Thread: Steam relief

Results 1 to 13 of 13

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. Collapse Details
    Steam relief
    #1
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    I got together with my old engine builder some time ago and he mentioned the tendency of Chevy big blocks to have steam pockets in the cooling circuits around #7 and #8 cylinders. On many of his race engines (IMSA Corvettes, Air Race Airplane, and offshore engines) he plumbed relief lines from the back of the intake manifold forward to the thermostat housing. I've been contemplating running pressure relief valves (2 per motor) into high pressure hoses and dumping the steam overboard or may back into the thermostat housing. One "off the shelf" solution is the bronze water heater safety relief valves. I would like you to critique this concept. Thanks.
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

  2. Collapse Details
     
    #2
    Registered Rookie's Avatar
    Join Date
    Nov 2008
    Location
    Grand Rapids, MI
    Posts
    109
    I believe this is a must do on all BBC after my exhaust valves collided with my pistons on 3 different occasions.
    When I switched out my heads from GM's to Merlin's I wiped out valves within 2-3 mins once on plane. (I also eliminated my water pump for a crossover)
    I would just dump the water and not run a pressure relief. You want flow for cooling. I have been running this way for 3yrs with no problem.
    I also run on Lake MI in 50*F water in the middle of October/November with no issues and can maintain 130*F water temps at idle and 160*F running.
    Here is my thread chronicling my ordeal.

    Another valve meets a piston - Boatfreaks
    Reply With Quote
     

  3. Collapse Details
     
    #3
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    Quote Originally Posted by Rookie View Post
    I believe this is a must do on all BBC after my exhaust valves collided with my pistons on 3 different occasions.
    When I switched out my heads from GM's to Merlin's I wiped out valves within 2-3 mins once on plane. (I also eliminated my water pump for a crossover)
    I would just dump the water and not run a pressure relief. You want flow for cooling. I have been running this way for 3yrs with no problem.
    I also run on Lake MI in 50*F water in the middle of October/November with no issues and can maintain 130*F water temps at idle and 160*F running.
    Here is my thread chronicling my ordeal.

    Another valve meets a piston - Boatfreaks
    Thanks Jason and more pix of your setup would be very appreciated, Jeff
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

  4. Collapse Details
     
    #4
    Registered Rookie's Avatar
    Join Date
    Nov 2008
    Location
    Grand Rapids, MI
    Posts
    109
    Not a problem next time I'm out to the shop I will get them.
    Basically I just drilled out the back corner of my intake like your builder suggests. Then I ran a 3/8"NPT brass barb to 3/8" hose to the water
    ports on my exhaust manifolds. You could just Tee into your water hoses that feed your exhaust manifolds from your thermostat housing.
    Reply With Quote
     

  5. Collapse Details
     
    #5
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    I get it in concept, I'm visual and a picture is worth, well you know........
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

  6. Collapse Details
     
    #6
    Founding Member / Super Moderator Ratickle's Avatar
    Join Date
    Oct 2008
    Location
    West Michigan
    Posts
    37,972
    Blog Entries
    45
    Was that problem only on the Gen IV ?
    Getting bad advice is unfortunate, taking bad advice is a Serious matter!!
    Reply With Quote
     

  7. Collapse Details
     
    #7
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    Not sure Paul, but my engine guy says that #7 and #8 are know steam generators and apparently some time the problem is wrong head gaskets (maybe a Mark IV/ Mark V issue). However, my guru Pat says that much of it is poor design and that his company did this "fix" as a matter of course. We will see.
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

  8. Collapse Details
     
    #8
    Founding Member / Super Moderator Ratickle's Avatar
    Join Date
    Oct 2008
    Location
    West Michigan
    Posts
    37,972
    Blog Entries
    45
    Somewhere in there was an issue with head gaskets blocking the passages in the front on one style block to the later style head, or something like that. If the gasket with the water passages open in the front was used the rear would overheat every time.
    Getting bad advice is unfortunate, taking bad advice is a Serious matter!!
    Reply With Quote
     

  9. Collapse Details
     
    #9
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    Indeed, there is an issue like that out there,
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

  10. Collapse Details
     
    #10
    Founding Member / Super Moderator Ratickle's Avatar
    Join Date
    Oct 2008
    Location
    West Michigan
    Posts
    37,972
    Blog Entries
    45
    I can find nothing on it being an issue in any other application.
    Getting bad advice is unfortunate, taking bad advice is a Serious matter!!
    Reply With Quote
     

  11. Collapse Details
     
    #11
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    One thought is that with crossovers, the flow isn't as good as can be. In any event the intake manifolds are over at a friends place that has a milling machine getting the rib milled down and then drilled and tapped for #6 AN fittings which will be plumbed back to the thermostat housings.
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

  12. Collapse Details
     
    #12
    Founding Member / Super Moderator Ratickle's Avatar
    Join Date
    Oct 2008
    Location
    West Michigan
    Posts
    37,972
    Blog Entries
    45
    Did your engine mention this at all? I think this was the main issue with bigblocks.

    Series-cooled block, parallel-cooling head gasket?

    Many parallel-cooling head gaskets have the big hole in the back blocked, greatly restricting coolant flow at the back of the head.

    If the block is a series-cooled unit, there's no coolant flow up to the head between the cylinders.

    End result is terrible coolant flow, overheating, and harsh language because NOTHING will help the overheating. It will not respond to different fans, different radiators, different timing or carb adjustments. No water pump on Earth, and no thermostat changes will help.

    Easy fix: Replace head gasket with series-flow unit, or remove heads, drill three holes in each block deck surface using the parallel-flow head gasket as a template. One hole in the block may exist, but need to be ground oblong to match the head gasket.
    Getting bad advice is unfortunate, taking bad advice is a Serious matter!!
    Reply With Quote
     

  13. Collapse Details
     
    #13
    Charter Member old377guy's Avatar
    Join Date
    Oct 2008
    Location
    Lake Oswego OR
    Posts
    3,740
    He was mentioning the BBC series/parallel block head problem. He also mentioned the asymmetrical design of BBC heads.Thanks for the extra info Paul, I'm going to pass it on to him. He's a pretty bright guy that has given talks (I think) at SAE conventions regarding the thermodynamics of IC engine cooling.
    People we meet in life are either a Blessing or a Lesson
    Reply With Quote
     

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •