1969 MGC Roadster
4 grooves in each cylinder - see picture on the right
Head shaved .069 Chamber Volume 48cc
Compression Ratio 9.4:1
The grooves create more low end torque and improve fuel economy. As well as eliminate the need for high octane fuel. Another advantage is with more of a complete burn the carbon in the cylinder is greatly reduced and leaves you with much cleaner oil.
This is not something for sale but rather an informational page. You can do it yourself or have it done by a machine shop. I am willing to share my experience if you have questions.
Google Somender Singh or click the link
http://www.somender-singh.com/
Here is some information from Singh's Site
For more comparison pictures go herehttp://somender-singh.com/content/view/65/43/
With the modified heads, very little unburned fuel remains during the exhaust stroke. With less burning fuel to expand during the overlap period, the gasses flowing past the intake valve are reduced, resulting in improved idle quality even below 500rpm !
It has been conclusively proven that the Grooves are effective because of the additional benefits they allow: Higher compression ratio, less advance, lower idle speed and lower octane fuel. The difference in a tuned up Grooved engine is simple to understand. If the same tune, advance, and CR was used for an unGrooved engine, it probably wouldn't even start!
Eliminating Ping (also called 'knock' or detonation) allows for an advance setting that is much closer to Top Dead Center (TDC) to get more power from each stroke of the Piston. This quality of a Grooved engine also enables a higher compression ratio with the use of regular octane fuel, thus adding more improvements to the quality of combustion and preventing knock, or worse, 'pre-ignition'. It has been well known that higher compression makes a more efficient engine, that's why diesels work so well. The problem is, that increased compression (pressure) and high temperature also leads to a more volatile combustion chamber and you usually get 'knock', which means the air-fuel mixture in the cylinder is igniting before the spark plug fires.
This can be damaging to the engine if combustion occurs too far before the piston gets to TDC because the expanding gasses are trying to make the engine run backwards in that one cylinder while the rest of the engine is going 'forwards'. Bad news.
Since Grooved engines 'seem' to burn the fuel faster, you can wait to ignite the fuel-air mixture until the piston is near the top of its stroke. That leaves more energy pushing on the piston as the burning gasses expand and exposes the piston and cylinder walls to heat for a shorter time period. This combination of effects safely allows for a higher compression ratio to be used.
The Groove 'seems' to create more mixing (turbulence) in the burning gasses, making sure that more of the fuel/air mixture gets to be completely burned before the exhaust ports open and the engine 'exhales' the used fuel/air mixture. By the way, a -surprising- amount of fuel/air mixture is NOT burned in every single stroke of your typical engine. It is allowed to exit through the tailpipe and is sometimes called pollution. It definitely is wasted fuel that you paid for with good money .
The Groove reduces the amount of unburned fuel/air mixture leaving your engine by turning more of it into power.