According to the factory manual it's .25mm +/- .02mm? Where is the typo?

 

In here. http://ken-gilbert.com/wrx/STi_Manu.../wrx/STi_Manual/02. ENGINE SECTION (STi)/04. MECHANICAL/08. Valve Clearance?pdf Thanks for the clarification. What do you think of an exhaust valve with .05 mm clearance. Car runs great but I get occasional misfires. Valve adjustment is about the last thing on the list of things to try.

 

What do you think of an exhaust valve with .05 mm clearance. Car runs great but I get occasional misfires. Valve adjustment is about the last thing on the list of things to try.

Well I assume clearance values are there for a reason but I would too do it as a last resort for fixing misfires

 

Sorry. That link doesn't get you to the procedure I was looking at. I did find the correct info though. Thanks. I swear I found a manual that said .35 mm, must have been for another engine or something.

 

I've had it back together for about a week and haven't had a misfire yet. Used to get them almost every morning when the car was almost warmed up all the way. I'm no mechanic but I've worked on a lot of cars over the years, and I've got to say if you have a WRX with over 105000 miles you should get this done. It also runs smoother and seems to have more torque. When I was at the dealer picking up the shims I asked if they did many valve lash adjustments and they said "more and more often". Then the guy looked at me and said "turbo charged car?" I said "yes" and he just nodded his head like I was smart to be doing it. It went together easier than it came apart. Getting the shims out is a wrestling match, but they just pop right back in. Replace the O ring on the oil filler tube. Mine leaked. Easy fix though. Cheers!

 

Yep, This thing is fixed! I just wanted to thank Donkey for the Misfires sticky. #3 on the list, and exactly what it was. I would not have had a clue if it weren't for this forum. Thanks again!

 

Did you have to take out the engine to do it?

 

It's easier to take the engine out but you don't have to. It's much easier with the shim over buckets.

 

No. That would be way more work. The intakes would be harder to mess with cause they are on top. I got lucky and my exhausts were the only ones needing adjustment. The special tool would be nice but for $300 forget it. I took out the battery and the washer fluid bottle on the driver side, and the air filter box on the passenger side. Then I took off the valve covers, (ordered new gaskets online) and measured clearances with a nice metric set of feeler gauges. It is important to measure the clearance accurately before you remove the shim because you will use this measurement to decide which size of shim to order. I wrote my measurements down on a piece of paper along with which valve they came from. Then it's time for the fun part, removing shims. I used several different screwdrivers to pry the bucket to where I could get the shim out with a magnetic tool. This part is frustrating and time consuming, I'm not gonna lie. When you get a shim out you need to measure it with a metric micrometer that will do 1/100th of a mm. write that down along with the clearance you measured earlier. Now you can calculate which shims to buy. Call the Subaru dealer and tell them the sizes you need and they will order them. Took 4 days to get mine. When they came in it was just a matter of popping the proper shim in the proper bucket. Easier than I expected after all the hassle getting them out. Then just install the Valve covers, battery, washer bottle, oil filler tube, and the filter box and you should be ready to go. Look here for the official procedure - http://ken-gilbert.com/wrx/mans/3 - DOHC ENGINE.PDF. This job is not for the faint of heart. If you are comfortable working on cars you should be fine. Your car will be down for a week because you have to order parts and there is no way to tell what you need until you take it apart. I know there are purists who would not appreciate the way I got my shims out, but the job went well and only cost valve cover gaskets and $70.00 worth of shims. Besides that, I'm done with it and you are worrying about it! Good luck! Oh, Mine is shim over bucket ('02) I have no clue about other models.

 

The other models are shimless bucket. The cams have to come off.