[TR] Water pumps.

[Michael Porter]

On 5/9/2017 4:52 PM, TERRY SMITH wrote:
>
> Just curious.  Is this an engine that sits a lot, with a long time 
> since last disassembly and boiling?  Wouldn't engines with corrosion 
> in the water channels may need additional coaxing to cool enough?
>
>
Corrosion is an interesting question.  In a cast-iron engine, it's 
desirable.  Little-known fact:  the highest rate of heat exchange of 
known metals is off rusty cast-iron.  That likely has something to do 
with the large amount of surface area created by rust.  Where corrosion 
becomes a problem is when microscopic flakes break off and combine with 
used-up anti-corrosion precipitates from the coolant. This forms an 
insulating sludge that can cause hot spots and nucleate boiling if the 
system pressure isn't high enough.  Probably everyone tearing down a 
Triumph engine with lots of mileage has encountered the stuff behind the 
rearmost cylinder, where flow isn't high enough to keep the particulates 
from settling out.

In short, rust is okay.  The by-products of that corrosion are not.


Cheers.

-- 


Michael Porter
Roswell, NM


Never let anyone drive you crazy when you know it's within walking distance....