mattkshook Posted January 20, 2012 Share Posted January 20, 2012 While the engine is out of my friends 98 2.5 gt for new heads, we are going to preemptively rebuild the bottom end and are just unsure of all we should do. Parts/suppliers, etc. We aren't trying to do anything performance, we just don't want to have to pull the damn thing out ever again. Could someone please send me in the right direction? Link to comment Share on other sites More sharing options...
Osei Posted January 20, 2012 Share Posted January 20, 2012 I'm sure you'll get good answers from the members here, but I would also suggest you join RS25.com. They have more members doing rebuilds of the 2.5. O. Link to comment Share on other sites More sharing options...
Highflyr Posted January 23, 2012 Share Posted January 23, 2012 Not to whore myself out or anything but I started where you are 6 months ago so there's a lot of good info in this thread: http://legacygt.com/forums/showthread.php/97-2-5-dohc-rebuild-165736.html Short version is I used ACL Race bearings and Subaru rings. I reused stock rods and pistons since they were in spec. and just had the crank jurnals polished. Link to comment Share on other sites More sharing options...
jamal Posted January 23, 2012 Share Posted January 23, 2012 yeah I've had the engine out of my 98 gt a couple times. A machine shop provided me with the parts and I put everything together, and it didn't actually cost that much to do. I used their standard build main bearings (not sure on the brand) and ACL race HX rod bearings, had the bores honed, and used new rings. If you're going to take apart the shortblock you really need have a machine shop measure the journals, crank, rods, bearings, bores, and pistons to ensure your clearances are right. Otherwise it's not likely to last very long. I even took a bunch of pictures when i did it: http://jamalb.net/gallery/main.php?g2_itemId=391 (page 4-5 is when I did the headgaskets over the course of about 10 hours) Link to comment Share on other sites More sharing options...
subikid90 Posted January 24, 2012 Share Posted January 24, 2012 I have done a few rebuilds on these motors. I use topline bearings and rings most of the time. Make sure you have a good set of outside micrometers and a bore gauge. You will also need to have the cylinders honed if you use new rings and the crank polished and measured for new bearings. This is not something you can do without the knowledge. I am still scared to start a subi motor after I have it assembled, they are just not an easy motor to rebuild. -Subikid90 1997 Legacy GT 5spd & EJ251 w/EJ25D heads ~10.5CR 1998 Legacy GT Limited waiting for EJ22T hybrid swap Link to comment Share on other sites More sharing options...
mattkshook Posted February 1, 2012 Author Share Posted February 1, 2012 Just want to throw out there we found a shop in our local area (charlotte, nc) that knows their shit (so it seems) We were trying to figure out an engine shop in the area and I remember driving by the place and seeing a ton of WRX/STIs and evos. Found it again, walked in and talked to the shop manager - Alex - he was a real cool guy and him and his shop clearly know what they are doing. They get and sell parts cheap - Even subaru OEM. Quoted 1500 to do all the clearance checks for the parts - deck/clean block, polish crank, bearings, rings, oil pump. We aren't expecting any issues from pistons or rods so they werent quoted in the price, we had zero issues out of the bottom end - hell you could still see crosshatching in the cylinder walls at 170K. Long story short - Need something done to your subie in the charlotte metro area, their labor rate is great too, give alex a call. Motion Labs Tuning - http://www.motionlabtuning.com/ Link to comment Share on other sites More sharing options...
Highflyr Posted February 1, 2012 Share Posted February 1, 2012 Make sure you still have the rods and pistons checked. Esp. the thrust side of the piston. Mine were pretty worn but just barely still within spec. Link to comment Share on other sites More sharing options...
mattkshook Posted February 13, 2012 Author Share Posted February 13, 2012 Update - Alex from Motion Labs gave us a call - needed VIN # since we brought the shortblock in out of the car. He is recommending piston replacement and as I had suspected - the skirts are about to the point of being noisy. He did say that they are completely useable, he just advises replacement as they would probably be out of spec by 50K. Also, went up there today to check everything out, turns out the engine HAD spun a bearing - just hadn't began to destroy everything. Bearings looked like shit, but didn't screw up the crank at all, I was amazed - didn't even think that was possible. It is a very good thing we decided to get it redone. He said unless pistons take forever and a day to get to him, it will be ready for pickup by the end of the week. Link to comment Share on other sites More sharing options...
