Paul,

In reviewing several of my rotary engine pictures I see there are several
installations that pressurize their water systems. Can you tell me the
benefits or shortcomings of that? (Three pictures attached, see yellow
arrows)

Thanks,


Sandy McNabb
Renesis in a Glass Goose


It is a good pre flight check. You need a pressure gage to go along with it.
Pump it up to 50 psi and watch the gage. If it holds pressure you have no
leaks.

Increased pressure delays boiling which is the Achilles heel of liquid
cooling systems.
Here is an illustration from my book How to Cool Your Wankel


Paul Lamar

So, It serves two worthy purposes: One, to check the system after
installation for leaks, and two, to delay boiling. Seems like putting
pressure into the system would introduce some air, also. Would that be a
problem?


Thanks,
Sandy

Not if you have vents in the right places. Namely from the highest point in the block to just under the pressure cap. Usually the heater return line in the end housing near the psru is the highest point in the block.  If you tap this out with a 1/4 pipe tap (NPT) you could crack the end housing. I recommend a straight thread AN with O-ring seal or soft aluminum washer. Been there done that :)

Paul Lamar