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

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11
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4answers
22k views

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 ...
9
votes
2answers
6k 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 ...
19
votes
3answers
6k views

Static vs. Effective compression: Why does higher effective compression not require higher octane gas?

Background I've been trying to do a lot of research on boost lately because I'm planning on running a moderate turbo setup on my daily/light-duty-autox car in the future. I'm trying to get into the ...
28
votes
9answers
5k views

What actually happens when there is not enough oil in a car engine?

When a car is topped up with oil, it clear to most people that you are supposed to fill it to the recommended amount as specified by the manufacturer (normally on a dip stick). What exactly are all ...
7
votes
4answers
27k views

Is engine braking harmful? [duplicate]

Possible Duplicate: Does Downshifting (Engine Braking) Cause Extra Wear and Tear? My wife and I have a disagreement about a practice of mine--engine braking. When I'm driving her manual ...
7
votes
3answers
32k views

Oil in coolant - how much trouble am I in?

I have oil in my coolant reservoir. Could it just be the head gasket or is it almost certainly the entire engine or might it be something else entirely? Thanks in advance...
9
votes
5answers
835 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 ...
27
votes
9answers
40k views

Is it necessary to 'burn in' or 'break in' a new car?

I've just bought a new 2011 plate car. I've heard stories of people 'burning in' engines for the first few hundred or couple thousand miles using methods such as: Not driving above 50 mph. Varying ...
2
votes
2answers
1k views

Mazda 323: Plugged in Coolant Temp Sensor - Now Car won't Start

I recently bought a Manual 97 Mazda Lantis 323 1.8L DOHC 16 Valve BP. I found the following wire unplugged on the drivers side of the engine, next to the water intake from the radiator: It plugs ...
11
votes
3answers
8k 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 ...
11
votes
2answers
13k views

WHY does an engine stall? (manual transmission)

Before you write off my question as one that's been answered a million times already, I want to clarify. I understand that the engine needs to go a certain rpm and when you try to engage the clutch ...
17
votes
7answers
89k views

Is idling bad for your engine?

If I sit in my car for 30-40 minutes with the AC and the car idling, does that "hurt" the engine, or does it simply waste gas and pollute the air? Would it be better if I turned off the car? A ...
14
votes
4answers
35k views

Why does a Turbocharger only produce boost when the engine is under load

As per the Title. Why does a turbocharged car only produce significant boost whilst the engine is under load. Is is something to do with how much exhaust is being produced or is there some kind of ...
6
votes
2answers
18k views

Engine Size and Fuel Consumption

I have this weird misconception that the engine size is related to the amount of fuel being burned in one cycle(4-stroke engine). I know this is stupid but how does engine size relate to the amount of ...
16
votes
2answers
10k views

Why doesn't the engine stall out when you come to a stop with an automatic transmission?

When you come to a stop with a manual transmission you have to push the clutch in or take it out of gear to keep the engine from stalling out. What keeps the engine from stalling in an automatic ...
6
votes
2answers
10k views

Oil pan threads stripped?

EDIT Helpful links on how threads got stripped and by who: http://tl.acurazine.com/forums/showthread.php?t=878261 Seems to be a common problem with some shops, where they don't take good care. ...
22
votes
3answers
97k views

What does a water-like drop coming out of the exhaust of the car signify?

Sometimes while driving in the traffic, I come across a car or two which would be dripping water-like drop from it's exhaust steadily in a break of 4-5 seconds. I tried to ask a couple of people at ...
18
votes
2answers
27k views

Is starting your car with the A/C on bad?

I was always yelled at by my father when I was first starting to drive when I left the A/C on when I turned off the car, and then later turned it back on, with the reasoning that I was ruining / ...
13
votes
6answers
2k 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 ...
9
votes
1answer
115 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 ...
8
votes
1answer
66 views

What is Lobe Separation Angle (LSA)?

What is Lobe Separation Angle (LSA) and how is it used in camshaft design? How is it measured? What difference does a long or short LSA make?
8
votes
6answers
15k 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 ...
8
votes
1answer
1k views

Car Suddenly Decides To Not Crank

Today I turned the key to start up my car and all the lights (headlights and instrument panel) came on bright and normal, but the engine made absolutely no sound. It wouldn't start, it didn't even try ...
6
votes
1answer
53 views

What exactly is a head gasket?

From what I have gathered, a "head gasket" is an important part of the engine on most cars, but that is about it. What is a head gasket? Where is a head gasket? Why is it necessary?
5
votes
3answers
108 views

What actually happens when there is not enough coolant in a car engine?

I know that a lack of engine oil can destroy an engine, so I was curious as to whether it is just as bad to drive a car with a very low engine coolant. What is engine coolant? What exactly are all ...
5
votes
2answers
140 views

Water leaking into frame case/engine?

I just had my 2012 Mini Cooper S (66K miles) repaired last week last week for a failed/leaky water pump. My car had an episode where it overheated and shut down and wouldn't start after pulling over ...
5
votes
1answer
105 views

Reliability of water test for valve seal

I took my valves out, cleaned and lapped them and put them back together. I also put new valve stem seals. At least on one side of my V6 Tacoma. I performed several water tests to check the seal of ...
5
votes
1answer
546 views

Acceptable amount of slack in a timing chain with high mileage?

