21
votes
Accepted
Why do two-stroke engine exhaust pipes look so strange?
There is this nice animation of a 2-stroke engine with an expansion chamber
Source
It works like this:
While moving downwards after ignition, the piston exposes the exhaust opening, and the burned ...
- 7,047
21
votes
Why do two-stroke engine exhaust pipes look so strange?
Briefly:
The exhaust pipes are shaped to suck gasses out of the combustion chamber over a range of RPMs.
Somewhat longer:
Imagine a 2 stroke engine without an exhaust*1. When the exhaust valve ...
- 589
13
votes
Accepted
Two-Stroke Diesel Engine - Do they use forced induction on them?
The only two stroke diesel i'm aware of is the Detroit diesel. The Detroit diesel does use forced induction but not in the way that you think. From your description it sounds like your describing a ...
- 16k
11
votes
Can I dilute 2-stroke gas and run it in my riding mower to get rid of it?
As long as you dilute it there should be no issues. Mixing a gallon or so with 5 gallons takes a 50:1 fuel-to-oil ratio to about 250:1. In other words, the engine will never notice it.
- 12.1k
10
votes
Accepted
What makes two-stroke engines less fuel-efficient than four-strokes?
Just so we're on the same page as to how two strokes work, here's a pic. I had to look it up because I had the wrong picture in my head.
In looking at how the cycle actually works, the power stroke ...
- 9,326
10
votes
Accepted
Starting a 2 stroke jet boat after several years
Water in the cylinder usually means water in the crankcase on a two stroke
Pulling water out of the cylinder doesn't mean you pulled out all the water. Two stroke engines use ports on the side of ...
- 33k
9
votes
Accepted
Two-stroke vs four-stroke design
Depends.
A key point of 2-cycle engines is that a thing called scavenging happens with the piston at the bottom: at the end of the power cycle/ beginning of the compression cycle. During ...
8
votes
What makes two-stroke engines less fuel-efficient than four-strokes?
The efficiency of any internal combustion engine is directly related to its Carnot efficiency, where efficiency equals the inlet air temperature minus the exhaust temperature divided by the inlet ...
- 81
7
votes
Accepted
Carb. Rebuild or Adjustment?
I'm not a watercraft Mikuni guy, but I've dealt with a few two-stroke carbs that work in this manner.
There's a few possibilities:
The internal filter screen is clogged, but I'm discounting this as ...
- 12.4k
7
votes
Accepted
Is it okay to run aviation fuel (100 low-lead) in a dirt bike?
You can run that fuel. I've run a 100 hours of aviation fuel through plus another 200 hours of race fuel that tends to destroy FI fuel pumps in various years of RM. I have a friend that is currently ...
- 33k
7
votes
Accepted
Can I dilute 2-stroke gas and run it in my riding mower to get rid of it?
You should be able to run this straight through your lawnmower without issue. As long as you aren't running it through your car with a catalytic converter it should be just fine. The thing which 2-...
- 153k
6
votes
Two-Stroke Diesel Engine - Do they use forced induction on them?
Renault are developing a small 2 stroke diesel with turbo and supercharger. It's name is the Renault 'Powerful' see for example - http://www.enginebuildermag.com/2014/12/renault-unveils-two-storke-...
- 24.9k
6
votes
Brake Specific Fuel Consumption of 2-stroke vs 4-stroke
BSFC is just engineer-speak for how much fuel is consumed by the engine per unit of energy output¹.
This webpage provides a very concise comparison for several different engines:
+-------------------...
- 39.1k
6
votes
What are the problems in building 2 stroke engines with a large displacement?
Perhaps you were thinking of 2-stroke gasoline engines when asking the question.
Evinrude built a 3.6 liter gasoline 2-stroke for outboard boat motors.
http://www.roadandtrack.com/car-culture/...
6
votes
Starting a 2 stroke jet boat after several years
Water in the cylinder?
