JMA Posted May 23, 2017 Share Posted May 23, 2017 I plan on building a short block for my 5th gen using an ej257 short block. Will re-use the rods and crank (if they are good) and swap out the pistons for a set of forged ones. I'm picking up this short block for really cheap. I've worked out that there are a few differences like the split oil pan and front engine mount location but those parts can be donated from the factory engine. Does anyone know what other differences there are between the short block or are they pretty much the same? Been looking at parts diagrams for the sti and the lgt and I want to get all the compatibility issues figured out before I start building. Link to comment Share on other sites More sharing options...
jojorios Posted May 23, 2017 Share Posted May 23, 2017 Subbed since eventually i will need to go through this at some point. Sent from my SM-N915T using Tapatalk Link to comment Share on other sites More sharing options...
islandborn Posted May 23, 2017 Share Posted May 23, 2017 Cases are the same. Link to comment Share on other sites More sharing options...
FLlegacy Posted May 23, 2017 Share Posted May 23, 2017 I believe it is a matter of a single bolt difference on the oil pan. IIRC the 5th gen has an extra bolt that other engines don't. I think a little extra sealer on the oil pan suffices for this issue. Sent from my SAMSUNG-SM-G920A using Tapatalk Link to comment Share on other sites More sharing options...
jojorios Posted May 23, 2017 Share Posted May 23, 2017 So, lets just say I was looking randomly and came across something like this (just searched random ej257 for sale): https://forums.nasioc.com/forums/showthread.php?t=2803810&highlight=ej257+short I could technically buy it and pretty much just slap it on? Link to comment Share on other sites More sharing options...
FLlegacy Posted May 23, 2017 Share Posted May 23, 2017 Pretty much, yes. Double check the CR for our blocks, or just plan on a new tune for more power! Link to comment Share on other sites More sharing options...
jojorios Posted May 23, 2017 Share Posted May 23, 2017 Good to know. When I asked the shop if theoretically I needed to do a rebuild for time and cost. They roughly estimated 7k. I have 0 knowledge of normal cost and everything associated with it so at least I know I have options elsewhere. Pardon my ignorance, but what is the CR? Link to comment Share on other sites More sharing options...
islandborn Posted May 23, 2017 Share Posted May 23, 2017 AWTuning sells their shortblocks for about $3600... AWD Stage 2 EJ Short Block -New OEM casehalves bored & honed -JE Forged Pistons -Manley H-Tuff Rods w/ ARP 2000 Rod Bolts -King or ACL Rod / Main Bearings -New Subaru Heat Treated 2012+ STi Crankshaft -Standard FHI Subaru Case bolts and Main bolts Well...thats what I'm starting with. Just FYI. Link to comment Share on other sites More sharing options...
jojorios Posted May 23, 2017 Share Posted May 23, 2017 What's the usual labor hours involved if buying an already built short block like that. ~16? Link to comment Share on other sites More sharing options...
FLlegacy Posted May 23, 2017 Share Posted May 23, 2017 (edited) What's the usual labor hours involved if buying an already built short block like that. ~16? CR-compression ratio Labor is probably going to depend on the shop, many of them are going to charge a set amount on a build and install unless there is something custom or out of the ordinary in which case they will be up front about it. In any case get the estimate in writing. I would think a build and install would be a minimum 16 hours labor. I think I would personally have the shop that is building the block do the install, just for peace of mind. It would also be a lot harder to deny a warranty if they did all the work themselves. Edited May 23, 2017 by FLlegacy Link to comment Share on other sites More sharing options...
JMA Posted May 23, 2017 Author Share Posted May 23, 2017 Well then, I'll pick up that ej257 short block. Thanks for the input on this. Haven't done much with Subaru engines except take them out and put them back in. I'll get it disassembled and inspected before taking it to the machine shop for honing. My cost to build should be around 1300-2000 depending on whether I need/want to install new rods or if the crank needs some time in the machine shop. Used ej257 SB: $100 Case & main bolts: $80 Bore & honing: $200 Wiseco pistons set: $500 OEM STI Rods (new bolts) or Eagle: $80-350 King bearings rods & mains: $160 Re-use crank: $0-250 12mm oil pump: $140 Misc cost: $50-200 Total: $1310-$1980 Link to comment Share on other sites More sharing options...
