Questions tagged [compression]

One of the four internal combustion engine strokes necessary for the complete combustion process to occur. The compression stroke compresses an air fuel mixture and prepares for it ignition by spark.

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Atkinson Cycle: Does the efficiency of a high-compression engine come from compression ratio, expansion ratio, or both?

I understand that, in an internal combustion engine, efficiency can often (up to a point) be improved by increasing the compression ratio, this being a major reason why diesel engines (which do not ...
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Misfire! Does good compression mean there are no valve issues?

I have a new old stock sherpa "O" series petrol engine 1991 that I installed 3 years ago. I have a misfire on cylinder 1 (detaching spark plug lead makes virtually no difference to the ...
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Help me understand the results of these cylinder compression and leakdown tests

I recently purchased a 2007 Subaru Outback 2.5i, with approx 146000kms on the clock. As its a recent purchase, I'm going through preventative maintenance to ensure its running as good as possible. ...
WeakMech's user avatar
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possible to replace rings in i4 from the bottom?

I'm checking out a 2007 Nissan Sentra 1.8 inline 4, 170k miles, for a friend. I have never witnessed this vehicle while running so here's what I "know." It takes like 20 minutes of cranking before it ...
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I have an '07 kow vulcan only 6k miles and recently rebuilt carb., now it is losing compression and is killing me to speed up even in low gear, could the clutch plates be shot even at this low mileage?...
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1991 Chevy Astro - O2 Sensor and Low Compression

I have a 91 Chevy Astro van with 15x,xxx miles. It idles very rough and drives extremely poorly at around 40mph, and, overall, seems to lack a bit of power. A compression test was performed on the ...
KellyM's user avatar
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2003 Chevy Silverado

Why does my 2003 Chevy Silverado 2 door pickup LQ4 Vin U engine Why does my 2003 Chevy Silverado LQ4 engine have no compression in one cylinder
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2004 Dodge Ram 1500 5.7 Liter Hemi 4x4 Automatic cranks, but won't start

I was driving 2004 Dodge Ram 1500 5.7 Liter Hemi 4x4 Automatic and it just died on me as I was going down the road, before I could get it parked, so I put it into neutral and I tried to start it ...
Booy Kogel's user avatar
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2007 jeep liberty 3.7 only start I completely remove "any" sparkplug from cylinder then ground,

Only starts take out any one plug then ground to alternator starts right up, thought had to be bad ground so grounded from battery to engine block still won't start with all six plugs in Jeep Liberty ...
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back compression in skoda Rapid

I have skoda Rapid 2012, there seems to be a oil leakage. Recently one mechanic said there is back compression in the engine but another said Skodas have back compression and nothing to worry. I am ...
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MAZDA 3 2006 no compression?

Okay so I am in need of advice, I have a Mazda 3 2006, the timing chain was super stretched out which caused the car to die at a stop light or if the gas was not being pushed the car would die. So I ...
Hailey Day's user avatar