The camshaft and pushers

On engines mounted hydraulic tappets, which automatically compensate for the gap between the cams of the camshaft and the respective valve stems. Check and adjust valve (thermal) gaps in such engines are not required. However uptime pushers must use motor oil recommended by the manufacturer, and replace it through the required ranges of operation. When starting a cold engine knock may occur valves, which takes about 10 seconds to as long as the oil pressure in the lubrication system is raised to the desired value and the hydraulic tappets not eliminate gaps. If the engine does not start up within a few days, the sound of valves can last longer. It is necessary to avoid sharp changes in engine speed, to avoid damaging the hydraulic tappets. When warming up the engine maximum rotational speed of the crankshaft must not exceed 2000-2500 min-1 for 10-15 minutes, or until the termination of knocking valves.

Removing the camshaft and hydraulic tappets

If knocking does not stop, check the serviceability of the pushers. To do this, follow these steps:

- Disconnect and remove the elements of the fuel injection system;

- Remove the cover 6 (Fig. 3.8, 3.9) of the cylinder head;

- Remove the slinger 4 (see. Fig. 3.8) and the gasket 5 (see. Fig. 3.8, 3.9) the cylinder head cover;

- Rotate the crankshaft until the installation of the cam follower checked up the work surface;

- Click on the pusher a wooden or plastic wedge (Fig. 3.10). If the free wheeling of a pusher is greater than 0.1 mm, replace the plunger.

To remove the camshaft and tappets, do the following.

For all engines:

- Set the first cylinder at TDC compression stroke (see. Sect. 3.1.4);

- Remove the top cover of a belt drive of a camshaft;

- Loosen the belt camshaft drive and remove it only with the camshaft gear, leaving him in engagement with the rest of the gears of other trees;

- Secure the upper end of the camshaft drive belt so as to maintain its tension;

- Remove the bolt and remove the camshaft sprocket.

For engines SOHC:

- Remove the gasket 12 (see. Fig. 3.8) bearing cap number 1 camshaft and the rubber plug 13 mounted at the rear of the cylinder head;

- Put the label serial numbers and positions of covers 2, 3, 4, 5 (Fig. 3.11) camshaft bearing 1 for their subsequent proper installation;

- Unscrew nuts 20 bearing caps 1 and number 3, then number 2 and 5. The nuts need to turn away alternately crosswise on a half-turn in one pass as long as they will not be able to turn away by hand;

- Remove the cover 2, 3, 4, 5 bearings;

- Remove the camshaft 1.

For engines DOHC:

- Make sure that the first cylinder is set to TDC of the compression stroke, wipe the oil from the chain drive of the inlet camshaft, check the coincidence of timing marks on the camshaft sprockets (see. Fig. 3.6), if the labels are not available, apply them to the stars;

- Put the label serial numbers and positions of covers 16 (Fig. 3.12) for their subsequent proper installation;

- Loosen the nuts 17 alternately fixing covers 16 bearing number 5, 7 and 9 of the camshaft 2 inlet valves;

- Unscrew nuts 17 bearing caps 6 and 8. The number must be nuts to turn on alternately crosswise on a half-turn in one pass as long as they will not be able to turn away by hand;

- Loosen the nuts 17 alternately fixing covers 16 bearing number 1, 3, and covers 23, 24 of the camshaft 1 exhaust valves;

- Unscrew nuts 17 bearing caps 2 and 4. The number must be nuts to turn on alternately crosswise on a half-turn in one pass as long as they will not be able to turn away by hand;

Remove the camshafts 1 and 2 together with the chain 7.

For all engines:

- Remove the hydraulic tappets 9 (see. Fig. 3.11) or 8 (see. Fig. 3.12) with a rubber suction cup, place the removed pushers in a container filled with fresh engine oil, in order of removal to follow them properly installed in its place .

Fault detection of a camshaft and hydraulic tappets

In the presence of the taper lateral surfaces of the pusher, it must be replaced. If, after a cold start knocking valves lasted a long time, and when testing it was found that lifters are OK, replace the engine oil and oil filter.

Inspect cams and necks of a camshaft. In the presence of cracks, scratches, pitting and wear they must be replaced.

