There is so much written about "Sex & Squish" !!!  It is not funny? One is about mating and the other is about mating without making contacts ! Meaning to say, the piston not ramming into the head ! After a point it becomes ridiculous  ~ Seeing the pains one goes to achieve these static  0.30 thou or less between head to piston with the help of chewing gum. All in the hope of finding the impossible hidden some where between ? Reminds me of the old days ~ Puffing smoke through ports to see gas flowing  past valves & seats. In reality, it is all happening so fast, it is way beyond ' blowing smoke ' to understand the happenings! I remember using water to study flow & lift ~ Was this more meaningful than blowing smoke ? Next came passing air through the flowing water to see the bubble formations in an immersed head. There is no end to reinventing the wheel ! Have you ever noticed or realized how we breathe in different moods ? Or observed animals breathe during chase, heat, or at war ? It is a variation in moods that brings about breathing.  Hibernating is another 'extreme' form of breathing to stay alive !

Coming back to Squish ~ The mean squish velocity out of flat squish areas ( like most normal cylinder head layouts ) are dependent on the " piston to head gap " ~ The smaller the gap, the harsher the displacement out of the squish areas. This again is dependent on the density of the charge, aspect ratios of the combustion chamber in relation to the squish area based on the bore & stroke of an engine and finally the ' length ' of the con rod. These displacements out of squish areas and their gaps tend to form into some sort of a boundary layer of turbulence, accelerating across the combustion chamber dividing them into upper and lower half's  ~ In a dished piston layout, the upper and lower half's are more distinctly divided ! The chaos is dependent on the density of the trapped charge backed by the turbulence generated out of the gaps and finally the ignition timing setting off the reverse-action ~ All this invariably leads to erratic combustion patterns of some sort or the other ! That's why most ' White Coats ' are convinced ~ No  two combustion cycles are the same !

Today all 2 strokes from the best to the worst come with at least 0.60 thou or 1.5 mm " head to piston  gap "  and more on the bigger engines, for longevity ! This is after spending close to 60 years of Billion Dollar Research programs ! Honda 4-valve jobs run with 1.5 mm if not more ~ They  have a recess in the head in some cases to provide the needed gap when using  thinner steel gaskets.  With tighter tolerances, engine vibrations also go up ~ Yes there is tons of info about this critical gap. The Hot Rodders believe " The tighter the better " While F1 and Pro Rally guys run much more gap because everything starts to physically grow as revs build up, some of these guys peak-out at 20,000 rpm ! This is more or less the conclusions of ' mating ' in the Squish without making contacts ~ and yet producing big power !

  What grooves or channels do manage to achieve is, to reduce the " splat " between the squish areas due to leaks springing up through the mirroring surfaces as the piston pounds the head. Grooves relieve these build up pressures more gently sprouting directional displacements towards the main combustion area, generating collective turbulence in the tightening atmosphere. All this is happening while ignition has triggered the combustion process close to tdc. I have seen the groove light up much more of that stagnant 10+ % mixture ' shadowed ' close to tdc. Grooves, along with larger tolerances, open up combustion chambers and bring down engine vibrations too ~ The larger displacements due to grooving (or call it channeling) end up exposing a lot more surface area of the piston crown to collective combustion taking place close to tdc. This form of " collective combustion " leaves a more distinct footprint on the face of the exposed parts of the combustion chamber in comparison to compact, shrouded, tight combustion chambers that end up ' rocking ' pistons & rings. The effects of grooving are very similar to Laughing gas / N2O - aided combustion ! The Most notable effects of the Groove are the Cleaner Plugs and exhaust tail pipes. Lower heat build-ups in the cooling systems along with lower CO & UHC, indicate more of the heat energy is going into pushing the piston down the tube to produce real Torque than Noise out of the exhaust pipe !

  The interesting part of the 4 stroke engine is ~ It  needs to draw its energy from a spinning flywheel to go past 3 of its 4 strokes before the power stroke recharges the spinning fly wheel with a Bang to keep the engine ticking ! The first one is the suck up stroke to fill the cylinder  ~ the next one is the compression stroke, which requires much more energy to compress the sucked in mixture into the combustion chamber ~ finally the exhaust stroke is all about pushing the hot expanding gases out of the cylinder to scavenge the cylinder clean for the next cycle. If the gasses are still expanding on the exhaust stroke when the exhaust valve opens ~ much more energy will be drawn from the spinning flywheel to push these still expanding hot gasses past relatively smaller exhaust valves and pipes ! The ' Big Bang ' out of the power stroke needs to overcome all these parasitic loses & drags to restore enough and more energy into the spinning flywheel to sustain stable idling and even more to take up loads in any engine !

