1980 FB Mazda RX7 Cooling System Upgrade – By Craig Muller

04/08/2017 09:00AM

Craig Muller of Australian Street Car magazine recently put together the below article on how he upgraded the cooling system in his 1980 Mazda RX7 including using a number of Davies Craig products. Read on…

One of the most important things for a rotary engine is good cooling. With rotaries it is known that sufficient oil cooling is very important, luckily I already had that box ticked with my new Proflow oil cooler and upgraded oil lines which were upgraded when I first purchased the car. Back then it had the original 12a extend port rotary engine. Luckily those parts were able to bolt straight up to my new 13b peripheral port rotary engine. I believe the oil cooler upgrade was covered a few issues back in an article.

My new 13b pp engine is a bit of a beast and generates a lot more heat than the smaller 12a extend port. My next step in upgrading my cooling system was to upgrade the radiator from the stock unit to a larger Proflow alloy radiator. This was a direct bolt in unit and measured the same dimensions in height and width as the stock radiator however the core was near double the thickness.

While we had the radiator out we figured this would be the perfect time to contact Davies Craig and upgrade to one of their electric water pumps and car controller. Davies Craig also sells top quality cooling fans so we matched up 2 x 13” fans to our new radiator. Best of all, the in car controller not only looks after the electric water pumps speed and flow but also controls the radiator fans. This is an awesome setup which I have known about for some time however I must say now I have been using it myself it really has exceeded all of my expectations. The in car controller monitors your water temperature and is able to set the flow rate of your electric water pump and can switch between a slow pulse right up to full speed flow. It also cycles the fan speed on the radiator fans too. All of this works together to keep power usage to a minimum and your car nice and cool even when sitting in heavy traffic in summer.

Another thing I like about this is the fact I was able to remove the belt driven water pump from my engine. Since I have no aircon and no power steering and no belt driven pump, the only belt driven accessory on my engine is my alternator. This has taken a lot of strain off my engine and also means less potential belt slip. I am now looking at ways to do this same electronic water pump setup on my turbo 2JZ as it really tidies up the look of the engine. The only problem is the 2JZ and 1JZ water pump setups are quite complicated if removed. I would need to have a series of block off plates with -12 or -16 AN bungs welded on so water is still re-directed as it exits and then goes back into the correct places on the engine block, all while still keeping clearance behind the belt that runs the cam gears. If only it was a nice and simple setup like my rotary engine which was just one single block off plate with 2 x –16 AM bungs welded on. One for water in and the outer for water back out to the radiator.

When running the new cooling lines I decided to use some nice -16 braided hoses and ProFlow -16 AN fittings as supplied by Racers Ink. Even though this was a fair bit more expensive than going the cheaper rubber hoses and stainless clamps I now have virtually no chance of a water leak. Everything is very tidy and easy to keep an eye on and I never have to worry about checking any hose clamps to see if they have loosened off. The other bonus is they match my fuel lines and fittings so my engine bay is starting to look really good.

The last part of the cooling system upgrade was the custom fabricated alloy radiator shroud which was welded up and fitted by CCC only two weeks before they unfortunately closed their business.

Although I did opt to spend a bit more money here and there on different parts I am really, really happy with how everything came together with my new water cooling system. My RX7 now runs at a perfect temperature all year round. I forgot to mention, the Davies Craig in car controller even works like a turbo timer. You can switch your car off and it will keep your fans and water pump running until it detects that your water temperature has dropped back down to a safe level. You can set the desired temperature yourself. This way it is suitable and customisable for a supercharged big block V8, turbo 4cyl, rotary or any size motor at all.

My setup was so good that our other staff member Daniel Ryan decided to get the exact same setup on his 13b BP Mazda RX7. The only difference with his system was he went with an alloy PWR radiator, black -16AN fittings and some really nice black braided hose. He now swears by this setup and wants to do it to his other cars too, something I certainly agree with. Feel free to come and say hello if you see either of our vehicles at an event. We are more than happy to show you and explain how it all works in person.

For pricing on a Davies Craig setup like we have, visit www.daviescraig.com.au where you can buy electric water pumps, fans and in car controllers as a bundle or individually.