positive seals valve steam - 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 04-02-2008, 05:32 AM
Registered User
 
Last photo:
Join Date: Mar 2008
Location: Piedmont Italy
Posts: 204
Wiki Edits: 0

Thanks: 8
Thanked 3 Times in 3 Posts
positive seals valve steam

hi guys, silly question...
i'm rebuilding a acouple of old heads of a 350, (386 are the final number of the casting) should be of the '69, anyway, i've bought a kit with everything to rebuild valvetrain and there are included the "new" positive valve steam seals, i know old engine like mine has just the upper o-ring in the stear the keeper and lock but if possible i prefer to install also the postive one to avoid further oil burning.
i was at the machine shop and we tried to put the positive seal in the valve guide, that seems to be to big for that, surely valve guides are in different size like .50, .53, .562 etc...
i didn't measured valve guides diameter yet , so, question is: once i know the valve seals diameter how much should be the guides one?
this to avoid the seal popping out or damaging due an not appropriate coupling.
any help will be apprecciated
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-02-2008, 07:56 AM
richard stewart 3rd's Avatar
Registered User
 

Last journal entry: 351W rebuild
Last photo:
Join Date: Jan 2006
Location: tremont, pa.
Age: 69
Posts: 2,174
Wiki Edits: 0

Thanks: 5
Thanked 6 Times in 6 Posts
Hi,
I hope this is what your talking about or looking for.
Good luck,
Rich
(seals)
http://store.summitracing.com/egnsea...DS=1&N=700+115
(cutting tool)
http://store.summitracing.com/egnsea...DS=1&N=700+115
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-02-2008, 07:59 AM
Member
 
Last photo:
Join Date: Aug 2005
Location: Virginia
Posts: 875
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The guide will probably need to be spot faced to accept that type of seal.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-02-2008, 01:45 PM
Registered User
 
Last photo:
Join Date: Mar 2008
Location: Piedmont Italy
Posts: 204
Wiki Edits: 0

Thanks: 8
Thanked 3 Times in 3 Posts
thank you for the quick replies guys, valves guide diameter is .562 and the new positive seals are probably for the .52 or .50 models, they need to be machined or replaced by new appropiate guides so i'll go with the o-rings as the stock configuration, unless change them later on, are spare heads so i have time to do it.
i apprecciate your advices,
thanx
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-02-2008, 02:07 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,437
Wiki Edits: 0

Thanks: 3
Thanked 331 Times in 288 Posts
Quote:
Originally Posted by jeepers creepers
hi guys, silly question...
i'm rebuilding a acouple of old heads of a 350, (386 are the final number of the casting) should be of the '69, anyway, i've bought a kit with everything to rebuild valvetrain and there are included the "new" positive valve steam seals, i know old engine like mine has just the upper o-ring in the stear the keeper and lock but if possible i prefer to install also the postive one to avoid further oil burning.
i was at the machine shop and we tried to put the positive seal in the valve guide, that seems to be to big for that, surely valve guides are in different size like .50, .53, .562 etc...
i didn't measured valve guides diameter yet , so, question is: once i know the valve seals diameter how much should be the guides one?
this to avoid the seal popping out or damaging due an not appropriate coupling.
any help will be apprecciated
The top of the guide has to be machined to accept the seal, your machinist should know that. There's a tool that fits a drill motor or drill press for that purpose. It pilots in the guide.

Speaking of guide's, they need to be renewed and finish honed to establish the correct clearance with the valve stem. Then the seats are cut piloting off the position of the guide to insure that a line drawn across the center of the seat diameter is at 90 degrees to a line drawn thru the center of the length of the guide. This insures the valve will settle completely against the seat at every point of its circumference.

The guide can be refurbished by:

1) Boring it oversize and using new valves with oversize stems.

2) Boring it oversize, pressing in a bronze alloy or cast iron sleeve which is then finish honed to the proper diameter to provide clearance for standard valve stems. The bronze alloy inserts work best with positive seal, guide seals as this material doesn't require much lube. When working against a hard chromed valve stem, both will hold tolerance a very long time, while the small amount of lube present in the guide/stem interface helps keep the backside of the valve from forming carbon coke in it.

3) The least desirable refurbishment method, short of doing nothing, is knurling the guide. This is a process that looks similar to thread cutting, but it uses a blunt edge spiral tool to bulge the sides of the guide inward. The bulged guide is then finished with a reamer. This of course leaves what is essentially a screw thread pattern in the guide which is a path for oil to simply run through so this kind of guide refurb should also include positive stem seals. Also, the working surface of the guide has been reduced by the "threading" action of the knurling tool, so the guide doesn't wear well in service.

Bogie
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
305 engine valve stem seals pablo Engine 4 11-21-2007 10:30 AM
chevy 350 valve guide seals wiretwister Engine 3 10-17-2007 07:36 PM
Valve seals which to use? 72 Chevy Nova Engine 1 02-18-2007 11:01 AM
351 Cleavland valve seals ImaPseudonym Engine 6 10-28-2002 03:43 PM
valve stem seals HQ Pete Engine 2 04-02-2002 12:04 AM


All times are GMT -6. The time now is 07:09 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.