Molasses is rich in chelates, chemical compounds which latch onto iron oxides and pull them into solution. Soak a rusty thing in molasses, the theory goes, and all the rust will go away. Eventually.
Molasses is also really cheap if you buy it from a farm supplies store. 12kg for about NZ$20. Mix it 1:3 with water, and soak away, stirring every couple of days to encourage the chelated rust to move away from the surface.
It works! It’s completely gross, but it works!
That’s what a tank of molasses looks like after sitting for 2 weeks. Not pleasant. It might have been less disgusting if I had left the lid off. The molasses won’t remove paint or oil, so I had to wash the block before soaking it. The engine paint was pretty crappy and came loose after a week’s soak, so a wire brush was enough to remove it.
Once the rusty thing has soaked for a couple of weeks, it comes out coated with black sludge, which hoses off easily to reveal lovely clean metal underneath.
Before and after shots:
I’m pretty happy. The results are better than the $100 hot tank clean we had done to our last engine, it cost $20, and the molasses bath is still perfectly useful for other things (I have the flywheel and pressure plate in there now).
The old parts washer worked adequately. Surprisingly well, actually, for a converted dishwasher. But someone wanted something a little more professional, and that could take diesel without bursting into flame. So picky.
It works pretty well, especially with a 300W heating pad on the underside to keep it warm.
Note the engine block in the first picture- it’s currently in a vat of molasses, slowly having the rust chelated away. More on that later (unless it dissolves completely).
The final thing I’ve achieved is to prime the wok with a grey/green epoxy primer. It’s not the right colour for the engine, but it’s *so pretty*. I’m tempted to leave it like that… maybe on the next car.
Work continues on the new/spare engine. I finally found the courage to try that welding trick to remove a bearing race from a blind hole. Bugger me, it works.
I shouldn’t have been so surprised. I’ve warped enough steel with weld to know that weld shrinks as it cools. Welding so close to a large, complicated, precision aluminium casting is a bit fraught though.
The fancy(?) airbox I built works well now, but is a tiny bit big- it sometimes touches the wiring loom, and you can hear it vibrating through the firewall. It’s almost like I built it to suit a car without an inch of Dynamat on the firewall. Weird.
It’s also a bit rectangular. I’m sure I can make something better. But first we design it with CAD:
I have discovered the joy of using a former. Spending half hour making something you were only going to throw away seems like a waste of time, but it makes shaping the sheet metal amazingly easy, and very accurate.
No, I’m not showing what the welds looked like before linishing them back. Pulse welding might keep the sheet metal from warping, but it’s not pretty.
Test fit box, add an air inlet, and then paint:
So pretty. I even treated it to a new air hose, since the old one was a bit crap. Rubber end seals made out of a bit of old gumboot for Kiwi authenticity.
The new air filter is from a Nissan Tiida or Cube, a 1.6litre engine that makes 112hp, so it should flow enough air.