Honeybadger43 Posted October 14, 2014 Share Posted October 14, 2014 Hello. I'm hoping someone can help. I purchased a 2005 Outback 2.5i with the 2.5L sohc EJ25 with a blown motor. The story from the previous owner was oil starvation. The original motor had a broken connecting rod on cylinder 4 and it pounded the piston into bits and it broke out the top of the crankcase on the upper seam. The right head had a couple gouges but no marks on the valves. I removed the heads and cycled the valves and they seemed to seat and move freely. The left head seemed to have no damage. I purchased a used 2009 2.5L sohc EJ25 complete with the newer active valve lift heads primarily for the EJ25 short block for $300 with intentions of having an engine rebuilder use the parts as a core for a refurbished engine. But after stripping the short block I decided it wouldn't hurt too much to at least try to piece it together myself. The Lord hates a coward or something like that. I cycled the block and inspected the pistons and everything seemed tight and moved freely with no scoring of the cylinder walls or any other visible indications of a problem with the short block. It was on an engine stand and was rotated upside down and nothing sounded loose. So I pushed onward. Anyway, new head gaskets, new head bolts, a new timing belt kit complete with a new water pump, tensioner and idlers, intake gaskets, etc... All went well until the heads were re-installed and torqued as per the factory service manual. I installed the timing belt and components exactly as stated in the factory manual and all timing marks were lined up as described in the manual. The engine will not make a full revolution. It turns about 170 degrees before making metallic contact with something. I removed the timing belt and turned the cams until all the valves were closed on both heads (note I have not confirmed if the exhaust valves are fully closed but the intake valves look to be seated tight when looking through the intake ports with the intake plenum removed) and the engine still refuses to make a revolution. My basic question is if the EJ25 short block is identical (which it appears to be) what would be the possible reason for the engine not rotating past approx. 170 degrees? There has been some discussion about different pistons being used on different years but even then it seems unlikely that with the valves all presumably closed that there should be any interferences between the piston and the head or valves? Please help me. I should add that the original 2005 heads were used on the donor shortblock. Link to comment Share on other sites More sharing options...
GEE-OTTO Posted October 15, 2014 Share Posted October 15, 2014 So the SB will rotate with the heads off but not fully with the heads on? Are the cam gears identical? What HG are you using? the 05 and 09 have subtle differences (WP placement, pistons and the valve train) but the same stroke (79mm). The pistons are different as well in the 253 vs the 251 to bump up the CR. What may be happening is there isnt a relief on the piston to allow for full extension of the valve. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 Gee-Otto Thanks for the reply. I'm very new and couldn't even find my own question to check for replies. Lol Yes, the short block looks to be in great shape and rotated prior to installing the heads. I pulled the oil pan to check for anything obviously wrong but it is pretty clean other than a small amount of sludge in the bottom of the pan which I assume is typical. The 2009 sb is marked as an EJ25, Z25, and the number 906. The original 2005 heads are also marked Z25 but the 2009 heads (I'm not using) are marked T25 and have active lift and electronics not included on my wiring harness. I did some checking on both heads tonight by rotating the cams with a wrench and inspecting the exhaust and intake ports and the valves seem to cycle properly and seat on the head with the pistons in the middle of the cylinders. So it seems that even though the valves are not raised (no timing belt) the pistons are contacting the head? I can see if the valves are open that there may be an interference with the piston but not with them closed. I'm stumped. Still. Also I checked and 2005 and 2009 pistons have the same part number? I'm not sure if that is true as I only checked rock autos online catalogue. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 The heads came off the original car and haven't been disassembled so I didn't spend much time inspecting them other than cycling the valves I was only worried about bent valves. I thought after doing some reading that the heads are compatible over several years so I assumed that they were compatible without changing pistons. I literally swapped the short block and reinstalled the heads. This may be my problem. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 Sorry but I'll have to read a bit more to know the difference between a 251 and 253. I've only had this car for 6 months and it has never run as I bought it as a project/replacement for an aging Montana family truckster. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 I read that 2.5 SOHC Outbacks in North America have EJ253's from 05 to 11. Active valves began in 06? If that's true then the heads should be the same. I really don't know. Lol Link to comment Share on other sites More sharing options...
GEE-OTTO Posted October 16, 2014 Share Posted October 16, 2014 So the 05 was that odd year that the 253 was "new" vs the 06-09 and then the 10-12. The CRs are different 9.7:1 vs 10:1 so Im curious if the thinner HG is allowing the piston to travel just enough about the sleeve to touch? This is one of those "I hate you car" problems that whenj fixed you're like "youre a fine SOB" Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 Lol. Well, new head gaskets are on order so the next step is removing the heads and doing a much better job of paying attention to clearances. I'm really really REALLY hoping that new pistons are the solution. I need something to do tonight anyway. Gasp. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 I meant not the solution. Omg Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 16, 2014 Author Share Posted October 16, 2014 Update: The 2009 block has pistons that have domes between the valves on both intake and exhaust sides. The t25 (2009) heads are dished out to accept these. The z25 heads are flat outboard of the valves and therefore have no clearance for the domed pistons. Hence the interference. All the replacement pistons I've seen are flat with 4 valve recesses. So, not being an engine builder I'm wondering if the pistons and rings can be replaced without an extensive rebuild of the case, and bearings. Failing that, can I-active valve heads be used without attaching the electric wiring? Totally bummed at this point but I should have seen the problem prior to installing the heads. I just assumed it was a straight swap with no clearance issues. It clearly wasn't that easy. Link to comment Share on other sites More sharing options...
klrtovfr Posted October 17, 2014 Share Posted October 17, 2014 You should be able to use the 09 heads and leave the avls unplugged. It will be in the high rpm cam mode all the time so you will have a rough idle/low rpms (loss of low end torque). There is a thread on nasioc about manual switching the avls. If you dont go that route, I will buy your 09 passenger side head since I managed to snap off two valve cover threads on my 07. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted October 19, 2014 Author Share Posted October 19, 2014 I ordered new pistons and rings, pins and clips. Looks simple enough to swap them out. I'd rather not use the avls heads as one head was partially disassembled prior to me getting them with the donor motor. I can look them over and see which one it was. I'm not sure what they would be worth as I assume it varies considerably with the condition. Link to comment Share on other sites More sharing options...
kred Posted October 19, 2014 Share Posted October 19, 2014 So you're using the 2005 heads? I've been looking for a 2005 outback 2.5i passenger side head. Link to comment Share on other sites More sharing options...
GEE-OTTO Posted October 20, 2014 Share Posted October 20, 2014 I ordered new pistons and rings, pins and clips. Looks simple enough to swap them out. I'd rather not use the avls heads as one head was partially disassembled prior to me getting them with the donor motor. I can look them over and see which one it was. I'm not sure what they would be worth as I assume it varies considerably with the condition. Good call swap the pistons but why couldnt you swap the piston from the block you had ? Link to comment Share on other sites More sharing options...
Honeybadger43 Posted November 23, 2014 Author Share Posted November 23, 2014 Sorry for the late reply. The original pistons were left in the destroyed block. One of the pistons was smashed to bits and I didn't trust any internal component from that shortblock. Link to comment Share on other sites More sharing options...
Honeybadger43 Posted November 23, 2014 Author Share Posted November 23, 2014 Yes kred, I'm using the 05 heads. Link to comment Share on other sites More sharing options...
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