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  • pistons hit new head

    I got a new head for my 196 in my '67 scout 800 and installed it. then found out the pistons hit the head. There is about a 1/8" difference in the circumference between the old head and the new head and that is where it hits. Should I carve the head out with a die grinder so the pistons clear, or should I look for another head?
    Keep in mind that I had to search long and hard to get this one as there are about a thousand different castings.
    Thanks
    Walker
    '67 scout 800
    '67 Chevy C-10

  • #2
    Not sure but it sounds like you have a 152 head?
    Wouldn't that be the same as a 304?
    And you need one off a 345 or 392...
    I think it works that way with the four cylinders just like the eights.
    [CENTER]1994 Buick RoadMaSSter Estate Wagon LT1/4L60E. White and Woodgrain Sleeper...PCM 16188051 With SS/V4P/Custom Tune! WOT 12.9 AFR!

    1990 Chevy Suburban Silverado 5.7L 2wd ECM 1227747 HiWay Lean Cruise 18.5 MPG and 12.5 to 1 AFR at WOT!

    1972 IH 1210 Isky Cammed Balenced 345 4 speed PCM 16197427 Project!

    [SIZE=3][B][URL="http://www.gearhead-efi.com/"]GearHead-EFI.com[/URL] EFI Conversions and Chip Tuners![/B][/SIZE]
    [B]May be all you need to know about EFI![/B]

    and I still help local JustIH members (for fun) free! :cool: [/CENTER]

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    • #3
      Might also be the difference between the dished piston head and the flat top piston head.
      I know the 2 345's I just tore down were like that and they had different combustion chambers.
      Bill USN-1

      COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
      HAMILTON FUEL INJECTION
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      • #4
        Well, I am not sure if I should call my pistons dishes or domes. They have a dome on the intake side that sticks up about 3/8" and a dish on the exhaust side that goes in about 1/2" so they are dishdome pistons. When I was trying to find a head I was amazed at how many different models there were. There were ones with smaller valves, smaller intake runners, smaller combustion chambers, or any combination of those. I just can't believe I got one that is identical in every way, only to find that small difference in the combustion chamber.
        I am supposed to go to the wrecking yard next week to look for some parts for my pick up. I noticed they have some IH stuff there too maybe I'll check those heads out.
        Walker
        '67 scout 800
        '67 Chevy C-10

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        • #5
          Do you have the original head for comparison?
          [CENTER]1994 Buick RoadMaSSter Estate Wagon LT1/4L60E. White and Woodgrain Sleeper...PCM 16188051 With SS/V4P/Custom Tune! WOT 12.9 AFR!

          1990 Chevy Suburban Silverado 5.7L 2wd ECM 1227747 HiWay Lean Cruise 18.5 MPG and 12.5 to 1 AFR at WOT!

          1972 IH 1210 Isky Cammed Balenced 345 4 speed PCM 16197427 Project!

          [SIZE=3][B][URL="http://www.gearhead-efi.com/"]GearHead-EFI.com[/URL] EFI Conversions and Chip Tuners![/B][/SIZE]
          [B]May be all you need to know about EFI![/B]

          and I still help local JustIH members (for fun) free! :cool: [/CENTER]

          Comment


          • #6
            Yes, I do have the original head. Unfortunately when I found the new head this was the one difference that slipped by me. I can put the head gasket on the old one and the holes on the head gasket are about 1/32" bigger than the head. On the new one the holes are about 3/16 bigger than the head.
            Walker
            '67 scout 800
            '67 Chevy C-10

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            • #7
              I hate when that happens!
              [CENTER]1994 Buick RoadMaSSter Estate Wagon LT1/4L60E. White and Woodgrain Sleeper...PCM 16188051 With SS/V4P/Custom Tune! WOT 12.9 AFR!

              1990 Chevy Suburban Silverado 5.7L 2wd ECM 1227747 HiWay Lean Cruise 18.5 MPG and 12.5 to 1 AFR at WOT!

              1972 IH 1210 Isky Cammed Balenced 345 4 speed PCM 16197427 Project!

              [SIZE=3][B][URL="http://www.gearhead-efi.com/"]GearHead-EFI.com[/URL] EFI Conversions and Chip Tuners![/B][/SIZE]
              [B]May be all you need to know about EFI![/B]

              and I still help local JustIH members (for fun) free! :cool: [/CENTER]

              Comment


              • #8
                Sounds like you got a flat-top head for your contour piston motor.

