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Bit of a noob question about domes & heads.


Uf21

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So been looking around and cant find a definitive answer nad want to know more about heads and domes.

 

1. What are domes and what is their purpose?

 

2. I know cool head is to keep the engine cooler but does coolheads give the engine more power?

 

3. With a coolhead do you need to change the domes?

 

4. Is changing the coolhead easy?

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Domes are what controls your compression besides squish. So stock is 24cc (i think) and by lowering the dome number it raises compression. For example i have 21cc's and i am supposed to be around 156 on a fresh rebuild. The biggest part of the cool head and what makes them desirable is the ability to change out the domes. On stock heads the only way to bump up compression is to get the stock head milled and with the cool head you can change the domes and control compression yourself. So yes you can get more power from changing to a cool head because you can change compression. You do not need to change the domes you can leave it at the stock compression numbers. As far as i know changing to a cool head is fairly easy just use a little bit of vasline or grease to keep the o rings in the correct place while changing. However if you do not plan on changing the compression numbers my opinion would be to keep your stock head. 

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Even if I dont plan on changing domes wouldnt a cool head still be a good thing to have since it keeps the motor running cooler?

 

BTW thanks for the explanation.

 

It doesnt really keep the motor running cooler. The main purpose is to allow you to change compression ratio by just swaping out the inserts, which are called domes. I prefer a 2 piece head because they allow you to visually conferm that the domes are properly lined up before you put the top cover on. You set the domes on each cylinder, then slide the outer shell on, the the top cover.

 

The Noss Machine head is a good 2 piece head. There are a couple site sponcers who sell noss heads with thier logo.

http://www.farmandsandtoys.com/partdetail.asp?partid=386

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