Vacuum Leak - Can't Find It - Page 4 - CorvetteForum - Chevrolet Corvette Forum Discussion



C1 & C2 Corvettes
General C1 Corvette & C2 Corvette Discussion, Technical Info, Performance Upgrades, Project Builds, Restorations
Sponsored by:
Sponsored by:

Vacuum Leak - Can't Find It

Reply
 
 
 
Thread Tools Search this Thread
Old 02-16-2017, 12:58 PM   #61
rahaul
CF Senior Member
Thread Starter
 
rahaul's Avatar
 
Member Since: Apr 2008
Posts: 477
Thanked 2 Times in 2 Posts
Default

Quote:
Originally Posted by Westlotorn View Post
Has a basic compression test been done on this engine? It would tell you if the rings are still healthy so you can rule that out.
Yes, one of the first things I did. All from 180 to 200.
rahaul is offline   Reply With Quote
Old 02-16-2017, 09:48 PM   #62
Westlotorn
CF Senior Member
Support Corvetteforum!
 
Westlotorn's Avatar
 
Member Since: Feb 2008
Location: Folsom CA
Posts: 2,843
Thanked 96 Times in 93 Posts
Default

Rings are good look elsewhere for the leak.
Westlotorn is offline   Reply With Quote
Old 02-19-2017, 08:15 AM   #63
rahaul
CF Senior Member
Thread Starter
 
rahaul's Avatar
 
Member Since: Apr 2008
Posts: 477
Thanked 2 Times in 2 Posts
Default

Quote:
Originally Posted by Westlotorn View Post
Rings are good look elsewhere for the leak.
There are two things that come to mind that may or may not be related to the "must be a vacuum leak" diagnosis and was not a problem until recently:
1. the plugs are oil fouling like never before. There even is oil on the threads. I rarely see any oil smoke from exhaust.

2. The exhaust at idle is so rich it will burn your eyes big time. I first thought this a carb problem but after swapping out 3 other carbs (1 new and 2 new rebuilds) I have to deduct there is something else here.
rahaul is offline   Reply With Quote
Old 02-19-2017, 09:59 AM   #64
59BlueSilver
CF Senior Member
 
59BlueSilver's Avatar
 
Member Since: Apr 2013
Location: Arlington TX
Posts: 1,531
Thanked 28 Times in 27 Posts
Default

Quote:
Originally Posted by rahaul View Post
There are two things that come to mind that may or may not be related to the "must be a vacuum leak" diagnosis and was not a problem until recently:
1. the plugs are oil fouling like never before. There even is oil on the threads. I rarely see any oil smoke from exhaust.

2. The exhaust at idle is so rich it will burn your eyes big time. I first thought this a carb problem but after swapping out 3 other carbs (1 new and 2 new rebuilds) I have to deduct there is something else here.
In reference to item 2, not necessarily. I went thru the same with 4 carbs. It seems the carbs from the builders are all set up on the rich side and you have to lean them out.
59BlueSilver is offline   Reply With Quote
Old 02-19-2017, 02:41 PM   #65
Westlotorn
CF Senior Member
Support Corvetteforum!
 
Westlotorn's Avatar
 
Member Since: Feb 2008
Location: Folsom CA
Posts: 2,843
Thanked 96 Times in 93 Posts
Default

Based on your first removal of the intake and finding all the oil in the ports and a wet gasket I think you found your problem but it did not get fixed.
You might be able to run a camera wand down the carb and inspect those intake ports again to see if the intake ports are oiled up again.
If it was mine I would pull that intake, put a straight edge on it and really closely inspect the gasket. It will have a crush area showing where the intake was torqued and maybe where there was no torque due to warp or other issues. Make sure the gasket you use is designed to seal cast iron block with aluminum heads. Aluminum moves a lot more than cast iron and the gasket needs to be able to allow for this slip or movement.
Many guys have switched to thicker intake gaskets to solve minor manifold imperfections.
Might inspect that intake for cracks on the bottom/oil side.
Bad valve stem seals could certainly leak oil into the combustion chamber but would not affect your intake gasket seal or put any oil at the top of the intake runners.
Oil at the top of the runners is coming down and is not from stem seals.
Have you run this engine with the PVC disconnected? Any chance it is open and pulling air and oil into the intake, big intake vacuum leak and it pulls oil if bad.
Just random thoughts on your issue, hope we strike gold with one.
Westlotorn is offline   Reply With Quote
Go Back   CorvetteForum - Chevrolet Corvette Forum Discussion >
Reload this Page
  • Vacuum Leak - Can't Find It
  •  
     
    Reply

    Related Topics
    Thread Thread Starter Forum Replies Last Post
    ported vacuum for power brake booster? alexandervdr C1 & C2 Corvettes 13 05-24-2016 07:44 AM
    Vacuum Leak 79vetter C3 Tech/Performance 29 04-16-2016 10:57 PM
    When is it the carb? MacVette86 C3 Tech/Performance 26 03-31-2015 07:54 PM
    TriPower Engine idle issue zuendler C3 Tech/Performance 16 03-03-2015 01:37 PM
    Gurus Needed Jim78SA C3 General 13 07-11-2013 12:40 AM


    Thread Tools Search this Thread
    Search this Thread:

    Click for Advanced Search

    Posting Rules
    You may not post new threads
    You may not 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 Off
    Pingbacks are Off
    Refbacks are Off

    Forum Jump


    All times are GMT -4. The time now is 06:08 AM.


     
    • Ask a Question
      Get answers from community experts
    What's your question?
    Send