2. Visually inspect the block for cracks, rust and corrosion. Check if the threads in the screw holes are worn out. It would be a good idea to have the block checked for hidden cracks at a workshop that has the special equipment for this job. If defects are found, take a refurbished unit or replace it.
3. Check the cylinder bores for jamming and wear.
4. Measure the diameter of each cylinder at the top (just under the ridge), in the center and at the base of the cylinder bore, parallel to the crankshaft axis (photo). Then, measure the diameter of each cylinder at the same three locations across the crankshaft axis. Compare results with Specifications. If the cylinder walls are seized or worn, or if the ovality or taper is outside the limits given in Specifications, the engine cylinder block must be bored in an auto mechanic's shop. If the cylinder is bored during engine repair, larger pistons and rings will be required.
A telescopic template is used to measure the cylinder bore diameter |
After the telescopic template is installed according to the cylinder diameter, it is removed and measured with a micrometer to determine the size of the hole and cone |
Measure the diameter of each cylinder just below the wear ridge (X and Y), at the center and base
5. If the cylinders are in good condition and not worn, there is no need to bore the cylinder. Sharpen only what is necessary.
6. Before turning the cylinders, install the main bearing caps (without bearings) and tighten the bolts with the specified tightening force Specification.
7. To perform boring, you will need a tool of the appropriate size (with small stones), lots of fine or sharpening oil, rags and an electric drill. Place the tool in the drill, clamp it, and insert it into the first cylinder (photo). Lubricate the cylinder thoroughly, turn on the drill, and move it up and down the cylinder until a crosshatch pattern is created on the cylinder walls, with the lines intersecting at approximately a 60° angle. Make sure to use plenty of lubricant. Do not remove the bore from the cylinder while the drill is running. Next, turn off the drill and continue moving the boring bar up and down in the cylinder until it stops completely, then squeeze the stones and pull it out. Wipe the oil out of the cylinder and repeat the procedure on the remaining cylinders. If you don't have the tools or don't want to bore it, take it to a car repair shop where they can do it for a reasonable fee. An acceptable result can also be achieved by using a hard wheel on the flap in a power drill or by using sandpaper by hand.
Cylinders should always be rebored before installing new rings to give the bore surface the proper smoothness for the ring seating surface |
The cylinder bore should leave dashed lines intersecting at approximately 60° |
8. After this work is done, use a small file to file down the ridge formed at the top of the cylinder bores so that the rings do not hit it.
9. The engine block should then be thoroughly washed again with warm soapy water to remove all traces of the hard sand left behind during boring. Make sure all lubrication holes and passages are clean and thoroughly flushed with water. After this, rinse it, dry the block and apply anti-corrosion oil to all surfaces. Wrap the block in a plastic bag to keep it clean and install it on the stand.