Questions tagged [engine]

Internal Combustion Engine. Most engines in road going vehicles are 4-cycle internal combustion gasoline engines.

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18
votes
7answers
11k views

Why or why not increase engine efficiency by running the car "fuel-lean" (using a turbo or supercharger)?

Everyone wants their cars to use less fuel, right? I read the following passage about running the car fuel lean from this website: Run the engine fuel-lean, that is, use excess air. It is well ...
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5answers
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What should always be replaced when rebuilding an engine?

If the purpose of the rebuild is to bring the engine back (or as close as feasibly possible) to its original performance, what are some things that should always be replaced? This obviously depends ...
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6answers
8k views

Where does the power in an idling engine go?

When the engine is running, but the vehicle is not moving fuel is still being consumed, where does the energy go?. I am guessing that it goes in rotating the flywheel and crankshaft and stuff, but I ...
18
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4answers
3k views

Maintenance tips to prolong engine lifespan for short trips

I just sold my car and will soon purchase a new one (probably a used one with 1-2 years on it). I decided on a Volkswagen up! with an EA211 1.0 TSI engine. I have heard from many different people (at ...
18
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6answers
116k views

Engine power specification at different rpm?

Car companies advertise the power of an engine at different rpms. Car 1: 80 PS at 6000 rpm Car 2: 85 PS at 6500 rpm What does the power at different rpm mean? Does it mean Car 1 has better power ...
18
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7answers
11k views

2000 Jetta runs rough, shudders on cold start only on wet days.

This is an issue I've had off and on for, embarrassingly, at least a year: On misty or wet mornings, everything starts out fine but, a few minutes into the drive (like clockwork. I even know the ...
18
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4answers
86k views

Driving in second gear at 65+ mph

I accidentally drove my 2000 Grand Marquis on second gear on the highway. I was going 65 for like 5 minutes and tried to get it to 70mph but the car was shaking, when I realized I put it into regular ...
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2answers
5k views

What is a leak down tester and what can I do with it?

Background There are quite a few head gasket related questions on the site. Coolant or water in the oil, oil in the coolant or water in a radiator, etc. I'm thinking that some instruction on howto ...
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3answers
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Is it true that most of the engine wear during its life time occurs during a cold start up?

I have heard this idea several times, but is it true? Theories I read about why that might be true: The engine is running rich at startup because it is running in open loop, which can cause damage ...
18
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4answers
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What is the difference between a 180° V4 and a true boxer motor?

Reading this thread which talks about V4 motors, I am wondering what exactly is the difference between a 180° V4 motor you'd find in a Subaru and a true boxer (or horizontally opposed) flat 4 cylinder?...
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1answer
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Why does diesel engine need a warm-up before the start-up?

When starting up, diesel engine needs approximately 5s before turning the key for ignition. Why is this neccessary and what can be damaged if you don't do that?
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3answers
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Is my head gasket cracked?

My wife hit a large puddle of water in her 2006 Mazda 5. Until then it was running fine. The check engine light came on and car shut down and would not start again. Mazda says it is a head gasket. Is ...
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6answers
70k views

Can you run an engine without a radiator?

I've heard of people starting engines in a build without a Radiator hooked up, to see if it fires. If you have an old engine and want to see if it will run: Can it be started without a radiator? ...
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4answers
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What does it mean to retard an engine?

I have come across this term. What does it mean to retard an engine? When would you typically have to do such a thing? What can happen if you don't or incorrectly retard the engine? What sort of ...
17
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3answers
41k views

Why does diesel engine have redline much lower than petrol engine redline?

Why do diesel automotive engines redline at around 4500 rpm whereas petrol ones go to 6500-8000 rpm? Does this have something to do with the compression ratio?
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2answers
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Diesel Engine Runaway - What is it?

I was watching some youtube videos and diesel engine runaway videos started to pop up where apparently the diesel engine runs out of control until it destroys itself. My Question What is diesel ...
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2answers
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What mechanical revolution is measured in "RPM"?

