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Old 01-17-2005, 01:32 PM   #1
johndingk2
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Default Camshaft gear removal 2.5L DOHC

From a 97 leg gt.

Anyone know about this procedure. I am worried about removal of cams without misalignment of valves. I want to know just how much movement I should expect from left (drivers) side when removed. Also want to make sure that all I need to do is just reposition them back at 12 o'clock and 6 o'clock when reinstalling, assuming they dont spin all over the place when removed. I am just freaking out about this and dont want to trash my engine you know.

ANy help would be great.
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Old 01-17-2005, 05:06 PM   #2
Pakin
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First off, for something like this, it will be very handy to have a service manual or a subscription to techinfo.subaru.com, as you will know all the information is correct from there. It will be the best referance you'll have handy.

If you are not confident at all, I suggest you find a friend or someone local in the area to help your or has experience in doing something like this. Paying a bit more is better than bending valves, although the procedure can be very straight-forward.

My take:

I haven't done DOHC's for a while so if someone smart notices an error please do correct.

Driver's side will be under load upon aligning the marks. The cam sprockets as I recall only go on one way if you remove them.

My rule of thumb is always have the sprockets unload (unless you are just doing a timing belt) and upon realigning the marks, find out which direction (Clockwise or counter-clockwise) will be shortest upon the cam lobe hitting the valves. Turn the cam sprocket with a 17mm to that shortest distance. Repeat for the bottom.

You should not get any interferance if you did everything right, but if you do feel interferance between the exhaust and intake valves, work your way around it unloading one and loading back the other.

After putting the belt and tensioner on, manually crank it both left and right to hear or see anything weird in both directions. Line everything back up one more time to check all your marks and make sure they are where they are suppose to be.

-paK +11
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Old 01-18-2005, 06:58 PM   #3
johndingk2
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Quote:
Originally Posted by Pakin
Driver's side will be under load upon aligning the marks. The cam sprockets as I recall only go on one way if you remove them.

My rule of thumb is always have the sprockets unload (unless you are just doing a timing belt) and upon realigning the marks, find out which direction (Clockwise or counter-clockwise) will be shortest upon the cam lobe hitting the valves. Turn the cam sprocket with a 17mm to that shortest distance. Repeat for the bottom.

You should not get any interferance if you did everything right, but if you do feel interferance between the exhaust and intake valves, work your way around it unloading one and loading back the other.
What do you mean unload?
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Old 01-18-2005, 09:04 PM   #4
Pakin
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Quote:
Originally Posted by johndingk2
What do you mean unload?
Releasing tension.

-paK +1
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Old 01-19-2005, 01:25 PM   #5
johndingk2
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So spin em back to where there is tension or the cam actually wont spin anymore? For the intake that is 12 o clock. ANd the exhaust is 6. If that is what you mean.

Still doesnt answer my question regarding removal. Do I need to take off the valve cover? I am really trying to avoid that but if that is the only way. I would rather try an offset adjustable wrench that would fit into the inset of the cam gear and then try using a cheater bar. THe thing is only supposedly 30-40 lb ft but it seems a little more than that.
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Old 01-27-2005, 12:59 PM   #6
johndingk2
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Just a final note on this should you all need to know.

When the cams released their loads (spun like a mofo) I reloaded them by reversing the spin they did when they unloaded. This required a bit of strength as they are under quite a bit of pressure when finally back at 6 and 12 oclock. At first I thought I was not gonna be able to reach 6 and 12 because the cams felt like they were hitting the piston but in fact it was just the tension they were under. When you reach this tension the cam will in fact continue on to 6 or 12 and stay there since it is now reloaded. If you twist the cam gear again at that point clockwise they will unload again. I thought I was going to have to hold the tension while re installing the belt but no, the cam gears will stay there. Just be careful as with just a little clockwise movement, they will unload again.

It is fun to learn.
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