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

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4answers
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Engine power specification at different rpm?

Car companies advertise 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 than ...
12
votes
7answers
14k views

Engine oil change and getting rid of old oil completely

After running the vehicle for a certain distance usually we will change the engine oil. This will not only give engine new life with the brand new oil but will also get sludge and other sediments out ...
12
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4answers
314 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 ...
12
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2answers
158 views

Motorcycle Four Body Carburetor Synchronization Balancing

I would like to adjust four-body carbs by myself, in order to avoid spent money every time. What are the basic rules, tools and secrets of synchronizing multiple carburetor bodies?
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5answers
3k 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 ...
12
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3answers
785 views

Cold air intake causing rich condition

This is a follow up question to my initial question which can be found here : LTFT and STFT values are off and don't make sense Car is a 2015 F10 M5 Mods : Cold air intake, aftermarket rear ...
12
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2answers
4k 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 ...
12
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3answers
26k views

What exactly is a “burnt valve” and what causes it?

I've come across this term a couple of times in the context of diagnosing engine-related issues, but don't know what it refers to. Here is an example from an automotive forum I frequent: I gotta ...
12
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2answers
105 views

What is meant by degreeing a cam?

In the hot rodding world, "degreeing the cam" is an often used term when installing an aftermarket camshaft. What does the term mean, what does it do for you, why should you do it, and what are the ...
12
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2answers
75 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 ...
12
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3answers
9k 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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3answers
5k views

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

why do diesel cars redline at around 4500 rpm whereas petrol ones around 6500 -8000 rpm? Does this have something to do with the compression ratio?
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4answers
2k views

Does putting an automatic car into neutral at stop lights significantly harm the transmission?

I drive a 2013 Mazda 3, in case that makes any difference to the answer. There seems to be a few discussions on the web which indicate that putting an automatic car into neutral does not ...
11
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3answers
19k 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 ...
11
votes
2answers
6k views

Why might I experience a power falloff after starting my car with the AC On?

I have a 2000 Chrysler Neon which generally runs well. I have noticed that if I start the vehicle, turn the AC on and reverse out of the driveway, the engine seems to struggle/sounds like it is going ...
11
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2answers
273 views

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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6answers
6k 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 ...
11
votes
1answer
660 views

Brake Specific Fuel Consumption of 2-stroke vs 4-stroke

How much fuel do various types of engines burn per power output? I'm especially interested in naturally aspirated piston engines, and comparing two-stroke to four-stroke. The wikipedia article gives ...
11
votes
1answer
362 views

2005 Subaru 2.5 RS - Engine-wise, how damaging is burning oil?

Assuming that an engine always has enough oil to be lubricated properly but burns quite a bit of oil, can it cause any damage in the long-term because it doesn't belong in the combustion chamber? I ...
10
votes
4answers
4k views

Why did V4 engines never take off?

I read that Ford Taunus (not to be confused with Taurus, it was a small model for German market) used to be made with a V4 engine but that's about it. How come V4 never became more used in modern ...
10
votes
4answers
368 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? ...
10
votes
6answers
17k views

What is the purpose of plastic engine covers?

I have a 2010 Toyota Corolla. What is the purpose of the large plastic cover that stretches over my valve cover? Does it have a particular function? Are they just for looks? Or are they designed by ...
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votes
6answers
10k views

Why does a diesel sound like that?

My car is in the shop for a repair, and they gave me a loaner. It's a Chevy Cruze Diesel. Sitting on the driveway, my wife said, "It sounds like a truck". It does. So what exactly it is about ...
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votes
4answers
26k views

What colour should power steering fluid be?

Recently started shopping for first car, so want to know as much as possible when going into a sale. Car I looked at recently has a brown dirty colour in the power steering reservoir, but the stuff ...
10
votes
1answer
543 views

What is a 6 Pack and will it add performance to my engine?

What is a 6 pack in the hotrodding world? Does it improve performance of my engine?
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2answers
9k views

Lugging the Engine (Manual Transmission)

So...lugging the engine obviously isn't something that is good. But why? For example when you feather a clutch to get the car moving, it lugs for a quick moment when you hit the catch point (When ...
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2answers
14k 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, ...
10
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1answer
195 views

How do I get more power out of a rotary engine?

