I've never put this in an engine, but I have used it to de-rust metal and it is next to amazing. This stuff really works.
http://www.harborfreight.com/1-gallo...ver-96431.html
Remove rust in seconds without scrubbing. Evapo-Rust™ is so effective it is used by the 4th Infantry Division to maintain the M1A1 Abrams battle tank.
- Removes even heavy rust completely
- Easy to use, just soak parts in room temperature solution
- Requires no special equipment
- No acids, bases, solvents or other toxic ingredients
- Will not harm unrusted steel, safe on other metals
- Biodegradable—can be disposed of safely into sewer
- One gallon derusts up to 300 pounds of heavily rusted steel
- Will not affect plastic, PVC, Viton and most paints
Some of the DFW guys have had good luck putting a little tide detergent in the engine and running it. gets nice and soapy and then you flush. I don't think that would get rid of your rust problem.
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1930 Cabriolet
1931 Coupe
1931 Roadster
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DMAFC / THEM! TX