Understanding the details and sizes

The engines used 16-valve timing mechanism with two located in the cylinder head camshafts. The drive shaft is carried by the crankshaft by two roller chains on engines and GA14DE GA16DE, a roller chain on the engine SR20DE.

The cylinder head is cast from an aluminum alloy, has four valves per cylinder; hemispherical combustion chamber. The cylinder head pressed into the seat and valve guides. Bearing housings camshaft handled integrally with the cylinder head and a detachable lid. The correct position of the head on the cylinder block is fixed with two mounting bushings.

The mechanism for the timing are: cylinder head, camshafts, intake and exhaust valves, valve springs with the details of the installation, valve guides, hydraulic pushers or pushers with shims, levers, drive chains, sprockets, tensioners drive chains (Fig. 2.13 and 2.14).

The height of the cylinder head engines GA measured between the surface mating with the cylinder block and the reference plane and head bolts of 117,8-118,0 mm.

The height of the cylinder head engines SR measured between the mating surfaces of the head and should be 136,9-137,1 mm.

Tolerance of flatness coupling with the cylinder block is not more than 0.1 mm. When sanding the surface allowed the removal of the metal does not exceed 0.2 mm.

Cast iron valve guides pressed into the cylinder head. Preload for pressing plugs in the cylinder head is 0,024-0,059 mm.

The diameter of the holes in the cylinder head for pressing guides, mm:

New 9,475-9,534

repair 9,723-9,734

The gap between the valve stem and guide bushing for intake valves 0.02-0.05 mm for the exhaust valves 0.04-0.07 mm.

The protrusion valve guides 11,5-11,7 mm.

Steel valve seats are pressed into the cylinder head.

The diameter of the holes in the cylinder head for pressing repair the valve seats, mm:

Inlet:

engine GA14DE 30,500-30,516

engine GA16DE 31,500-31,516

Graduation:

for all engines 25,500-25,516

The dimensional characteristics of engine valve stems GA are presented in Table. 2.5.

Table 2.5 Dimensional characteristics of the valve seats and the engines GA14DE GA16DE

Cylinder head gasket made of synthetic material (asbestos-free) silicone is harness on the perimeter and metal edging

holes around the cylinders. Gasket set the mark "TOP" in the direction of the cylinder head.

On engines GA14DE and GA16DE apply mechanical pushers cylindrical holes moving in the cylinder head. On top of the pushers has a recess for setting shim. The outer diameter of the pushers 29,960-29,975 mm. The diameter of the holes in the cylinder head 30,000-30,021 mm. The clearance between the pusher and the wall of the bore in the cylinder head 0,025-0,061 mm.

The engine SR20DE mounted hydraulic pushers providing gapless operation timing. The outer diameter of hydropushers 16,980-16,993 mm. The diameter of the holes in the cylinder head 17,00-17,02 mm. The clearance between the pusher and the wall of the bore in the cylinder head 0,07-0,04 mm.

In each combustion chamber has four steel valves (two inlet and two exhaust), driven by camshafts pushers. The dimensional characteristics of engine valves are shown in Table GA. 2.6.

Table 2.6 Dimensional characteristics of engine valves and GA14DE GA16DE

On the valve guides are pressed valve stem seals. Each valve has a spring, the same for the intake and exhaust valves.

The length of the spring in a free state:

- Engines and GA14DE GA16DE 41,19 mm;

- Engine SR20DE 49,36 mm.

Spring length under a load of 34.5 kg should be equal to 25.26 mm.

The maximum allowable misalignment of turns spring:

- For engines and GA14DE GA16DE 1,8 mm;

- Engine SR20DE 2,2 mm.

The camshafts are made of cast iron, intake shafts - pyatiopornye, graduation - shestiopornye.

Height cam camshaft engines is:

- Engine GA14DE: 39,38-39,57 mm;

- Engine GA16DE: 39,38-39,57 mm for the inlet camshaft: 39,88-40,07 mm for the exhaust camshaft;

- Engine SR20DE: 28,408-38,598 mm for the inlet camshaft; 37,92-38,11 mm for the exhaust camshaft.

The maximum allowable wear cam 0.2 mm.

The gaps in the mechanism of the valve motors GA at the hot / cold engine up, mm:

intake valves 0,32-0,40 / 0,25-0,33;

exhaust valves 0,37-0,45 / 0,32-0,40.

The diameter of the bearing journals camshafts, mm:

GA14DE engines and GA16DE:

neck ?��1 (from the camshaft drive) 27,935-27,955

Cervical ?��2-5 23,935-23,955

engine SR20DE 27,935-27,955

Radial clearance of camshafts, mm:

Rated 0,045-0,086

maximum 0.15

The axial clearance of camshafts, mm:

GA14DE engines and GA16DE:

Rated 0,070-0,143

maximum 0.2

engine SR20DE:

Rated 0,055-0,139

maximum 0.2

Camshafts on the intake valves is marked with ?�I?�, the exhaust valves - "E" (Fig. 2.15).

The numbering of the camshaft cover is shown in Fig. 2.16.

GA engine timing are shown in Table. 2.7 without clearance between the cams of camshafts and pushers.

Table 2.7 Valve timing engines GA

Timing on engines GA held by the crankshaft with two chains. One chain, which has 80 units, rotates the intermediate star, second, has 54 managers, transmits the rotation of the intermediate sprocket camshafts. Camshafts Engine SR20DE are a roller chain. The chains are tensioned with hydraulic tensioners.