sense of nature Posted February 13, 2012 Share Posted February 13, 2012 Oem Block (yours)Sti pistons ,Sti rods ,Sti Head Gasket, your crank, cleavite bearings, Dohc heads = Torquey ,fuuuuuunnnn motor! I believe the compression comes out to like 12.48:1 & NO the valves will not hit, I'm running this set up & have been for over 12k ,It's a Blast! Link to comment Share on other sites More sharing options...
subikid90 Posted February 13, 2012 Share Posted February 13, 2012 ^How did you get 52mm rods to work on your 48mm journal crank? -Subikid90 1997 Legacy GT 5spd & EJ251 w/EJ25D heads ~10.5CR 1998 Legacy GT Limited waiting for EJ22T hybrid swap Link to comment Share on other sites More sharing options...
SpecBamf41 Posted February 13, 2012 Share Posted February 13, 2012 how did you get 12.5:1 cr with basically a sti bottom end? wtf i hope that the sti has lower cr then that! thats what im putting if for my built motor. this guys mental. stock on our car is 10.5 iirc sti is lower for boost how the hell did you get 12.5? thats like NA race spec. BNR18g on 93oct Link to comment Share on other sites More sharing options...
subikid90 Posted February 14, 2012 Share Posted February 14, 2012 Stock is under 10:1. An EJ521 short block with our heads milled 0.25mm and STi headgaskets only yields only about a 10.8:1 compression ratio. You NEED to have your rod length, compression height, stroke and deck height to determine if it will fit, then with head volume and piston dome/dish volume you can find static compression ratio. Then you also have to worry about your quench area, this effects detention. STi stuff has a 79mm stroke vs out 75mm stroke, 130.5mm rod vs our 131.7mm rod length and compression height of 30.25 vs our ???(I forget what it is). Deck height on all subaru's is 201mm if it has never been machined. -Subikid90 1997 Legacy GT 5spd & EJ251 w/EJ25D heads ~10.5CR 1998 Legacy GT Limited waiting for EJ22T hybrid swap Link to comment Share on other sites More sharing options...
jamal Posted February 14, 2012 Share Posted February 14, 2012 yeah. sti rods don't work on a phase 1 2.5, and sti pistons would bring the CR down to about 8.2:1. Link to comment Share on other sites More sharing options...
sense of nature Posted February 14, 2012 Share Posted February 14, 2012 ^How did you get 52mm rods to work on your 48mm journal crank? My 98 has 52 mm journals how did you get 12.5:1 cr with basically a sti bottom end? wtf i hope that the sti has lower cr then that! thats what im putting if for my built motor. this guys mental. stock on our car is 10.5 iirc sti is lower for boost how the hell did you get 12.5? thats like NA race spec. Stock pistons nare dished, sti's are domed , there is a bunch of numbers out there on cc volume of heads & deck height of pistons,also there is a online compression calculator, I gathered the info typed it in & thats what it spit out. This engine is amazing & anyone who has drivin in it thinks the same Stock is under 10:1. An EJ521 short block with our heads milled 0.25mm and STi headgaskets only yields only about a 10.8:1 compression ratio. You NEED to have your rod length, compression height, stroke and deck height to determine if it will fit, then with head volume and piston dome/dish volume you can find static compression ratio. Then you also have to worry about your quench area, this effects detention. STi stuff has a 79mm stroke vs out 75mm stroke, 130.5mm rod vs our 131.7mm rod length and compression height of 30.25 vs our ???(I forget what it is). Deck height on all subaru's is 201mm if it has never been machined. You guys are forgetting head cc also dictates compression. yeah. sti rods don't work on a phase 1 2.5, and sti pistons would bring the CR down to about 8.2:1. Sti rods & pistons do work on my 98 LGt phase 1 motor I'll pull the numbers together & then everyone can see. Link to comment Share on other sites More sharing options...
sense of nature Posted February 14, 2012 Share Posted February 14, 2012 I'm not tryin to step on toes, I just put together what I had & when I put the numbers in That's what came up. Link to comment Share on other sites More sharing options...
