charles.harbert wrote:

Paul, I'm using the stock pump and pulleys and having no problem cooling

the

turbo 20B engine (180-190 degF) in a pusher at over 250 hp. I not so

sure that

it's inadequate for the job.

Also, is the 180-190 deg temp taken at the back of the waterpump housing
(where the
probe is on the stock 13b) or after the coolant has passed through the
radiator? And could
somebody refresh me as to ideal and max. temps in both places?
Thanks,
Lonnie

I don't know about ideal but it would be best to take the temperature
of the rotor housing right at the spark plug adjacent to the combustion 
chamber and keep that temperature less 
than 400 degrees or so. That is the bottom line regardless of what the 
water temp is. If necessary drill a small hole and bond in a
thermocouple with JB weld. A 1/16 inch diameter hole 1.3 inches
deep right along side and inline with the leading plug would be perfect.
Best to do this when the rotor housing is separated from the engine.

You can use a Super Omegaclad type J thermocouple page A87
in the Omega catalog #Vol.29 1(800) 872 9436. http://www.omega.com

Either 48 inches or 72 inches long and from .005 to .0032 inch
in diameter. Teflon or glass braid insulation. 
I would immerse the thermocouple in JB weld and let that cure first 
to be sure it was insulated from the aluminum housing. 
JB weld claims to be good to 600 degrees F. You can also
get 1/16 inch diameter ceramic, teflon or fiberglass insulators 
from omega. The teflon is rated to 450 degrees F. Glass braid
is good to 900 degrees F.

The under-the-spark-plug type washer thermocouples will not fit the rotary.

Analog read out meters are simple, reliable and relatively cheap at $112 each.
3.5 inch square. No electrical juice is required. That is what came 
with my Cessna.

Basically what you wind up with here is a CHT gauge.

Paul Lamar
 
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