Camshafts alignment

xallenx · Post by **xallenx** » 13 Dec 2011, 19:38

Hi,

I opened up my timing belt cover to see if I could spot the camshafts marking to align it to properly change the timing belt. Are the markings on the camshafts looks like a "w"? That's the only markings I could find on the cams to align it with the top timing belt cover. Thanks.

xallenx · Post by **xallenx** » 13 Dec 2011, 19:48

I found this online:

http://ww2.justanswer.com/uploads/PhilH ... 6_xc90.pdf

Looks like from the illustration at the very bottom, it's just a small dot. I really didn't see a small dot..hmmm. Anyone got pixs?

Northern Chev · Post by **Northern Chev** » 13 Dec 2011, 20:29

Try this... put the crank shaft at top dead center on the compression stroke and confirm it with the number one spark plug out. Make darn sure it's at the very top of dead center according to the crankshaft.

Then look for the marks at the top of the gears. I'm sure you've tried this but just making sure. My marks are extremely hard to see vertical lines. Very hard to see. Very, very hard to see. On mine anyway.

xallenx · Post by **xallenx** » 13 Dec 2011, 20:40

Ok so I'm looking for vertical lines on top of the gears not the side?

Post by **JimBee** » 13 Dec 2011, 21:50

I agree the marks are hard to see. They are actually on the side of a tooth, either right up the middle of the tooth or at the valley between two teeth. Mine exhaust sprocket has the line on the tooth, intake it's a little off center at the valley between 2 teeth.

The M's on the sprockets must be there for a reason, but they are not where the lines are. On my 850, the M on the intake sprocket is around 2:00 o'clock when the little tiny mark is pointing to the cutout on the plastic shield.

Your #1 piston can be a TDC with the crank in either of 2 positions. You need it on the compression stroke (and actually just a tad back (CCW) from TDC. The mark on the crank sprocket is also hard to see but if you think you've got your cam sprockets aligned, it will be right on (assuming the last person who changed it, got it right on). You might see it more easily at night with a flashlight. It could actually be two marks on tooth tops, either side of a valley.

Another clue will be if you take a 12" ruler and lay it flat against the sides of the sprockets with the straight edge across the screw heads that hold on the cam sprockets, the edge should touch the tops of 2 screws on one sprocket and one on the other. I think the two screws are on the exhaust. (If you can't see the marks, roll the engine around 180 and try that again.) The marks might not be exactly on, but they'll be close. That gives you approximately the alignment you'd get it you had the distributor and timing sensor off the back ends of the camshafts and you could see the slots back there. Then you should be able to see the little timing marks on your sprockets pointing to the cutouts. If there's rust on the sprockets, a light wire brushing might help reveal them.

While you have the ruler there and have confirmed the marks ARE PROPERLY ALIGNED, take a Sharpie marker and scribe a line along the ruler across both sprockets. That line will help you in aligning things when putting it back together.

Good luck.

xallenx · Post by **xallenx** » 14 Dec 2011, 09:37

Thanks...i'll give it a go!

xallenx · Post by **xallenx** » 14 Dec 2011, 19:38

So I went and looked again tonight. No such thing as a line but I did find two dots. See pixs below:

Intake cam:

Exhaust cam:

Are these the markings?

Post by **jimmy57** » 14 Dec 2011, 20:34

The hash mark is it.
On these Volvo motors and on many other engines these days, Top Dead Center is not where the crank marks will be. The #1 on compression stroke TDC is valid for millions of engines but not all engines and not any Volvo engine made since the old red motors.