Timing belt replacement, Driver side Cam under tension?

dickydck · 12-18-2023, 07:19 PM

Hello everyone! haven't been here for a while since things happened and I had to deal with family crap. I'm back to the rebuild of my ej253 in the 09 2.5i and I can't remember since it has been years since I did anything major on it. I have the heads bolted on, all the new pulleys, water pump, etc etc. As I'm snaking the timing belt around, the crank mark lined up stright vertical as it should be, the passenger side camshaft lined up vertically with the cylinder head base and it is pretty loose and free spinning in either direction. Now here is where I am having the brain fog, maybe it was the covid who knows, but lining up the drivers side mark with the timing cover (new timing covers all around as well) the cam seems to be under a lot of tension, as though the cam lobes are depressing the valves down into the cylinder, I think #2 intake but not positive. Is this supposed to be the way it is? literally has been maybe 8 years since I did the timing belt last, the timing marks line up and everything but to save my ass I cannot recall last time if the drivers side cam was under tension like this. Thank you in advance for any insight and assistance that can be given, it is much appreciated.

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Elbert Bass · 12-18-2023, 08:38 PM

Yup - right bank unloaded - left bank loaded. Line up your marks. Since it's SOHC as long as the crank is in the timing position (keyway at 6 o'clock) you can spin the cams without fear.

dickydck · 12-18-2023, 08:53 PM

Quote:

Originally Posted by Elbert Bass

Yup - right bank unloaded - left bank loaded. Line up your marks. Since it's SOHC as long as the crank is in the timing position (keyway at 6 o'clock) you can spin the cams without fear.

Thank you! I did put a screwdriver in each cylinder to make sure each TDC had the valves shut, just wanted someone knowledgeable to validate my suspicion. Thank you mah dood!

Elbert Bass · 12-19-2023, 09:59 AM

Quote:

Originally Posted by dickydck

Thank you! I did put a screwdriver in each cylinder to make sure each TDC had the valves shut, just wanted someone knowledgeable to validate my suspicion. Thank you mah dood!

The thing you have to understand is you do not time a Subaru at TDC. With the crank set on the timing mark all the pistons are halfway down/up the bore. That is why you can spin the cams on a SOHC without bending a valve. That also allows the right bank cam to be unloaded and the left bank loaded "between" lobes.

crazyhunter2.5 · 11-17-2024, 04:57 PM

I did my timing belt not too long ago, and yes I remember the driver side cam had a lot of "tension" on it, because I was trying to perfectly line it up, call me crazy but, and I rotated it a little that required a lot of force and then afterwards it immediately let go and allowed me to turn it, turning it back was rather simple. I think it is completely normal.

12-18-2023, 07:19 PM	#1
dickydck Scooby Newbie Member#: 485066 Join Date: Apr 2018 Location: east coast Vehicle: 2009 Impreza 2.5i Grey	Timing belt replacement, Driver side Cam under tension? Hello everyone! haven't been here for a while since things happened and I had to deal with family crap. I'm back to the rebuild of my ej253 in the 09 2.5i and I can't remember since it has been years since I did anything major on it. I have the heads bolted on, all the new pulleys, water pump, etc etc. As I'm snaking the timing belt around, the crank mark lined up stright vertical as it should be, the passenger side camshaft lined up vertically with the cylinder head base and it is pretty loose and free spinning in either direction. Now here is where I am having the brain fog, maybe it was the covid who knows, but lining up the drivers side mark with the timing cover (new timing covers all around as well) the cam seems to be under a lot of tension, as though the cam lobes are depressing the valves down into the cylinder, I think #2 intake but not positive. Is this supposed to be the way it is? literally has been maybe 8 years since I did the timing belt last, the timing marks line up and everything but to save my ass I cannot recall last time if the drivers side cam was under tension like this. Thank you in advance for any insight and assistance that can be given, it is much appreciated. * Registered users of the site do not see these ads.

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12-18-2023, 08:38 PM	#2
Elbert Bass Scooby Specialist Member#: 283429 Join Date: May 2011 Chapter/Region: South East Location: Down yonder. Vehicle: 2016 Crosstrek Silver	Yup - right bank unloaded - left bank loaded. Line up your marks. Since it's SOHC as long as the crank is in the timing position (keyway at 6 o'clock) you can spin the cams without fear.

11-17-2024, 04:57 PM	#5
crazyhunter2.5 Scooby Newbie Member#: 539579 Join Date: Nov 2024 Vehicle: 2009 Impreza	I did my timing belt not too long ago, and yes I remember the driver side cam had a lot of "tension" on it, because I was trying to perfectly line it up, call me crazy but, and I rotated it a little that required a lot of force and then afterwards it immediately let go and allowed me to turn it, turning it back was rather simple. I think it is completely normal.