ESE's works engine tuner

[Buckets4Me]

one of the nicest guys you will ever meet.

[RMS eng]

Oh shit. I've been too scared to txt him as time has gone on, last time I talked to him he was too tired to talk long.

RIP mate.

this is all a bit of a shock to me,done a few jobs for Keith over the years,nice guy,all my thoughts to his family RIP Keith

chris P

[wobbly]

A sad day for a top bloke RIP buddy.
He rang me a couple of months ago re bringing down the RS125 to sort the ignition, I wondered what had happened to that.
More than happy to help out if Av wants it done.

[jasonu]

.

Keith Biddle, Av's Dad, had been unwell lately and passed away peacefully this morning.

He was someone we enjoyed the company of very much and his passing is a great loss.

I'm very sorry to hear it. My thoughts and condolences are with all concerned.

[andrew a]

Sad news sorry to hear. All the best to Av will be some toughf times ahead. Keath seamed a nice guy from few times I had spoken to him.

[Rick 52]

It's a cruel world sometimes, a sad loss to everybody, a real gent !

[quallman1234]

A sad day for a top bloke RIP buddy.
He rang me a couple of months ago re bringing down the RS125 to sort the ignition, I wondered what had happened to that.
More than happy to help out if Av wants it done.

I was talking to James Jarman in the weekend. Keith got him to make a exhaust flange to suit the JHA chamber recently to get it ready for someone to use.

Such a massive loss, as they say couldn't of meet anyone nicer. Rest in peace mate. You will be massively missed.

[TZ350]

I'm starting to come to the belief that the limiting factor in air cooled 125 development may be the ability of an iron linered barrel designed for a commuter bike to handle the heat rejection levels required for those power levels.

A safe level may actually prove to be around 27 - 28 hp....unless you go to fan cooling....

At the moment the bike does not even have any real ducting, so yes, it might be time to fit some ducts and re visit fan cooling for purging hot air from between the roots of the fins.

Here's a pic of my head and a CPU fan/heat sink that I thought had possibilities. I was thinking of using 4 of these on the head with the idea that they switch on and off as the head heats or cools.

Copper with twice the thermal conductivity or half the thermal slope (less heat resistance), looks like it could remove heat from the combustion chamber surface much more efficiently (quickly) than aluminium.

I have talked before about using fans and copper for removing waste heat from the combustion chamber and the thermal gradient involved in pushing the heat to the outer fins.



My latest idea is to sandwich a cooper sheet between two heat sinks in such a way that the copper is positioned very close to the combustion chamber shell and the heat is carried away from there to the outer fins much faster and that would keep the combustion chamber much cooler than if it was just an all alloy head.

If the fins aren't too deep then ducting and big CPU fans could be used to assist the natural airflow to move the cooling air along the fins and purge the fin roots of stagnant hot air.

Another possibility is to use a heat resistant gasket to thermaly isolate the head from the cylinder.

Yes, I think your right, some attention to fin spacing, some ducting and a fan or two would greatly improve the cooling.

[Ocean1]

I have talked before about using fans and copper for removing waste heat from the combustion chamber and the thermal gradient involved in pushing the heat to the outer fins.

You're unrestricted as far as home made parts is concerned?

Stupid question... why not a copper alloy head, with optimised fin mass/spacing?

[TZ350]

... why not a copper alloy head

Pure polished copper is a good reflector and heat conductor but from what I have read, too soft on its own for a head as the plug threads tend to give way and the head studs tend to crush and distort it.

And copper alloys are not as conductive as pure copper and often much worse than aluminum alloys.

Thermal conductivity of metals http://www.engineeringtoolbox.com/th...als-d_858.html

From experience, the other problem with polished copper is that it tarnishes in the combustion chamber and becomes the perfect heat absorber instead of reflector.

1.5mm of copper sprayed on the head to transfer heat from the combustion chamber.

Polished aluminum does not tarnish in the combustion chamber like polished copper does, but a thin clear ceramic coating over the polished copper chamber surface might fix the tarnishing problem.

[Yow Ling]

From experience, the other problem with polished copper is that it tarnishes in the combustion chamber and becomes the perfect heat absorber instead of reflector.

.

are you trying to keep the heat in the engine or remove it?

[Grumph]

are you trying to keep the heat in the engine or remove it?

Actually, at some points it is profitable to try to retain heat whereas at others removal asap is necessary....

There are a number of heat barrier type coatings on the market now which are showing good results for piston crowns etc - some gains could be expected there.

The multi - metal, add a layer of copper approach is flawed as far as i can see, because every time you introduce another layer the juction between different layers is another barrier to heat transfer.

A well designed sunburst type head with the fin roots actually on the chamber does work well but can be hard to cast...

[TZ350]

are you trying to keep the heat in the engine or remove it?

I would like to keep it all in the super heated and expanding combustion products to help push the piston down but once any thermal energy has leaked into the combustion chamber shell, piston crown or cylinder walls through radiation or conduction the cooling system needs to shed it ASAP to avoid over heating the engine.

[TZ350]

A well designed sunburst type head with the fin roots actually on the chamber does work well but can be hard to cast...

Yes I like the sunburst head as it has the fin roots right on the combustion chamber shell and hence a shorter thermal path than the conventional Suzuki GP125 head.



On my Suzuki the copper fin extends right into the combustion chamber and forms the squish band area.

[Ocean1]

And copper alloys are not as conductive as pure copper and often much worse than aluminum alloys.

Thanks. I stupidly assumed there would be an alloy that was mechanically as rigid as aluminium yet retained most of copper's thermal properties.

And yes, radial finz is good, Mr Maico had a winner, there.