The engine is in bad shape from improper storage. Even if you get it freed up there will be rust on the cylinder walls and piston rings, which will cause more damage if you ...
- 8,010
6
votes
Two-stroke vs four-stroke design
For Two Stroke engine:
One working stroke in each cylinder per revolution of crankshaft.
Light in weight.
Moving parts are few.
Mechanical efficiency is more.
Thermal efficiency is less because a ...
- 169
5
votes
Accepted
Adjust carburettor without hi-speed adjustment
Yes, you can bend the tab
The metering diaphragm enriches the entire range on every circuit. If the fuel level is higher it will require less vacuum under Venturi's Law to pull the fuel from the '...
- 33k
5
votes
Accepted
Two-Stroke vs. Four-Stroke Diesel Engines - What is most commonly used in heavy vehicles?
Most small(ish) diesel engines in cars, diggers, generators etc are 4-stroke.
The main reason being efficiency - Although a 2-stroke engine is technically capable of more power output, a 4-...
5
votes
Accepted
If an engine starts does that mean compression is fine?
You cannot assume just because it starts it has good compression. It can have minimal compression and still start and run just fine. That minimal compression is going to be different for every engine, ...
- 153k
5
votes
Poor man's 2-stroke strimmer air filter
I would actually suggest you to buy a foam air filter element that is big enough. Usually they are sold for certain specific types of engines, like certain lawnmowers or certain generators. However, ...
- 14.5k
4
votes
Honda R8X-S heat seize
It depends on where the engine is seizing
Since your scooter/motorcycle is a two stroke, if you are seizing due to a lack of oil in the gas at the crankshaft you are in big trouble. More than likely ...
- 33k
4
votes
What makes two-stroke engines less fuel-efficient than four-strokes?
I have to both agree and disagree with your statements in the question and the article.
The higher fuel consumption of a two stroke engine is mostly due to the fact that it has a power stroke per ...
- 8,956
4
votes
Is an exhaust mute bad for 2 stroke engines?
It depends on the exhaust system. If it is a road bike with an exhaust system designed for the road, you need to keep the silencer/muffler/mute on it for optimum performance. Only a full race system, ...
- 559
4
votes
Two-stroke vs four-stroke design
Not sure if you count that under “besides the apparent”... but IMO the single most striking peculiarity of a two-stroke is that it uses both sides of the pistons to work on gas volumes†. That's what ...
- 435
4
votes
Accepted
Which engine type gives more HP- two or four cycle?
Theoretically, with all other factors being equal, the 2 stroke engine should produce 2 times the power of the 4 stroke engine. The reason being that the 2 stroke engine has twice as many power ...
- 12.1k
3
votes
Two-stroke vs four-stroke design
Yes, number of power strokes per revolution, less complicated : fewer moving parts, emissions or pollution levels. Have a look here : http://mechstuff.com/differences-advantages-disadvantages-of-4-...
- 34.6k
3
votes
Accepted
No compression on my two stroke
TL;DR:
Either there's a problem with the head gasket, or with the piston rings.
Remember, the piston rings fly over the openings in the cylinder wall, and there's no radial force onto the section ...
- 7,047
3
votes
Accepted
Snowblower - 2 cycle oil without stabilizer
I think you could very well be ok. I think some mitigating circumstances are these surround if the gasoline was extremely hot repeatedly. Sitting outside in the sun every day would qualify. The ...
- 33k
3
votes
Poulan chain saw
A light weight grease can be useful to keep the needle bearings in place while completing the assembly. It will provide lubrication and eventually be worn or be washed away by the normal lubrication ...
- 4,455
2
votes
Is it okay to run aviation fuel (100 low-lead) in a dirt bike?
AVGAS 100LL has TEL (tetra ethyl lead), locally about 1.3g / US Gal. The TEL may cause some fouling of the spark plugs. It will not shorten your engine life. It is used extensively by motocross and ...
- 2,115
Only top scored, non community-wiki answers of a minimum length are eligible