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Dishes, Domes, Compression Heights and Chamber Volumes

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  • #1

    Dishes, Domes, Compression Heights and Chamber Volumes

    I'm trying to assemble some tabular data for the purpose of future assembly of mongrelized engines. Anyone care to help?

    So far, using data from this thread: http://www.60degreev6.com/index.php?...iewtopic&t=310
    I have assembled the following table:

    Code:
    Application     Dish/Dome     C/H
2.8 LO          0 cc's        1.578
2.8 HO          0 cc's        1.599
3.1             12 cc's
3.4             8 cc's
2.8 Gen2        21.2 cc's     1.608
3.1 Gen2        26.4 cc's
3100
3400
TDC
DOHC

Head     Chamber size
Gen1     
Gen2     28 cc's
Gen3     ~28 cc's
TDC
DOHC
    Misc: Gen2 stock head gasket: 0.060
    Gen1 stock head gasket: 0.040

    Please feel free to make corrections/additions as necessary.

    RacerX11, what's the source of the info you used in that thread?

    What were the C/R's of the iron head 3.1's and 3.4's? It doesn't make sense for the 3.4 to have more displacement and a smaller dish unless it had higher compression, which I don't really accept as reasonable yet.
    Current:
    \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
    \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
    \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

    Gone, mostly forgotten:
    \'90 Pontiac 6000 SE AWD: slow but invisible
    Tags: None
  • #2
    I dug up pretty much all of that data from catalogs and other published specs for both stock pistons, Silvolite, Slealed Power/FM, and Mahle stock replacements, and actually measuring some pieces I had.

    I put a spreadsheet together several years ago to calculate different part combinations and compression ratios. There are some assumptions that aren't 100% acurate, such as the dish volume being an exact cylinder (they are actually curved at the botom), and I didn't include the volume between the top ring and the piston top. Both of this can account for maybe a 0.1 point or so compression difference.

    I think at one point we had this posted on the main site, but it might have got lost in the transitions. Here is a copy of the spreadsheet. You can play around with rod length, piston compression height, dish volume, head gasket thickness, etc. Feel free to modify it to be more accurate

    Marty

    EDIT: I removed this spreadsheet. See later post for more recent version of file.
    '99 Z-28 - Weekend Driver
    '98 Dodge Neon - Winter Beater
    '84 X-11 - Time and Money Pit
    '88 Fiero Formula - Bone stock for now

    Quote of the week:
    Originally posted by Aaron
    This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

    Comment

    • #3
      Thanks. I don't have excel on this computer but I'll find somewhere to look at it.
      Current:
      \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
      \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
      \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

      Gone, mostly forgotten:
      \'90 Pontiac 6000 SE AWD: slow but invisible

      Comment

      • #4
        3400 compresion is 9.6-1
        3100 and 97-99 venture 3400 compression 9.5-1
        3.1 compression 8.8-1

        sorced from Shop Key (Snap on) computer manual

        Comment

        • #5
          gen 1 heads are about 48cc

          Comment

          • #6
            Re: Dishes, Domes, Compression Heights and Chamber Volumes

            Originally posted by Will'sFiero
            Code:
            Application     Dish/Dome     C/H
2.8 LO          0 cc's        1.578
2.8 HO          0 cc's        1.599
3.1             12 cc's         [b]1.450[/b]
3.4             8 cc's            [b]1.457[/b]
2.8 Gen2        21.2 cc's     1.608
3.1 Gen2        26.4 cc's
3100
3400
TDC             [b]4? cc's[/b]   [b]1.457[/b]
DOHC         [b]should be about the same as above[/b]

Head     Chamber size
Gen1     [b]52 cc's[/b]
Gen2     28 cc's
Gen3     ~28 cc's
TDC
DOHC
            Misc: Gen2 stock head gasket: 0.060
            Gen1 stock head gasket: 0.040
            I added some stuff there. hope it shows up.

            Comment

            • #7
              Re: Dishes, Domes, Compression Heights and Chamber Volumes

              double post

              What I added was supposed to be in html bold but it didnt' work.

              just look for ubb tags

              Comment

              • #8
                Re: Dishes, Domes, Compression Heights and Chamber Volumes

                Code:
                Application     Dish/Dome     C/H
2.8 LO          0 cc's        1.578
2.8 HO          0 cc's        1.599
3.1             12 cc's       1.450
3.4             8 cc's        1.457
2.8 Gen2        21.2 cc's     1.608
3.1 Gen2        26.4 cc's
3100
3400
TDC             4? cc's       1.457
DOHC            4? cc's       1.457

Head     Chamber size
Gen1     52 cc's
Gen2     28 cc's
Gen3     ~28 cc's
TDC
DOHC
                Misc: Gen2 stock head gasket: 0.060
                Gen1 stock head gasket: 0.040



                Ok, thanks. I tried HTML bold, but that doesn't seem to work with the code tag either.

                I'm still puzzled about the relationship of the Gen1 3.1 and Gen1 3.4. What are the compression ratios of each? Does Gen1 3.4 actually have significantly higher compression than the Gen1 3.1?
                Do you have TDC/DOHC chamber volumes?
                Current:
                \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
                \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
                \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

                Gone, mostly forgotten:
                \'90 Pontiac 6000 SE AWD: slow but invisible

                Comment

                • #9
                  According to my specs, Gen1 3.1 CR is 8.5, Gen1 3.4 CR is 9.6.

                  Marty
                  '99 Z-28 - Weekend Driver
                  '98 Dodge Neon - Winter Beater
                  '84 X-11 - Time and Money Pit
                  '88 Fiero Formula - Bone stock for now

                  Quote of the week:
                  Originally posted by Aaron
                  This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

                  Comment

                  • #10
                    I did the calcs and came up with 8.43 and 9.5 which is close enough to those numbers (which I presume are published specs) to satisfy me.

