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Cam Gear Adjustment Question?

frozenwaffles
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frozenwaffles Mentor

frozenwaffles

Posted
Posted

hey guys, just quickly, when we speak of '4 deg retard' or 3 or whatever, are we talking 4 deg of cam gear adjustments notches or 4 deg of crackshatf movement? as from what i gather 1deg of cam gear movement is the equivelent of 2deg of crackshaft movement...

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https://www.sau.com.au/forums/topic/218772-cam-gear-adjustment-question/
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Duncan Grand Master

Duncan

Posted
Posted

we are talking about o of cam movement. so 4o retarted would be 2 marks on the cam gear if it is 1 mark = 2o.

sorry I just reread the question and can't confirm whether it is crank or cam o. But for sure the measurements you hear mentioned on here are relative to the marks on the cam gear.

rev210 Grand Master

rev210

Posted
Posted

getting individual degrees onto the cam gear would be pretty hard to do, let alone look at them properly without some magnificication.

4 degrees is generally accepted as benificial, however there are underlying assumptions about the setup. There is no substitute for testing to get it right for your car. I have done a few cars and there can be a little variation on that figure either way that has actually quite a bit of impact.

frozenwaffles Mentor

frozenwaffles

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Posted

gallery_30866_2551_172.jpg

here is a pic of my gear....now i know that each mark = 2deg of crack as it states on the gear

what im asking is when somesays i 'retarded the cam gear by 4deg' are they talking about crack 4 deg or gear 4 deg (= crack 8 deg)???

GeeTR Grand Master

GeeTR

Posted
Posted (edited)
here is a pic of my gear....now i know that each mark = 2deg of crack as it states on the gear

what im asking is when somesays i 'retarded the cam gear by 4deg' are they talking about crack 4 deg or gear 4 deg (= crack 8 deg)???

I couldnt help myself :)

Edit, I took it to mean, 4deg at the crank. So two marks on the cam gear.

Edited by GeeTR
Duncan Grand Master

Duncan

Posted
Posted

yeah sorry iw as too lazy to check, the car is under a cover. but the trust ones are the same I am 99% sure. 1 mark = 2o crank. So people are talking crank degrees.

BTW when setting my gears the other day we tried 8o on the intake and lost 40kw just like that. very small adjustment makes a very big difference

Sydneykid Grand Master

Sydneykid

Posted
Posted
how do you get 4deg retard on the exaust gear?

To retard the exhauits cmashaft 4 (crankshaft) degrees, you rotate the camshaft 2 slots anticlockwise, because the engine turns clockwise.

The camshaft is connected to the centre of the pulley, the cambelt is conected to the outside of the pulley.

You keep the outside of the pulley (the cambelt) still while you rotate the inside of the pulley (camshaft) anticlockwise.

Simple isn't it?

Cheers

Gary

666DAN Grand Master

666DAN

Posted
Posted

OK I've tried the following on the exhuast cam, base timing was adjusted to 20 degrees each time (auto)

4 degrees retarded (car seemed less responsive, could dial in a fair bit of base timing though, didn't seem to drastically improve matters) Had to drop EBC gain to 20% to not go over 0.85Bar

2 degrees retarded (much the same as before, more response) Had to drop EBC gain to 30% to not go over 0.85Bar

2 degrees advanced (seems to have picked up a bit of power) Had to raise EBC gain to 40% to get 0.85Bar

Now this is the same setting as another SAU'er told me he was using and picked up about 10rwkw on the dyno.

My next thing to try is adjusting on the dyno when it's getting tuned and see the real results.

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