Rotary engine Mazda RX-8-dismantle the engine.
(all photos clickable)
After the increase of customs duties on cars in 2011 year to lovers of powerful cars with the rear-drive become more difficult: because the old cars wear out and bring something with a motor has become quite expensive. However, motorists are still available secondhand Mazda RX-8 with a rotary-piston engine which is only 1.3 liters and power that ranges from 192 to 231 BHP is whether to get involved with this motor, trying to figure out the correspondents, together with specialists of ONE HUNDRED.
A bit of history
German inventor Felix Wankel in the 20 's. The 20th century sought to simplify engine design, delivering him from a large number of details. He succeeded in RAP no crank mechanism, Pistons, valves, and a complex system of their drive. The role of the cylinders does the stator shape epitrochoids (similar to the razduvšuûsâ in the middle of the figure 8). As the piston is a triangular rotor. He glides over the surface vertices of the stator, forming three enclosed cavity. In each of the three cavities for one revolution is 4 cycles: intake, compression, stroke and release-as usual. The rotor is moving along a complex path, which provide two gears. One of them, inside, still attached to the rotor and "runs" fixed gear, mounted on a side wall of the stator. The rotor rotates on the shaft with an eccentric. With the shaft and torque of the engine. However, to understand how this works, just study this video.
Ideally, all looks great: a minimum of details, maximum ease and efficiency. Rotary motor dimensions significantly smaller piston engines and takes not so much space. The RAP is capable of withstanding high revolutions, vibronagružennost′ less. Due to fewer parts engine has a small inertia, and therefore in response to the gas spins up instantly!
But, as is often the case, the rotary engine flaws stem from the same advantages. Imperfect combustion chamber shape-cause of an inefficiency and high content of harmful substances in exhaust gases. Fuel consumption is higher than that of classic motors. In addition, a large area of the combustion chamber causes a greater teplonagružennosti of the motor. The main enemy of any rotary engine is generally disappointing Apex experience wear and tear-seal between combustion chambers. This very small plate have to be huge changes in temperature and pressure with a small spot of contact with the surface of the combustion chamber. To ensure proper lubrication of the seal into the intake manifold has to additionally inject oil. And this increased oil consumption and the deterioration of environmental parameters. And stuff, stuff, stuff-the motor that you can talk for hours. The design at first glance seems to be easy, but the nuances are not considered.
Many automakers at the time refused to RAP development, although a patent on production of engine bought: Daimler-Benz, General Motors, Nissan, Alfa Romeo, Toyota. Seriously some time engaged in the rotors of VASES. And yet there was this car as the NSU Ro 80, from 1967 onwards was produced a few years with a rotary engine capacity of 995 CC power 113 HP but in the end, only Mazda continued to work on improving the design of the Wankel, having achieved very good results. And today we are at the station, specializing in repairs of engines, Mazda RX-7 and RX-8.
Proceed to disassembly
Us motor 13v. His power-192 HP, mileage is about 180.000 km. The overhaul was carried out at 120,000 miles. The owner of the car came with complaints of poor starting warm engine and high oil consumption through burning. It's time to talk about a resource and cost of repairs.
-In the United States, Japan and European countries, these motors are driving without the intervention of about 200 thousand kilometers, says master specialized HUNDRED Viatcheslav. -But we have the motor resource is 100 thousand. There are fewer, because often they don't get proper maintenance and fuel quality. The first sign of an approaching major overhaul is the increased consumption of oil, bad run "hot" and a low level of compression. Before purchasing such a vehicle, be sure to use the special kompressometrom-compression must not be below 6.5 atmospheres. The cost of work on the bulkhead of the engine is about $ 1000 repair kit-about 1500. It provided that no partition, no major details were not injured. If inside a big wear and tear, scratches or damage, it is recommended that you replace the section, which costs about $ 700. If the motor care, do everything on time, the engine can drive and 150 thousand. All very predictable: change oil after one enough to measure compression-it should be 6.5 -8 atmospheres. Gradually, but it falls below 6-6 5 atmospheres, it is better not to bring, otherwise a remkomplektom did not get.
There are times when the cost of repair might not be practical. According to Vyacheslav, in this case from America you can order an engine overhaul, which took place in the factory, where all the basic details it replaced. The new engine of the can and does not distinguish. It cost about $ 4500. You can order a new one from Japan at a cost of about $ 6000 -6500. Can be seen and used.
