60Patrol

That's a Patrol water pump. Here is a picture of mine...

That spring is actually a bimetallic spring, that expands or contracts with temperature, allowing movement of the weighted valve. Unfortunately, it is unobtanium. In my case, it broke decades ago, and the hole for the axle of the valve enlarged a little, and small backfiring developed. I welded shut the hole, with the valve inside in the hot position. A pity but I had no choice.

What position is the exhaust valve in the attached photos? I want to know the open position since the spring is broke and the vavle is "flopping around"......

Thanks, Tom

I will try to take a picture tomorrow to clarify.

I took pictures on an engine that is sitting over a dolly in my garage, with the manifolds facing the floor. I manually moved the exhaust valve (exhaust riser valve) and took pictures in the two extreme positions. The pictures are looking straight into the chamber where the valve is located. I used your pictures as reference for the following collage:
In position #1, all the exhaust gases go out. See blue arrows showing the flow. This is the position you want to lock the counterweight on the outside.

In position #2, the valve closes the natural flow to the exhaust pipe, and diverts the gasses to the top around the valve, heating the intake manifold, and then follows to the exhaust pipe. This is during cold weather where the diverted heat helps vaporize the fuel mixture.

The flow of the exhaust gasses will try to force open the valve also.

Thanks ton Esteban. You're a true pro. So the exhaust flow should force it open. When I get it running again I'll verify. I'd like to have that feature of warming the air intake. Carburetor icing is a big deal in aviation: https://en.m.wikipedia.org/wiki/Carburetor_icing

Future project for me is to run a push-pull cable from the cab to the valve so I can manually control it. I'm not going to weld it open right now.

BTW, that Doorman 902-1017 thermostat housing you recommend as a possible replacement for my corroded original was just a little to big from bolt center to bolt center. I think I could have made it work but the outlet was also 180 from where it needs to be. But I went to the Doorman website and may have found a suitable replacement candidate. I'll update when I got that figured out. Thanks again, Tom

I searched the site for "petcock" and I think I found my answer, but just to make sure, reference the photo, the red circle is the petcock, right? I am worried if I get it out, I will open a can of worms or corrosion

I found a similar thing on the left / driver's (US) side of the engine. Is this also a petcock? Side note: the "?" is an oil breather, right? It requires no maintenance, right?

As I recall neither of those are petcocks. The one by the starter is close, the petcock is higher up. I think it's actually the rear manifold bolt. On the other side - yes, that is a breather. Not sure about maintenance. I guess as long as it can breath it's good.

The circled one next to the starter is a petcock. Older Patrols used to have a valve there.

The one on the driver’s side is an oil pressure plug. You can connect a separate oil pressure gauge there.

Esteban wrote:The circled one next to the starter is a petcock. Older Patrols used to have a valve there.

I guess it's been a while. I'm probably mistaking it for the petcock where the short heater hose connected and also had the engine hoist tab on it.