1995 Chevy S-10 Blazer - 4.3 L Vortec V6 (vin W with PCM) - 230,000 miles original owner. FWIW, this model car/engine does not have timing chain inspection and/or changing as part of the routine ...
3
votes
1answer
170 views

What is a stress riser?

What is a stress riser and why is it important to avoid them during engine construction or rebuild?
3
votes
2answers
6k views

What exactly is Honda's i-VTEC technology

I see that almost all of Honda's cars have an "i-VTEC" logo at the back. I googled it and came to know that it has something to do with different cam profiles. Can someone explain? A diagram or ...
2
votes
1answer
1k views

How can I identify which cylinder is responsible for a petrol engine misfire?

My petrol engine has developed a persistent misfire. How can I figure out which cylinder is the culprit in order to hone in on the root cause?
1
vote
3answers
408 views

My 2001 Mitsubishi Airtrek revs at 2250rpm for 30 seconds before slowing. Will this speed harm the engine?

My 2001 Mitsubishi Airtrek 2wd with 86000k revs at 2250rpm for 30 seconds before slowing. Will this speed harm the engine?
13
votes
4answers
27k views

what is difference between DOHC and SOHC?

I want to know the SOHC and DOHC configurations. On what factors an engine manufacturer decides to go with SOHC or with DOHC, what should I choose? DOHC or SOHC?
7
votes
2answers
261 views

How do modern engines differ than older ones

Modern engines produce more horsepower with more fuel economy but with the same procedure of burning the fuel air mixture and moving the piston, but the old ones and new ones are both four cylinders ...
19
votes
6answers
21k views

Is Start & Stop technology good or bad for my car? (Alfa MiTO)

I was recently in the lucky position to obtain an (almost brand new) Alfa Romeo MiTo, Progression. Like many new cars coming out these days, it has "Start & Stop" technology that turns the engine ...
11
votes
2answers
301 views

Why did Ducati decide to use the desmodromic valve train rather than a more tradition valve train?

Ducati's use a unique method to open and close their valves. It's called the desmodromic valve train. The desmodromic valve system does not use springs to close the valve, it uses the cam and has a ...
7
votes
1answer
722 views

Why does an engine's idle RPMs take time to settle from a cold start?

I've noticed my car's (healthy) engine will idle at a slightly higher RPM for a few moments after it's been started from cold/not run for a day. I also noticed that my (somewhat less healthy) other ...
4
votes
2answers
2k views

Dealership Installed “Oversized” Oil Drain Plug As Solution

In this question, we discuss stripped oil pan threads. I learned it is a result of user error - over tightening and cross threading, by the dealership I consistently go to. Many people have come ...
9
votes
2answers
12k 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, ...
8
votes
2answers
102 views

Fiat Punto Wont Start. Fuel Light & Three warning lights flashing

My Fiat Punto 1.2 Year 2000 MK2 (I believe) will not start. The engine turns over but the car won't start. The fuel light is flashing and petrol gauge says empty which isn't the case. There are three ...
8
votes
5answers
11k views

Doing my own fuel induction service - how to, and how difficult?

I was recommended to get a fuel induction service for a 2002 V4 Camry, and am considering doing it MYSELF. The reasons for considering this are: My car idles a bit rough, especially when the AC is ...
7
votes
5answers
270 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 ...
6
votes
1answer
2k views

Heater smells like sulfur

I drive a 2006 Toyota Sienna. When driving with the heater on I often smell sulfur. This is more common when I am driving up a hill, but if I turn the heater off, the smell goes away. What causes this ...
5
votes
1answer
75 views

What is spark plug heat range

I was watching a show and their project was adding a bolt on turbo kit. In the process they mentioned that they needed a colder spark plug. What does a hot or cold spark plug mean? What changes ...
5
votes
3answers
454 views

What do these compression figures mean

This is a follow up question to What are the causes of fluctuating intake manifold vacuum I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. After ...
4
votes
3answers
936 views

What exactly is a clutch?

I found out recently that the flywheel, driven by the crankshaft, is connected to (or part of) the clutch. I have a basic understanding of what a clutch does due to the fact that I know how to drive a ...
4
votes
2answers
160 views

Is it reasonable to charge the customer $1000+ to assemble the top of the engine?

I recently have an engine overheat issue and see my previous post for details: How long does items in the engine last in general for standard size cars? This is an interesting follow up on that at ...
4
votes
1answer
1k views

Effects of driving through deep water WITHOUT hydrolocking (car still bogged down and died)

So, yesterday we had very heavy rains, and unfortunately I was driving in an unfamiliar area of town. I drove through high water, which caused my car to sputter and so I turned around. The car behaved ...
4
votes
2answers
3k views

What happens to a car engine when giving max throttle while not in gear

I was driving (well standing still actually) during rush hour, and I was suddenly wondering what would happen to a car engine when I would push the accelerator pedal all the way down while the engine ...
4
votes
3answers
4k views

Ford Taurus common oil leak area?

On my last oil change, the technician noted some oil around top and side of the engine block and said there is a small leak. The only way to find where it is coming from is doing the whole dye test, ...