-Resource strongly depends on how frequently the "Accesories" and what are they quality. Your customers, we recommend that you change the oil every 5 thousand miles. For different markets have different intervals: in Europe, for example, they make up 20 thousand. The air filter must be changed every 20 thousand kilometers. Tank fill only 95-th petrol, but best 98 minutes, although this is, of course, expensive. After all, the RX-8 fuel consumes mercilessly: in 15 litres or more. While I believe that consumption is quite adequate engine power.
Proceed to disassembly. Master drew attention to oil nozzles. In the rap section there is no direct contact with the pallet, so it forces the oil is fed into the section on the intake cycle.
-If they do not change, it could end badly. Note: rotary engine oil consumption should be. Which One? Original oil canister holds 5 liters, 1.5-3.5 liters pour enough for 5 thousand kilometers. It's all healthy. If there are nuances, the expense may be higher. If the flow is less, this should cause concern-means problem with nozzles. According to statistics of immature they almost 50 thousand kilometers.
The Mazda RX-8 has a oil cooler, depending on the version, there may be two or one. Our eyes have the oil temperature gauge. Oil is not immediately enters the radiators, but only reaches a certain temperature.
According to Vyacheslav as any motor, Rotary 13B fears of overheating, but it happens infrequently-total cooling system capacity is 9.5 liters, the big heat sink.
Turn off tray-gaze is tricky system protivootlivov. The RX-8 can safely participate in amateur track days.
Oil pump, according to Vyacheslav, very productive, there are two pressure reducing valve, overpressure oil.
Remove the lid of the oil pump. Vyacheslav said that the only chain (oil pump drive) in the motor almost eternal, problems with it never had.
Going Deep. The engine is mounted with screws 19 which are clamped in a certain sequence. Each bolt has a seal to prevent leakage of antifreeze. Unscrew them.
And here is the rotor. This video talks about the principle clearly Vyacheslav of RAP.
The specialist noted that the role of the compression rings here are apeksy.
-Small resource Problem is that seals should be on three planes. But this is difficult, so initially the compression ratio is lower in the rap, hence a lot of problems. In the old RX-7 all better. Turbocharged rotary engine of this car is more than 200, 000, subject to the competent services. The Mazda RX-8 height Apex is 5.3 mm, 4.5 mm is recommended for replacement, hence the "zhizn" give 0.8 millimeters. The RX-7 Apex is 8.1 mm height, it can rub off on a 1.6 mm. Therefore artificially underestimated resource, it seems to me-to get into the environmental framework and enhanced oborotistost′ engine.
-A set of four special candles worth 100 dollars. You cannot use the usual-you can instantly destroy the engine. You need to change them every 30-40 thousand kilometers. The main thing is not to confuse markings-different candles.
Less than an hour of work in the tranquil pace the engine was completely broken up. Check the status of items in the two sections showed that the first shifted insert the rotor. In both sections the signs of increased oil consumption-exhaust window half-zakoksovany. Inner wall partitions have the bully.
Vyacheslav argues that the engine overhaul was not practicable:
-General wear of the motor is high, moved down rotor, insert large sites require replacement. If restored, the kind of money you can buy two second-hand motor or one "rebildingovyj". Here you need to change the shaft, bearings, gaskets, apeksy, section. That is the price of quality restoration of motor-about 4000 dollars. But it's not scary. Sometimes, Apex falls and causes serious damage to other parts. By the way, the motor can start and ride on one partition. In this regard, of course, the engine suffers terrible bullying.
Is it worth it?
Vyacheslav, apart from the fact that repairs these machines myself on them goes. What he thinks about them? Is it worth buying?
I have family there and the Mazda RX-7 and RX-8. In fact in these cars very much good. The ride is nice: the motor spin up to easy elastic, 9000 rpm, depending on model. Great handling, design very interesting. Just in time to change the "Accesories", monitor the condition of the nozzles and compression. Besides the engine, there are extremely reliable-with electrical problems and nuances in the car chassis No. There is a choice-from more Mazda RX-8. You can safely buy. But it is worth remembering that such machines are expensive to maintain, the last money they bought, while just buy a not so expensive: the 15,000-16,000 dollars you can pick up a good copy. If everything works, Rotary Mazda-continuous positive.
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