grooved chamber...

[simemk]

1.
http://www.speedtalk.com/forum/viewtopic.php?t=7770

http://somender-singh.com/content/view/6/49/

2.
Having done some actual testing to see the effects on weight reduction in regards to hp. I have found that there are substantial gains to be made if weight is removed from the rods and the pistons. At one point a few years ago we made a titanium rod forging and toyed around with making an affordable set of titanium rods for the B and K engines. Unfortunately titanium prices more than tripled during a 1 year time frame and the prices we would have to charge rose to a level that people in this industry simply wouldn’t be able to afford.

Doing engine dyno testing on a b18c engine. A 140 gram weight reduction per cylinder on each con rod yielded a 5 hp peak gain. Mind you this was under the same load and the same motor, the only change was the con rod weight. Even more significant than the 5 peak hp gain was the 13hp gain at 800 rpms after peak power. The power curve basically flat lined after it peaked, where as the heavier steel rods would taper off much faster.

As rpm increases there is also an increase in the amount of force/hp required to change the direction of the piston and rod. The heavier the piston and rod the more force that it wasted to change its direction. The crank shaft also has centrifugal force that acts on it. If the weight can be reduced there will be less force required to change its speed or rate of acceleration.

For me its really strange to see people buy aftermarket rods that weigh the same or more than stock rods. There is no gain what so ever and if the rod is heavier then you actually loose something. The stock rods are plenty strong and as long as you don’t do stupid things like over rev or rev beyond what is needed, then they really don’t have any problems. Aggressive marketing has trained people to believe that they need to replace certain parts that don’t really offer any benefits.

As far as rod materials and titanium rods go i have concluded that the 6AL4V titanium grade isnt suitable for connecting rods. There are other grades that are suitable but the cost is more as well. 6AL4V lacks the tensile strength to provide adequate longevity for long term use. For short term use its fine just like aluminum.

There are ways to make 6Al4V adequate but it requires reducing the weight of the pistons. this reduces the amount of strength required to hold on to it at high RPMs.

4340 steel can be heat treated to 250,000 psi TS (tensile strength) normal 6Al4v is only 110,000 psi TS. Although 6al4v can be heat treated to 160,000 psi TS it rarely is. There are grades of steel such as 300m that can be heat treated to over 300,000 psi TS. 300M costs a 3rd of what titanium costs but it weighs twice as much. So....... it’s really only about 30% less to make than titanium after these factors or taken into place. Also these materials are equally difficult to machine and the cutter life is greatly reduced.

Few people spend the money or have the money to spend to buy the optimal part. so they end up settling for what they can afford. This is part of the reason you don’t see these "exotic" parts available, people simply can’t afford them.

If I do an engine for my self 9 times out of 10 I use the crower maxi lite rod. They are about 100 grams lighter than the stock rods. Cost is about 700ish a set. I have used them for about 10 years and never had any problems with them. They weigh about 400 grams ish. Cunningham also makes a really nice rod that weighs about the same and is priced similarly.

Weight reduction, no matter where it’s applied has numerous benefits.

better gas miliage

[Acki]

The grovves are rubbish in my mind. Against the rule that you should have a small area/volume ratio.

[simemk]

http://theamcforum.com/forum/topic8062_page1.html

Thanks. The groove in the head helps shoot the flame front into the quench area of the piston for a more complete burn. It allows a 10:1 compression engine to run on 87 octane. You can read up on it at the following links.



HEAD GROOVES:



http://speedtalk.com/forum/viewtopic.ph ... sc&start=0 – Racer forum discussion … I have chatted with Randy Naquin ( aka Automotive Breath ) on this forum and he has been modding a lot of heads with the grooves and good success in torque & MPG increases, along with decreased ping. He gave me feedback on where to place the groove on the AMC heads, since we have the angled spark plugs.



http://somender-singh.com/content/view/119/49/ - Pics of grooved heads (from 2006)



http://somender-singh.com – Guy who stumbled onto it over in India



http://www.youtube.com/watch?v=Ss7slCT0Vpw – Youtube video of a guy grooving his 3000GT 4-valve head



Just food for thought, I am also wondering if the groove helps to promote a swirl in the combustion chamber during the compression stroke, as the piston forces air/fuel up into the chamber.



Yes, the Fish carburetor is a very strange beast … goes against a lot of conventional carburetor ideas. The one pictured is a 1 5/8â€