Timing belt job - cam gear rotated

[NateDN10]

Hey all -
I'm doing the timing belt on our '07 Subaru Outback (H4).

I got everything lined up and marked before I took the old belt off, but after I got the belt off the cam gear on the driver's side of the engine rotated by maybe 30 degrees. As I was turning it back I went a bit too far and the spring action rotated it in the other direction - it wound up approximately 180 degrees from its original orientation (where the mark was straight up).

So I rotated it back and this time had my wife hold it in place while I got the belt on. All the marks are lined up nicely, but before I put it all back together I want to make sure it's right.

So if all the timing marks are lined up, am I OK, or is it possible for the camshaft to be 360 degrees off?

Thanks!

 

[Smoky14]

You can't be 360 off, you are back where you started.

 

[AVB]

You did it right.

 

[JamesBond]

Agree with the above poster, 360 deg. off is...back where it started.

If you're worried about it, turn the engine over a few times with a wrench to make sure the marks continue to line up and there's no interference.

I'm always nervous when I do a timing belt job too. Don't rush, read the instructions again and check all your work.

 

[dgcamero]

Rotate the crank two or 4 times by hand (breaker bar) just to be on the safe side, you'll hear it if the valves are going to hit any pistons --- but it sounds like you did it right!

 

[thomasflaherty]

I have never done a belt on a Subaru but rotate the crankshaft 360 and make sure it all lines up again if you have the valve cover of and all the lines line up you will be on the compression stoke so both #1 valves will be closed so check you rocker arms on #1 they will have play if you have no play on the exhaust rocker you are off 180. the play is the amount of lash so it small play but you will feel it

 

[NateDN10]

Thanks all. Since the cam gears are larger than the crank gear, I had myself convinced that there would be no way to know. But I tend to overthink things.

 

[AVB]

Originally Posted By: thomasflaherty
I have never done a belt on a Subaru but rotate the crankshaft 360 and make sure it all lines up again if you have the valve cover of and all the lines line up you will be on the compression stoke so both #1 valves will be closed so check you rocker arms on #1 they will have play if you have no play on the exhaust rocker you are off 180. the play is the amount of lash so it small play but you will feel it

It takes two revolutions to get back to tdc on #1 of the compression stroke, if that is where you started. That may be what you meant, but 360° will put you at the end of the exhaust/begining of the intake stroke.

 

[shDK]

Originally Posted By: thomasflaherty
I have never done a belt on a Subaru but rotate the crankshaft 360 and make sure it all lines up again if you have the valve cover of and all the lines line up you will be on the compression stoke so both #1 valves will be closed so check you rocker arms on #1 they will have play if you have no play on the exhaust rocker you are off 180. the play is the amount of lash so it small play but you will feel it


Are there really rockerarms on such a new subaru engine ?

 

[Hokiefyd]

Nate, you did it right. As others suggested, rotate the engine over by the crankshaft one complete revolution just as a last gut-check measure. But yes, as long as the timing marks are where they should be, you are good to go.

 

[Hokiefyd]

Originally Posted By: shDK
Are there really rockerarms on such a new subaru engine ?


Many engines use rocker arms still. Some OHC engines use bucket lifters where the cam actuates the lifter directly, but many still transfer the energy through a rocker arm.

 

[andyd]

My Bentley manual for the 528e says to test rotate the crankshaft TWO full revolutions, 720 degrees to ensure a good TB install. 2 crank turns equal 1 complete cam shaft turn. I set the marks to TDC before I start the job. Next I pull all the spark plugs to make it easy to turn things. Also, isnt there a set of marks on the cam sprocket?

 

[NateDN10]

Update - successful. Fired right up. I used the trick of rotating the crank pulley once the timing belt was on and making sure everything stayed lined up.

I realized that I was thinking about it backward - the crank gear is smaller than the cam sprockets, which means that it takes to rotations of the crank to get one rotation of the camshaft. Ergo, if it's lined up, good.

Thanks!

 

[shDK]

Originally Posted By: Hokiefyd
Originally Posted By: shDK
Are there really rockerarms on such a new subaru engine ?


Many engines use rocker arms still. Some OHC engines use bucket lifters where the cam actuates the lifter directly, but many still transfer the energy through a rocker arm.


Thanks. Learnt something new there. I think the reason it supprised me is that here 9 out of 10 engines are 4 cyllinder ohc or dohc.

 

[MarkM66]

Originally Posted By: shDK
Originally Posted By: Hokiefyd
Originally Posted By: shDK
Are there really rockerarms on such a new subaru engine ?


Many engines use rocker arms still. Some OHC engines use bucket lifters where the cam actuates the lifter directly, but many still transfer the energy through a rocker arm.


Thanks. Learnt something new there. I think the reason it supprised me is that here 9 out of 10 engines are 4 cyllinder ohc or dohc.


OHC engines can still use rocker arms. i.e., Honda's.

 

[artificialist]

Originally Posted By: shDK
Originally Posted By: thomasflaherty
I have never done a belt on a Subaru but rotate the crankshaft 360 and make sure it all lines up again if you have the valve cover of and all the lines line up you will be on the compression stoke so both #1 valves will be closed so check you rocker arms on #1 they will have play if you have no play on the exhaust rocker you are off 180. the play is the amount of lash so it small play but you will feel it


Are there really rockerarms on such a new subaru engine ?

SOHC Subaru engines have rocker arms, belt driven DOHC Subarus don't.

The chain driven DOHC Subaru engines have rocker arms but you clearly don't have one of those engines.

 

[Errtt]

So if you rotated the cam 360 (while crank remain still), no valves hit any piston = non-interference, if started at TDC #1... right?

 

[Hokiefyd]

Originally Posted By: shDK
Thanks. Learnt something new there. I think the reason it supprised me is that here 9 out of 10 engines are 4 cyllinder ohc or dohc.


Most engines over here are OHC or DOHC as well. It just depends on the specific engine design. I have a DOHC I-4 and a SOHC V-6 and both use rocker arms. GM's DOHC Ecotec 4 uses rocker arms. Most Toyota 4s and some Ford 4s I think use direct-acting lifters.

So again, it just depends on the particular engine design.

 

[NateDN10]

Originally Posted By: Errtt
So if you rotated the cam 360 (while crank remain still), no valves hit any piston = non-interference, if started at TDC #1... right?

Subaru put the timing lines so all the pistons are mid-way in their stroke, so even if the gear rotates there's no interference. This is an interference engine though.