jonathan909 Posted March 18, 2021 Share Posted March 18, 2021 Hey, guys... arising from the dead (of winter) here and trying to catch up. I got much less done in the time of cold+snow than expected. I'm trying to revive my girls' '01 Forester (EJ251). It ate the #1 rod bearing last summer and took out the crank. I just got ahold of what I'm guessing is an EJ253 or 255 - that's based on the guy it came from apparently having been into '08 or thereabouts Imprezas. If someone could explain how to tell the difference (or if it matters) I'd be appreciative. The goal is to either swap the crank from this new motor into mine (will it fit?), or just use this short block instead of my old one (after splitting the block and inspecting the bearings, of course). The new one has "bottom end knock" written on it, but I don't feel any slop or clunk while playing the crank. Regardless, I'm not about to just bolt it up and pray. Guidance? Thanks as always. Quote Link to comment Share on other sites More sharing options...
forester2002s Posted March 18, 2021 Share Posted March 18, 2021 Wikipedia has an online article about Subaru EJ engines. As usual with Wikipedia, completeness or accuracy cannot be guaranteed. Quote Link to comment Share on other sites More sharing options...
jonathan909 Posted March 19, 2021 Author Share Posted March 19, 2021 (edited) I know, I read it first. That's where I got my guess about it being probably either a 253 or 255. But it's not a substitute for actual first-person knowledge and experience, hence my question. Edited March 19, 2021 by jonathan909 Quote Link to comment Share on other sites More sharing options...
ocei77 Posted March 19, 2021 Share Posted March 19, 2021 Pull the crank and have it checked. If its a bottom end knock then more than likely a rod bearing is gone, so will damage the crank. If salvageable use it with the 01 pistons and a rod to replace the broken one. The 01 block has to be cleaned thoroughly to make sure there are no metal pieces lurking in the oil passages. Change the piston rings, rod and crank bearings, and all timing components( getting quality components. Gates is no longer a reliable mfg) Download FSN here:Index of /Auto/Japan/Subaru (jdmfsm.info) O. Quote Link to comment Share on other sites More sharing options...
jonathan909 Posted March 19, 2021 Author Share Posted March 19, 2021 (edited) That's pretty much my plan - I was really looking for confirmation that the new crank would fit the old block, and which pistons are appropriate. Didn't break the rod, though - the bearing just spun and chewed the crank. I actually haven't gotten as far as measuring the rod to see if it's still usable. I'll be splitting the (new) block first thing tomorrow, and have reasonably high hopes that the crank is okay. As I said, I only have someone's Sharpie scribble to suggest there's a problem; so far I haven't detected any play between the crank and the pistons. I was planning to have the block tanked at a shop (rather than DIY cleaning) just because it's so much nicer to have a really clean substrate to build on. Bearings and rings, natch, and the belt and idler sprocket got replaced (during a head gasket job) with HQ parts only about 8 months before this bearing went, so they'll be reused. Edited March 19, 2021 by jonathan909 Quote Link to comment Share on other sites More sharing options...
ocei77 Posted March 19, 2021 Share Posted March 19, 2021 Yes the crank is the same. O. 1 Quote Link to comment Share on other sites More sharing options...
Numbchux Posted March 19, 2021 Share Posted March 19, 2021 11 hours ago, jonathan909 said: I know, I read it first. That's where I got my guess about it being probably either a 253 or 255. But it's not a substitute for actual first-person knowledge and experience, hence my question. 253 and 255 are very different engines. 253 being SOHC and 255 being DOHC Turbo. All USDM shortblocks since the mid '90s have the VIN stamped into a flat on the RH side of the block next to the bellhousing. 2 Quote Link to comment Share on other sites More sharing options...
jonathan909 Posted March 19, 2021 Author Share Posted March 19, 2021 Ah, okay - obvious now looking back at the wikipedia page. So this is likely a 253. I'll check the VIN. Quote Link to comment Share on other sites More sharing options...
jonathan909 Posted March 19, 2021 Author Share Posted March 19, 2021 Awright, here's what I've got. Hoping Smart People (tm) can enlighten me. Pulled "new" block apart, with the pistons off felt a little play in rod 1 - maybe a couple of thou. Once I split it and yanked the caps, I could see that the bearing was just starting to come apart. I think I was lucky here, and that as soon as buddy detected a slight bottom end knock he didn't push it - he stopped and immediately pulled the engine. Will mic the crank over the weekend and confirm it's okay. But I'm really curious about the block diffs. This new one says "EJ25 304" in the casting. Where the halves mate at the top of the bell housing are the numbers 745578 (starboard) and 730865 (port) - I assume those are production serial numbers for the halves. Further over on the port side top (near the starter) is D408442, which I'd guess is the engine's serial number. Nothing that even remotely resembles a VIN. Is anything to be read from those numbers? Other than that, we've got different pistons and rods that are about .050 shorter than the '01 EJ251's. So I'm wondering: Not that I want to do this, but if I did, could I use my old pistons and rods (and heads) with the later block and crank? Or would there be little gotchas waiting to mess me up along the way? Quote Link to comment Share on other sites More sharing options...
Numbchux Posted March 19, 2021 Share Posted March 19, 2021 The VIN is on the RH side, vertical surface. Quote Link to comment Share on other sites More sharing options...
jonathan909 Posted March 19, 2021 Author Share Posted March 19, 2021 I see the land you're talking about, but none of my blocks appear to have markings there. I'll give these a good cleaning to confirm, but I suspect that this is a US marking requirement and they don't do it with Canadian market engines. Quote Link to comment Share on other sites More sharing options...
ocei77 Posted March 19, 2021 Share Posted March 19, 2021 (edited) Just clean it, its there. That's the power steering line in the pic The pistons may be a different shape, but all the 2.5 cranks ( other that the ej25D , have 52mm journals) with thrust on #5. The rod length is the same also (79mm) IIRC. look at the FSM on the specs page. The answer to your questions are yes. The blocks are the same. Use the old heads. O. Edited March 19, 2021 by ocei77 Quote Link to comment Share on other sites More sharing options...
jonathan909 Posted March 19, 2021 Author Share Posted March 19, 2021 (edited) Confirmed: No such VIN marking on any of these blocks. I do still have (somewhere outside) the borken block from our late '02 Forester, which was a US production car i.e. MPH speedo instead of KM/H. When I get a chance I'll clean it off and look, just for yuks. As for the rods... I make mistakes, but rarely any this obvious. And how are rods measured? I don't get where the 79mm comes from. Edited March 19, 2021 by jonathan909 Quote Link to comment Share on other sites More sharing options...
ocei77 Posted March 20, 2021 Share Posted March 20, 2021 The 79mm is not the length of the rod, but the stroke. All 2.5 engines have a stroke of 79mm and a bore of 99mm.Measured from center of king pin to center of shaft at either tdc or bdc.. That's how they get the total volume of 2498cc Piston design (placement of king pin) effects stroke. So if the piston centers are different the rod will be different to make the CR the same The cam qty does not change that. Only the deck height. Quote Link to comment Share on other sites More sharing options...
Numbchux Posted March 20, 2021 Share Posted March 20, 2021 On 3/19/2021 at 4:50 PM, jonathan909 said: I see the land you're talking about, but none of my blocks appear to have markings there. I'll give these a good cleaning to confirm, but I suspect that this is a US marking requirement and they don't do it with Canadian market engines. Ah, I didn't catch that you were in Canada. Yea, I know JDM cars don't have it, so that doesn't surprise me. Quote Link to comment Share on other sites More sharing options...
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