The Great Pumpkin - '71 Duster

I conducted an experiment last night to try and de-rust the water jackets in my 340 block using Evaporust. It worked!

If you've been following along, I am in the process of slowly rebuilding my 416". I am at the point where the block needs to be cleaned before I can start re-assembly. I got the oil galley plugs out and was all set to go at it when I noticed a lot of scale through the deck water jacket holes. When it was first built, the block was hot taked but then it sat for several years and was exposed to temperature fluctautions. Seeing as I have a bunch of fancy new aluminum parts, I decided it would be best not to have a bunch of rusty scale from the bottom of the block flowing through them so the decision was made to try and clean out the coolant passages.

Problem is, the block is on a stand so a regular coolant flush is not an option. So how to accomplish? Evaporust! Before pouring the solution in, I chipped out whatever scale I could from the top. Some had actually closed up the larger openings which likely would have been a problem down the road. After that process, the two timing cover bolts exposed to the coolant passages were threaded in with pipe tape and the solution was poured in as far up as possible. It started reacting immediately and bubbled up through the front water pump outlet. After it settled down it was topped off just below the pump outlet hole which put it about an 1 1/2"-2" below the deck surface.

Honestly, it worked beautifully. Everything below that fill point level literally looks brand new. It is frustrating that I couldn't get the liquid all the way up to the top though. The block was rotated on the stand so the deck was parallel to the floor. The water pump outlets are obviously below the deck surface at that angle so I would have needed a large stopper or something. I probably could have rigged something up but didn't put the effort in. Perhaps on the other side.

Anyway, here are some pics. The area below the red line is what was cleaned. This is a huge improvement.
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Draining the liquid and cleaning the remaining residue out will be a bit messy but it was definitey worth doing. Evaporust cleans up with straight water so once it stops raining out I'll stick a hose down there and flush it out as best as I can. Then it's rinse and repeat for the other side.

In other news - I transferred the existing piston rings from the previous lower compression slugs to the new ones. I found some of the ring corners to be really sharp so I gently filed the edges down, just to break the sharpest points. I cleaned the crank up as well. There are some slight grooves in one rod journal (which is why I replaced the rod bearings) but not enough to catch a nail on it so I'm going to let it ride. It's eye opening how easily dirt and debris can wreak havoc on these things.

From the wiring dept., my new Holley EFI "Power Distribution Module" thing showed up yesterday. This box provides a central point for powering the EFI, ignition box, fuel pump, a cooling fan and a few other accessories. The module comes with the newer Sniper 2 systems so I will have to translate the connections to the Terminator X ECU. The main harnesses for the two systems are completely different so it will take a little doing but should work without much hassle. This box should really help streamline the wiring but I will have to re-configure some of things I did already. I just wish it had been available when I bought the Terminator ECU last year.

More to come.