Timing Mystery

[sid_vicious]

Hi,

 

I've got a problem lining up my timing belt that I hope some experts here might be able to help with.

 

My car's a 2000 Outback, 2.5 SOHC, with 184,000 miles on it. I bought it for next to nothing because the previous owner ran it out of oil and seized the engine. I had an engine from a 1999 Impreza RS that I installed. The engines are both EJ25 SOHC, but I used the intake manifold, crank pulley, crank sprocket and cam sprockets from the car's original engine. That detail will become important when I explain the problem with the belt.

 

I lined the crank sprocket mark up with the mark on the oil pump, and then lined the cam sprocket marks up with their respective marks on the passenger-side head and driver-side timing cover. Using these sprockets allowed me to get the timing belt installed and the car started and running, but it idled like there was a timing problem. I did NOT use a compression gauge to set the engine at TDC on cylinder 1 at that point.

 

Just today I brought cylinder 1 to TDC (cylinder 1 in compression stroke and notch in crank pulley at zero mark on timing cover) and removed the timing cover. I was surprised to see that the marks on the crank sprocket and cam sprockets were nowhere near the marks they should be lined up with. They're all counterclockwise of their marks by quite a bit. This has me confused, especially since the crank sprocket is keyed and cannot be rotated to meet the mark in the oil pump when cylinder 1 is at TDC.

 

Is there a different spot for the mark on the two different crank sprockets? Or do different crank pulleys have the notches in different spots? Should I keep the crank sprocket where it is and line the cam sprockets up to the proper position and install the belt? Naturally, I no longer have the RS engine's original crank sprocket to compare to the one I now have installed.

 

Thanks a lot,

Andrew

[Ricearu]

there are arrows and there are tick marks. use the tick marks. make sure you are not comparing the arrows. They confuse people alot

[sid_vicious]

I've definitely not used the arrows instead of the tick marks. I should have mentioned that. I've replaced timing belts on Subarus a few times without issue, but never replaced timing sprockets or crank pulleys with ones from another car.

[Ricearu]

well i am not sure but some subaru engines use timing marks from tdc and some have timing marks at center bore. I wouldn't swap any timing components unless I swapped all components, including crank sprocket, and use the marks on the set to set it all up

[porcupine73]

It's possible they are different, especially the cam sprockets. There was an endwrench note about certain cam sprockets going with certain ECU's, but that was more because of the back of the sprocket that the cam position sensor was reading. I don't remember if it said anything about crank sprockets being different.

 

Just today I brought cylinder 1 to TDC (cylinder 1 in compression stroke and notch in crank pulley at zero mark on timing cover) and removed the timing cover. I was surprised to see that the marks on the crank sprocket and cam sprockets were nowhere near the marks they should be lined up with.

If by "marks on the crank sprocket and cam sprockets were nowhere near the marks they should be lined up with" you mean the hash marks lining up with the backs of the timing belt cover and the mark under the oil pump, those will _not_ align with cylinder 1 at TDC. When those marks are aligned, none of the cylinders is at TDC, purposely, so that you don't risk hitting any valves into the top of the piston during timing belt replacement.

[sid_vicious]

Ah, I see. I had always just lined up all the tick marks before removing the belt and not worried about the cylinder 1 TDC step. I didn't realize that you bring cylinder 1 to TDC and then rotate the engine again to line up the marks.

 

I rotated the crank to line up the tick mark on the back of the crank sprocket and that brought the cam sprockets' tick marks into alignment as well.

 

I was thinking the marks needed to be in alignment at TDC, but now I realize that's impossible because there would be interference between valves and piston. Duh.

 

I'll have to keep hunting for the solution to my idle problem, which does not appear to be a timing issue.

 

Thanks for all the help.