jp71ss Posted August 30, 2014 Share Posted August 30, 2014 I have rebuilt the lower end of my 97 2.5 and shaved the heads, ground the valves and new seals. Now that I try to time the engine with the new belt, idlers, tensioner and water pump I can't seem to get the timing marks to line dead nuts perfect. I have the subaru tools to keep the gears in position but nothing helps line up the 2-4 cylinder timing marks. Now I have gotten these things as close as I can get them and I still don't have as much compression on the 2-4 cylinders as the 1-3 cylinders. Now I did run the motor and had to pull it because the exhaust valves were bent (the pulleys spun when the tool slipped). I had the valves reground and I still cant get the compression up to what the 1-3 cylinders are. Is it possible to have the pistons on the wrong side? I know they have a certain way to be put in the engine. Any suggestions short of putting in a 2.2? I'm not doing that. Link to comment Share on other sites More sharing options...
johnegg Posted August 30, 2014 Share Posted August 30, 2014 are you using the correct timing marks? the hash marks, not the arrows? regardless of compression, how close is the timing mark on the 2-4 side, a tooth off, half a tooth off? what are the compression numbers? i have heard something about piston position, but i do not really know. Link to comment Share on other sites More sharing options...
jp71ss Posted August 30, 2014 Author Share Posted August 30, 2014 Yeah I'm using the hash marks not the arrows. It is about a half mark off on the double marks. If I move it on the timing belt one tooth it is half mark off on the double marks the other way. Just turning the engine over by hand I am getting 90 psi on 1-3 and 60 psi on 2 and 30 psi on 4. I will verify 1-3 again but that is what I was getting on 1-3 before I had the valves reground on 2-4. Link to comment Share on other sites More sharing options...
Osei Posted September 2, 2014 Share Posted September 2, 2014 The pistons are marked A or B. If you put an B piston in an A (larger) bore, then you will have lower compression. Did you use a fsm when you did your rebuild? O.Specifications Engine.pdf Link to comment Share on other sites More sharing options...
jp71ss Posted September 2, 2014 Author Share Posted September 2, 2014 My pistons are new and 25mm oversize so the block was professionally bored to the correct size. Yes I used a manual. Link to comment Share on other sites More sharing options...
Osei Posted September 2, 2014 Share Posted September 2, 2014 Run the engine. Let it break in, then check your compression. O. Link to comment Share on other sites More sharing options...
Legacy_Guy Posted September 2, 2014 Share Posted September 2, 2014 I know it's a bit pricy but you could always try these if you're not more then 1 tooth off http://www.rallysportdirect.com/LIC-Motorsports-Adjustable-Timing-Belt-Idler-Bearings-Subaru-DOHC-EJ-Series-inc-2002-2011-WRX-STI Link to comment Share on other sites More sharing options...
jp71ss Posted September 3, 2014 Author Share Posted September 3, 2014 I know it's a bit pricy but you could always try these if you're not more then 1 tooth off http://www.rallysportdirect.com/LIC-Motorsports-Adjustable-Timing-Belt-Idler-Bearings-Subaru-DOHC-EJ-Series-inc-2002-2011-WRX-STI Thanks! I was trying to figure a way to do this. I am only about half a tooth off. Link to comment Share on other sites More sharing options...
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