We can say for certain that practically every part of an engine is important. Without one unit or the other, your car’s entire motor may not even work as it should. Among those in the hall of heroes for your engine’s operations is the crankshaft. Its absence would mean that your engine’s many bangs and explosions would yield no movement. Hence, why crankshaft repairs are vital when needed.
But with a component that’s usually hidden deep in the bowels of an engine, why does this matter? Moreover, some wonder if a crankshaft can even be repaired, or is an even costlier replacement the only way out for your broken crankshaft? Well, we aim to turn these questions into answers. All the while, we’ll also take a peek at what goes behind crankshaft repairs, and see if they’re worthwhile.
What Do You Need To Know About A Crankshaft?
Before we get into crankshaft repairs, it helps if we could understand more about what it does. So, what does this magical crankshaft do in your car, and what role does it perform? Well, we know an engine creates power by combusting a mixture of compressed fuel and air. However, how does that ignition yield into movement? That’s where our friend, the crankshaft, comes in to help us.
As many controlled explosions repeatedly occur inside your engine’s combustion chamber, the force pushes the pistons up and down within the cylinders. This up and down movement is referred to as reciprocating motion. Unfortunately, the reciprocating motion of numerous pistons exploding at varying intervals can’t be effectively turned into energy that could drive the wheels smoothly.
The crankshaft’s job, therefore, is to turn this reciprocating motion into usable rotational motion. As the name suggests, the crankshaft is a ‘shaft’ driven by a ‘crank’ mechanism. The crankshaft can be found at the bottom of where the pistons lie and are attached via connecting rods. Once the conversion into rotational motion from the pistons is underway, the crankshaft is then connected to the flywheel.
The flywheels help to reduce any pulsation or vibrations. Further down the line, this flywheel could then transfer this rotational motion from the crankshaft to the transmission. Your car’s gearbox can from here on out sufficiently moderate the motion into power that can effectively drive the wheels. Thus, making your car move. In all, the crankshaft is a crucial component in making it all happen.
What Causes Your Crankshaft To Fail, And Need Crankshaft Repairs?
Generally, a crankshaft is made to last for the lifetime of the vehicle… As long as sufficient care and regular maintenance have gone into it. While they may be durable, a crankshaft can fail under a set of stressful situations, hence necessitating crankshaft repairs. Among the more vulnerable parts, for example, are the crankshaft bearings. Mainly, they help to support the crankshaft.
As if that’s not important enough, those bearings also help to reduce friction between the stationary engine, and a rotating crankshaft. In any case, be it the bearings or the entire crankshaft, a service as simple as a scheduled oil change is more than enough to keep it running smoothly. Overall, there are quite a few reasons why your crankshaft is failing or has failed far too early in its lifespan.
Causes Of Crankshaft Damage Or Failure:
- Excessive exposure to heat, assuming the motor oil isn’t able to provide enough cooling. Or, if the engine continuously overheats.
- High pressures, or basically an excess of load from the engine that may overstress the crankshaft into premature failure.
- Corrosion, etching, or damage, as the crankshaft is exposed to contaminated engine oil that may contain chemicals, acid, or corrosive contaminants.
- Contaminated motor oil can have debris or dirt in them, and circulating it around the crankshaft could scratch its internal componentry, such as the bearings.
- Low oil levels, possibly due to a leak somewhere in the system, may lead the crankshaft to dry out. When this happens, there will be a lot of metal-on-metal contact, resulting in the entire system wearing itself out.
- Incorrectly sized or poorly fitted bearings can lead to increased friction or vibrations from the engine to rock the crankshaft, wearing it out quicker.
- Jamming of the engine, as it may happen if there’s any gearbox failure, which can seize up and put a lot of wear on the crankshaft.
- The counterweights that balance the rotation of the crankshaft could be loose, thus throwing the movements of the crankshaft out of whack.
Have Crankshafts Evolved Much Between Old And New Cars?
Interestingly, modern cars are much harder to suffer crankshaft damage or failure than in older cars for a very simple reason. As we’ve established, crankshaft repairs are mainly prompted due to a lack of oil quantity or maintenance. In modern automobiles, we have countless sensors to alert us if the motor oil is way due or needs a check-up. Older vehicles, however, didn’t have this luxury.
Therefore, more recent cars can, for instance, have their sensors signal the car to run in its limp home mode. This lowers the workout of the engine when these sensors and the ECU have found a fault of some kind. By reducing the overall workload, any potential complete failure of the crankshaft may be spared. On the other hand, older cars could still keep running until the crankshaft breaks.
There is another side to this story, mind you. Modern crankshafts can withstand heavier loads. For example, a crankshaft in some up-to-date diesel engines could survive loads equivalent to 10,000kg. That’s around 22,000lbs worth of load, or ten tonnes acting on the crankshaft. This is only for just one connecting rod – this is what connects the pistons to the crankshaft – so imagine 4, 6, 8, or 12.
Although, there’s also an argument to be made that older crankshafts are more robust. Recently, many carmakers are leaning towards efficiency, and one of the sacrifices made is weight reduction. The crankshafts in some of today’s cars, for instance, are made of aluminum instead of cast iron. While it may be lighter, it’s certainly not as long-lasting or as bulletproof as a solid billet of iron.
