Yair G'day Rusty and all,

SHORT ANSWER

We need some way to determine the temp of the housing just
below the Leading plugs to avoid boiling out the coolant.  My good
mate Paul "Let's run the numbers" Lamar,  (bless his TES O
rings),  was correct in that there really needs to be a temp probe in
that area.  Any sensor anywhere else (Especially in the rad) will
actually read lower.

The point is that you need to sense the temp close to the plugs as
that is where the engine is hottest,  and where damage will occur if
you convert it to a Stanley Steamer.  The mod is easy to do.  Just
drill and tap a hole to fit a temp sensing SWITCH just below (AND
to the side - there is a web directly above and below the plugs) of
the Leading #2 plug area.

All it needs to do is communicate with the water jacket in that
area.  WARNING !!   Before you all start drilling,  have a CAREFUL
look at an old rotor housing to see EXACTLY where it needs to go,
... be careful ... there are through bolts above and below the plug
holes!!

As for sensors, it is possible to buy a variety of pretty reliable temp
switches from VDO etc. You want someting that comes on at
around 110 Deg C. They are small,  and reasonably cheap to buy.  
My preferred solution is to have one in each housing,  and
connected in parallel to the pump relay as well as a BIG BRIGHT
warning light and / or a piezo-electric 'screamer" to get your
attention in case you ar blind (like most race drivers!!).

Yeah I know, ... more complication,  but it will save you a rebuild,  
and also save you from aborting your flight (or race).

LONG ANSWER ( 25,000 words or more coming!)  }:>)

Cheers,

Leon

On 18 Oct 2003, at 10:45, Russell Duffy wrote:

SNIP>>

> What are your thoughts (in 5000 words or less <g>) about using temp to
> notice the failure of a pump?  In other words, you're flying along
> with only one pump running, and it fails.  How long do you think it
> will take before the aux pump will kick in due to the higher temp?
> More importantly, what do you figure the chances of boiling out
> coolant, or damaging the engine will be before the aux pump comes
> online?  I'm betting that you and Lynn (who's also been mighty quiet
> on this subject) have had seen failures than all the rest of us
> combined.
>
> Thanks,
> Rusty    
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