318 Small-Block Budget Build, Part 1

Before we ordered any parts, we needed to know what to order. Did we need new pistons? To find out, we used an inside expansion tool and a set of veneer calipers to determine the condition of our cylinders. We found our worse cylinder was 3.912 inches in diameter, so we were good. We also used the expanding tool to check for out-of-round and tapered cylinders. All cylinders were within tolerance.

To clean the block, we used a pressure washer, biodegradable cleaner, and brushes. Don't worry about the grass; that's where the new garage now stands.

Make sure all gasket surfaces are clean.

As soon as everything was cleaned, we coated the cylinders with motor oil. Just because we weren't going to bore our 318's cylinders didn't mean we had to prep them. Using a simple cylinder hone, we honed each cylinder until a nice crosshatch pattern appeared. After that was done, we cleaned the block again and then oiled the cylinders. Even letting the block sit just overnight in a home garage will allow the cylinders to flash rust.

Installing cam bearings may not be something everyone is willing to do. It takes a special (read "expensive") tool and is a tricky process if you don't know what you're doing. Also, many times the bores are slightly off, and the cam journals will need align-honed. It's a good idea to have you local machine shop do this portion for you.

Our next step was to disassemble the heads so we could take them to the shop. This simple valvespring compressor tool is an inexpensive one we found at Sears for $20. Begin by adjusting the tool so that it compresses the valvespring just enough to remove the locks. (TIP: gently hit the top of the retainer with your mallet before compressing the spring).

After we removed the valves, we realized the exhaust guides were excessively worn and some of the valve seats had severe pitting. This was when we decided to replace the guides and go with larger valves.

Since we were having the heads worked on anyway, we decided a little home-porting wouldn't hurt. we simply did some gasket matching to the runner ports, removed the pinch area where the pushrod hole is located, and blended the guide bosses. Be careful not to take too much metal from the "pinch" area or you'll break through the casting. You can see in the photo that the port on the left is finished, and the one on the right is untouched.

This photo shows the difference between the finished port on the left and the untouched surface of the port on the right.

Tune in next month when we start reassembly.