big Block Questions Mustangsaly Engine 6 01-21-2006 07:59 PM
454 bbc valvetrain wear. what is too much? MuscleBlock81 Engine 8 09-12-2004 01:50 PM


All times are GMT -6. The time now is 05:47 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.