Possible to have cam sprockets on backward?

[Zenja]

With cylinder 1 at TDC, the cam sprocket dowel pins both face up and the timing notches line up. However, I noticed that my intake cam has "OUT" written in whiteout across it on the outer face and the exhaust cam has "IN" written on it. I imagine this may be the previous owner marking which way the sprockets should face, but for some reason one is facing with the outer face marked "IN".

Since the sprockets are interchangeable, this shouldn't matter if the timing marks on them are 180* apart and 90* compared to the dowel pins. But according to a post on these boards (http://www.dsmtuners.com/forums/tun...ng-aligned-right-post1577975.html#post1577975), they're not 180* apart. This means that if a sprocket was put on backward, wouldn't the notch correspond to a different position compared to the cam? I would be trying to line up the mark on the opposite side (ie the marking for exhaust purpose on the intake sprocket) and this seems like it could cause cam timing to be off.

Is it possible to put a sprocket on so the inside face is actually facing out? Would this affect mechanical timing? Is there a way to tell which side of the sprocket should face out? Or does none of this matter because if the timing marks line up and the dowel pins are up then it's set right either way?

 

[steve]

I don't have a spare set to look at but when I was talking about one side vs the other side I wasn't talking about flipping them over. I was saying that the mark you wind up using when the sprocket in on the intake cam is on one side and the mark you use when it's on the exhaust is on the other and those marks are placed so the cams are in the correct location when the dowels are up and two inside marks line up parallel with the head to rocker cover mating surface. So the marks on a gear aren't 180* apart.

I don't think there are marks on the back side, are there? So it's not possible to put them on backward.

 

[Zenja]

That makes sense.

I thought the indented mark goes all the way across the tooth on the sprocket but maybe not. I'll check tomorrow. I just noticed that the sprocket looks symmetrical front to back at fairly quick look. I don't remember how it bolts in there and whether there is some mechanism to prevent people from putting it on backward. The notch is a good call though, I'll take a look.