JMA Posted May 23, 2017 Author Share Posted May 23, 2017 Pretty much, yes. Double check the CR for our blocks, or just plan on a new tune for more power! CR for our engines is 8.4:1 but most of the aftermarket pistons out there are 8.2:1 or 8.5:1. Link to comment Share on other sites More sharing options...
jojorios Posted May 23, 2017 Share Posted May 23, 2017 So if planning a retune, then this doesn't matter regardless correct? Link to comment Share on other sites More sharing options...
FLlegacy Posted May 23, 2017 Share Posted May 23, 2017 CR for our engines is 8.4:1 but most of the aftermarket pistons out there are 8.2:1 or 8.5:1. There are different head gasket thicknesses to account for a different CR, if it is an issue I don't think 3/10s of a point is a big deal. Link to comment Share on other sites More sharing options...
JMA Posted May 23, 2017 Author Share Posted May 23, 2017 There are different head gasket thicknesses to account for a different CR, if it is an issue I don't think 3/10s of a point is a big deal. 8.5:1 with a slightly thicker head gasket would probably do it. Like .1 or .2 thicker. Link to comment Share on other sites More sharing options...
JMA Posted May 26, 2017 Author Share Posted May 26, 2017 (edited) Picked up the empty case halves yesterday. Bought it for $250 but it's machined and ready to go. Saved me the time it would've taken to disassemble, clean up and take to the machine shop. The guy I got it from is reputable and well known in the Subaru community around here but I'm definitely going to double check all the measurements before I go and buy any parts for it. Edited May 26, 2017 by JMA Link to comment Share on other sites More sharing options...
mwiener2 Posted February 4, 2020 Share Posted February 4, 2020 2010-2012 LGT Case Halves are different from all other EJ motors. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
A_A_ron Posted February 8, 2020 Share Posted February 8, 2020 How are our case halves different? Also I've done a bit of reading on the 255 vs 257 and the stock pistons that come in them appear to have different dish volume and someone deduces the head combustion chamber volume was quite different between the models. Any one have any good info on what our factory heads are and the affect aftermarket pistons have on compression ratios and tuning? Build Thread Link to comment Share on other sites More sharing options...
stewdogg Posted February 8, 2020 Share Posted February 8, 2020 The baffle on the bottom of the case that the oil pan mounts on is different on our block. The guy who built my block told me that there was an extra tapped hole somewhere, but I'm not positive about that. I don't have any info on the heads and pistons. Link to comment Share on other sites More sharing options...
dgoodhue Posted February 9, 2020 Share Posted February 9, 2020 The baffle on the bottom of the case that the oil pan mounts on is different on our block. The guy who built my block told me that there was an extra tapped hole somewhere, but I'm not positive about that. I don't have any info on the heads and pistons. Ours heads are E25 which I basically can't find information on besides what farside posted. Farside said our heads have 57cc chambers. I looked in the service manual and they only thing that they mention is the CR is 9.5:1, which surprise me a little because I didn't think it was that high. No mention of piston or cylinder volume. Link to comment Share on other sites More sharing options...
mwiener2 Posted February 12, 2020 Share Posted February 12, 2020 2010-2012 LGT motors mount to the body by the oil pan. There are extra bolt holes (2) along the front edge of the pan mounting surface. These are 8mm holes whereas the rest of the EJ's are all 6mm holes. 4 of the 6mm holes have been enlarged to 8mm for a total of six 8mm mounting points that the rest of the EJ's don't have. The actual block casting is slightly different. It has been reinforced to accept these larger mounting holes. While it may be possible to retap and add these 8mm points to an EJ257, the lack of reinforcement may cause the oil pan to separate and leak, or the case could crack under the stress. Other than these changes to the oil pan mounting, the blocks are the same. This information provided by http://www.5250Performance.com My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
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