Creature from the Black Lagoon

Dyno day is approaching rapidly, in fact it's tomorrow. In preparation for dyno tuning, I thought it would be good to get my cooling system in order. Running an engine on a dyno, especially at high load steady state conditions, puts a lot of stress on a cooling system. I'd read somewhere that a significant portion of a dyno session can be cooling time and dyno time is not cheap. So not only does it make sense from a performance standpoint to have a good cooling system, but also from an economic standpoint.

Since this engine has a cast iron head and block it can accumulate a fair amount of rust inside it. In the past couple years, I've kept straight water in the system because I didn't want to deal with sticky coolant every time I had to unhook a coolant hose. Living in Southern California, it never freezes so I can get away with this. On the flip side, this created even more rust in the system.

mmm iron hydroxide!

I knew that there are a number of rust removal products but I searched for quite a while before I found a product I wanted to try. I settled on Thermocure, made by EvapoRust. They claim it dissolves the rust and suspends it in the water. I had tried standard EvapoRust on a bunch of old bolts and it worked like a charm. The evaporust turned black, and the bolts came out clean. ThermoCure seemed to have good reviews and was a reasonable price, so I ordered a bottle and added it to the radiator.

The instructions say to let the vehicle run for four hours with the product in the coolant. I'm not sure I ran it that long, but I let it go through several heat cycles and sit for a couple weeks. I drained both the radiator and the block and got this nice dark brew. 

Not quite convinced that all the gunk was out, I filled the system with pure water, heat cycled it, and drained again. This turned out to be a good idea because as you can see, there was still a bit of sediment left in the engine.

At this point I called it good and filled up with a 50/50 coolant mix.

This time tomorrow I'll be heading to the dyno. Hopefully my tuner (who is NOT Matt Happel) doesn't subscribe to the Matt Happel School of Tuning. Wish me luck!

PS: I never put in my HP bets on the last post so here goes. 91: 280HP / 300TQ  E85: 340HP / 360TQ