From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Cooling problems.
Date: Fri, 29 Dec 2017 06:14:03 +0800
References: <list-10481978@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-10481978@logan.com>
Message-Id: <7E7A57A6-8443-4573-B178-42DC05C2CD0D@gmail.com>

Hi Lynn
I really appreciate your input and would appreciate seeing a picture of =
your cooling circuit.
I should have mentioned, I have temp senders on the in and out of both =
oil and water,
In the test yesterday after 20 minutes of running the oil cooler (Rx7 =
turbo - not sure which model) drops the temps by about 12F while the =
water Rad is only about 6F.
I=E2=80=99ve seen this as high as 18F oil and 9F water previously.

Apart from the cooling system, what else can cause overheating?
If I pressurise the system it holds that pressure for some time for over =
30 mins.

Cheers

Steve
I
> On 29 Dec 2017, at 1:32 am, Subscriber Lehanover@aol.com =
<flyrotary@lancaironline.net> wrote:
>=20
> I started racing rotary powered cars in 1980. An RX-2 with a junk yard =
engine. Had to pour motor oil and hot coffee into it in order to start =
it. No compression. People gathered around just to watch me do it. Ran =
well, never a reliability problem. No overheating problems. Oil cooler =
was an air conditioning core from a large GM car. Cheap and available.
> =20
> I copied the cooling system from the stock RX-2. It had a coolant =
recovery tank made of plastic. The pressure cap was on this tank. The =
radiator cap was just to seal the system. Those engines had the giant =
monkey motion thermostat that closed a hole in the water pump body after =
a quick warm up.( Pollution control). Stock radiator. Bigger oil cooler. =
No problems.
> =20
> Then I started building bridgeported engines. Big problems. I =
installed a big aluminum radiator. A double pass top to bottom. This put =
both inlet and outlet on the same end. Very handy. No problems for a =
while. Then an occasional overheat after an engine change. I could not =
get all of the air out of the engine after a rebuild.  I lifted an idea =
from the Cosworth installation manual and installed a swirl pot. The top =
of the swirl pot plumbed to the bottom of the stock RX-2 recovery tank. =
So as the engine warms up any air removed by the swirl pot enters the =
bottom of the recovery bottle. The bottle is kept half full of coolant, =
so the air pops to the top of the bottle. On cooldown or off throttle =
situations only coolant can return to the engine. After several sessions =
of refilling the bottle to one half full, the engine has removed all of =
the air and full RPM shifting is available. For us that was shifting at =
9,600 RPM. Coolant temps 180. Oil 160. At low RPM the air will not come =
out of its hiding places. My idle was 2,200 RPM. Timing is checked at =
4,000 RPM. Clear out the bubbles at least at 4,000 RPM.
> =20
> On cool days (below 65 dgrees) we would install a thermostat that had =
two 5/16 holes drilled through the flange.
> And tape over half of the radiator.
> =20
> Some items are not obvious.
> =20
>  The best coolant pump location is at the very bottom of the coolant =
loop. The rotary pump is at the top of the coolant loop. The pump will =
gleefully stop pumping if a dose of air enters the suction side. Very =
bad MOJO.  The center irons on 12-A engines at first had a temp sender =
hole. Great place to let air out of the coolant before start up. Then =
the hole was filled in but the machined flat was still there as well as =
two tapped holes. I drilled and tapped for 1/4 pipe and installed a =
radiator bleed fitting. Got out lots of air before even running the =
engine.
> =20
> The recovery bottle need not be mounted high in the circuit. That =
bottle in the racer is mounted on the passenger floor. Also the top of =
the swirl pot need not be mounted high in the coolant circuit. Does not =
matter.=20
> =20
> I found a Stant pressure cap for the RX-2 bottle rated at 28 pounds. I =
installed a Shrader valve in the swirl pot and pressurized the whole =
system to 28 pounds before start up. This also tests the pressure cap.
> =20
> My coolant is 10% prestone antifreeze. 1 bottle of RedLIine Water =
Wetter, or 1/2 teaspoon of Dawn dishwashing soap. The rest is distilled =
water.  And 28 pounds of pressure.
> =20
> The racer is gone now but the last iteration of the coolant system is =
as above. The oil cooling had to be improved as HP went up. (Store =
bought engines). Daryl Drummond 250 HP 12-As. So the last oil system was =
a full dry sump with one 44 row setrab in the pressure loop. And two 44 =
row setrabs in the scavenge loop. We ran 100 pounds of oil pressure with =
40 weight RedLine racing synthetic. No oil related failures
> since 1980. The modern "Square" Peterson pumps tend to split open the =
pressure section. I changed to the older round body Peterson, no =
problems.
> =20
> Lynn E. Hanover
> =20
> I will draw the coolant loop if you like. It was published many times =
but died several computers ago.