Engine Cooling

Below is some cooling information from a very experienced two stroke tuner:

All the testing I have done with water cooling more , or less , in certain areas, sees only small gains individually.

But combine them and the effect is synergistic.

Arrange the plug threads to have water close , cut a ditch above the squish band with coolant holes from that , dropping right up close to the boundary layer , ceramic coat the chamber only as well as the area inside the squish on the piston, have the coolest water flow passing over the transfers first - then around the exhaust - then across the head and out.

All these together make an engine that is HUGELY deto resistant, makes more power, and is way less influenced by tuning errors, be they too rich or too lean.

As an example of just one experiment was changing the coolant flow on a TM - KZ10C.By moving the water entry to above the boost port as well as drilling 1/8" holes in the water plugs blanking flow underneath the Exhaust duct and then rebiasing the area of access holes into the head was worth just over 1 HP . But take away the Ex duct coolant holes and ceramic coat the Ex internally  duct lost just over 1 Hp but even very conservatively tuned it detoed like hell , to the point I aborted the dyno run.

Lohring Miller

Lohring,

I found greater detonation resistance with toroidal type head designs could be achieved by cutting a deep trough adjacent to the plugs threads. 

JA

I'm not sure how much difference coatings would make in our small engines.  Another approach is to make the head button so only the plug threads and squish areas are cooled.  The head button looks something like yours but with a cylindrical area where you have a rounded corner on the outside over the combustion chamber.  Water is routed around the squish and around the plug, but not over the combustion chamber.  Heat loss issues should be more pressing with gasoline since it has higher combustion temperatures.

Lohring Miller

Here is what I do on my nitro eng. This is a new eng set up I am trying and the head cooling system I am using.

I have used a similar set up on all my eng builds. Just this time I spent more attention to the cooling of the squash band.

The cooling channel is right on top of the squash band and the head is cut to get the water closer and more in line with just the squash band.

I am also thinking I will  cut 3 small groves to the chamber to spray water on the plugs.

Still mulling that around.

I may also cut a mirror channel in the button also.

This is the ONLY water cooling the engs I build.

It was funny how you posted this as I was building my head set up.

Great minds think alike.  Yours and the person I stole this from, not me.

Lohring Miller