Sanity Check- Oil Routing w/out Engine Oil Cooler

[KTL]

Experts please check me on this. Engine in question is a 3.2 Carrera case.

If I install the RSR t-stat blank like this



AND I were to block off the engine mounted oil cooler ports externally (let's say that we didn't want to have an oil cooler here, nor install the typical 993/965/RSR oil filter housing) such that both ports are blocked and cannot flow between each other, then the crank is going to not receive oil, correct?

My belief is based on the following diagrams, the color one being the most telling of the two.





1. Oil is fed from the oil pump up through the "J" pipe cast into the engine case.

2. The stem of the "J" goes into the bottom of the t-stat bore in the case.

3. In the t-stat bore there is the bottom port which is incoming oil from the pump. Two peripheral ports in the bore are one cold, one hot.

4. With a t-stat installed the cold window in the t-stat is open & sends oil to the cold port drilled in the case. From this cold port the oil goes onward to the crank.

5. When you install the RSR blank, it effectively blocks the cold port drilled in the case. I've visually confirmed this on my engine case. The diameter of the blank is a nice slip fit in the bore and is fairly tight against the bore. Certainly no intention here of allowing oil to pass the cold port.

6. With a t-stat installed & oil temp hot enough to "open" the t-stat, the t-stat regulator moves to close off the cold window in the t-stat. This directs oil thru the hot window in the t-stat. This hot window aligns with the outbound hot port in the case bore, sending it off to the oil cooler. Oil goes thru the cooler & returns to the engine case thru an adjoining inbound return port in the case.

7. With the RSR blank installed, regardless of oil temp, oil ONLY goes directly to the outbound hot port (as noted in #5, the cold port is totally blocked by the RSR blank's shape) & exits the engine. If we have a filter or cooler installed, oil flows as it should. However, if those oil cooler ports are blocked externally and not connected to each other, the oil has nowhere to go and will not reach the crank.

One might think the diagrams show the oil can reach the vertical gallery that feeds oil to the low oil pressure warning light & the bypass valve. This is the bypass that regulates oil pressure and returns it to the inlet side of the pump. However, that vertical gallery is fed by oil coming from either:

1. The cold port, which, in the case of the RSR blank installation, is blocked.

or

2. The hot inbound port, which, in the case of the RSR blank installation, is not receiving oil due to the outbound hot port being blocked by blockoff plate.

So ultimately this blockoff plate idea depends on what type of piece is installed in the engine's t-stat location. I believe to install a blockoff plate, you have to either:

a) gut the original t-stat so oil can flow thru either the cold or hot windows at any given time regardless of temperature.

b) if the RSR blank is installed, that blockoff plate has to have an internal connection. Meaning the ports are joined inside the block. Thinking of it another way, the block has to act like an imaginary length of hose that connects the two ports together.

Make sense? I think it does.

Thanks for taking the time to consider the above

[James Brown]

wow, head scratcher. If you block off both H and C ports than no oil will reach the crank (rockers and cams) and since the oil pump is positive displacement, the safety relief valve opens and dumps oil back to the sump blowing up the engine in a HOT condition. but if the RSR plug is installed, it is in the COLD position only all the time than all the oil regardless of temperature goes out to the engine. blanking off the oil cooler makes no change as oil is not routed to the internal cooler. the external oil cooling circuit and the pressure relief valve will work normally. as i see it, the RSR t-stat has to port oil to the cold side in order to blank off the cooler.

[Eagledriver]

I don't know how this RSR plug works or is supposed to work. Why does it have a hole in the top? If you want to just remove/block the oil cooler, there is an easy way. Pull the thermostat and remove the "guts" of it. The bottom of it comes off easily, it's just a stamped piece of steel. The rest of the parts will fall right out. Then you can block off the cooler. I did this due to a leaking cooler by putting in a couple of slugs of aluminum turned to the size of the holes.

Maybe the RSR plug is meant to direct oil to a filter mounted where the cooler used to be?

-Andy

[304065]

See post #27 in this thread

Ultimate Oil Pressure Relief Valve Thread

[KTL]

Thanks for the feedback guys. I just wanted to make sure I wasn't missing something.

Yes the RSR thingamajig is simply an elegant way to direct the oil from the bottom of the t-stat bore upward to the outgoing port in the case that leads to the filter housing. I agree w/Andy that the simple solution is to gut a 74-89 t-stat, problem solved Or if someone wants to add some temperture readings, you could put a 964 cap in place of the stock gutted t-stat.



Andy, I think the RSR piece is hollow for lightness? The hollow serves no purpose on the exterior of the engine that I can see.