OutbackXT05 Posted December 26, 2012 Author Share Posted December 26, 2012 Can I do that through my accessport? If not then I should just get a tune for break in with the 740s? Link to comment Share on other sites More sharing options...
ssbtech Posted December 27, 2012 Share Posted December 27, 2012 Make sure the machine shop checks the valves, too. My knock was a result of two exhaust valves in #2 being worn and too tight and 1 in #4. As for the shim clearances it should all be in the vacation pix Here's a calculator I found online. Not sure of the accuracy. XLS spreadsheet will open from the link. http://www.google.ca/url?sa=t&rct=j&q=subaru+valve+bucket+calculator+xls&source=web&cd=1&ved=0CD4QFjAA&url=http%3A%2F%2Fblog.1aauto.com%2Fwp-content%2Fuploads%2F2012%2F03%2FSubaru-Valve-Clearance-Tool-V1.xls&ei=eKrbULbENYTVigKQzoGgDQ&usg=AFQjCNG44z9hXs7wypKEt6PtykP_7Ytw9g&bvm=bv.1355534169,d.cGE Link to comment Share on other sites More sharing options...
OutbackXT05 Posted December 27, 2012 Author Share Posted December 27, 2012 Out of curiousity how is a valve too tight? Like the spring is too stiff? Or the valve just fits too snug? My drivers side head was rebuild due to the mechanic believing the head was the reason for compression loss the first time around. After the head was rebuild (valve regrinds and new bucket shims) The compression changed zero for ovious reasons of the piston being broken. Link to comment Share on other sites More sharing options...
ripemeat Posted December 27, 2012 Share Posted December 27, 2012 as the heads age, the valve wears further up into the head thus the bucket gets closer to the cam lobe(this where valve lash is measured with a feeler gauge). from the factory subaru sets them on the tighter end of the specs so that they are quiet in operation, unfortunately as it ages it will get tighter and leaves a greater possibility of the valve no longer completely sealing with the head, thus the loss in air tight seal- and compression(though leakdown test is better for a suspected valve issue). also, when it's too tight, the lack of proper seal AND the bucket being too close to the came lobe causes the valve to get hotter and will lead to a crack or a chip off the valve. the longer the valve is sealed to the head during compression stage the cooler the valve becomes because the aluminum of the head acts as a heatsink for the valve and dissipates heat. so i like my valves set to a looser spec, though they may be loud, but as long as they are within lash spec from subaru Link to comment Share on other sites More sharing options...
ssbtech Posted December 27, 2012 Share Posted December 27, 2012 A compression test won't necessarily show a valve problem. In my case, the valves were esaling nice and tight and the compression was 140psi in all 4. Mine weren't chipped or cracked but the valve was wearing flat where it meets the seat on the head. Link to comment Share on other sites More sharing options...
ripemeat Posted December 27, 2012 Share Posted December 27, 2012 leakdown will confirm valve sealing problems thus contributing to lower static compression. Link to comment Share on other sites More sharing options...
ssbtech Posted December 27, 2012 Share Posted December 27, 2012 Correct me if I'm wrong, but here is my understanding: Valves that are too tight can be sealing just fine, but when they heat up and expand, they stop sealing properly which can result in misfires, knock, etc.. Link to comment Share on other sites More sharing options...
ripemeat Posted December 27, 2012 Share Posted December 27, 2012 correct, that's from typical wear. Link to comment Share on other sites More sharing options...
ssbtech Posted December 27, 2012 Share Posted December 27, 2012 I don't call needing a valve job at 90,000 miles "typical wear". Here I was worried about head gaskets on this thing... Link to comment Share on other sites More sharing options...
ripemeat Posted December 27, 2012 Share Posted December 27, 2012 some wear faster than others, seen it with my own eyes multiple times. that's why getting a stage 1 tune is beneficial in more ways than one, more timing, less exhaust valve heat. Link to comment Share on other sites More sharing options...
OutbackXT05 Posted December 28, 2012 Author Share Posted December 28, 2012 Well looks like im buying new bearings. theres a small pit in one of the mains and some small scoring on the mains. Crankshaft looks good tho. Havent taken the rods off tho. Link to comment Share on other sites More sharing options...
qikslvr Posted December 28, 2012 Share Posted December 28, 2012 Can I do that through my accessport? If not then I should just get a tune for break in with the 740s? Let me look up the StreetTuner/AccessTuner scaler value and latency values from one of my old tunes where I had DW740's running in my LGT and I'll post em up for you. The AccessPort maps don't use the same scaler numbers as OS tuning software. Let's kick this pig! Link to comment Share on other sites More sharing options...
