Four reasons why installing a crankcase guard is more harmful than necessary.
Guess from three times what extra is imposed by dealers when buying a new car, besides, of course, the mesh in the bumper and floor mats? Well, of course — this is the crankcase protection! It so happened that any modern car seems almost unthinkable to the buyer without this attribute. Why? Anyone will answer you: on our roads he gape a little — and already got a cobblestone between the wheels … And if he is going to the dacha, then protection and at all like «Our Father» is not even discussed.
Familiar position, isn’t it? And the arguments, whatever one may say, cannot be called far-fetched. But today I propose to look at a simple device under the bottom of our cars from the other side. With the one that the absolute majority does not even think about.
And here the reader will probably be surprised: what has this got to do with it? And despite the fact that the engine, transmission and in general everything that is in the engine compartment is not just some kind of impeccable mechanism that is completely content with a flooded cooling system and radiators in any conditions. The margin of «heat resistance», of course, is, but it is not unlimited. And if you open the hood on a sultry July day after half an hour of inactivity in some Moscow traffic jam, you will literally be swept by a wave of heat, and it is quite possible to burn your hand on the surface of the hood itself. Because the engine + box is such a large stove, which requires not only a directly closed cooling system, but also active ventilation to remove hot air.
If you look at any sports car, you will certainly find the characteristic ventilation grilles behind the engine. So, these so-called «gills» are made just to remove heat from the engine compartment. Because the constant flow of fresh air through the engine compartment is of paramount importance to loaded powertrains.
So, putting this massive piece of iron (or a composite, it doesn’t matter), we tightly shut off the air flow in the area of the engine crankcases and the box. Of course, our conventional «Solaris» or «Octavia» is not a supercar, and the engine there does not generate hundreds of horsepower and kilowatts of heat. But this does not mean that it does not require cooling from below. Even at the design stage, the designers calculate the aerodynamics not only for the body contours, but also for the underbody. Look at the photo below — why do you think the ribs are cast on the engine crankcase? For more efficient heat dissipation. it
At this point, one can object, because most of the crankcase protectors have ventilation holes. And so it is. But let’s be honest: how much air will pass through the cracks that the manufacturers of such shields leave?
Of course, the installed crankcase protection does not radically affect the oil and coolant temperature. But in light of the concern of many comrades about the high operating temperature of the oil of modern engines (in loaded conditions — above 100 degrees), their categorical confidence in the need to install a piece of iron under the bottom looks strange. She will easily add the same 2-3 degrees to the oil, which already works at the limit of possibilities.
In traditional lightweight crankcase
Yes, most likely, nothing would have happened. In 99% of normal road situations, which are described with aspiration on the forums in favor of protection, the speed and height of the «fall» of the car with its belly is so low that such a blow is easily tolerated even with an unprotected bottom. After all, the engine and gearbox are not bolted to the body or subframe tightly — they have a fairly high degree of freedom and shock absorption due to their silent blocks (so-called «pillows). And the details are made, after all, not from plasticine. Therefore, if in your family sedan or crossover you do not go for the result on the rally track or do not conquer rocky passes, the absolute majority of accidental «pokes» under the bottom of your car will transfer absolutely calmly and without any protection.
In general, in order to get rid of unnecessary fears, it would be nice to understand what is generally going on between the front wheels of your car. You can take a look at your leisure and see for yourself: in addition to the crankcase, which, according to the forums, is simply created to be punched and demolished at the earliest opportunity, there is still a bunch of «unnecessary» parts. Levers, subframe, exhaust, gearbox bell joint — all this, as a rule, hangs below the engine crankcase. And in order to break through the pallet, you need to «swing» and pointwise hit a stone or a hard ice groove of the track. But in this case, I assure you, and protection will not be a panacea. It will ruin her too, but she stands almost close to the pallet.
And the last thing about the off-road. It is unlikely that you will argue that cars and even crossovers are not designed for serious off-road conditions. Their maximum is the very shallow soggy track to the suburban area. And even if you slipped into it and touched the inter-track with the crankcase, then, as we discussed above, nothing bad will happen.
Moreover, if no protection is installed, there is a high probability of continuing to move on! But when I sat down to defend myself, it often ends with a hike behind the tractor. After all, the protection of the crankcase steals from the city car the last, and without that not record, centimeters of ground clearance. The same goes for overcoming road jumps if you get out on a picnic to the nearest river. The already small angle of the ramp becomes completely scanty. And the lower the landing of the car, the less is shown for him «ski» under the bottom.
Finally, there is another point that casts doubt on the absolute usefulness of the device under discussion. It is mass. The most advanced composite (not even talking about carbon) models with low weight cost a lot. Therefore, in the main course, classical steel and a certain lightweight alloy (in catalogs for beauty it is also called a composite), in fact, does not differ much from steel in weight. In any case, this is no less than 5 kilograms, and more often 7-10 for an average passenger car. Not a monstrous weight, no doubt about it. But this is to the question of saving each gram of fuel, for which motorists compete so much, showing off pictures with readings of the on-board computer on the Web. With protection, you chronically carry a conventional bucket of water in your car.
What I want to say summing up. I am sure that the majority of readers will still not accept and condemn the sedition written in this article. But I would like to be understood correctly. I do not call for anathema to the crankcase protection as such. I only urge you to sensibly approach the need to install it on your specific car. Forced to regularly drive a passenger car or city crossover in difficult off-road conditions? Yes — probably the engine underside protection is worth considering. But, most likely, for 95% of those reading these lines, the entire «off-road» ends with a rolled primer to the suburban area and snowdrifts after a snowfall in the courtyard of a high-rise building. And it is an ordinary car enthusiast in an ordinary city car that I urge to think: you definitely