                    Interesting that they ran the iron heads at 9.6 and run the Gen3 heads at 9.6 as well... one would think that they'd run the Gen3 heads at 10.6 or even a little more...

                    But that would only happen if GM gave a shit about the V6/60, which they've proven over and over again they do not.
                    Current:
                    \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
                    \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
                    \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

                    Gone, mostly forgotten:
                    \'90 Pontiac 6000 SE AWD: slow but invisible

                    Comment

                    • #11
                      I found a newer version of my spreadsheet that has some more accurate numbers, plus a little cleaner appearance. Also, there is a summary page with specs on all of the engines.

                      Here is the summary:

                      Engine | Bore | Stroke | Gasket Thickness | Piston Compression Distance | Dish Diameter (in) | Dish Depth (in) | Comp Ratio
                      2.8 Iron LP | 89mm / 3.504" | 76mm / 2.99" | 0.040" | 1.578" | 0.000 | 0.000 | 8.5
                      2.8 Iron HO | 89mm / 3.504" | 76mm / 2.99" | 0.040" | 1.599" | 0.000 | 0.000 | 8.9
                      2.8 Gen2 | 89mm / 3.504" | 76mm / 2.99" | 0.060" | 1.608" | 2.470 | 0.270 | 8.8
                      3.1 Iron | 89mm / 3.504" | 84mm / 3.307" | 0.040" | 1.450" | 2.950 | 0.106 | 8.5
                      3.1 Gen2 | 89mm / 3.504" | 84mm / 3.307" | 0.060" | 1.450" | 2.880 | 0.247 | 8.9
                      3100 | 89mm / 3.504" | 84mm / 3.307" | 0.060" | 1.470" | 2.880 | 0.230 | 9.6
                      3.4 Iron | 92mm / 3.622" | 84mm / 3.307" | 0.040" | 1.457" | 2.750 | 0.080 | 9.6
                      3400 | 92mm / 3.622" | 84mm / 3.307" | 0.060" | 1.460" | 3.000 | 0.233 | 9.6
                      3.4 DOHC | 92mm / 3.622" | 84mm / 3.307" | ?? | 1.457" | 1.000* | 0.080* | ??
                      *Note: Dish info for 3.4 DOHC is estimated. Rough number based on 4 valve reliefs.

                      Iron Comb. Cham. Volume 2.96 cu.in. 48.5 cc
                      Aluminum Comb. Cham. Volume 1.61 cu.in. 26.4 cc
                      Deck Height 8.82" 224 mm
                      Connecting Rod Length 5.7" 144.78mm
                      2.8, 3.1 Gasket Bore ~3.69"
                      3.4, 3400 Gasket Bore ~3.75"


                      Marty
                      '99 Z-28 - Weekend Driver
                      '98 Dodge Neon - Winter Beater
                      '84 X-11 - Time and Money Pit
                      '88 Fiero Formula - Bone stock for now

                      Quote of the week:
                      Originally posted by Aaron
                      This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

                      Comment

                      • #12
                        Sweeet. Thanks. That fills in a lot of holes...

                        Got anything on TDC/DOHC chamber volume?
                        Current:
                        \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
                        \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
                        \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

                        Gone, mostly forgotten:
                        \'90 Pontiac 6000 SE AWD: slow but invisible

                        Comment

                        • #13
                          So the table looks like this now:

                          Code:
                          Application     Dish/Dome     C/H
2.8 LO          0 cc's        1.578
2.8 HO          0 cc's        1.599
3.1             12 cc's       1.450
3.4             8 cc's        1.457
2.8 Gen2        21.2 cc's     1.608
3.1 Gen2        26.4 cc's     1.450
3100            24.5 cc's     1.470
3400            27 cc's       1.460
TDC             4? cc's       1.457
DOHC            4? cc's       1.457

Head     Chamber size
Gen1     48.5 cc's
Gen2     26.4 cc's
Gen3     26.4 cc's
TDC
DOHC

Misc: Gen2 stock head gasket: 0.060
      Gen1 stock head gasket: 0.040
                          Current:
                          \'87 Fiero GT: 12.86@106 - too dam many valves; ran 12.94 @ 112 on new engine, then broke a CV joint
                          \'88 Fiero Formula: slow and attention getting; LZ8 followed by LLT power forthcoming
                          \'88 BMW 325iX: The penultimate driving machine awaiting a heart transplant

                          Gone, mostly forgotten:
                          \'90 Pontiac 6000 SE AWD: slow but invisible

                          Comment

                          • #14
                            Originally posted by Will'sFiero
                            Sweeet. Thanks. That fills in a lot of holes...

                            Got anything on TDC/DOHC chamber volume?
                            Nope, sorry. Haven't started playing around with the DOHC yet. Other than the pistons, that is.

                            Marty
                            '99 Z-28 - Weekend Driver
                            '98 Dodge Neon - Winter Beater
                            '84 X-11 - Time and Money Pit
                            '88 Fiero Formula - Bone stock for now

                            Quote of the week:
                            Originally posted by Aaron
                            This is why I don't build crappy headers. I'm not sure, I don't know too much about welding.

                            Comment

                            • #15
                              advertised cr of the gen 1 3.4 is 9.1 to 1

                              if its accually 9.6 then I need to get a bigger cam

                              and the c/h of the iron head 3.1 & 3.4 is backwards on the table...

                              the 3.1 is 1.48 and the 3.4 is 1.45( at least thats what the trw piston pages say)
                              1995 camaro 3.4 5-speed

                              Comment

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