A money shift can be summed up pretty simply: it’s a shift gone wrong. Horribly wrong. Wrong enough that you’ll likely be coughing up big bucks in order to get your ride back to working order.
That’s where the term originates from. Even though a money shift sounds like it could be the gear change that means all the difference between a new record run and just another lap of the track, it actually refers to the expensive consequences of butchering a shift bad enough that it damages your engine’s internals.
Money Shift Glossary
These concepts are at the heart of why money shifts strike fear in the hearts of hot rodders.
In simple terms, the ratio between two different gears as calculated by the number of teeth on each gear. If gear A, which has 50 teeth, is driving gear B, which has 25 teeth, you have a gear ratio of 2:1. To simplify how this works in a car, gear A is on the output shaft from the engine, while gear B can be any of the drive gears in the transmission.
The sweet spot where an engine is making power most efficiently. Note that this doesn’t necessarily mean peak power, but rather the RPM range where the engine is creating power most effectively.
RPM: Revolutions Per Minute
It’s used to measure how fast the engine’s crankshaft is turning. If engine is said to be running at 5,000 RPM, that means the crankshaft is spinning at a rate of 5,000 revolutions per minute.
Money Shifting & My Transmission
Let’s go back to the transmission, that great arbiter balancing road speed and engine speed. Through the use of different gear ratios, transmissions enable an engine to operate within its powerband whether when you’re tootling around town or barreling full-bore down the interstate.
Here’s the kicker about transmissions: the same ratio that makes first gear such a great choice for parking-lot speeds would suddenly grenade your engine if you engaged it at 50 mph. Why? Because the gear ratio would effectively force the engine to spin at unfathomable RPMs in an attempt to keep up with the road speed.
And that’s exactly what happens when someone money shifts. Choose a lower gear than intended - say, second instead of fourth - and, depending on your speed, the gear ratio of that particular cog can force the engine to blow past its redline. And what happens when you exceed that little red no-go zone on your tach? The gods of combustion demand sacrifice - and usually, it’s your valves or bearings that must atone for your mistake.
What Exactly Happens to My Engine When I Money Shift?
There are a number of consequences your car may suffer if you money shift, but the first thing you’ll notice is a horrific, sinking feeling that you’ve made a very, very unfortunate mistake. All those funny videos where you can visibly see somebody die a little inside? That will be you. Pray your dash cam cannot capture interior footage, or you will be YouTube fodder. On second thought, if anybody happens to catch footage of you money shifting, you will likely become YouTube fodder anyway. Expect infamy regardless.
But back to the car. To understand what exactly might go wrong in a money shift, it’s worth quickly reviewing how an engine works. Essentially, your engine is a big vacuum pump. The cylinders use the principle of vacuum to suck in an air/fuel mixture through the valves, which is then detonated after being compressed by the piston in its upward stroke. The force of this combustion pushes the piston into its downward power stroke; the leftover gasses are sent out the exhaust valve on the next upward exhaust stroke. Finally, as the piston moves downward once more, the intake valves open, and the vacuum generated in the cylinder pulls in the next squirt of air and fuel to begin the four-stroke combustion cycle anew.
How fast this process takes is tied directly to the engine speed: the faster the engine is spinning, the faster the four-stroke cycle is happening. And while engines are miraculous feats of engineering, they aren’t infallible. Once you surpass a certain engine speed, all the shiny little rotational bits of metal that allow an engine to suck, squeeze, bang, and blow will begin to fail.
A properly executed money shift - if that’s what you want to call it - can make that happen. Let’s raise a hypothetical here and say that you were approaching 6,000 RPM in third gear and went to grab fourth. As you pull your foot off the clutch, you realize you actually ended up in second gear. Without getting into exact speeds and gear ratios, let’s also assume that this mistake sent your engine - which redlines at 6,500 RPM - racing to 8,500 RPM.
An engine running at 2,000 RPM over its redline is spinning well beyond its comfortable operating range. Though there’s plenty that could go wrong in this scenario, two of the biggest concerns would be valve float and bearing failure. These are two different issues that usually share the same unfortunate result: a very expensive, very violent end to your engine.
What Is Valve Float?
Let’s talk valve float first. Even though valves need hardly an eyeblink to open and close, that fraction of a second they do require is critical. When valve float occurs, that fraction of a second is lost - the engine is spinning so fast that the valves literally cannot keep up. Because the valves aren’t able to fully close and reopen, they’re left in a partially opened state even when the piston is at its top dead center position.
In a non-interference engine, where the design ensures that the travel of the pistons and valves won’t overlap in any scenario, the results of valve float likely won’t leave your motor DOA. But on an interference engine, where the paths of pistons and valves can overlap? You’re looking at major heartache. Think bent valves and damaged pistons - expensive internal damage that will require major surgery. Don’t be surprised when your mechanic takes a break from dissecting your broken valvetrain to start quoting you for a new engine.
What Is Spinning A Bearing/Spun Bearing/Bearing Failure?
We also mentioned bearing failure. The connecting rods that enable a piston to travel up and down in the cylinder aren’t bolted directly to the crankshaft; they instead rotate around bearings, which ride along a thin film of oil and enable the pistons and crankshaft to work independently yet together. Kind of like you and your coworkers, only without the drama.
Over-revving an engine from a money shift can lead to bearing failure, which is when things go south in a hurry. When a bearing gives up the ghost, it seizes and begins to spin with the crankshaft, taking the connecting rod and piston with it. Known as a spun bearing, it has the potential to destroy your engine in short order.
What about the transmission itself? Luckily, it’s pretty hardy - you’re more likely to suffer bearing or valve failure before you tear up your manual gearbox. Your clutch, on the other hand, may not be a fan of slamming against the flywheel when the engine shoots past 8,000 RPM. Still, the real damage - the expensive stuff that gives the money shift its name - occurs in the engine.
Is Every Bad Shift a Money Shift?
To be clear, not every bad shift is a money shift. In fact, if you’re obeying the laws when you’re driving on public roads – and our lawyers want us to remind you that this is exactly what you should be doing at all times - catching the wrong gear should cause nothing more than a bit of embarrassment.
Generally speaking, money shifting while putzing around town is highly, highly unlikely. The synchros in most stock gearboxes turn recalcitrant when you try to engage first or second gear at anything faster than school-zone speeds, anyway. If you’re not the type to dump the clutch from every red light and stop sign, you’re probably not going to money shift on your commute – even if you do mis-shift every now and then.
On track is a bit of a different matter. Stakes are higher, speeds are faster; your car is likely being driven at its limits or close to it. If you’re not careful, a money shift is entirely possible.
The last thing anyone wants to do is money shift, yet it can happen to the best of us - for proof, just search ‘Money Shift’ on YouTube. If you think you money shifted, relax. You haven’t. You’ll know when you money shift because the resulting theatrics would make any playwright proud.