Jump to content

Recommended Posts

Posted

Does anybody know the specs for cool heads?

22mm = what compression?

21mm = ?

20mm = ?

19mm = ?

 

I want to run pump gas with stock motor (moded) and currently have .030 shaved off my stock heads. I live in Virginia about 400 ft above sea level if this helps. Will I see a performance difference with the cool heads over stock? I need to know what domes to get...

Posted
Does anybody know the specs for cool heads?

22mm = what compression?

21mm = ?

20mm = ?

19mm = ?

 

I want to run pump gas with stock motor (moded) and currently have .030 shaved off my stock heads. I live in Virginia about 400 ft above sea level if this helps. Will I see a performance difference with the cool heads over stock? I need to know what domes to get...

Sea Level 1000' 2000' 3000' 4000' 5000'

18cc 197 178 171 170 165 145

19cc 183 167 160 158 152 137

20cc 169 156 149 146 140 129

21cc 156 145 138 134 128 121

stock 130 125 118 112 106 100

Posted (edited)

Well does anybody know what is equivilent to a stock head shaved .030's? Is there any performance in buying a cool head vs a stock head shaved when running pump gas (93octane)?

Edited by dante
Posted

cool heads do run alittle cooler, and they give you the option of changing the domes when you decide to change up your engine combo.

The after market domes also have a little different squish angle cut in them which will give a little performance difference.

Posted

You should be okay with 21cc domes if you run premium pump gas unless your timing is advanced quite a bit.

 

-David

Posted

As long as you run good fresh 93 octane, you should be okay with 21cc domes.

Posted
20cc is the cutoff for regular gas

19cc usually uses race gas, 20 or 21 would be fine

 

 

So do you think 20cc will work with pump? Or should I stick with 21cc remember I'm 400 ft above sea level.

Posted
Hey guys I got my noss head and it says to check the squish clearance. LOL I feel a bit foolish but how do you do that? :blink:

 

Thanks

Kevin.

 

 

Not foolish at all... Been there!

 

OK...

 

Take out your spark plugs...

 

Get yourself a 9" long piece of solder...

 

Make a hook type shape (or a "C") with it... Put the solder in the plug hole... Now, find the area of the dome that meets the cylinder... (it's the outside area where the dome step meets the jug) Make sure you are careful not to put the solder too far down in the jug... If you do, you have a chance of cutting a piece off the solder stick... (you will be splitting the cases!)

 

Now, by hand push over the kick starter letting the piston "squish" the solder...

 

Pull the solder out and measure the squish to your liking.

 

Hope this helps!

Posted
So do you think 20cc will work with pump? Or should I stick with 21cc remember I'm 400 ft above sea level.

 

The best way to know is by doing a compression check. You really can't be 100% without knowing how much compression you have in each jug. Remember the more compression, the more octane you need so you don

Posted

I'd be a little worried about 20cc domes at 400' on pump gas.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...