Engine break-in after overhaul - expert advice
Drivers with experience know that after buying a new car, it is necessary to carry out the so-called hot engine break-in for some time. That is, for the first few thousand kilometers, adhere to optimal driving modes, do not press sharply on the gas or brake, and do not let the engine idle and at high speeds for a long time. On our website Vodi.su you can find quite complete information on how to properly conduct a hot engine break-in.
However, over time, almost any engine needs a major overhaul. Symptoms that the “heart” of your car needs to be diagnosed and repaired are as follows:
- the consumption of fuel and engine oil gradually increases;
- characteristic black or gray smoke comes out of the exhaust pipe;
- compression in the cylinders decreases;
- loss of traction at low or high speeds, the engine stalls when shifting from gear to gear.
There are many ways to get rid of all these problems: replacing the cylinder block gasket, using various engine oil additives, such as XADO.
However, these are only temporary measures that correct the situation for a while. A major overhaul is the best solution.
The very concept of "major" means that a complete diagnosis of the engine is carried out and a complete replacement of all worn out and failed elements.
Here are the steps it usually consists of:
- engine dismantling - it is removed from the car using a special lift, having previously disconnected all systems and components associated with the engine - clutch, gearbox, cooling system;
- washing - in order to assess the real level of damage and defects, it is necessary to completely clean all internal surfaces from the protective layer of oil, ash and soot, only on a clean engine can all measurements be taken correctly;
- Troubleshooting - minders evaluate engine wear, look at what needs to be replaced, make a list of necessary parts and work (grinding, replacing rings, boring, installing new crankshaft main and connecting rod bearings, and so on);
- the repair itself.
It is clear that all this is a very expensive and painstaking undertaking, which only good specialists can implement. The cost of work increases many times when it comes to foreign cars. That is why we would advise against buying foreign cars with a mileage of more than 500 thousand kilometers. It’s better to buy a domestic Lada Kalina or Priora already - repairs will be much cheaper.
The process of running the engine after overhaul
After the masters finished the repair, put the engine back in place, changed all the filters, connected everything and started the engine to make sure it was working properly, the car was ready for use again. However, now you are dealing with a practically new engine, so you need to run it in for a while so that all pistons, rings, and plain bearings get used to each other.
How is the run-in after the overhaul?
It all depends on what kind of work was done.
The run-in itself implies a certain set of events:
- the use of gentle mode when driving;
- flushing the engine several times by filling and draining engine oil (it is advisable not to use any flushes or additives);
- replacement of filter elements.
So, if the repair work affected the gas distribution mechanism, changed the camshaft itself, the chain, the valves, then it is enough to run the engine in the first 500-1000 kilometers.
If, however, a complete replacement of liners, pistons with piston rings was carried out, the clutch was adjusted, new main and connecting rod bearings were installed on the crankshaft, and so on, then you need to adhere to a gentle mode to 3000 kilometers. The gentle mode implies the absence of sudden starts and braking, it is advisable not to accelerate faster than 50 km / h, the crankshaft speed should not exceed 2500. No sharp jerks and overloads.
Some may ask - why is all this needed if the work was done by masters of their craft?
We answer:
- firstly; piston rings should fall into place in the piston grooves - with a sharp start, the rings can simply break and the engine will jam;
- secondly, during the lapping process, metal shavings inevitably form, which can only be eliminated by changing the engine oil;
- thirdly, if you look at the surface of the pistons under a microscope, then even after the most thorough grinding you will see a lot of pointed tubercles that should level out during the break-in.
It is also worth noting another factor - even after complete maintenance of the break-in regime for the first 2-3 thousand kilometers, complete grinding of all parts occurs somewhere after 5-10 thousand kilometers. Only then can the engine be required to demonstrate all its capabilities.
Advice of specialists
So, before you start running the engine after a major overhaul, try to check the battery charge - it must be fully charged, because the first engine start is the most crucial moment, the crankshaft will rotate quite tightly and all the battery power will be required.
The second important point is to install a new oil filter and fill in high-quality engine oil. It is impossible to wet the filter in oil before installation, since an air lock may form and the motor will experience oil starvation at the most crucial moment.
Once the engine starts, let it idle until the oil pressure returns to normal - this should take no more than 3-4 seconds. If the oil pressure is kept low, the engine must be turned off immediately, because there are some problems with the oil supply - an air lock, the pump does not pump, and so on. If the engine is not turned off in time, everything is possible that a new overhaul will have to be done.
If everything is fine with the pressure, then let the engine warm up to the required temperatures. As the oil heats up, it becomes more liquid and the pressure should decrease to certain values - about 0,4-0,8 kg / cmXNUMX.
Another problem that can occur during break-in after overhaul is leakage of technical fluids. This problem will also need to be solved urgently, otherwise the level of antifreeze or oil may drop, which is fraught with overheating of the engine.
You can start the engine several times in this way, let it warm up to the desired temperature, spin it at idle a little and then turn it off. If at the same time no extraneous noises and knocks are heard, you can leave the garage.
Stick to the speed limit - the first 2-3 thousand do not drive faster than 50 km / h. After 3 thousand, you can accelerate to 80-90 km / h.
Somewhere at the mark of five thousand, you can drain the engine oil - you will see how many different foreign particles are in it. Use only the oil recommended by the manufacturer. It is also worth considering that if the geometry of the cylinders changed - they were bored, repair pistons with a larger diameter were installed - an oil with a higher viscosity will be needed to maintain the desired compression level.
Well, after passing 5-10 thousand kilometers, you can already load the engine in full.
In this video, a specialist gives advice on proper operation and engine break-in.
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