[jim_howard_pdx]

Wads56 is out there thinking.

Love ya man....

That is what this post was intended to do.

YES AND NO WADS56.

I should have said that a factory torque engine builds torque in a certain and silly way. Not what a racer like you or I would do to make efficient torque.

For a factory engine built for trucks and off road or marine use, the factory will reduce the compression ratio due to the load it expects the engine to run against during its life cycle. So they reduce the compression by enlarging the cc of the wedge, and by adding dishes to the pistons. This is the cheapest way for them to lower the static compression ration.

However, this just eliminates the quench all together. Still the engines build great torque. Why? Because the factory correctly made the wedge larger allowing a large dense mixture to ignite properly with reduced compression ratio.

Did you know ignition events are always EASIER as you increase compression? So as you decrease compression you need more fuel in that wedge just to get it to burn at all.

Less quench means the initial flame propogation will be faster and more downward thrust will be produced from the rapidly burning mixture. If you look at the combustion at say 10 degrees after top dead center, the combustion event has collapsed due to the lack of quench. So alot of fuel remains unburned or partially burnt. That is why most street engines require smog control systems. On a properly built street engine, you could control smog by just running a CAT alone.

Now here is another zinger for you all. As RPM increases in an engine the volume of intake charge is reduced in the cylinder. That is why torque engines fall off in power so quickly. They are efficient at low rpms where the vacume pulls sufficient volumes of air and fuel for the combustion. But as RPM goes up, the short duration of the valve events works against the vacumes ability to pull the intake mixture into the cylinder. In order to regain the power in higher rpms we need more valve event, and more overlap. Overlap will be another issue all together.

YES YOU ARE RIGHT, it is still important to have tight quench at the edges of the piston or that fuel will not burn.

Just as an aside, FORD did build one engine that had great low end torque and really good horsepower. This was the 351 Cleveland 2 barrel. It made 275 horsepower, got 18 mpg and pulled a 3250 lb car to 60 mph in only 7.5 seconds.

The head and the piston top look very much like a Chrysler Hemi head. The flame travel is extremely fast and strong rather than slow and complete so it never built the same horsepower as a 4V head.

Just for grins, I can tell you we ran many a 2V engine at 400 hp without any detonation problems even with the whacky open chambers.

Most of the pinging engines I come across are of the wedge combustion chamber variety. They have little to no swirl, have low compression by big wedges and piston dishing. Their quench is NON EXISTANT. THIS IS WHAT YOU POINTED OUT.

But this is what the factory does to save money. Yes it is back a s s w a r d. That is why we need to correct their mistakes when we put together a performance piece.

Now I hope others out there correctly think this through as WADS56 has done. Wad, you know your stuff.

You and I can build a high torque engine with small quench. Absolutely. All my tow vehicle engines run tight quench to eliminate detonation. JUST AS YOU POINTED OUT.

Man I love how many of you really know your stuff out there. I am glad no one is letting me get away easy. You are all going to learn some great things over the coming weeks.

NOW AS FOR THE COMMON GUY NOT GETTING MUCH OUT OF THIS... Humph...... It costs about 75 bucks to have a shop angle mill the heads. Another 75 bucks for the shop to correct your intake's angle. It costs 50 bucks to have them enlarge the intake bolt holes and square the head bolt bosses. So for 200 bucks you can now build a 10-11 to 1 ratio engine, pick up 30-35 horsepower, and have a chance at trophy. $200.00 bucks. This is half the price of the forged pistons I run. This is less than a tenth of the price of cranks that are built for 8 second brackets.

NOW AS FOR I WOULD NEVER TAKE A DYE GRINDER TO A PISTON TOP, then use a sanding wheel, belt sander, what ever you need. Do just one, and ask the shop to cnc the other 7 to match, then clean them up so they are all the same.

I would never hand prepare 8 pistons anymore. The cnc machine takes only a few minutes to program and will do all 7 so precisely it makes me ill to think about all the time it took to build a 9 second car in the 70's and 80's.