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M60B40 Heads on M62B44 Block

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    #61
    Piston to head clearance, also known as quench or squish. It's the distance between the quench pad on the piston and the quench pad on the cylinder head when the piston is at TDC.
    Much less than .035 and you risk piston to head contact at high RPM
    Much more than .050 and combustion quality, mixture tolerance and detonation resistance all suffer.

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      #62
      Bumping this again.

      Anyone think doing a little grinding on the combustion chamber to get rid of the lip around the bore is a good idea? I'm talking about the lip that's created from the bigger bore head gasket, you can see how the m62 gasket is 1.5mm away from the m60 lip, leaving a sharp 90* edge. I'm thinking it would reduce compression, remove a hot spot to help reduce knocking, and possibly even improve combustion?

      Seems like it would be easy, just throw the m62 head gasket on, trace around the bigger bore, and grind a smooth radius.

      Last edited by JGood; 02-27-2014, 01:33 AM.
      85 325e m60b44 6 speed / 89 535i
      e30 restoration and V8 swap
      24 Hours of Lemons e30 build

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        #63
        KEEP IT. That's quench/squish area. You want that. It will help you stay knock free at high compression.

        As the piston comes up to TDC, the mixture in the quench area is pushed violently out into the main volume of the chamber. This results in turbulence and mixture motion that benefits flame front propagation and helps mix up the end gases that are responsible for detonation.

        In your shoes, one thing I *WOULD* spend money on is a set of Cometic gaskets with the bore size as close to the block bore as possible (they're normally up to .030" over) and with a thickness that puts your piston to head clearance in the .035 to .040 range.

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          #64
          I bought stock m62 fiber gaskets. I'm not doing any machining so I didn't want MLS. I assume they'd match the bore perfectly, that's what they're made for. Cometic doesn't have anything for m6x's, I don't know what it would cost or what the turnaround time would be on custom gaskets, but I don't have any extra of either.

          I've read that sharp edges create hot spots, which create detonation. I wasn't sure if the increased quench area would do more then grinding a bit of that sharp edge down, in regards to detonation. I woulda thought even just doing a little filing to get rid of the point would be beneficial, without sacrificing most of that quench area.
          85 325e m60b44 6 speed / 89 535i
          e30 restoration and V8 swap
          24 Hours of Lemons e30 build

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            #65
            With the piston at TDC, that's not a "sharp edge"... that is, it's not an "exterior corner" in the chamber. It ends up being an interior corner. It only has high heat on one side, not both.

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              #66
              M60b44

              Hi All,
              I bought an M62tub44 engine and gearbox recently. Although it wasn't what I was looking for it was too good a buy not to. Anyway I'm looking to put it into my E30 but as the heads need rebuilding and it was a CANBUS engine I'm thinking of trying to find some M60B40 heads and converting it. Can this be done bearing in mind the different piston shape? Is it still the same as the M60B44 convertion documented here? I know its not the cheapest option, but feel its probably better than just an M60B40 and ditching the current engine.

              Any guidance would be very welcome!
              Cheers Chris.

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                #67
                Yes, the pistons are different, but probably work in your favor, as they have small valve reliefs. Compression should end up the same, about 11:1.
                85 325e m60b44 6 speed / 89 535i
                e30 restoration and V8 swap
                24 Hours of Lemons e30 build

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                  #68
                  Originally posted by JGood View Post
                  I bought stock m62 fiber gaskets. I assume they'd match the bore perfectly, that's what they're made for.
                  Also, due to production tolerances, the fire rings on fiber gaskets are typically noticeably larger than the bore. (e.g. .030-.040)

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                    #69
                    m60 heads on m62b46

                    Hi I'm looking to replace my e34s m60 with a new one but why not go bigger, curious if I could get a m62b46 out of an x5, if I found one, the non vanos m62/m60 heads would work on the Nanos block, as on the vanos only effects the wiring harness in the swap, and I'd have nice compression boost

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                      #70
                      Yes, you can do that.
                      You will need to remove the X5 oil pan and pump and use the pan & pump that are on the engine that's in your car now, so it won't be a straight R&R operation. However, it sounds like you want to use the heads that are on your current engine, so swapping the pan as well isn't a big deal.

                      If you use one from an X5, I can take the oil pan and oil pump off your hands.

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                        #71
                        Christmas Eve Miracle Thread Resurection!! Wait, probably the wrong holiday for that.. Oh well. :)

                        Since this seems to be the best thread on the whole internet (that I can find so far) in which someone might know actual combustion chamber volumes for M60b40 and M62b44 heads, I thought it might be valuable to ask here. Did anyone involved in this thread ever actually measure them?

                        I measured up some tonight, but I suspect I messed up something somewhere along the way because the measured difference was very small. I used ATF as my measuring fluid since that's what we used to use at the race kart shop for some reason, but it was really cold in my garage, so it yielded thick ATF. Also I ended up with a little puddle of ATF on top of my measuring plate by the time I was sure I had all of the chamber completely full, so I just tried to have it be consistent between the two heads.

                        When all was said and done, I came up with about 55cc for the M62 chamber (including filling up the conical recess in the 1/8" measuring plate down to the fill hole, and the slight overfill), versus 52.7cc for the M60 chamber under the same conditions...

                        I really doubt the accuracy of my measurements, so I think tomorrow I will re-do them with a mixture of isopropyl alcohol and food coloring.

                        If the difference between the combustion chamber volumes is really only 2.3cc, it changes the complexion of these Frankenmotors a little bit, doesn't it? Not a lot, but a little.

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                          #72

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                            #73
                            Thanks! I will re-check my measurements the next time I'm able. I will remake my chamber cover plate like that with the hole at one side. Should help improve accuracy, and then I will have direct M62 to M60 comparisons.

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                              #74
                              I used a Jegs economy CC kit:



                              I used Sta-Lube Engine Assembly moly grease to seal the plexi to the cylinder head and to the block when I made my measurements, mostly because that's what I had in my garage

                              The syringe in the jegs kit uses milliliter, which directly translates over to CC's. In order to measure the piston tops I needed to make the edges of the piston flush with the deck surface and then put on the piece of plexi, even then the surface tension of the water was fighting me a bit to actually fill the piston crown but eventually I got my measurement.

                              The M60B40 heads were "self leveling" when flipped over so there was no need to use the stands or hardware. I did need to rotate my engine so the pistons I was currently measuring were straight up.
                              Last edited by Mykk540i/6; 12-25-2017, 08:57 AM.

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