K&S sells small 1/16, 3/32 and 1/8 diameter copper tubing. If need be I can pop some in the mail for you, the local hobby stores have it in stock.

I thought about the water jacket or marine type cooling head as well, certainly a possibility. Or do like many did many years ago before the manufacturers made the marine heads, wrap a copper tube round the head (I think Octra may have marketed one line that).

However, if you cool the engine too much with one of these heads or jackets, might that not have a detrimental effect on the idle??

cheers, Graham

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Many thanks Graham, but I'm headed to Sudbury for the weekend and the shop there just told me they'll be putting some of the 1/8th aside for me.

How cool our engines, (diesel of glow) can be run is a good question. I read the other forums a bit and the car guys use a temperature gauge to tune their needle valves. These are laser devices and their accuracy is suspect in some quarters. So, many just tune by ear and by running the car on a stretch at high speed. For the longest time, we were told that 1/2As throttle poorly because, among other things, they run too cool. The math may be correct but in the real world, I tested the notion and it doesn't seem to hold. You can see what I mean here.

http://www.youtube.com/watch?v=o-uvAb-vQgM

And here.

http://www.youtube.com/watch?v=wwWz9Liv81g

In the second video, we have an engine converted to rear exhaust and idling at 1.5K lower than is typically needed in a plane. It took a while for the ice cube to affect the idle. Later runs showed that a little tweaking of the idle mixture helped prolong the idle. Hotter or cooler running will affect the compression setting and THIS will affect where your main needle will be and this can affect your idle setting unless you have a means to adjust it. Adjusting the idle is not provided for on PAWs and the like. I can't imagine why, I've added the feature and it helps a great deal.


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I appologise for coming in late with my additions but what the. . . .

As a kid I recall the instructions that came with all my ED marine engines stated that a diesel is being cooled the right amount if is running so you can place your finger tips on the cylinder head and keep them there for justa few seconds.

I know that's a bit impirical but that's what it said.