SpecBamf41 Posted February 14, 2012 Share Posted February 14, 2012 sti piston are not domed. lmao BNR18g on 93oct Link to comment Share on other sites More sharing options...
jamal Posted February 14, 2012 Share Posted February 14, 2012 stock sti pistons: http://jamalb.net/pictures/stuff/IMG_0900.JPG not domed. Link to comment Share on other sites More sharing options...
subikid90 Posted February 14, 2012 Share Posted February 14, 2012 My 98 has 52 mm journals Never heard of this...but I wonder if some how you had a short block swapped at one point in time. You guys are forgetting head cc also dictates compression. No I didnt lol, re read -Subikid90 1997 Legacy GT 5spd & EJ251 w/EJ25D heads ~10.5CR 1998 Legacy GT Limited waiting for EJ22T hybrid swap Link to comment Share on other sites More sharing options...
SpecBamf41 Posted February 15, 2012 Share Posted February 15, 2012 there was a rare case that i saw some one find a phase 2 bottom end in a 99 outback BNR18g on 93oct Link to comment Share on other sites More sharing options...
jamal Posted February 15, 2012 Share Posted February 15, 2012 I think most 99 legacy/outback 2.5s are phase 2 blocks with dohc heads. But using sti pistons in one of those is still going to drop the compression ratio by a lot. Link to comment Share on other sites More sharing options...
SpecBamf41 Posted February 15, 2012 Share Posted February 15, 2012 yup^^^^ this guys motor should be slower then ours. BNR18g on 93oct Link to comment Share on other sites More sharing options...
mattkshook Posted February 28, 2012 Author Share Posted February 28, 2012 Update: Just got the bottom end back from Motion Labs on Saturday. We had to wait for head gaskets from them (70/pair vs 120/pair from dealer). Just picked them up today and started working on putting it back together with the recently rebuilt heads (about 200 miles on them - someone had them rebuilt but didn't do shit to a 200K+ mile engine). New pistons, bearings, block was decked, crank polished, new oil pump, etc. Started about 6. and about 30 minutes ago this is where we got before saying that will be all tonight. Just want to say - words cannot describe how much I hate the tightening sequence for the heads.... http://img.photobucket.com/albums/v215/tweekshook/2012-02-25192442-1.jpg Cylinders 1/3 http://img.photobucket.com/albums/v215/tweekshook/2012-02-25192457.jpg 2/4 http://img.photobucket.com/albums/v215/tweekshook/2012-02-27221218.jpg Where we got. Bonus: One of our next projects... http://img.photobucket.com/albums/v215/tweekshook/2012-02-27171517.jpg http://img.photobucket.com/albums/v215/tweekshook/2012-02-27171710.jpg http://img.photobucket.com/albums/v215/tweekshook/2012-02-27171543.jpg http://img.photobucket.com/albums/v215/tweekshook/2012-02-27171918.jpg That will be fun. Still can't decide if we want to rebuild the v12, drop in a chevy 350, or go all out and drop in a 572 Link to comment Share on other sites More sharing options...
monkeyposeur Posted February 28, 2012 Share Posted February 28, 2012 First thing you should do is to invest in a good leaf rake, next thing to do would be to come to your senses. Link to comment Share on other sites More sharing options...
mattkshook Posted February 28, 2012 Author Share Posted February 28, 2012 First thing you should do is to invest in a good leaf rake, next thing to do would be to come to your senses. Tell that to his parents. Their house - Car was parked in 94' - shift mechanism just crapped out. It was his dad's car (so was the old ranchero we now have in our yard that is next in line) The motor still actually turns fine - just doesn't fire. Believe it or not - quarters and hood are rusted through, but frame and floor are a 7/10 - completely repairable. And about the 572 - that was a joke obviously 13 grand without a transmission. His dad signed the title of the car over to him on his 16th birthday - kind of as a joke, but it will be one of those projects that take forever and are barely worth it. Ranchero is do a little bit of body work - new brakes all around, good tune-up and a new carb - engine is alright. Edit: their house is literally in the middle of the woods (roughly 8-10 acres) - a rake is almost pointless. I installed their Dish Network when I worked there... Dish is mounted about 30 feet up on a tree to clear trees on the other side of the house. Crazy thing is, their signal goes out less than mine. Link to comment Share on other sites More sharing options...
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