Ask the Mechanic

Steve Thompson, Contributing Columnist

READER: I am overhauling the engine in an 851 Ford with the crankshaft still in the engine. I found out that this engine has liners. I am not familiar with dry liners, but I have heard from friends that they can be tight to get out and tight to install.

I borrowed a puller setup from a mechanic and got them out. Yep, they were very tight. Now, I am scared that the new liners will not go in the bore. I tried to push one in, and it was tight from the start.

What is the best way to get the new liners in the engine block? I have heard that can be a problem.

STEVE: You are dealing with a problem that is quite common, especially when you are doing an in-chassis overhaul when the engine does not go to a machine shop. (This answer also serves well as May's Safety Tip of the Month).

To make sure you get the liners in the bore without a problem, you need to buy about 5 pounds of dry ice. It will come frozen in a chunk in a bag and stored in a very cold freezer.

Dry ice is frozen CO2, which is carbon dioxide. The ice needs to be handled with special care, because CO2 likes to eat oxygen as it turns to a gaseous form. Therefore, you need to break up the ice in the bag and pour the ice over the liners in a box with ventilation. Breathing too much of the gas can be dangerous. I usually cover the box with a towel or garbage bag.

As it turns into a gas, the solid CO2 gets extremely cold. I mean really cold, at -109.3ºF.

Wait about 45 minutes, pick up the liners individually with gloves and quickly drop them in the engine bore. I suggest honing the block and cleaning it thoroughly before you buy the dry ice.

If you want to be certain the liners will go down without any trouble, while the liners are freezing, take a torch and warm up the block a little inside each cylinder. Keep a hammer and block of wood nearby to assist in knocking down the liners, if needed. The liners do not break easily. The key is to work fast.

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-- Write Steve Thompson at Ask The Mechanic, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email mechanic@progressivefarmer.com, and be sure to include your phone number.

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