Timing question

[MilesA]

Is 2 full revolutions of the crank a full stroke? might I be 1 revolution of the crank off?

Each camshaft rotates at one-half the speed of the crankshaft. IOW, for every full revolution of a camshaft, the crankshaft rotates two revolutions.

 

You would not be off as long as the alignment marks were followed. Every revolution of the crankshaft is the same. It is valve timing that controls whether a cylinder is in intake, compression, power or exhaust stroke. The pistons are always mid-way in the cylinders when the crankshaft line mark is at 12 o'clock.

[FLlegacy]

Is 2 full revolutions of the crank a full stroke? might I be 1 revolution of the crank off?

 

It doesn't work that way, when the engine compresses on the first stroke all the valves are closed, when it evacuates the cylinder on the second "compression" stroke the exhaust valves are open.

 

When you line it up on the crank sprocket it makes no difference to the engine block which stroke is which. The piston is still making the same movement.

 

So no matter how you look at it the timing issue would be with the cam or somewhere in between the crank and cam.

 

If you aren't sure what you are doing is correct there are some great youtube vids that cover the sohc ej25 specifically.

[xt2005bonbon]

op, did you find the page in the service manual showing how to check timing counting the number of teeth between the cam and crank pulleys? This is the sure way to check if your timing is right.

[Bobsousley]

Headed on vacation for the next week, as soon as I get back a friend of a friend from a subaru shop is coming by to check things out. Hopefully get things wrapped up then.