Question for the engine builders

Discussion in 'Modifications & DIY how-to' started by GTscoob, Feb 21, 2007.

  1. GTscoob

    GTscoob Black is Beautiful

    I was reading through the service manual earlier on replacing the timing belts on a WRX and noticed something about removing a couple timing belt guides. It specified that that was for MT cars only and my car was originally an AT car, does that piece serve any mechanical purpose or is it just for lining up the timing belt when installing a new one?
     
  2. mckenzietj

    mckenzietj Member

    There are 5 belt guides, one for each cam gear and one over the crank sprocket. The ones on the cam gears can be left alone but I recommend checking the "belt to guide" clearance (should have the spec in the manual) just to be on the safe side b/c they are adjustable. The one over the crank is not adjustable but I always remove it to get the belt on easier and to make the timing mark easier to see.. I believe their purpose is to prevent the belt from jumping teeth under sudden belt load changes that are possible on manual that are otherwised dampened by the torque converter on the auto trans. The boxer t-belt is as long or longer than quad cam V6 belts.
     
  3. GTscoob

    GTscoob Black is Beautiful

    I was just reading your recommendation to swap timing belts and figured I'd read up on it. Timing belt is supposed to be swapped at 60K and I'm at 55K so I guess I'll pick up a couple of those for when I pull it off. I'd assume you'd notice if your belt jumped timing? That sort of stuff should bend valves right?
     
  4. mckenzietj

    mckenzietj Member

    I don't know how many teeth it takes to bend valves on a Subaru but you would notice a definite performance difference w/ a jumped belt that was still turning. The belt issue in the other post wasn't that it jumped timing but rather the belt had stretched which altered cam timing just enough for a CEL. Or it could have been from lack of belt tension from the belt being longer.The timing difference w/ this condition was about a half a tooth on the intake and 3/4 of a tooth on the exhaust. Those are eyeball estimates. I'm curious to know if the holes to bolt the guides in exist on the AT back cover. Also, the guide fasteners are allen head bolts b/c there is not room for a regular bolt and socket to fit over it as far as I know.
     
  5. GTscoob

    GTscoob Black is Beautiful

    Me too. I'll probably take it up to SOG to service it, I just enjoy reading how to do it. Do you have to pull the motor to change the belts or just jack the car up a bunch to get to the lower bolts on the belt cover and various cogs?
     
  6. mckenzietj

    mckenzietj Member

    I remove the radiator w/ the fans and it's WIDE OPEN. The last WRX t-belt took me 1 hour from start to finish except for the time to let it run w/the rad cap off to let the air out of the coolant. Don't expect to pay 1hr. of labor for the job though! Experienced mechanics would starve to death! I believe it's about 3.5 hrs of flat rate labor.
     

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