Removing rust from cylinder walls

Question:

I pulled the cylinder heads from my engine in order to replace the gaskets and, unfortunately, I wasn’t able to replace them in a timely manner. As a result of my delay, rust has formed on the cylinder walls. My question is should I tear it all down in order to remove the rust in the cylinders or can I assemble the gaskets and heads without any damage to my engine?

Answer:

You don’t say how long the heads were off and how severe the resulting cylinder wall rust is.

If it’s quite heavy I would suggest taking the engine apart to address the problem. If it’s limited only to light surface rust you can carefully clean the cylinder walls without taking the engine apart.

There are numerous ways to remove light surface rust but for your situation I’d recommend using a very fine Scoth-Brite pad and kerosene.

Before attacking the rust, cut a piece of heavy plastic or cardboard into a circle that fits snugly down into the cylinders. Putting this into each cylinder will help keep contaminants from falling down onto the pistons and past the pistons into the crankcase.

Wear chemical-resistant gloves and keep the Scotch-Brite pad well moistened with kerosene as you scrub the rust off the cylinder walls. The kerosene will help remove the rust and will also keep the rust that comes off wet. By keeping the rust wet you prevent rust powder from getting into the engine.

Another way to solve your problem is to use a chemical rust remover. Chemical rust removers are available from various sources, including The Rust Store (theruststore.com).

Regardless of whether you remove the rust by scrubbing it off with a Scotch-Brite pad or strip it off with a chemical, it is essential that you thoroughly clean any foreign material off each cylinder wall. Use clean, lint-free rags and a solvent such as lacquer thinner to remove all traces of dirt, kerosene, rust remover, etc. and then put a very light coating of engine oil on the cylinder walls.