                You may have also snagged a head for a 345 or 304/152, not a 196/392.

                For a 196, you need rectangular intake ports, and the big valves, with the .414 exhaust valve stem.

                Of course, with a contour piston, you need a contour head. You could also swap out the pistons for the later flat-tops to match the head you seem to have gotten.

                You can put flat-top piston 304 heads on a flat-top 345, and flat-top 345 heads on a flat-top (other than the relief in the top of the piston) 392.

                Comment


                • #9
                  Originally posted by Travis
                  Can't 345 heads fit on the 196 for improved compression?
                  Some 345 heads, on some 196s, result in a compression increase.

                  Not sure you can run a contour 345 head on a contour 196 without the piston hitting the head, though.

                  A contour 345 head on a flat-top 196 will drop compression.

                  And, of course, if the 196 is IC, it doesn't matter, you're stuck with the IC head.

                  If you really want to up compression on a 196, the right way would be zero-deck the block, and/or offset grind the crank for a little more stroke and a little less decking to hit "0".. then cut some off the head to go a little farther.

                  John Comer built a 196 for Jerry Muncie a few years back.. the 196 was built to "run with 304s".. I still haven't heard if Jerry's finished putting it into the Scout he wanted it for.

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                  • #10
                    Not really sure what IC means when reffering to a 196 IC or IC head. Also the pistons I have are contoured pistons, they pop up above the block where the intake valve is and have a deep dish where the exhaust valve is.
                    The original head has retangular intake ports with big valves. The replacement head also has rectangular intake ports with big valves. The combustion chambers are alike in shape except for the slightly smaller circumfrence of the chambers. I'll have to measure the exhaust stems though.
                    It would make sense that I had a 345 head if the 345 has smaller piston bores and similar shaped pistons. That would account for it being alike in every manner but one.
                    Walker
                    '67 scout 800
                    '67 Chevy C-10

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                    • #11
                      Originally posted by walker
                      Not really sure what IC means when reffering to a 196 IC or IC head. Also the pistons I have are contoured pistons, they pop up above the block where the intake valve is and have a deep dish where the exhaust valve is.
                      Improved Cooling. A change in design around 1973 in the 392 and 196. The water pipe exits the water pump and goes back into the block, NOT into the head.

                      Have you CC'd the chambers on the new head vs. old head?

                      It still seems like you have an "E"mmissions head designed for the flat-top pistons.

                      You need a pre-73 head.

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                      • #12
                        Well, I finally figured out my head problem thanks to a web site with casting numbers that was on another post. It seems I have a contour head from a 345 v-8 and what I need is a contour head from a 396v-8. The 345 has a bore of 3 7/8 or so and the 396 has a bore of 4 1/8 so that accounts for the smaller combustion chamber. I have commencd with the die grinder to see it the 345 head can be turned into a 396 head. After I am done I'll cc the chambers and give her a try. I'll let you all know how it works out.
                        Walker
                        '67 scout 800
                        '67 Chevy C-10

                        Comment


                        • #13
                          Originally posted by walker
                          Well, I finally figured out my head problem thanks to a web site with casting numbers that was on another post. It seems I have a contour head from a 345 v-8 and what I need is a contour head from a 396v-8. The 345 has a bore of 3 7/8 or so and the 396 has a bore of 4 1/8 so that accounts for the smaller combustion chamber. I have commencd with the die grinder to see it the 345 head can be turned into a 396 head. After I am done I'll cc the chambers and give her a try. I'll let you all know how it works out.
                          Note that the 392/196 heads used bigger intake and exhaust valves than the 345 heads.

                          I don't know that it's a problem for you, just something to note.

                          That's the big difference, aside from the chamber volume and diameter.

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                          • #14
                            It does have the bigger intakes and exhaust valves. So far I have two cylinders enlarged and found out the pistons bump in the middle of the chamber too so I had to relieve that too. So far so good.
                            Walker
                            '67 scout 800
                            '67 Chevy C-10

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