I do realize that it stands for revolutions per minute, but what are the revolving pieces that are measured? Assuming it is the crankshaft, is RPM calculated by the crank shaft sensor, or by some ...
16
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4answers
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What does a liter class engine mean?

I have had this question for a long time, can I assume that a 1000 CC engine is able to hold a liter (1L) of water content? Please let me know if my understanding is correct, so I can understand more....
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4answers
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Car crash: when does a car catch fire?

Which kind of crash does it need for a car to catch fire? I'm asking because I was discussing about an accident where a car crashed into a full-grown brown bear. Is it realistic under normal ...
16
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4answers
38k views

When does it make sense to replace a camshaft?

Preamble (Rant) I was reviewing this question in which the OP presents a repair quotation that includes replacing the "intake camshaft" to fix an engine that had overheated. To me this ...
16
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3answers
4k views

Why has my car burnt through all the oil?

I have recently run in to trouble with my Vauxhall Corsa 1.2 2013. I broke down the other day after a huge cloud of white smoke out the exhaust followed by a severe loss of power. The AA came had a ...
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4answers
15k views

350z cranks won't start

2003 350z cranks but won't start VQ35DE / FIXED * partially [ Stock / DC intake / Straight pipes ] (11/11/2016) My Cousin is a certified mechanic and took over the repair! -Car idle rough and ...
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10answers
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Diesel vs Petrol motorcars. Pro's and cons?

I realize this may be a silly question to those of you on here who are proper petrol-heads and this may even be a repeat question, but I could not find anything on it on here, so here goes: What are ...
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3answers
5k views

Why do Internal Combustion Engines have specific "Firing Orders"?

What's the point of having a firing order? I read that it helps balance out the power so as not to be too much on one side if the crankshaft, but why do we have such a specific order? If that was the ...
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5answers
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Cascading Repair Costs following Blown Head Gasket on a 2004 Subaru Outback

This question concerns a 2004 Subaru Outback with ~167,000 miles. All major and minor maintenance was performed (original owner car). Nonetheless, it has suffered rapid demise. How much of the ...
15
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3answers
14k views

Why does GM still insist on push rod engines?

GM continues to design and produce push rod (Over Head Valve or OHV) engines while most of their competitors have gone to over head cam (OHC) configurations for their performance engines. Is there a ...
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2answers
2k views

Why is a W-16 called, well, W?

The term "W-16" seems to imply some sort of configuration that resembles the letter W, which implies three banks of cylinders with one sharing a common cylinder head. In fact, the Bugatti W-16 in the ...
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9answers
94k views

My car's coolant temperature reaches almost 100 C / 212 F in a fast pace

Today, after a very hot day, I saw that my coolant was almost reaching 100C/212, I pulled over, stopped and took a look over the hood. The very little water that remained in the coolant tank was all ...
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4answers
52k views

What's the cause of Diesels' typical clatter noise?

I guess it's related to their basically running off knocking, but if I were to explain it to someone like this, it wouldn't convince me neither. [Edit] From http://www.ford-trucks.com/forums/369700-...
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5answers
271k views

Car shakes when in gear at red light

I bought a '96 Toyota Camry about a month ago. When I first turn the car on and the engine is cold, I can have the car stopped (in gear) and it will not shake. The idle RPMs will be at 1000. After ...
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4answers
23k views

How to Remove Core Plugs? (aka Freeze Plugs)

I have been removing core plugs from an engine I'm rebuilding with varying levels of violence. The engine block is aluminium and I'd like to reduce the chance of of me damaging it. How do I remove ...
15
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1answer
2k views

Dynamometer Question - How is it operated and what are they doing?

When guys are doing dyno runs they to do it in a gear, interact with the keyboard and then do it again in another gear. It seems they do multiple runs in multiple gears. In this post Paulster ...
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8answers
14k views

Why smaller engines on newer vehicles

I've been searching for some cars on the internet and I've observed that newer cars get smaller engines. For instances, I've found a Ford Focus diesel 1.6, or even a Mercedess A Klass 2015 diesel has ...
14
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4answers
8k views

Do pistons keep moving when the car stops?

