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**UPDATE** to compression test only showing 150 over all four.......


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heya guys,

so tonight i got home and checked my timing.removed rocker cover etc as my mechanic friend said it maywell be out a bit.....

lined all the relevant markings up and this came to light on the cams....................tooth out on cams

timing%20out%20a%20tooth.jpg_zpsjkmen7ac

soooooo i went about correcting it,

timing%20fixed.jpg_zpsfvsvadva.jpg

timing%202.jpg_zpsmwzd4wgt.jpg

timing3.jpg_zpsub29zyda.jpg

as above its all now lined up CORRECTLY.

have yet to see what compressions like but my mechanic friend has said despite it being just one tooth it should make a difference.

does seem to rev up alot quicker on the throttle , hopefully this sorts things

Edited by mikey4410
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potter all I can think is that it was the opposite way wrong to mine as mine "drives fine".

started hot or cold.reved up.afrs fine.and all the rest of it.

I am looking forward to driving it tommorow to see if theres a difference.

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I have worked out on my car that the inlet valves would have remained open a fraction longer than it should as my inlet timing was "LATE" on the compression cycle .

this would obviously lead to a small amount of compression/ air and fuel to be lost and put back into the inlet system which isnt great. lol.

Edited by mikey4410
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Screenshot_2015-03-26-14-44-02_zpsr12jbz

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found this as doing research and bored at work... remember I believe my inlet valves opening late and shutting late .

The point that the intake valve goes closed has a large effect on cylinder pressure. When the piston is traveling back up the cylinder, it will force some of the fuel/air mixture past the still open intake valve into the intake port. If the intake valve closes later in the cycle, some of the fuel/air mixture will be forced past the intake valve into the intake port, which will reduce cylinder pressure.


The point in the cycle where the intake valve opens is very important. If the intake valve opens too late in the cycle, the initial amount of fuel/air mixture draw into the combustion chamber is reduced and spent gasses will not be effectively flushed from the chamber.

Edited by mikey4410
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The point that the intake valve goes closed has a large effect on cylinder pressure. When the piston is traveling back up the cylinder, it will force some of the fuel/air mixture past the still open intake valve into the intake port. If the intake valve closes later in the cycle, some of the fuel/air mixture will be forced past the intake valve into the intake port, which will reduce cylinder pressure.

The point in the cycle where the intake valve opens is very important. If the intake valve opens too late in the cycle, the initial amount of fuel/air mixture draw into the combustion chamber is reduced and spent gasses will not be effectively flushed from the chamber.

That's not true mate, look at the cam specs of the E series and you will see that the valve closes at 42 degrees ABDC, so the piston is already coming up the bore. The reason behind this is because the mixture can continue to plough in the cylinder, more air = more fuel required = bigger bang.

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Don't believe everything you read online :thumbsup:



I've got some good engine test data I did here when I was last in the engine test cell with a BMW Mini Turbocharged engine if it would make for some educational reading if you wanna take a look? Obviously the engine is different but the principles are the same.


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It might well change, but not because of the reasons you mentioned. The reason being is that the overlap period had been changed.



What you have found with your motor is that opening and closing the intake valve later alters the engines power spread, have you looked at other dyno graphs of those running the same turbo and same boost? Compare the low-mid range as you might find that your low top end power is because it's been sacrficed for the mid range power.



Dwelling on it a little longer, an N/A engine may well push air back out the inlet valve, however that would be a case of an engine with a volumetric efficiency below 100% and a poorly designed inlet tract where airflow doesn't reach the correct velocity,


Edited by AdamB
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