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Questions tagged [engine]

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

58
votes
9answers
698k 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 ...
26
votes
4answers
449k views

What actually happens when there is way too much oil in a car engine?

I saw the answers to a question I posted recently highlighting the disadvantages of having too little oil in an engine, but that got me wondering what if the complete opposite were to occur! I know ...
19
votes
3answers
45k 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 ...
18
votes
2answers
3k 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 ...
9
votes
3answers
209k 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...
4
votes
1answer
3k views

What is a stress riser?

What is a stress riser and why is it important to avoid them during engine construction or rebuild?
17
votes
6answers
96k 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 ...
29
votes
3answers
12k 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 ...
36
votes
3answers
320k 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 ...
10
votes
2answers
4k views

BSFC (Brake Specific Fuel Consumption) - How is this a beneficial measurement?

Brake Specific Fuel Consumption or BSFC Measuring various attributes of an ICE (Internal Combustion Engine) and how it performs certainly gives a greater understanding of how a particular ICE ...
29
votes
4answers
346k 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?
11
votes
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 ...
25
votes
6answers
41k 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 ...
9
votes
5answers
2k views

What can cause a gasoline engine to suddenly & mysteriously stop (non-catastrophically)

I was thinking about this question and found myself wondering what could cause a gasoline engine to suddenly stop, and then be restartable? So not things like running out of fuel, or suffering a ...
19
votes
3answers
73k views

What does a flywheel do and what is it connected to?

I understand roughly how an engine works and that there is a crankshaft which is able to turn the flywheel using internal combustion. I have just realised that I have got absolutely no idea how the ...
10
votes
4answers
69k 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 ...
4
votes
2answers
3k 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 ...
2
votes
1answer
1k views

Hole-in-One. Small extension and socket fall into valve

I am very poor so I work on my house/SUV (2002 Ford Expedition) myself. Recent misfires had me changing coils and spark plugs. Well, everything is going fine until my extension comes off my socket ...
37
votes
10answers
65k 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 ...
19
votes
4answers
169k views

What is a rod knock?

What is a rod knock? What causes a rod knock, how bad is a knocking rod, and how can I tell if a rod is knocking?
17
votes
3answers
43k 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 ...
9
votes
3answers
57k 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 ...
14
votes
3answers
21k 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
1k 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?
22
votes
2answers
19k 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 ...
21
votes
7answers
291k 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 ...
9
votes
6answers
5k 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 ...
19
votes
6answers
40k views

Is it OK to mix oil of different viscosity in a Wankel engine?

I have a Mazda RX-8 (with a Wankel rotary engine). Mazda advises North American owners to use 5W-20 oil. The engine was just replaced 200 miles ago by the dealer so it currently has 5W-20 in it. ...
9
votes
1answer
1k views

Carburettor jetting on installation of aftermarket air filter

I have a 150cc motorcycle and am planning to install an after market air filter(K&N) since the stock one was favoring fuel efficiency and not performance. The bike has a carburetor (Mikuni) not ...
8
votes
4answers
11k views

Do fast cars need to occasionally be driven fast?

In the broad spectrum of cars, there's higher end models with sport-focused engines. Examples would be an BMW M3, and even more so Ferraris and Koenigseggs etc. Apparently they're more fussy, in that ...
20
votes
4answers
86k views

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

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 valve mechanism that ...
19
votes
10answers
59k 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 ...
9
votes
1answer
941 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?
9
votes
3answers
16k views

Should I avoid full throttle when driving with a cold engine?

Apparently I should avoid full throttle until my engine temperature is warmed up fully (to 90 degrees on the gauge) Normally I just get in and drive normally after about 10 seconds, and then after ...
5
votes
2answers
2k views

Lean Fuel Code on V10

I have 1999 V10 Ford chassis on a 2000 Coachman motorhome. Engine starts great when cold, runs great, idles great, no skipping, missing, etc. Problem is that after driving more than 30 minutes or so ...
2
votes
1answer
11k 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?
22
votes
7answers
63k views

Aluminium engine vs Cast Iron engine

What is the advantage that the aluminium engines provide over the cast iron engine apart from the fact of rusting and weight reduction. Manufacturers like to boast about their all new aluminium ...
6
votes
2answers
61k 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 ...
25
votes
6answers
198k views

What are the risks of overfilling a small engine with oil?

I recently overfilled a 4 stroke lawnmower engine with oil. It has been run for about 1.5 hours while overfilled. It smokes a lot right after being started but after 30 seconds or so the smoke clears. ...
18
votes
2answers
9k 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 ...
11
votes
4answers
183k 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 ...
22
votes
2answers
13k views

Why do we need to cool air after it leaves a turbocharger?

When we are using a turbocharger to compress the incoming air, the air gets hotter. Usually this hot air is cooled by using an intercooler before it's passed to the engine. What is the reason behind ...
17
votes
2answers
4k 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 ...
13
votes
2answers
39k 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
votes
1answer
649 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 ...
8
votes
2answers
43k 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 ...
7
votes
2answers
18k 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. ...
3
votes
3answers
7k views

92 Civic engine won't start after replacing head gasket

I just replaced the head gasket in my 1992 Civic. Started it up before putting everything back together (just a second since it had no coolant, exhaust wasn't connected, etc.) and it ran fine. But now ...
3
votes
1answer
503 views

Turbo Charging Suzuki Splash/Ritz

Can I turbo charge my Suzuki Splash/Ritz? Its a 1.2 liter petrol engine with 85HP. What types of engines can be turbo-charged. If it's possible, how would I do it?
2
votes
1answer
548 views

Supercharger calculations

How to determine safe supercharged pressure and CFM for a motor cycle engine (fuel injected 149cc (9.31 cubic inches) 12.9 bhp?