Split Gear: what is it, setting and adjusting

The car has a lot of interesting details, which only car mechanics or people who are very keen on technology know about. One of these details is a split gear. Fans of tuning also know about this element. Let's find out what kind of detail it is, and what it's for.

Phase Shifters and their function

Most of the new engines are equipped with phase shifters, which make it possible to perform the adjustment of the power unit on the basis of the crankshaft speed. This is necessary in order to obtain the maximum torque in a larger speed range.

If you take any manual for the car, then it will indicate the characteristics of the horsepower of the engine and the maximum torque that the engine can produce at certain crankshaft speeds per minute.

Here's to take, for example, a common model of Renault-Logan. The engine is capable of delivering 170 horsepower at 6,000 revolutions of the crankshaft. The maximum torque is 270 Nm at 3250 rpm. From these figures it can be seen that the index of the maximum torque can be achieved even at medium revs. And the maximum power becomes available only after 6000 rpm. If such a motor is equipped with a phase shifter system, it will have a wider range at which the engine produces the highest torque, and not the one that is built into the design by the manufacturer.

The camshaft timing gear performs roughly the same functions as the phase shifter. This part has a similar design as the camshaft. It can be rotated for certain angles forward or backward.

Split Gears Function

A conventional pinion mounted on the camshaft is designed to transmit torque from the camshaft to the camshaft . The part is a single piece without any moving parts. The split gear consists of two components - they can move relative to each other. This design allows you to change the angles of the camshaft, without affecting the tension of the timing belt or drive chain.

For example, this part on VAZ engines can rotate the shaft 5 ° in one or the other direction. It is necessary to understand here that it is possible to change the characteristics of the engine operation only in specific modes - in the upper or lower ranges.

Very often to increase the power and other characteristics of the engine change the camshaft and its gear. If you replace them, you can adjust the valve timing in different ways. It will also be possible to change the valve retard angles. If the engine is replaced by a gear instead of the camshaft, then only the overlapping angles can be changed.

How it works?

For example, the torque changes from 4000 turns to the lower side, for example, to 3000. This effect is achieved by turning the camshaft in the direction of the crankshaft. In this case, the phases of the gas distribution are set so that there is a slight advance. This affects the reduction in the closing angle of the intake valves.

But it must be remembered that if the engine spins to the maximum possible speed, its cylinders will not have such a dense filling. This does not have the best effect on speed and power output.

Design

The cut-off gear represents two elements - a crenellated wheel and a hub. They are connected together by means of bolts. The holes for this are made so that the hub can be turned in relation to the crown. The hub is attached to the camshaft via a key. Such a fixation ensures the rotation of the hub together with the camshaft.

The main reasons for setting the split gear

Specialists in engine tuning distinguish two reasons why many install this part. It should be taken into account that the sports camshaft does not give anything unless the camshaft timing gear is additionally installed (VAZ will not go faster). When assembling at the factory, the manufacturer often deviates from the data indicated in the drawings. Therefore, the parameters of the motors intended for one model of cars differ from the initial ones. These errors are no more than ten degrees in each side. Naturally, this has an effect on the power characteristics of the motors. Having installed the split gear, the owner of the car gets the opportunity to adjust and perform the optimization of the torque moment.

The installation of tuning camshafts allows to significantly increase the torque of the power unit. Split gear WHA - more + 5% to power characteristics. It's pretty good.

Method of adjustment

Today in the automotive market there are gears designed for virtually any car from AvtoVAZ. For each model, there is a customization technique. Consider the principle of adjustment in the example of VAZ-2108-2112.

VAZ-2108-21099

So, the first thing on the gear is the points on the moving and fixed part. They are needed to perform the correct installation - all operations are the same as in the case of the standard part. Further, after the points are dotted, the slit gear is put in place. Installation of it does not differ from the standard one. Then you can put on the belt just installed.

It is important to check several times that the labels are completely identical. To obtain optimum performance, it is necessary to monitor the degree of opening of the valves. This indicator is strictly defined and set at the design stage of a particular camshaft. If the valves are open at a large value from the passport data, then loosen the bolts on the gear which are located outside. Then turn the distributor element to the outer half of the split so that the parameter can easily be adjusted.

When the camshaft position is correctly set to zero, more precise phase adjustment is required. If the upper shaft is turned in the direction of rotation of the lower (cranked), thus increasing the thrust. Torque will be available in the middle and low ranges. If the camshaft sprocket (VAZ-2108 or another car model is not so important) and the shaft itself is rotated to the side opposite to the crankshaft rotation, then the power increases.

By performing this correction procedure, it is important not to leave the initial point more than half the tooth on the pulley. If the gear is adjusted for the carburettors, then after each manipulation with the shaft, correction of the ignition angle is required. Otherwise, there will be a malfunction in the system.

16-valve engines VAZ-2110-2112

If the adjustment of the split gear is carried out for these motors, then it is recommended to install the tuned camshafts together with it. Orientation follows the marks made at the factory. The closing / opening of the valves is approximately adjusted around them. Then the piston in the first and second cylinders is fed to the top dead center position. Also on the gear carefully put on the belt.

After that it is necessary to set the indicators. They will help to determine how the valves will move. It is necessary to find a position in which the mechanisms of the fourth cylinder are completely closed. Then, with the aid of the gear and the indicator, adjust the closing. Then you can tighten the fixing bolts, assemble the power unit and perform a test run.

Classic VAZ

On the classic eight-valve engines, the gear is exhibited at standard factory marks. Further, the closure of the valves is adjusted. The first and fourth pistons are placed in the TDC. The legs of the indicator should rest against the rocker.

In turn, set the point when the valves are closed on the first cylinder. After that, the exact position of the TDC on the tuned gear is set. Do not forget about the gear ratios on the rockers and the point where the indicator is set. Then the gear is fixed, the engine is assembled and started.

Conclusion

Thus, with the help of one gear, it is possible to significantly improve the initial parameters of VAZ engines. This is a rather popular tuning of domestic engines.