What Are The Symptoms To Look Out For If You Need Crankshaft Repairs?
Alas, the tell-tale signs that you need crankshaft repairs are rather subtle and can be confused with other faults. Once again, crankshafts aren’t one of those replenishable items on a car that has to be swapped out every now and then. They’re made with longevity in mind, so most people won’t ever need to be concerned with crankshaft repairs. But every so often, they do occur.
Since these faults are clearly unexpected, how can you tell when you need urgent crankshaft repairs done? Well, there are a few symptoms exhibited by the car if the crankshaft is running awry. These shouldn’t be ignored, as their occurrence does still give you some time to have it fixed. If not, and upon ignoring crankshaft repairs, it could leave you to spend a whole lot more on a seized engine.
Here are some of the more typical symptoms telling you that crankshaft repairs should be on the to-do list, right away:
- A loud knocking noise may be heard as the engine is running. This is likely signaling that there’s metal-on-metal contact and physical impacts with the crankshaft. Additionally, you may also notice odd vibrations.
- Low oil pressure, which should tell you that there’s probably a leak somewhere in the system. Leave it for too long, and the crankshaft (as with many other components) will be starved of lubrication.
- Stalling engine, and this is perhaps the most severe case where the crankshaft is close to failure or has already failed. In this scenario, the engine has stopped running, which possibly indicates that pricey rebuilds are in order.
What Sort Of Crankshaft Repairs Are Usually Done?
Now, it’s a good time to talk about what exactly are crankshaft repairs. The crankshaft is an entire system by itself, consisting of numerous interconnecting and built-in components. What exactly are the things done during crankshaft repairs to bring it back to life? In a nutshell, crankshaft repairs are incredibly complex, and can’t be feasibly done expertly by just any workshop.
Not only does it require taking apart the whole engine, but you’ll need some special equipment for thorough crankshaft repairs to be completed. Consequently, you’ll also require trained specialists to do this, as most mechanics aren’t experienced with reconditioning a crankshaft. Some might argue that getting a brand new engine is easier (and possibly cheaper) than repairing the crankshaft.
Here’s an example of the processes that take place during crankshaft repairs:
- Grinding – This is needed to grind away at the worn-out surfaces which may have been scratched or left corroded.
- Straightening – For surfaces of the crankshaft that are left distorted or bent due to metal-on-metal contact, or intense heat exposure.
- Polishing – It helps to remove any debris or contaminants stuck onto the crankshaft, and remove all the fine scratches or grooves.
- Pulley – Also called a ‘harmonic balance wheel‘, it helps to connect the crankshaft to the serpentine belt (or drive belt), which powers accessories like your aircon and stereo, and could do with a repair.
- Bearings – These are often the key failure points of any crankshaft as they take the brunt of the stress, and could do with a replacement.
- Cleaning – The crankshaft has numerous channels and passageways to enable oil to lubricate it efficiently and could be cleaned out during the repair.
- Balancing – This refers to the counterweight of the crankshaft during its rotations, and it should be rebalanced during the reconditioning process.
How Can You Proceed With Crankshaft Repairs?
For a bit of fun (and learning), we thought we’d share with you a step-by-step process of how one can proceed with crankshaft repairs. Again, this is a highly complex process that requires the right tooling, skills, and determination. Even the most talented of DIYers would often stay away from this sort of work, and leave it to the professionals instead.
Besides, it needs to be done right to prevent any calamity from befalling your engine down the line. In certain vehicles, like race cars, the tolerances of the crankshaft are incredibly tight. Machining the surface needs to be done, sometimes, within 0.0003 inches from the manufacturer’s specifications. While this may seem like a deterrent, it shouldn’t prompt you to spring up for a replacement yet.
At least, not right away, and not while your crankshaft could still be saved if there’s hope for that still. You should certainly consult with a technician to conduct a detailed diagnosis, just to see if any crankshaft repairs could do you good. If it can still be reconditioned, here’s what the experts over at Ohio Crankshaft typically do to bring a battered crankshaft back to life.
1. The Inspection
As we’ve recommended, a thorough diagnosis should be done prior to deciding if you need a repair or a full replacement. Some crankshaft damage, unfortunately, is beyond repair. If it’s salvageable, then the folks over at Ohio Crankshaft will make a thorough inspection of what sort of damage it has. This gives them a better understanding of what needs to be done to repair it.
They put the faulty crankshaft through a magnetic particle testing process called “magnaflux“. This is where a ring of electrical current is induced all around the crankshaft. As a result, it can produce a magnetic field. A liquid (and magnetically attracted) solution that contains iron fine iron powder is thrown into the mix. Technicians then check how the iron powder flows across the crankshaft.
If there’s a crack on the crankshaft, that split metal will interrupt the magnetic flow. Subsequently, the iron powder solution is concentrated along the sections where there’s a crack. This makes it far easier to point out where there’s surface damage. Plus, technicians can use a UV light to visibly and clearly illuminate the iron powder residue on the cracks, where it would otherwise be hard to see.
