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Thread: AFR... additional head cooling

  1. #1

    AFR... additional head cooling

    Need some input from those that know

    SBC... AFR 220... #1103 heads. Am running -10 braided lines from the 4 corners of intake/injectors to thermostat crossover area. So far so good.

    I emailed AFR and inquired about additional lines, either removing or supplying coolant to the area between siamesed exhaust ports. On my old Brodix heads, I had 1 line from between the intake mani center bolts on each side, and 1 lower on each side of heads, between exhaust port area.

    Has anyone plumbed their 220 heads with these types of lines? Perhaps a link or email addy to someone who has. Diagrams??? Help !

    We have tons of knowledge from porters, and Tony usually chimes in when AFR pops up. If anyone would know, or have info on passage locations or thickness it would be these folks. I'm trying not to use the provided holes for temp senders/sensors, as I would only be able to utilize only one.... as the other is for temp gauge.

    By the way Tony, job well done from a Joisey Guy 8)

  2. #2
    Senior Member DYNO OPERATOR
    Join Date
    Nov 2006
    You know ,I wonder if you could pass to much water past the heads like NOT running a thermostat???? DR...

  3. #3
    In my application with a 23* SBC I have two main problems.

    1. Aftermarket aluminum heads have thicker decks, larger ports and valves, and more material around the rocker arm stud areas.

    This equates to "smaller" water jackets/passages if you will and less water in said head(s). After all, there's only so much external area a 23* SBC head can have.

    2. SBC engines have this "flaw" of the siamesed exhaust ports in the center of the heads. Kind of like double trouble as far as heat being absorbed from this area.

    Hot spots are common in this area of the head(s)... and the pressures generated by the steam from the coolant boiling are sometimes so high, that the system can't displace/remove the steam/air pockets.

    Now when the thermostat opens coolant flows into the rad to be cooled. Most of the water released comes from the front portion of the heads. That's why I run additional corner lines... to get the hot, almost boiling coolant up front faster to be cooled. Same thing goes for the center exhaust port areas. After all, the thermostat won't close until it senses a cooler temp than its rating. So I use a line at the top center of heads to remove the hot coolant... but the plus side is i'm also forcing cooler fluid INTO the side of the heads, between the exhaust ports to remove/displace hot spot/boiling coolant. All of this flows to the thermostat area.

    Now don't get me wrong, i'm not an engineer or some sort of fluid dynamics guy, but all of this makes sense to me, and has seemed to work quite well.

    VERY open to other ideas/thoughts on this, as well as an answer to my original question(s) about where, if any I can add the other lines in heads.

    Thanks a bunch guys

  4. #4
    Racefab57..... IMHO it's not the idea of passing to much water thru the engine/heads. Just having water flowing thru something doesn't necessarily mean it absorbing lots of heat.

    Air, water, even your hands can't absorb anything very well unless it's touching it. Only the outside edges of coolant are in contact with the hot passage walls. The center of the column of water are still cool so we use pressure to force the liquid thru the system. This causes it to tumble/swirl so the inner cooler part can contact the passage walls also. Just think of intake ports. They have this boundry layer that's touching the walls... the rest isn't.

    Same goes for inside your radiator. It must tumble/swirl around so ALL of the coolant has time to touch the fins & get rid of its heat, otherwise it comes out still warm/hot.

  5. #5
    Junior Member SHOW GUEST
    Join Date
    Aug 2003
    I have noticed on SBC engines similar to mine the exact modification you are refering to. I have a set of AFR227's that I added additional coolant fittings to in the area between the center two exhaust ports just above the head bolt flange with -8 supplied directly from the electric water pump body proir to it's engine bolt flange. I personally would not attempt this mod on the head without being able to inspect the water passage from the deck mating surface to determine the least intrusive spot to drill without comprimising it's integrity.
    Cause: provide coolant directly to this HOT spot that has not been preheated from passing through the cylinder wall jackets.
    Effect: Lower temperature coolant is able to absorb additional heat taking it away from the HOT spot.

    This was applied to a 13.75 to 1 compression motor that see's ALOT of street driving with NO overheating problems and seems to stabilize coolant temp's between cyl's. This was evident by the absence of the dark spot usually found on the head gasket between the center cyl's. Hope this helps.

  6. #6
    Pro642... thanks for the reply and input. I'm sure we will hear from others that are away at PRI, and return on Monday. Maybe Tony will chime in.

    Your heads "might" be a bit more easy to do this mod to, due to the spreadport setup. I'm running std. ports on mine. The engines in mock-up mode now, but still am beating the bushes for more input from other like minded folks.

    Glad another looks at head gaskets for more than holes/blown out spots. Lots of info on them..... and those stabilized cylinder temps do wonders for tuning :>) !!

    Even had another engine that utilized cooling lines thru the core plugs on sides of block. Helped some, but not enough to justify the expense/cost factor. Then there's the block filler problem on some builds. The majority of heat is in the heads, thus our way of removing it can't do anything but help. Build more HP, build more BTU's to remove.

    -8 is quite a bit of line to fit in there :>) i'm looking for about a -6 on mine, top and bottom.

    Thanks again for your thoughts.................

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