Background I'm looking at a few cars for a track day car that I can abuse. One of the vehicles I'm considering is an older Mazda RX7. The primary reasons being that it has a rotary engine as well ...
10
votes
1answer
117 views

Coolant Reservoir

Two questions, One, is there any reason why some coolant bottles are shaped in this way? Two, if this coolant bottle was placed on its side such as in the image below for example would coolant ...
10
votes
1answer
77 views

What is the efficiency delta between rotary and modern four-stroke engines

Background There is a lot of opinion out there regarding the efficiency delta between wankel rotary engines and four stroke engines of various configurations (forced induction, etc). This delta, ...
10
votes
1answer
94 views

Formula 1 valve trains

There was a statement in a post regarding Formula 1 valve trains being pneumatic or magnetic. Are there valve trains driven magnetically or pneumatically that are on the market? When did they start ...
10
votes
1answer
78 views

Computing Wheel Torque From Engine Torque

It seems possible to obtain engine torque and RPM from a truck CAN bus. I'd like to estimate tractive force at the wheels given these two values. How should I go about computing torque at the wheels? ...
10
votes
1answer
59 views

What Can I Learn From Exhaust Manifold Temps?

I was wondering what I can learn from the temperatures on the individual exhaust pipes coming out of each cylinder. The question is general, and my specific example is on my 98 Mazda 626 GF 2L. Last ...
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2answers
109 views

1982 Yamaha Virago - Several things are wrong and i'd like to repair myself

Several things have happened in the past couple days and I would like to know what could possibly be wrong before I take it all apart. Engine dies after letting off the throttle while on the road. ...
10
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1answer
47 views

VW Bora V6 2005 - Sump Replacement Question

My sump cover has a huge hole and I'm going to replace it. Can I take the cover off from underneath the car or does the motor have to be lifted to recover the sump cover?
9
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4answers
3k views

What happens if unsuitable oil is used in a vehicle engine?

I recently heard an urban legend-like story about a guy in a developing country who decided engine oil was too expensive and so used some vegetable oil instead. The story says the car ran for some ...
9
votes
5answers
902 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 ...
9
votes
6answers
459 views

Fuel consumption at same speed of different engine

I am wondering why two car running at 100 km/h for example with a 100 hp consume less fuel that an engine of 300hp. Even if I take a supercar lighter and more aerodynamics it will consume more. But ...
9
votes
3answers
95 views

Should I replace piston rings on chevy 350?

I recently acquired a chevy 350 manufactured in 2015 for free because of some crank issues. I'm in the process of rebuilding it and have finished the disassembly of the engine. The engine itself only ...
9
votes
2answers
812 views

How would I go about becoming a mechanic?

So, for the most part, I know how an engine works. I understand how a car converts liquid fuel to physical power, and most of the concepts behind the operation of a vehicle. Recently, i've begun to ...
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2answers
554 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 ...
9
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6answers
20k views

Do I need to torque my spark plugs?

I have never torqued them before on several vehicles that I do tune ups on. I just apply a bit of anti-seize lube and get them "snug" and everything seems to work fine. Should I be using a torque ...
9
votes
2answers
398 views

Why do Formula 1 cars use engines with many volumetrically small cylinders?

What's the benefit to Formula 1 using engines like a 3.0L V8 or a 2.4L V8? I read this Reddit discussion on why it's not practical to put small many-cylindered engines into production cars. Cost ...
9
votes
2answers
2k views

Modern cars and diesel warm-up time

First of all let me say that I already read this question and its answer, so it's clear to me why diesel-powered cars need a warm-up time. My question is: do modern cars need it too? I have VW Golf ...
9
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3answers
278 views

Location of exhaust manifold

In four cylinder engines, why are some cars designed with the exhaust manifold towards the front of the car while other cars have it towards the back? Is there any advantage in one design over the ...
9
votes
2answers
193 views

What are Performance Camshafts?

I read the following question recently: What is it about performance cams that make engines produce more power when they are installed? I know there are a few components for cars that have "cam" ...
9
votes
2answers
59 views

How do I go about replacing the head gaskets in my Dodge truck?

It's a 1999 Dodge Ram 1500 4x4, Laramie SLT, automatic transmission, 5.9l magnum engine, and crew cab (222k mi). It seems to have some head gasket leaks, as there is some coolant burning. I have only ...
9
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1answer
96 views

My feet turn black

I left the pedicure salon, started my car and drove less than 3 miles to pick up something from the store, when I stepped out of my car my feet were black... and I don't meant just from dirt, It ...
9
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1answer
191 views

How does intake manifold runner length effect the power curve of a car?

Recently I learned that a number of things such as the cam profile, compression ratio and the intake manifold runner length and volume can all effect the power curve of the engine. Here is an ...
9
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1answer
74 views

What exactly is a piston?

Here is a diagram of a disk brake. Notice that there is a piston (in red): This is a piston, most commonly used inside the internal combustion engine: Image 1 Source: ...