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To go from No. 1 TDC on power stroke to No.1 TDC on power stroke ie one rev of the engine requires two turns of the crankshaft
P38A Thor engine RPM
- Thread starter kermit_rr
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Just to be really annoying, the engine doesn't actually turn!! Unless it's an old plane engine 
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OK, I didnt know that but that is not engine revs
Just to be really annoying, the engine doesn't actually turn!! Unless it's an old plane rotary engine
Now let’s not start on rotaries
J
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A revolution is 360 degrees
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Oh yes it does
Ooops wrong season
Ooops wrong season
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Not 720A revolution is 360 degrees
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A single 4 stroke cycle is 2 revs
tomcat59alan
Well-Known Member
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Rpm is the number of times the crankshaft turns along its longitudinal axis per minute and is double the number of power strokes on a four stroke engine and the same on a two stroke.
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Yes it is
But engine revs are not crank revs but I am not sure what the rev counter measures
Is a single cycle not an engine revolution?
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I agree with Alan and a cycle is a power stroke to power stroke and if the rev counter measure cycles eg no. 1 spark to no 1. spark then that is two crank revs.
Ignore the redundant spark bit
Ignore the redundant spark bit
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Now about my target engine speed being 4x actual..
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Is one engine rev not a full cycle>
In old days the rev counter was taken from the spark which would be one rev of engine
In old days the rev counter was taken from the spark which would be one rev of engine
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I still think i should tap the crank sensor.. what's the worst that could happen, another wrong value? Surely i won't fry anything..
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I have no idea where the 4x comes from
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There were several ways to measure revs.. spark being one of them, but the electrical gubbins that measured the spark, adjusted the value to actual RPM
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Nor me unless it just 'looks' 4x to the eyeI have no idea where the 4x comes from
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