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Simple test for detecting head cracks

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  • Simple test for detecting head cracks

    So, you've just acquired a set of heads from the swap meet and you want to send them out. The physical condition of the heads is unknown though. It could have come from a running car, or it could have come from a field car, but you're not sure. Well here's a simple way to test your heads before sending them out. The portion of the head we're interested in is the water jackets. These circulate the water around the head and keep the heads cool. They can also harbor standing water, which over a number of freeze and thaw cycles through the years(meaning going through the four seasons of the year up here around Chicago), the water, if it's straight water in particular, may expand and contract, possibly damaging the head. The water jackets act like containers when the car is running, so it's more than possible that they can behave like bowls if inverted.

    So what an individual can do is, flip the head over, and put them over someplace where the water can run out. A pair of sawhorses in the driveway, or in my case, a pair of buckets, like so:



    Plug the water pump and temp sender holes so that the water will not run out. I used some overly large Kim Wipes we have here, but rags should also work. Basically something to keep the water from escaping.

    Fill the jackets up with water using a cup. Be careful which hole you fill, because some are oil holes, and some are water jackets. The large hole in the center over the exhaust port will suffice. The water will spread out and fill up the areas around the intake and exhaust passages. Fill the head until the water is flush with the top of the hole.





    This is the crucial step. After this, take a flashlight and look down all of the intake and exhaust ports for any seepage. If there is none, the head is still usable. If water starts streaming out one of the intake or exhaust passages, the head needs to be repaired or replaced.
    1964 Studebaker Commander R2 clone
    1963 Studebaker Daytona Hardtop with no engine or transmission
    1950 Studebaker 2R5 w/170 six cylinder and 3spd OD
    1955 Studebaker Commander Hardtop w/289 and 3spd OD and Megasquirt port fuel injection(among other things)

  • #2
    Thank you for that schooling lesson,I can use this in checking a bunch of heads when I tear down engines.
    Joseph R. Zeiger

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    • #3
      The only catch is frequently cracks will not show until under pressure and/or at operating temperature.

      Magnafluxing is the way to go, and not very expensive.

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      • #4
        That's definitely a better-than-none-at-all test, but I'd still pay an engine shop with a pressure test bench to put 15-20 PSI in them and tell me there aren't any small cracks before I started any extensive port or valve work.

        The pressure test is especially important if the heads have had hard exhaust seats installed. Some heads are thin between the two center exhaust seats. The cut for the seat can make the iron so thin it will seep under pressure. Also, if a head has been ported, the intake ports can be made so thin they will leak when the cooling system has 15 PSI and the intake port has 15" of vacuum.

        As always, your engine, your money, your decision.

        thnx, jack vines
        PackardV8

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        • #5
          Yeah, the caveat is this doesn't replace pressure testing a head in a shop. What this does is that it simply checks that there isn't any MAJOR cracks or breaks that in the head.
          1964 Studebaker Commander R2 clone
          1963 Studebaker Daytona Hardtop with no engine or transmission
          1950 Studebaker 2R5 w/170 six cylinder and 3spd OD
          1955 Studebaker Commander Hardtop w/289 and 3spd OD and Megasquirt port fuel injection(among other things)

          Comment

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