Show Posts
1
Quannon / Re: Quannon Sprockets and Mods
« on: June 29, 2013, 09:09:34 AM »
@defated 143 still sounds a little high for the sprocket set you have but I'll take your word for it.
@bad joke I don't know if I wrote milling the piston heads. I thought i said just milling the heads, might have been a typo. Milling the heads is when you take block head off the top of the engine, you take that to the machine shop and they mill/cut a very thin cross section off the base of the heads. This brings the top of the combustion chamber closer to the top of the piston when reinstalled. Although this constitutes a very small reduction in overall displacement, it also constitutes an increase in compression ratio which provides more torque. Same amount of fuel and air but more compression. Horsepower is a measure of work which is energy and distance. The energy comes from the fuel, so same amount of fuel = same amount of horsepower generally speaking. Torque is an analog of force which translates into acceleration as Force = Mass x Acceleration. So more force, same mass = more acceleration.
The primary risks associated with this modification are three fold. 1) too much metal is removed resulting in collision between valves and piston head 2) Too much heat generated by the extra compression results in early detonation of the fuel (thus cooler spark plug). This phenomenon is observed in diesel engines that only use a "glow plug" to start and then ignite fuel by compression alone. 3) Improper surface roughness can cause the head gasket to seal poorly and you lose your extra compression and leak fuel and oil.
So its not without risk but it is relatively inexpensive and almost all but high output engines usually have enough clearance to take off a few thousandths. The same procedure can be done on the base of the jugs/block and occasionally a thinner head gasket can be utilized to accomplish the same thing, with the added benefit of being capable of returning to stock with a simple gasket. One more option is to purchase a domed piston which increases compression by simply adding more material to the top of the piston ( these tend to be expensive and they can take a lot of research find the right one for your bore and stroke)
As for the Carburetor mods, these sound more complicated than they are, The shims are often just little washers that adjust anchoring points, Jets are unscrewed and new jets are screwed in. So long as you really pay attention and follow provided instructions you probably be just fine.
@bad joke I don't know if I wrote milling the piston heads. I thought i said just milling the heads, might have been a typo. Milling the heads is when you take block head off the top of the engine, you take that to the machine shop and they mill/cut a very thin cross section off the base of the heads. This brings the top of the combustion chamber closer to the top of the piston when reinstalled. Although this constitutes a very small reduction in overall displacement, it also constitutes an increase in compression ratio which provides more torque. Same amount of fuel and air but more compression. Horsepower is a measure of work which is energy and distance. The energy comes from the fuel, so same amount of fuel = same amount of horsepower generally speaking. Torque is an analog of force which translates into acceleration as Force = Mass x Acceleration. So more force, same mass = more acceleration.
The primary risks associated with this modification are three fold. 1) too much metal is removed resulting in collision between valves and piston head 2) Too much heat generated by the extra compression results in early detonation of the fuel (thus cooler spark plug). This phenomenon is observed in diesel engines that only use a "glow plug" to start and then ignite fuel by compression alone. 3) Improper surface roughness can cause the head gasket to seal poorly and you lose your extra compression and leak fuel and oil.
So its not without risk but it is relatively inexpensive and almost all but high output engines usually have enough clearance to take off a few thousandths. The same procedure can be done on the base of the jugs/block and occasionally a thinner head gasket can be utilized to accomplish the same thing, with the added benefit of being capable of returning to stock with a simple gasket. One more option is to purchase a domed piston which increases compression by simply adding more material to the top of the piston ( these tend to be expensive and they can take a lot of research find the right one for your bore and stroke)
As for the Carburetor mods, these sound more complicated than they are, The shims are often just little washers that adjust anchoring points, Jets are unscrewed and new jets are screwed in. So long as you really pay attention and follow provided instructions you probably be just fine.