bhazard Posted February 6, 2017 Share Posted February 6, 2017 I think the time has come to get on with the shortblock replacement in my car. I bought the car after it suffered a turbo failure and was replaced, but not before the damage was done. I've driven it a couple thousand miles now with a faint knock around 4000 rpm but this morning it was a more noticeable knock throughout the rpm range. I know I have a few options for replacing my shortblock but I wanted some opinions. Obviously the safest and most straight forward way is a new shortblock thru Subaru. Usually around $1800. However I've found an eBay seller out of New York that rebuilds ej257 short blocks with forged pistons, ARP bolts, ACL bearings and the like. Good feedback rating, probably trustworthy. Around $1600 shipped for such a thing. Seems like a better deal overall than a Subaru block. However I've heard forged pistons can be bad for a daily driven car. Something about expansion rates and such. Another option is to rebuild what I have but I'd rather not. Have more downtime than I need. Any opinions? Link to comment Share on other sites More sharing options...
MilesA Posted February 6, 2017 Share Posted February 6, 2017 There is a nice write-up about pros & cons of forged pistons here: http://legacygt.com/forums/showthread.php/those-you-considering-aftermarket-forged-pistons-130635.html The short version is, you don't really need them unless you exceed the HP limits of the EJ257 shortblock, and there are some significant disadvantages. Link to comment Share on other sites More sharing options...
bhazard Posted February 6, 2017 Author Share Posted February 6, 2017 Yeah I don't really plan on going beyond the capabilities of the vf40. Maybe, a big maybe, a vf52 or something down the road. Are ring land failures a concern with the Subaru replacement blocks? Link to comment Share on other sites More sharing options...
MilesA Posted February 6, 2017 Share Posted February 6, 2017 One could wish for more durable stock pistons, but the forged pistons have many drawbacks. People say the stock pistons are weak, but one could argue the stock pistons are more brittle than weak, so once you exceed their limits, they break. It's also been noted that the stock pistons run tight ring tolerances, which may be for emissions reasons. The ring land failures seem to be caused by detonation and hotspots, which could be attributed to overly aggressive tune and staying in boost for too long. You will find many examples of people who use their cars as daily drivers, with a mild stage 1 or stage 2 tune that seem to avoid it. The people who play at the limits tend see it a lot more often. It's also been observed that 08+ cars seem to be more prone to ring land failures. Other people on the forum may have more insights. Link to comment Share on other sites More sharing options...
bhazard Posted February 6, 2017 Author Share Posted February 6, 2017 It's also been observed that 08+ cars seem to be more prone to ring land failures. Wouldn't the new shortblock basically make the car an 08+? Link to comment Share on other sites More sharing options...
MilesA Posted February 6, 2017 Share Posted February 6, 2017 Wouldn't the new shortblock basically make the car an 08+? When I say 08+ I'm including all turbo Subarus, including WRX/STI. I believe there are differences for the 08+ cars in several areas -- factory tune, heads, fuel injection, emission equipment, etc. Ring land failure has been seen on factory tune, and is commonly thought to be due to running lean under boost, especially running WOT at lower RPM, such as 3000 - 3500 under load. There is a delay in the factory tune before it transitions to open loop. Let's say your turbo system is heat-soaked - this is a recipe for detonation. So, we are not just talking about "weak pistons". Link to comment Share on other sites More sharing options...
dga Posted February 6, 2017 Share Posted February 6, 2017 Staying with a factory turbo there is nothing wrong with the stock rotating assembly on a good tune. There are a few things you could add to your build, ARP head studs, quality head gaskets, maybe EL headers, but overall the stock block can take the VF52 power. After all you could spend well into five figures for a bad ass engine build, but melt it down in matter of minutes with a bad tune. Link to comment Share on other sites More sharing options...
bhazard Posted February 6, 2017 Author Share Posted February 6, 2017 Yeah I plan on having XRT take care of the tune. Link to comment Share on other sites More sharing options...
Max Capacity Posted February 10, 2017 Share Posted February 10, 2017 I think you need to read my click here link in my sig. It's all in the tune. 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...
FJuan Posted February 10, 2017 Share Posted February 10, 2017 However I've found an eBay seller out of New York that rebuilds ej257 short blocks with forged pistons, ARP bolts, ACL bearings and the like. Good feedback rating, probably trustworthy. Around $1600 shipped for such a thing. Seems like a better deal overall than a Subaru block. However I've heard forged pistons can be bad for a daily driven car. Something about expansion rates and such. $1,600 for a rebuilt with forged pistons is a hell of a deal, make sure you research the builder that they have good reviews with their motors. I had my SB rebuilt with forged pistons by a popular shop in L.A. Cost just a little over $2,000 with shipping. My recommendation is to go with the forged piston with that pricing. There is really no difference in driving as long as you have a good tune. The ONLY difference with the forge pistons is piston slap on really cold days. When temps are below 50* my motor sounds like a diesel truck until fully warmed up, which is very common. This happens when the installer fits the pistons with a slightly looser tolerance to the cylinders, since the forge pistons like to expand when heated. Under warmer days, 60* or more, I don't hear a thing. My wife's balls are delicious. Link to comment Share on other sites More sharing options...
bhazard Posted February 11, 2017 Author Share Posted February 11, 2017 $1,600 for a rebuilt with forged pistons is a hell of a deal, make sure you research the builder that they have good reviews with their motors. I had my SB rebuilt with forged pistons by a popular shop in L.A. Cost just a little over $2,000 with shipping. My recommendation is to go with the forged piston with that pricing. There is really no difference in driving as long as you have a good tune. The ONLY difference with the forge pistons is piston slap on really cold days. When temps are below 50* my motor sounds like a diesel truck until fully warmed up, which is very common. This happens when the installer fits the pistons with a slightly looser tolerance to the cylinders, since the forge pistons like to expand when heated. Under warmer days, 60* or more, I don't hear a thing. Well, you live in Cali and I live in northern Ohio. It's below 50 for a much larger part of the year here. Link to comment Share on other sites More sharing options...
MilesA Posted February 11, 2017 Share Posted February 11, 2017 The California central valley is extremely hot (90-100+) many weeks out of the year. Feels like an oven. That said, $1600 does sound like a bargain. Link to comment Share on other sites More sharing options...
I Donated Too sigmafour Posted February 12, 2017 I Donated Too Share Posted February 12, 2017 ebay for forged pistons, arp stuff and all done right for $1600 = doesn't seem right. Link to comment Share on other sites More sharing options...
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