With near zero tolerances between head and piston  you will require a lot more energy to compress these end gasses along with the added vibrations of near contacts at TDC. This will multiply with higher compression ratios & charge densities. The effects start to multiply even further with Super Charging and Turbo Charging ! Force feeding is a trade-off on the suction stroke using lesser energy to fill the cylinder more appropriately. This type of force feeding will require bigger exhaust valves to scavenge the still hot expanding gases too ! The Conclusion? ~ It is a compromise within the 3 strokes to achieve the ' loudest bang ' on the power stroke !

Once the groovy effects come into play through the squish areas ~ Existing engines can be made to idle much slower (by at least 20 %). The Mystery about Grooving starts to clearly display slower idle speeds which can comfortably absorb the extra loadings of the Alternator & A/C without any shudder or hesitation or hick-ups! It is still amazing that the Grooved CO readings drop from 1.5 % to a range of 0.1 to 0.3 % with proportionate reductions of Unburnt Hydrocarbons in ppm !!! ( as recorded in Non Catalytic Converted systems ) These were the first amazing observations of grooving quenched combustion chambers with any form of squish ! The next is the Exhaust pipe temperatures along with water temperatures remaining extremely low while the engine continues to slowly idle with consistency ~  Sounding like a " hibernating " engine ! Some call it "Silent Power" !

One of my F1 fans told me, the fuels that propel F1 engines are ' The Bomb ' ! If you ran a F1 engine on regular gas it would fail to make 60 % of the power and reach 3/4 the revs, with difficulty ! He said everything is so special, only Mr. Burney E,  knows the ingredients along with Mobil, Shell, Elf and Petronas !  According to him ~ The fancy port layouts achieve tumble motion to create enough and more turbulence as the revs build up. The zero flywheel effects help build up the revs real fast. The F1 community are so bloody secretive about their internal layouts and their functions ~ You don't  get to see any pix or info about their engines any where on the net or other wise. Except the externals of aero dynamics  and the placements of fancy  Wings & Winglets !  i rag these guys ~ Telling them ~ A poor Bare Footed mechanic in a third-world country is showing the world how to build F1 technology into their existing engines ~ Using barbaric hand tools and the famous Eyeballing methods to scratch a groove in the face of the head to channel the energies in the right directions to awaken the ' Flame ' ! Very Similar to forcefully blowing air into a burning fire with a pipe !? 

These limits of  " opening up " combustion chamber can take us further comfortably into the next stage with the help of Grooves or Channels requiring no major or minor modifications to existing engines ~ Opening up a ' new feel ' in Drivability in any gear. The last bit being able to run SI engines ultra lean like CI engines without hick ups or leaping flames or overheating of any kind, displaying the added advantages of collective turbulence spreading through the combustion chamber while fuel is turning into fire !  

I also want to remind you ~ Compression alone in psi is not the end of the road. Volumetric Efficiency needs to build-up the compression as the revs build to sustain the extra loads generated out of " Speed & Drag ".  Passing these limits will require a compromise in psi along with tighter tolerances using regular gas to ensure you don't come close to encountering the famous ' Mr.Knock ' & ' Miss Ping ' as you step full-footed on the gas !

Lets hope the good times keep " Rock & Rolling " !!  I wonder how much longer ??? Soon we will have to spend twice more to buy Food ! Forget Beers & the rest ! And ~ Filling up " Tank Full's " of gas will be a thing of the past ! 

 Did you know ~ F1, 2400 cc V-8 engines produce over 100,000 BTU per minute (1,750 kW) of heat that needs to be dumped, into the atmosphere via radiators and the exhaust, which can reach temperatures over 1,000 degrees Celsius (1,800 to 2,000 degrees Fahrenheit). They consume around 650 litres (23 ft³) of air per second. Race fuel consumption are normally around '75 litres per 100 kilometres' !  Giving Approx 3.1 US mpg - 3.8 UK mpg. ( Ever thought about the emissions & CO2 spilling out  @ 20,000 rpm's ?)   Nonetheless,  Formula One engines are over 20% more efficient at turning fuel into power than even the most economical small car in the world !

I wonder how many of you know about fractional hp / cc model airplane and car engines revving past 40,000 rpms with no spark plugs or ignition systems but needing a sizable gap between the ' Piston & Head ' to prevent Knock, Ping or making contacts or Mating while explosive Fuel is turning into Fire with the help of Air !

More recently, these tiny engines have ' woken up ' after grooving their tiny little squish bands ! For more on button mods check out http://www.jonehrc.com/2007/01/21/maxx-crazy-fast-lrp-button-mod-the-how/ 

 Some times  " Seeing & Hearing "  ends up in believing  ...

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