When you are driving and stop at a light, do the pistons still move up and down due to combustion? If not how will the engine know when to combust the fuel to keep it moving?
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4answers
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What are the differences between a dual mass flywheel and a standard flywheel?

Recently in chat, a discussion arose about a dual mass flywheel. I am blissfully ignorant regarding how a dual mass flywheel actually functions and what the delta is between a dual mass flywheel and ...
14
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7answers
5k views

Is it possible for a diesel engine computer to detect (and prevent) a runaway condition?

Although diesel runaway is not so common... ... the consequences are spectacularly catastrophic. On old-school engines, I can understand that there isn't much you can do about it except try to cut ...
14
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2answers
3k views

How do I troubleshoot the source of oil in my coolant?

I would like to know the step by step troubleshooting procedure for discovering the source of oil appearing in coolant. There are several different points of failure that can be the root cause for ...
14
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3answers
28k views

How to begin learning engine tuning?

Quite simply, I want to begin tuning and modifying automotive engines for hobby. I have always been fascinated with cars, and I want to become knowledgeable in as many aspects of car tuning as ...
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4answers
120k views

What would be the most likely cause of engine sputter?

Most of the time my 2001 Honda Civic sounds like this... Vrooooooom. But some times when I start driving it sounds like this... Vrooom putt pa putt pa putt pa vrooooom. When it's in the "putt pa putt"...
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4answers
88k views

What does O/D mean on a dashboard & a button under the transmission button?

My car has an O/D button under the transmission button. When I press it, it turns O/D off. When O/D is off, the revs go up more than when O/D is on. What does O/D mean and what does it do to the ...
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3answers
2k views

How do you get more horsepower out of a 1979 Mazda RX7?

Moar Horsepower? The 1979 Mazda RX7 - Desireable Track Car It seems this platform is very popular in club racing today. You see them as prized possessions at SCCA gatherings to simple track days. ...
13
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5answers
40k views

Why can some cars go through water while others can't?

Why can some cars (mostly old Russian cars on YouTube) seemingly go through water while others can't? I'm talking about situations when the water level is at half the height of the car, so the engine ...
13
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6answers
1k views

Second hand car - Engine/Tyres/Etc

I am looking into buying a second hand car from a reputable Mercedes-Benz dealer (not just some dodgy salesman by the side of a road lol....). Anyway, there are a few maintenance/mechanical things ...
13
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4answers
97k views

What disadvantages a car with 4-speed transmission have compared to 5, 6 or 7 speed with similar engine?

This seemed to be most relevant site to ask my question. I am planning to purchase a new car and my shortlisted car has 4 speed automatic and 1.6 litre engine. The thing that worries me is that it ...
13
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4answers
25k views

2000 VW Polo struggles to/won't start when engine warm

My 2000 1.4 petrol polo struggles to start when warm and sometimes will not start, until the engine has cooled down a bit, when the engine is on the hot side of warm. Embarrassingly, I have lived ...
13
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2answers
35k views

How does ambient temperature affect engine efficiency and fuel consumption?

I remember from my physics class that the ideal-gas Carnot engine is more efficient if the temperature difference between the heat source and the thermostat ("heat recipient") is larger (http://...
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5answers
6k views

How to properly change out spark plugs?

I am looking into how to change out my spark plugs on my 4 cylinder 2005 Mazda 3. All I know to do is: 1: Open each cylinder. 2: Use a spark plug socket (with the rubber insert) to remove the old ...
13
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3answers
31k views

Why (almost) all dirt bikes have single cylinder engine?

Every dirt bike i know has a single cylinder engine. I myself ride a Yamaha XT660Z which has a huge 660 cc cylinder. What are the characteristics of those engines? what are the benefits of such ...
13
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2answers
49k views

How much power (HP) do the components on the engine belt generally use?

In general, how much power (HP) to the components on the the engine belt actually use? I'm trying to come up with an estimate of how much horsepower an engine wastes on things like the AC compressor, ...
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2answers
2k views

How to determine injector size for custom engine?

I've got a 2.5 L engine here for which I do not know the performance specs (yet), because it's customized. I need to select injectors for this build, but there seems to be only one equation on the ...

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