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Workshop => Engine and Bottom End => Topic started by: chrisr on August 23, 2013, 11:38:51 AM

Title: Cool head questions
Post by: chrisr on August 23, 2013, 11:38:51 AM

Been thinking about getting a cool head.  Been looking more at the Duncan and ESR versions with O-rings so I don't have to fool with head gaskets.  Right now I run a 50/50 mix on nonethanol premium and race gas in my 2strokes.  I'm thinking about going to just race gas in them and want to bump the compression up to take advantage of using it so I was wandering what dome I should use with a pretty much stock motor(pipe and reeds are the only motor mods)?

Title: Cool head questions
Post by: corvetteZ06 on August 24, 2013, 04:53:26 PM

I run cool-heads on all my 2 strokes, with 18cc domes (highest compression dome available pro-design) and have to use race gas. I use a cometic copper head gasket, (thinner than oem for even more compression) and never had a problem. The torque/low end gained just from the cool head is fantastic! You can't go wrong with ESR, Duncan, or a pro-design cool head, all are great quality and will make a nice difference with a stock bolt on cylinder, to a professionally ported cylinder. By the way, never head any issued with over-heating on a motor I was using a cool-head with.

Title: Cool head questions
Post by: christph on August 24, 2013, 05:50:46 PM

You use a copper gasket with a billet cool head?  I thought they used o-rings only?

Title: Cool head questions
Post by: derby on August 25, 2013, 01:48:55 PM

I am assuming you are talking about oem cylinders or ?

For oem cylinders
Most of them use gaskets.  I have only seen a handful of oringed cool heads.  Esr heads for oem cylinders are also gasket style.  You can get the head oringed for extra.  You will probably have a hard time finding oringed domes off the shelf unless you get someone to cut them for you.

Title: Cool head questions
Post by: derby on August 25, 2013, 06:17:02 PM

Who sells the o-ring cool heads?

Title: Cool head questions
Post by: broken1 on August 25, 2013, 09:30:21 PM

The o-ring cool head on my oem cylinder is pro design. I think it's got a 19 or 20cc dome but it's been a while since I've had if off. .040" over with a weisco piston & compression is about 210psi.

Title: Cool head questions
Post by: jamieg45 on August 27, 2013, 12:35:19 PM

I also have a o-ringed pro-design cool head on my ct 265 motor with a 16cc dome I do believe, whicall wa available back in the day. You can stilget the 16cc and 17cc domes from pro-design also.

Title: Cool head questions
Post by: derby on August 27, 2013, 09:19:13 PM

I see gasket domes all the time for sale.