2. Welding It Together
When technicians have ascertained that there are cracks or splits on the surface of the crankshaft, it proceeds to the welding station. But before that, the crankshaft in question is lightly ground down and sanded to get rid of any foreign materials. These contaminants, like fine particles left behind from the worn bearings, can be caked into the surface.
Those tiny particles can easily get in the way. When they’re gone, the welders use something called a “submerged arc“. This machine enables them to effectively penetrate any material build-up, which can make it easier for the machining process later on. Here, a gravity-led flux covers the entire point where the arc appears away from the high-amperage of its welders.
Moreover, this submerged arc creates a gas that shields the arc from any impurities in the air. As a whole, this allows the specialist manning the welding station a more careful and pinpoint precise welding to be done. It ensures that those tight tolerances in the crankshaft are met. Plus, it makes certain that later stations have an easier time.
3. Straightening It Up
We’re getting close to the end now, as a technician passes the crankshaft off to be straightened. Here, the straightening station double-checks to guarantee that the prior welding and machine haven’t altered the crankshaft. Dimensionally, it has to remain straight and true. The radius along the ends of the crankshaft has to be spot-on, as well.
For the most part, the straightening process could be considered somewhat old-fashioned. Rather than rely on high-precision tech, it’s all about the experience of each technician. The crankshaft is placed inside a hydraulic press. This machine has numerous indicators to point at the length and various sections of the crankshaft.
The technician then carefully, once all calibrations are done, puts pressure to literally bend the crank back into its proper specifications. Once more, their experiences are crucial here, as they’re able to tell precisely how much counter-bending is needed to keep the crankshaft within tolerances. Any over-correction could damage the crankshaft for good.
At the end of the line, the crankshaft goes through heat treatment. Often, this is done both before and after the crankshaft repairs processes detailed earlier. The type and intensity of heat subjected to it depend mostly on what variation the crankshaft it is. The technicians always follow the specs recommended by the manufacturer, as overheating could severely harm the crankshaft.
How Much Would Crankshaft Repairs Cost You?
Now, we can move on to a move bitter topic – how much would crankshaft repairs cost you? Frankly, it’s not cheap, seeing how much work needs to go into repairing it in the first place. On top of that, there could be several parts that require repairing at once. And, you have to remove the entire engine and take it apart to access the crankshaft, which is commonly at the very bottom.
If your damage is light and you’re keen to DIY a fix, you could possibly remedy it with a crankshaft rebuild kit. These kits can be had for around $400, and they include components such as bearings (both main and connecting rods), as well as gaskets and seals. Granted, such kits are only applicable if the items around your crankshaft are at fault, without severe damage done to the crankshaft.
Mostly, the costs between a repair and replacement are almost similar. For a complete repair, as we detailed earlier, you could be looking at a price tag of between $1,600 to $2,200 in most vehicles. A new crankshaft by itself isn’t too expensive. It could be found for anywhere around $400 to $800. However, the real bearer for the ludicrous expense would be labor costs.
Getting to your crankshaft is time-consuming, and that doesn’t even factor in fixing or replacing it. With many cars, it can take days worth of intense labor, costing you at least $1,200 just in hourly rates. You can alleviate this cost somewhat by opting for remanufactured parts instead of a shiny new crankshaft. You can find these sold for as little as $200, and they should be just as strong.
Could You Skimp On Crankshaft Repairs?
Having understood now how expensive crankshaft repairs (and replacements) are, is it possible to skip ahead? In other words, could you keep on driving a car that has a bad or failed crankshaft? To put it bluntly, the answer is a strong NO. Repeated use of an ailing crankshaft is only going to jack the repair bills much higher, as it can cause a lot more damage to the rest of the engine.
Furthermore, remember that crankshaft damage or failure is often caused by something else, not the crankshaft itself. Most likely, it’s due to low motor oil, which can present danger to other parts of your engine. A lack of oil can wear down the pistons, rings, seals, gaskets, valvetrain, and more. Ignoring crankshaft repairs is another way of putting a blind eye to oil starvation.
Combined with a faulty crankshaft, you could be driving yourself into causing catastrophic engine failure. Rebuilding a seized-up motor isn’t cheap. On the flipside, swapping out for a brand new motor is doubly pricey, possibly costing you $3,000 at the very least. It may go up to $10,000 or higher, depending on what car you have. Comparatively speaking, crankshaft repairs aren’t so bad.
Crankshaft Repairs – Conclusion
That then ends our look at crankshaft repairs. In all, you’ll most likely never encounter them, as the crankshaft is engineered to last as long as your car. Nevertheless, and when proper maintenance is not administered, the crankshaft – and most other parts of your car – will suffer the consequences. Something as simple as a lack of motor oil is sufficient in causing disastrous damage to be done.
Once it’s too late, a repair or replacement of the crankshaft is necessary, despite how bulletproof it may seem. The repairs here aren’t easily possible, even for the more ardent of hobbyists out there. It can be highly complex, not to mention expensive. Should your crankshaft (and engine) be too far out of order, it may even prove worthwhile to sell or scrap your car entirely, if it’s not all too valuable.