VW Golf4 BCB not start

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Re: VW Golf4 BCB not start

Postby Fat Freddy » Sun Dec 11, 2016 8:24 am

I found myself in the past counting for crank pulses after TDC mark, to be more sure about timing events and angle, not trusting the rulers.

No need to count. Use edge count if you require that sort of accuracy. Way quicker. :)

Volkswagen_Golf_2002_Petrol_20161211-0001.psdata
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Which in fact makes the exhaust cam appear even more advanced by a further 4* approx.

HTH
FF
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Re: VW Golf4 BCB not start

Postby Fat Freddy » Sun Dec 11, 2016 8:48 am

victor2k wrote:My madness started from a similar event to the following images(captures was made with the same setup on Ford Puma 2002 /petrol/1.6l):30* diference on a non-vvt engine between first and second measurement(vvt or non-vvt does not matter at cranking and idle anyway)! :evil:
Thank you.



I don't think I'm totally understanding what you are measuring. I could be wrong but it looks like you are comparing exhaust ramps between cranking and idling. It's never going to be comparable. As a cylinder under vacuum on the exhaust stroke (idle, 1/2 a bar) is never going equalize to exhaust at the same rate of rotational degrees as one cranking - poofteenth of a bar vacuum to equalize to exhaust pressure.
Two different pressures to equalize at two different crank degrees per second. It's not really comparable.

You would get better results measuring the start of the event.

Hope that makes sense.
FF
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Re: VW Golf4 BCB not start

Postby victor2k » Sun Dec 11, 2016 12:00 pm

Fat Freddy wrote:
I found myself in the past counting for crank pulses after TDC mark, to be more sure about timing events and angle, not trusting the rulers.

No need to count. Use edge count if you require that sort of accuracy. Way quicker. :)

Volkswagen_Golf_2002_Petrol_20161211-0001.psdata


Which in fact makes the exhaust cam appear even more advanced by a further 4* approx.

HTH
FF

Hello,
Thank you for solution.
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Re: VW Golf4 BCB not start

Postby victor2k » Sun Dec 11, 2016 12:16 pm

Fat Freddy wrote:
victor2k wrote:My madness started from a similar event to the following images(captures was made with the same setup on Ford Puma 2002 /petrol/1.6l):30* diference on a non-vvt engine between first and second measurement(vvt or non-vvt does not matter at cranking and idle anyway)! :evil:
Thank you.



I don't think I'm totally understanding what you are measuring. I could be wrong but it looks like you are comparing exhaust ramps between cranking and idling. It's never going to be comparable. As a cylinder under vacuum on the exhaust stroke (idle, 1/2 a bar) is never going equalize to exhaust at the same rate of rotational degrees as one cranking - poofteenth of a bar vacuum to equalize to exhaust pressure.
Two different pressures to equalize at two different crank degrees per second. It's not really comparable.

You would get better results measuring the start of the event.

Hope that makes sense.
FF

Hello,
If you will look at my first post/eight post again ...the question was how the opening moment of exhaust valve(135*-145*after TDC) can be good but the half of opening is wrong at the same time?
About your last opinions...let's go to the theory:
-the timing is the same at cranking and idle?
-the speed of filling cylinder is very high(the brownian moving it is responsible for this and is the same if the spark plug is removed on a petrol engine(brownian moving is 0 m/s at -273.15*C,340m/s at 20*C)?
I do not want to offend anyone, just looking for answers.
Thank you.
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Re: VW Golf4 BCB not start

Postby Fat Freddy » Sun Dec 11, 2016 3:32 pm

Absolutely no offence taken by me. It gives me food for thought, something I enjoy. But I haven't come across Brownian before so I will certainly have a read up. :D

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Re: VW Golf4 BCB not start

Postby Technician » Mon Dec 12, 2016 12:19 am

Alternative Title: Brownian movement
physics

Brownian motion, also called Brownian movement, any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations. It was named for the Scottish botanist Robert Brown, the first to study such fluctuations (1827).
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