OutbackXT05 Posted January 7, 2013 Author Share Posted January 7, 2013 Alrighty need some input. Just talked to the machine shop said all the cylinders looked good. Number 4 had a light score in it that he just ball honed out. Crank is perfect so thats just gonna get a polish. So for pistons are the CP 99.5mm pistons essentially the same size as stock? So id need a light hone to get my clearance I want? Or would I be left with too big of a gap on the cleanaces in I got the 99.5mm pistons? Link to comment Share on other sites More sharing options...
ripemeat Posted January 7, 2013 Share Posted January 7, 2013 I haven't heard many good things about cp pistons, and from reputable individuals and shops. Nevertheless, 99.5 is the typical forged piston "drop-in" size. a hone job shouldn't take much off the wall at all, if it does, then he's not using a ball honer or is machining the cylinders completely for you(which would mean you'll probably need 100mm). have him hone it to remove the glazing and/or scoring and that's all. drop in 99.5's. expect piston slap regardless. I ran a shortblock for 2k miles before I blew apart 2 ej257 pistons, (2 and 4 go figure!), no scoring, just did a quick hone to restore the hatching and dropped wisecos in. and here i am today. make sure to run 5-40w with forged pistons, your cyl wall will thank you. Link to comment Share on other sites More sharing options...
Max Capacity Posted January 7, 2013 Share Posted January 7, 2013 X2 for Wiseco's over CP's. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
HellShadow70 Posted January 15, 2013 Share Posted January 15, 2013 Ok here goes my #4 tested at 75 psi no smoke but i need a hitch in the back with 10,000 Gallons of oil:p. That's way i Did The Test. stage 2 cobb tune OTS i belive the piston went before i started moding the car i called mike at infamous and he seed they use cp's on all there builds. im also doing a overhaul soon, here's the list. CP or Wiseco Pistons 06 Legacy GT full gasket kit Gates racing kevlar timing belt OEM NGK sparkplugs ARP headstuds ACL or King rod and crank bearings oem water pump sti 11mm oil pump new oil pickup only 48,000 miles on the car on another note i use 5w30 castrol syntec with titanium please input on the oil. please input on all. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 15, 2013 Share Posted January 15, 2013 Ok here goes my #4 tested at 75 psi no smoke but i need a hitch in the back with 10,000 Gallons of oil:p. That's way i Did The Test. stage 2 cobb tune OTS i belive the piston went before i started moding the car i called mike at infamous and he seed they use cp's on all there builds. im also doing a overhaul soon, here's the list. CP or Wiseco Pistons 06 Legacy GT full gasket kit Gates racing kevlar timing belt OEM NGK sparkplugs ARP headstuds ACL or King rod and crank bearings oem water pump sti 11mm oil pump new oil pickup only 48,000 miles on the car on another note i use 5w30 castrol syntec with titanium please input on the oil. please input on all. Weren't you getting any misfire cells? Rough idle when cold? How much was your oil consumption? Man 48k Link to comment Share on other sites More sharing options...
Max Capacity Posted January 15, 2013 Share Posted January 15, 2013 Ok here goes my #4 tested at 75 psi no smoke but i need a hitch in the back with 10,000 Gallons of oil:p. That's way i Did The Test. stage 2 cobb tune OTS i belive the piston went before i started moding the car i called mike at infamous and he seed they use cp's on all there builds. im also doing a overhaul soon, here's the list. CP or Wiseco Pistons 06 Legacy GT full gasket kit Gates racing kevlar timing belt OEM NGK sparkplugs ARP headstuds ACL or King rod and crank bearings oem water pump sti 11mm oil pump new oil pickup only 48,000 miles on the car on another note i use 5w30 castrol syntec with titanium please input on the oil. please input on all. Your in NY, did you contact Mike at AZPinstalls.com in NJ ? He's about 30 minutes from you. The oil didn't cause your problems. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
OutbackXT05 Posted January 15, 2013 Author Share Posted January 15, 2013 Mine didnt throw a misfire code at all with ~50psi of compression even tho it had a noticable miss/stumble. Link to comment Share on other sites More sharing options...
OutbackXT05 Posted January 15, 2013 Author Share Posted January 15, 2013 And my friends sti went at 41k. Has about 4k on the new block now. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 15, 2013 Share Posted January 15, 2013 I forget, are you running equal length headers? (btw, I have a feeling I'll be in the same boat---getting misfire on #4 only once so far but crappy idle when cold...fun) Link to comment Share on other sites More sharing options...
Max Capacity Posted January 15, 2013 Share Posted January 15, 2013 I forget, are you running equal length headers? (btw, I have a feeling I'll be in the same boat---getting misfire on #4 only once so far but crappy idle when cold...fun) Have you replaced the o-rings at the intake to TGV's yet ? 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 15, 2013 Share Posted January 15, 2013 Have you replaced the o-rings at the intake to TGV's yet ? No I have not. My first step will be to swap injectors between 2 and 4. Then if the code reoccurs in #4, I'll do a compression test. So far, only got the CEL once 300 miles ago but I have noticed my cold idle often sucks right now (if rpm is below 1000). Once warmed up, it's fine and hits max boost without hesitation.. Note: crappy cold idle has been happening since weather has been cold and very humid (no snow here). Link to comment Share on other sites More sharing options...
OutbackXT05 Posted January 15, 2013 Author Share Posted January 15, 2013 Yes the the new motor i was running equal lengths from the moment it was broken in. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 15, 2013 Share Posted January 15, 2013 Yes the the new motor i was running equal lengths from the moment it was broken in. Then, we definitely cannot attribute your busted ringland to the cylinder having run hotter than the others. From what I've been reading, a lot of 'experts' attribute busted #4 pistons due to running UEL, making the piston run hotter than others (hottest being 4, then 2, then the rest). Link to comment Share on other sites More sharing options...
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