Noob Question

Chad_Broski

Chad_Broski

Active Member
So I am trying to decide whether I want to get a CNC cylinder head or not. I'm wanting to make plenty of mods that I am almost sure will make my engine run hot (hence I want a head with good air cooling properties); but on the other hand, I do not want to spend $40, half the price of the engine, on a head that could potentially have less compression than it's generic counterpart.

so, is this product worth it? ------> Racing CNC Cylinder Head 66cc / 80cc Gas Motorized Bicycle Silver New
 
Chad_Broski said:
So I am trying to decide whether I want to get a CNC cylinder head or not. I'm wanting to make plenty of mods that I am almost sure will make my engine run hot (hence I want a head with good air cooling properties); but on the other hand, I do not want to spend $40, half the price of the engine, on a head that could potentially have less compression than it's generic counterpart.

so, is this product worth it? ------> Racing CNC Cylinder Head 66cc / 80cc Gas Motorized Bicycle Silver New
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Quality costs $$ that's a billet piece. There's alot of surface area for cooling

You said you were gonna do Modifications, so set the squish to where you want it

Maybe a Member who has one of those will chime in.
 
I don't have one but my neighbor does, he has the red one. His runs cool , the tall fins are good for hot weather or moded engines. The wide squish band should produce power over a wider rpm range. Like wrench said you need to check squish to get the most out of your engine. I have a large piece of thick glass that I sand the deck of the cylinder on to get the gap right.
 
Thanks for the info (^). I was starting to worry bcuz I was afraid that the smaller design would hinder the head's cooling ability (the design I am getting has a height of 4.4 centimeters and the "high quality" heads are normally 5.5 centimeters). But in the long run I have no choice because the frame has only enough clearance for a 5 centimeter head. Thanks again!
 
Chad_Broski said:
Thanks for the info (^). I was starting to worry bcuz I was afraid that the smaller design would hinder the head's cooling ability (the design I am getting has a height of 4.4 centimeters and the "high quality" heads are normally 5.5 centimeters). But in the long run I have no choice because the frame has only enough clearance for a 5 centimeter head. Thanks again!
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You could still use a head that's 5.5cm but you would have to shave the fins down with a grinder so it wouldn't hit the frame.
 
I do what I want to on my engines and use stock heads with no overheating, as long as you keep the jetting correct and run the right heat range plug it works.
 
The larger the head, the more metal it has the better of a heat sic it will be and the cooler your engine will run. You want large fins that support air cooling over the top, a good head costs money. That head looks kinda thin but it will still be slightly better than stock.
 
okay, fats forward 2 weeks, I bought the head and it came in. Now I have a slight problem. the cylinder head has obviously been machined for a smaller bore size, and now the piston is larger than the squish band. Could this be an issue? if it would be, could I alleviate the problem by taking a dremel and widening the squish band, or am I better off reselling this head and buying a new one? It should also be noted that the head gasket that is shown in the photograph is a reference tool, the gasket is an accurate representation of the bore of my engine [47 mm by the way]

Pictures:
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As a slightly unrelated question, on a scale from 1 to 10, how does this cylinder head look on my engine? With 1 being "Ugly as Sin" and 10 being "Absolutely Gorgeous".

Picture:
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Chad the squish band width is not a problem, it's at the correct angle to the piston. You can't get the angle right with a Dremel, you'll reduce compression and hurt performance. I don't recommend doing anything to it, a lot of research and development goes into a design before it is produced.
 
Greg58 said:
Chad the squish band width is not a problem, it's at the correct angle to the piston. You can't get the angle right with a Dremel, you'll reduce compression and hurt performance. I don't recommend doing anything to it, a lot of research and development goes into a design before it is produced.
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so are you saying i should just go ahead and use it, and that it [squish band width] won't matter in the long run?
 
When you have time download the two stroke tuners handbook and Graham Bells book on two strokes, both are great to get a grasp on how a two stroke works and how to make it better.
 
Greg58 said:
it should run fine.
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Okay, just wanted to make sure. I was afraid that the piston might hit the cylinder head at TDC during peak RPM, but I heard that only 1% of the stroke's length is enough clearance for the piston to avoid hitting the head, and I can confirm that there is more than 0.4 mm of clearance, so I should be good!
 
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