Arospeed Adjustable Cam Gear Markings Backwards?

[CEF11E]

Hi I have just been looking at my new exhaust cam gear and want to confirm something.

firstly i have searched and come up with nothing.

Please correct me if i am wrong...

1. RB20det cam gears rotate clockwise...

2. The cam gears have markings saying RETARD is the the left

3. If you rotate the blue center piece to the left effectively you are actually moving the cam to the right or clockwise

4. Seeming as the motor rotates clockwise this would mean infact you are ADVANCING the cam

5. Therefore the markings on the cam gear are WRONG.

can someone please confirm this. Picture below.

http://www.skylinesaustralia.com/forums/in...st&id=71726

If this is correct why? and if not could someone please explain?

Thanks all

[Adriano]

Thats right, they are the wrong way around, cant believe noone picked up on this before

[CEF11E]

jeebus,

how can a product be engineered to a level of 0.10 tolerance and cad designed and milled to such a high standard and have backwards bloody markings?!

I am starting to wonder if the actual markers represent 2deg each..

[Adriano]

i suppose at the end of the day it doesnt really matter, as they should be setup on the dyno, and then you record what the settings are, but yes a bit strange. interestingly enough it says crankshaft degrees, so in theory they are correct because instead of advancing the cam, you are retarding the crank relative to the cam.

[CEF11E]

true

Thanks Adriano

[Adriano]

Ive got some mitsu ones downstairs, ill go have a look.- they dont have any A or R markings, just the lines

[blind_elk]

The blue centre is attached to the camshaft - yes? Then moving the blue bit to the left (ANTI-clockwise) moves the camshaft ANTI-clickwise (retarded).

[CEF11E]

Yep but if you look at the cam gear if you moved it to the left the markings would say it was advanced

weird huh.

as adriano pointed out it is crank adv or retard. still... a silly marking method.

[DJRIFT]

thats what you get for being chap and american! no japs have designed these. americans drive on the wrong side of the road anyway so the probably andvance and retard there cams wrong to. haha

[Adriano]

Wonder if we should mention this in the group buy?

[CEF11E]

yep very good idea...

[rob82]

You always work realative to the crank position. So if you loosen the bolts and move the cam anticlockwise you are moving the lobe centerline of the camshaft to the left, meaning the cam is now retarded as it takes longer for the valve to reach the same lift relative to the same crank position. ie the lift at TDC will be less with a retarded camshaft and greater with an advanced camshaft.

So they have machined the A and R in the right direction.

[CEF11E]

why do Tomei, Greddy, Nismo and HKS have markings in going in the opposite direction?

not trying to be argumentative...

[rob82]

why do Tomei, Greddy, Nismo and HKS have markings in going in the opposite direction?

not trying to be argumentative...

Do they - havn't seen that. It does depend on wether the advance or retard is on the section of the cam gear that is fixed to the cam or on the outer ring that is not fixed to the cam. Maybe thats where your being confused???? Its a little ambiguous. Its a hell of alot easier to think about camshaft postion relative to crank position.

Wait until you try to dial in a BA XR8 - 4 camsahfts four cam chains.

Edited March 1, 2007 by rob82

[CEF11E]

yep just looked at the just jap website.

just have to keep it in mind :0

[Adriano]

I guess the way to think of them is in order to advance the cam timing, move the cam in the direction of the a mark, but in doing so you will be using the other marks.