Assembly of the Mazda 6 car engine

Assembling the engine after preparing and inspecting parts for assembly

Blow compressed air through the cooling channels, lubrication channels, cylinders and crankcase

Insert the connecting rod into the piston, lubricate the piston pin with engine oil and press it into the connecting rod using a tool, or with a hammer and a suitable mandrel inserted into the inner hole of the pin

The piston should be pressed with the boss against the upper head of the connecting rod in the direction of pressing the pin, which will allow it to take the correct position

The pin is inserted into the upper head of the connecting rod with an interference fit, therefore, to facilitate assembly and maintain its fit, it is recommended to heat the connecting rods by placing them with the upper heads for 15 minutes in an electric oven heated to 240º

The heating temperature of the connecting rod can be checked with a thermochromic pencil

To properly connect the pin to the connecting rod, you need to press the pin in as quickly as possible, since after it cools down, the position of the pin can no longer be changed

Install the piston rings in the reverse order of removal, arranging them as shown in the figure

Install the lower compression ring downward with a recess (shown by the arrow) into the second groove

The "Y" markings on the compression rings must point upwards

Orient the rings as shown

Install the rings on the rest of the pistons

The locks of the upper and lower rings of the composite oil scraper ring should be located at a distance of 25-30 mm, respectively, to the left and right of the expander lock

We lay the upper main bearing shells in the bed of the cylinder block

Lubricate the liners with engine oil

Install the crankshaft into the cylinder block

We put the lower shells in the main bearing frame caps

Upper and lower main bearing shells may differ in the location of the oil supply hole

We install the liners so that these holes coincide with the holes of the channels for supplying oil in the beds of the main bearing supports

After installing the liners in the sockets, their ends protrude slightly, therefore, for the correct orientation of the liners, when finally tightening the bearing cap bolts, make sure that the protrusion of both ends is the same

Lubricate the crankshaft main journals with engine oil

Lubricate the liners in the crankshaft main bearing caps with engine oil

Installing the main bearing cap frame

To install the frame of the crankshaft bearing caps, you need to use a soft-faced hammer made of brass, lead or polyurethane

It is forbidden to install the covers by tightening the fasteners, since in this case the seating surfaces of the covers and the cylinder block will be damaged

We install the bolts of the covers, evenly tighten the bolts to failure, without completely tightening

After that, unscrew the bolts one turn and tighten with a torque of 50 Nm and tighten by 50º, and then another 15º

We must replace the bolts of the main bearing caps with new ones

We check the correctness of the assembly by turning the crankshaft by hand a few turns.

The shaft should rotate freely and smoothly

Install the liners in the connecting rods

Lubricate the cylinder mirrors, pistons, piston rings and connecting rod bearings with engine oil

We install a device for compressing the rings on the piston and, turning the screw, compress the piston rings

Turn the crankshaft so that its connecting rod journal, on which we mount the connecting rod and piston group, is set to TDC

We install the piston in the cylinder, in accordance with the marking of the cylinder number on the connecting rod

We press the hammer handle on the piston and move it from the mandrel to the cylinder

We also install pistons in the remaining cylinders

When installing pistons in cylinders, the arrow on the piston and the inscriptions on the connecting rod must face the front of the engine

When installing the piston into the cylinder, you need to be careful not to damage the connecting rod journal of the crankshaft with the lower head of the connecting rod

Installing the connecting rod bearings into the connecting rod caps by aligning the mounting tab of the bearing with the notch on the cap

Lubricate with engine oil the connecting rod bearings in the connecting rod caps and the connecting rod journals of the crankshaft

Install the connecting rod cover by connecting the connecting rod to the crankshaft journal and aligning the marks on the connecting rod and the cover

We screw in the connecting rod bolts without completely tightening them

Tighten the connecting rod bolts to failure without completely tightening them, then unscrew them one turn, tighten with a torque of 25 Nm and tighten by 30º, and then another 15º

Checking the ease of movement of the connecting rod along the crankpin.

When jamming, unscrew the connecting rod bolts and re-tighten them to the nominal torque

Check the side clearance of the connecting rod, for the engine it should be 0.14-0.36 mm

Increased clearance indicates excessive wear on the crankshaft crank webs. In this case, replace the crankshaft

In the same way we fix the covers of the remaining connecting rods

We check the axial clearance of the crankshaft, for the engine it should be 0.20-0.45 mm

Increased clearance indicates wear on the crankshaft support flanges or the middle main bearing bed.

In this case, we replace the crankshaft. If this does not reduce the axial clearance, the cylinder block will have to be replaced

Installing the crankshaft rear oil seal

Install the oil receiver and oil pump

Installing the oil sump

Installing the flywheel

Next, we assemble the engine in the reverse order of disassembly

After installing the engine on the car, we run it in a simplified cycle in the following order

We start the engine and let it run without load for the following cycle:

• 820-900 min-1 for 2 minutes;
• 1000 min-1 for 3 minutes;
• 1500 min-1 for 4 minutes;
• 2000 min-1 for 5 minutes;

Do not bring the engine to maximum speed

During engine operation, we check the tightness of the engine and its systems, oil pressure, pay attention to the presence of extraneous noise

If extraneous noises or other malfunctions are detected, we stop the engine and eliminate their cause

When operating a car, you must follow the modes provided for the break-in period of a new car