Inspect the camshaft sprocket and chain drive of the inlet camshaft. If sprocket worn or damaged sprocket and the camshafts must be replaced.

Inspect the working surfaces of bearings of a camshaft. In the presence on them of cracks, scratches, pitting and wear necessary repair the cylinder head in a specialized workshop or replaced.

Measure by a micrometer diameter necks of a camshaft at several locations each. If the diameter is at least one less than the nominal neck, the camshaft must be replaced.

To determine the axial play of the camshaft, remove the hydraulic tappets, clean working surface of the camshaft bearings, camshaft and install the bearing caps. Measurement of an axial backlash with a dial indicator (Fig. 3.13) in the following sequence:

- Set up the tripod dial gauge;

- Set the indicator, with his measuring rod should rest on the end of the camshaft;

- Move the camshaft to the stop in the direction of the indicator;

- Set the zero indicator;

- Move the camshaft in the opposite direction until it stops;

- Determine the amount of axial play of the camshaft on the testimony of the indicator.

If the backlash exceeds the limit, measure again. If the second metering gap is maintained, it is necessary to replace the camshaft and / or cylinder head. Consult an expert.

Installation of hydraulic tappets and camshaft

Before installing a new camshaft, make sure that it corresponds to the model of the engine. To identify the camshaft thereon stamped character string A (see. Fig. 3.11, tab. 3.3) and B cell labeling.

Assembling the cylinder head in the following sequence.

For all engines:

- Lubricate the hydraulic lifters and sockets for installation in the cylinder head;

- Set the hydraulic tappets to their seats;

For engines SOHC:

- Grease necks and cams of a camshaft with engine oil and install the shaft in the bed of the cylinder head so that the cams of the first cylinder are pointing upwards;

- Set the cover 3 and 5 (see. Fig. 3.11) bearing number 2 and 5;

- Tighten the nuts 20 bearing caps 2 and number 5 alternately crosswise on a half-turn per pass to 10 N ?� m;

- Set the cover 2 and 4 bearing number 1 and 3;

- Tighten the nuts 20 bearing caps 2 and number 5 alternately crosswise on a half-turn per pass to 10 N ?� m;

- Lubricate sealing lips 18, set the collar to the camshaft and a mandrel insert into the cylinder head;

- Install a new rubber plug 19 and the front pad 12 (see. Fig. 3.8) the cylinder head cover.

For engines DOHC:

- Set the circuit 7 (see. Fig. 3.12), the drive of the inlet camshaft so that the timing marks are opposite each other;

- Establish camshafts in bed bearings and check coincidence of adjusting labels (see. Fig. 3.6);

- Install a new oil seal 22 (see. Fig. 3.12) on the front end of the exhaust camshaft, after brushing her working edges of engine oil;

- Set the cover 16 bearing number 6 and 8 inlet camshaft into place in accordance with the numbering giving sections on the corners of the covers to the intake manifold;

- Tighten the nuts 17 bearing caps number 6 and 8 alternately crosswise on a half-turn per pass to 15 N ?� m;

- Place the cover back of the cylinder head;

- Set the cover 16 bearing number 5 and 7, giving the sections at the corners of the covers have to intake manifold;

- Tighten the nut bearing caps 17 number 5 and 7 to 15 N ?� m;

- Set the cover 16 bearing number 2 and 4 exhaust camshaft so that sections in the corners of the covers have been directed to the intake manifold;

- Tighten the nut bearing caps 17 number 2 and 4 alternately crosswise half a turn per pass to 15 N ?� m;

- Establish covers 23 and 24 and cover 16 bearing number 1 and 3, the exhaust camshaft and alternately tighten the nut covers 17 to 15 N ?� m;

- Lubricate sealing lips 22, install it on the camshaft, and a mandrel insert into the cylinder head.

For all engines:

- Install the woodruff key 21 (see. Fig. 3.11), or 25 (see. Fig. 3.12) and the toothed pulley 6 (see. Fig. 3.11) or 3 (see. Fig. 3.12), the exhaust camshaft;

- Set the timing belt and adjust its tension (see. Sect. 3.1.4);

- Install the slinger 4 (see. Fig. 3.8) and the cylinder head cover;

- Set the elements of the fuel injection.