2 stroke heatsinks

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i was just thinking of using the heatsinks of the 2 stroke bike engines for as class A project. this is only an attempt to be different than the norm. anyone know if these are of any good? not sure what is the termal resistance thou, could be poor as the Al+ block seems thick but can be easily machined down.
 
i have access to the machine shop to dimension this thing. but the material seems to be of harder AL alloy than the usual softer AL heatsinks. this is because the inner bore also houses the piston to work against the surface.

i still suspect the thermal resistance could be high.
 
I just thought of something, don't completely fill the cylinder with fluid, leave some air space for expansion and screwing the spark plug in. or it WILL leak no matter how well you try to seal it.

There are some nice finned diff covers for Dana 44 and Dana 60 depending what size you want. nice big round bowl shapes.

valve covers may not have enough surface area for more than about 5 watt class A amp. very thin too, high thermal resistance unless you mount a thick plate on the bottom and oil fill them too.
 
have been on a set of junked ajs units below. they are about 8ins finned towers. can mill the bores down for 2 flat sides to mount devices and then fit a computer grade fan atop with bottom open for air inlet. tough getting the toroidal in as well thou.
An externally hosted image should be here but it was not working when we last tested it.
 

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Bigred said:
hrmmm.... some of the air-cooled 2 stroke bikes I have seen and owned in the past appeared to have some pretty hefty fins. Looks like they would dissipate considerable amounts of heat to me.

The thing is, you never run the engines flat out without moving - the heads are designed to have air streaming around them, either from the bike moving itself or from an impeller. This makes a heatsink of any king MUCH more efficient. Also, air cooled engines run at considerably higher temperatures than your semicondustors can stand... so take that into account as well.
 
Air movement over the heatsink makes it much more efficient? YOUR KIDDING ;) Yes your not running flat out without air movement over the engine but you stated that it also runs considerably higher temp than a semi conductor could stand. So factor that its designed to dissipate MORE heat than the semi conductor requires but having no air movement it may balance out in the end. Do we know how powerful is the amp gonna be?How much heat dissipation is gonna be required? I think a straight this is to small and will not work isn't the case. I would think its a matter of trial and error. Might need to add air cooling such as a computer fan maybe not.
 
Well, if you ever have build class A amp you would know that heat sink dissipate more efficiently as temperature goes up ;-) so the story that you can balance air movement across fins with lower power dissipation won't work...you will get higher c/w factor and that’s not so good ;-) ... unless you have good reserve ;-)
 
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