Changing Valve Stem Seals SBC - 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 12-10-2009, 08:17 AM
Sinister's Avatar
Registered User
 
Last photo:
Join Date: Aug 2007
Location: Los Angeles, CA.
Posts: 221
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Changing Valve Stem Seals SBC

I need to change out my valve stem seals on a 350 at some point. I have the spark plug adapter to hook up to my air compressor. What PSI should I use to hold the valves up with out turning the motor?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-10-2009, 08:43 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,098
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
why do you need to change your seals? and just run it at full pressure. probably around 100-120 psi.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-10-2009, 08:54 AM
Sinister's Avatar
Registered User
 
Last photo:
Join Date: Aug 2007
Location: Los Angeles, CA.
Posts: 221
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sometimes I get a little blue smoke at startup. Vacuum indicates that my valve guides are good. Motor is of unknown mileage, but good compression and oil pressure.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-10-2009, 09:00 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,098
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
vacuum indicates your guides are good?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-10-2009, 09:04 AM
Sinister's Avatar
Registered User
 
Last photo:
Join Date: Aug 2007
Location: Los Angeles, CA.
Posts: 221
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Yes, vacuum is steady. Excessive vibration that steadies as RPM increases would indicate worn guides.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-10-2009, 09:09 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,098
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
I've seen plenty of cases of worn guides with steady vaccuum. I've also seen plenty of cases of shaky vacuum with excellent guides.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-10-2009, 09:13 AM
Sinister's Avatar
Registered User
 
Last photo:
Join Date: Aug 2007
Location: Los Angeles, CA.
Posts: 221
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Hmmm, something to think about.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-10-2009, 09:16 AM
engineczar's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Sep 2002
Location: In Flowbench nirvana
Age: 52
Posts: 1,655
Wiki Edits: 0

Thanks: 5
Thanked 49 Times in 45 Posts
I always rotate the motor to TDC on the cylinder I'm working on. I wouldn't run any more than about 10-20psi or just enough to hold the valve up. This way if something happens like a sudden loss of pressure you won't drop the valve out of the guide. Running full line pressure can be enough to rotate the engine but isn't enough to allow you to break loose the locks from the retainers if they've been together awhile.
__________________
BSE Racing Engines
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-10-2009, 09:22 AM
poncho62's Avatar
Out of the Loop Moderator
 
Last wiki edit: Streetbeasts links
Last journal entry: at car show
Last photo:
Join Date: Oct 2003
Location: Hanover, Ontario, Canada
Age: 62
Posts: 16,899
Wiki Edits: 5

Thanks: 20
Thanked 261 Times in 213 Posts
Just a note for people without compressors, or don't trust them......Take some nylon rope and shove it in the spark plug hole (leave a bit out)....turn so piston pushes it up.......change your seals.....lower piston, pull rope out.
__________________
Ontario Rodders

Budget RVs
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-10-2009, 09:43 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,098
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
Quote:
Originally Posted by poncho62
Just a note for people without compressors, or don't trust them......Take some nylon rope and shove it in the spark plug hole (leave a bit out)....turn so piston pushes it up.......change your seals.....lower piston, pull rope out.

the ol' rope a dope trick. much more reliable, and not that difficult.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 12-10-2009, 10:41 AM
tnsmith10's Avatar
when will it rain???
 
Last photo:
Join Date: Jul 2003
Location: where its very dry and dusty
Age: 43
Posts: 1,297
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by ap72
the ol' rope a dope trick. much more reliable, and not that difficult.
i tried that with poor results. i ended up having to unbolt my headers and compress the cylinders. i also used full pressure, if i hadnt, due to the keepers being "locked" on, if i had used any less, i wouldve lost a valve. as it was, even with full pressure, some of the keepers didnt want to let go and took some effort to release.
i believe the reason it ( the rope trick) didnt work for me is because of the heads im running. the chambers arent open to the whole cylinder and when i tried to bring the piston up, the rope would get pushed up to the head before it could make contact with the valves.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 12-10-2009, 10:46 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,098
Wiki Edits: 0

Thanks: 17
Thanked 335 Times in 315 Posts
Quote:
Originally Posted by tnsmith10
i tried that with poor results. i ended up having to unbolt my headers and compress the cylinders. i also used full pressure, if i hadnt, due to the keepers being "locked" on, if i had used any less, i wouldve lost a valve. as it was, even with full pressure, some of the keepers didnt want to let go and took some effort to release.
i believe the reason it ( the rope trick) didnt work for me is because of the heads im running. the chambers arent open to the whole cylinder and when i tried to bring the piston up, the rope would get pushed up to the head before it could make contact with the valves.

Did you remove the rockers before you tried turning it over?
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 12-10-2009, 10:59 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 tnsmith10
i also used full pressure, if i hadnt, due to the keepers being "locked" on, if i had used any less, i wouldve lost a valve. as it was, even with full pressure, some of the keepers didnt want to let go and took some effort to release.
For the next guy wanting to use the compressor method (the way I do it)- put a large 1/2" drive socket-open end down- over the retainer and with the cylinder exactly at TDC and pressurized, whack the socket w/a large rubber mallet. This will at least separate the retainer from the locks, and if done 'right', will often eject one of the lock halves in the process. It will be caught inside the socket.

Occasionally, if not on TDC, the engine will rotate from the compressor's pressure. Keep hands and tools out of the way of the belts and fan, and for heaven's sake- turn the key to off (better yet, remove it and put the key in your pocket so a 'helper' listening to the radio or something doesn't turn the key to RUN. You wouldn't want to start the thing up by the compressor turning the engine over).

Instead of bumping the engine over w/the key (the easiest way to have the key left ON, BTW), use a breaker bar and socket/extension on the crank bolt to move from cylinder to cylinder.
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
Valve stem seals dirtinla Engine 1 11-28-2008 10:20 PM
valve stem oil seals marc737 Engine 1 08-03-2008 04:13 PM
Valve stem seals atlantis Engine 3 03-26-2006 04:31 PM
GM fast burn heads batman09 Engine 1 10-26-2004 09:32 AM
Valve lash changing, sbc! al37ford Engine 12 09-21-2004 10:16 AM


All times are GMT -6. The time now is 08:46 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.