CLUB OF CAR FANS
CASE OF THE MASTER
AT THE RECEPTION AT ORTHOPEDIS
To correct the curvature of the “Volgovskiy” crankshaft is not only possible, but also necessary …
Dmitry DANSHOV, chief engineer of the company "Mechanics"
The Volgov engine, manufactured for over forty years, was once famous for its durability. Low-boosted, with a huge margin of safety, the unit really served 350 thousand km (or even more!) Until the first overhaul. Today, this figure, once established by the factory, causes only a bitter grin of car repairmen - they recommend the current engine ZMZ-402 right away, right on the new machine! Especially this advice is useful to owners of "gazelles" - it is a workaholic and a half more often buy in the cheapest configuration with the "old" lower engine. The car has to travel a lot to pay for itself: why is it not reasonable to immediately lay a solid "foundation"?
Solved! We remove the engine, disassemble, remove metal chips from the secluded nooks of the block and wash all the insides. Traces of ordinary negligence during assembly are visible to the naked eye. Here the studs stick out higher than necessary - we cut the thread and wrap them, as expected. The groove for the retaining ring is too small - we’ll cut it deeper so that the ring does not fall out … But the crankshaft will have to be dealt with thoroughly and here you can not do without machines and an accurate measuring tool. However, both that and another can be found even in the outback - at motor depots, in rural workshops.
The crankshaft cranked on prisms, alas, often demonstrates curvature (photo 1). Of course, bent, pulled to the block by the covers of the beds, it will quickly wear out the liners and cause a drop in oil pressure and subsequent engine failure. You can correct the congenital "dislocation" by minting the shaft fillets with a beard of crude (mild) steel. At the same time, it is better not to rush and carefully choose the place and strength of the blow, periodically checking the heartbeat indicator. After the middle part is brought to “zero” (in extreme cases, up to 0.05 mm), be sure to adjust the toe under the belt pulley - it is also curved on almost all shafts.
But this is only the beginning. Without exception, all the crankshafts of the “Volgovskiy” engines are not centered and unbalanced. What is easy to verify by placing any shaft purchased in a store or removed from a machine in a lathe. The indicator will show the beating of the main necks relative to the conical alignment in the toe and the undercut under the bearing in the rear end, which means that when the motor is running, vibration and quick failure of the camshaft drive and the input shaft of the gearbox are inevitable. The constant runout of the pulley and knurling under the rear oil seal cause an unrecoverable oil leak on both sides of the engine. In short, we fix the cutter on the support - there is nothing to be done, you have to remove the chips …
If the runout of the root necks does not exceed 0.2 mm, they can be taken as the base. Having fixed an additional rest on the machine (see photo 2), we correct the centering in the toe with the cutter - now it will be aligned with the main shaft necks. Then we bore the bearing housing under the repair sleeve (photo 3). After that, remove the oil-driven knurling with a cutter and … do it again (photo 4), however, now it is already aligned with the necks. In general, we put everything on the same axis: toe, root necks, centering, knurling and undercut under the bearing. If the initial beat of the root necks relative to the knurling is large (even 0.5 mm is not the limit!), You will have to drag them under the repair liners, taking the sock and knurling as the base. In this case, the order of work is almost no different from that provided for overhaul. Is it … wildly aware that all this has to be done with a new crankshaft. Before removing the shaft from the machine, slightly touch the cutter of the attachment plane of its flange and weave it through - now the flywheel will not “walk in figure eight”.
The crankshaft brought to mind must be balanced dynamically - only then your motor will not shake, as soon as it has just left the factory, and it will last much longer. For example, in “Mechanics” we do this in three steps: first, the shaft itself is balanced, then assembled with the flywheel and finally assembled with the clutch. The result is excellent, and even if the clutch or flywheel is replaced, the balance will not be disturbed.
1. Check the beating of the crankshaft journals on the prisms.
2. If the runout of the oil-gas knurling is too large - remove it with a cutter. Once rolled, it will be aligned with the root necks.