Let's talk about the merits and demerits of ZMZ 402

In the early 50-ies in the USSR there was an engine for sedans GAZ-21, which was called 24D. It had a volume of 2.5 liters and used AI-76. The compression ratio was 7.2. Soon it was modernized, after which the light appeared ZMZ 21 and ZMZ 24. Their characteristics were somewhat improved, but the design solutions are almost completely the same. Well, the evolution got to ZMZ 402. It appeared in the world of engines of GAZ cars in the early 80's. Immediately mention that he was removed from production, he was in 2007, when he was replaced by ZMZ 406 and 405.

This engine proved to be reliable and unpretentious, in addition, its resource, compared with its predecessors, was significantly increased. Now it is, in principle, morally obsolete, since the lower location of the camshaft has long been recognized as the most inefficient timing. But let's not forget the fact that some brands of cars in the US still use such engines on their new cars.

The fact is that this is the simplest design, which allows you to avoid the chain or belt drive camshaft. Yes, it somewhat reduces the noise of the work, but it is fully compensated by the barbells and pistons-pushers. Thus, in order to drive one valve, four parts are used: the camshaft, the pushrod, the rod and the rocker. I must say, all this creates no less noise than the chain. But let's not forget about the other side: this simplicity and deserved such popularity of ZMZ 402 among the owners.

In addition, this design protects against overspeeding, since for such a timing it is problematic to untwist the crankshaft over 3000 due to too large a mass of parts. Even the fact that the pushers and rods are made of aluminum can not save the situation. And what is so harmful excess of speed?

The rear crankshaft bearing ZMZ 402 does not rotate in the stuffing box, but in the stuffing, which is a different material impregnated with graphite. With careful operation, it does a good job of its duties, but when this threshold is exceeded, oil begins to be expelled in incredible quantities.

Apparently, all these are shortcomings. But it is worth remembering about the taxi that went to different cities. Every taxi driver was happy if his official car was GAZ 24, because at one time he had such characteristics that competitors could envy.

With regard to GAZel, we can say the following: it was the ZMZ 402 engine that brought them such popularity, which they possessed and possess to this day, because 402 and 406 engines are taken as the basis for 402 engines . Many see in it only flaws and malfunctions, but most believe that for the early 90's such a motor was very good. The combination with a five-speed box, with a thrust reducer of the bridge and a gross weight of less than 2 tons helps to open the entire potential of the ZMZ 402. The characteristics are emphasized by the 15-inch wheels on the Volga cars, which compensate for the low engine rpm.

In conclusion, we can say that the owners have long been engaged in the development of the 402nd, there are even precedents of injection, which is quite expensive. And the result is not worth it. But still it does not stop connoisseurs, but only warms up their interest.