Here is what I did to my '71 Wolseley 16/60. The engine requires high octane gas. I wanted to use regular. Doing so caused it to ping, knock and diesel when you turned the key off. So, I used cooled Marvel Mystery oil to solve the problem.
The goal was to reduce combustion temperatures which would reduce the need for hi-octane gas, as well as cause the engine to run cooler.
Upper Cylinder injection systems are very similar to water injection:
http://www.ampcolubes.com/I have the one using the metal can reservoir. ( You don't want to use the plastic or glass units as they will insulate the oil from the airstream). I mounted the can in the front of the car where the airflow hits it. This cools the Marvel Mystery Oil ( a simple, lightweight oil that will not burn in the engine's combustion chamber) that is in it. The oil is then sucked ( by engine vacuum) through a small transmission cooler, which is also in the airflow in the front of the car. This cools it some more. It then enters the intake manifold via a spray nozzle, where it is distributed to the 4 cylinders via the intake valves. It gets sucked into the cylinders and pushed back out, via the exhaust valves, and then out through the exhaust. It never burns, in the cylinders. This results in a cooling of the combustion temps of the cylinders. The way I know that it is doing so, is that with this simple system, I can use regular gas in this engine with no pinging or dieseling. If I stop the flow of the cooled oil, the engine pings upon acceleration and diesels at shutdown.
The Ampco unit's flow rate is controlled by a metering valve on the container. All of this could be duplicated at home, and you can buy the spray nozzles separately from Vaco, Inc, P.O. Box 6, Florence MA 01060 (413) 586-0978
Perhaps a system like this would solve your specific needs?