mountaingoatgruff Posted June 2, 2008 Share Posted June 2, 2008 from the swap i'm doing, its a 96 ej25 with 170k and bad hg's. i pulled the heads and the left head is warped badly, probably could be milled to spec but i don't think i wanna mess with these heads. block looks good, bottom end is sound so i'd like to do something with it. i can get a set of rebuilt heads for $200 but i've seen references to "frankenstein" engines with 2.5 blocks, 2.2 heads, etc and i'm interested in going that route... what different heads (engines and years, please) will fit this block? i don't really want to tear into the bottom end but any build recommendations are appreciated! eidt: i did some reading and i'm just having trouble finding clear specific info. everything is phase II this, phase I that - i don't know the differences hence the request for years. also, i wanna run on regular fuel! i'm just looking to build this thing up a bit if its not too ridiculous then maybe drop it into my wife's legacy. if my best option for this goal is just new hg's and rebuilt dohc 2.5 heads i can do that but i'm leary of future hg issues (which i've read are mostly cuz of the heads...true?) i'll be reading up in the meantime, thanks Link to comment Share on other sites More sharing options...
johnceggleston Posted June 2, 2008 Share Posted June 2, 2008 if you warped the head that much you better double check the block for problems. Link to comment Share on other sites More sharing options...
mountaingoatgruff Posted June 2, 2008 Author Share Posted June 2, 2008 if you warped the head that much you better double check the block for problems. its bad enough that it would need to be milled, the worse one is .008" off and the other is not bad at all. i checked the block surfaces over and over and i couldn't find more than .002" anywhere and there's no visible cracks. maybe i'm just not doing it right. the engine ran well when i pulled it but i didn't think to do a comp check. i don't really know how much the guy overheated it - neither does he for that matter, he said the temp gauge was all over the place. i don't want to hotrod the engine. if i don't just end up selling it i'll use it to replace the 2.2 in my wife's legacy while i go to town on it doing anything i can to up the mileage. after that i'll probably sell the 2.5 anyways which is why i don't want to bother tearing it down. i can get a set of 95 ej22 heads in good shape for $120 but i need to know if they'll bolt up and how they'll affect the engine. Link to comment Share on other sites More sharing options...
hankosolder2 Posted June 2, 2008 Share Posted June 2, 2008 its bad enough that it would need to be milled, the worse one is .008" off and the other is not bad at all. i checked the block surfaces over and over and i couldn't find more than .002" anywhere and there's no visible cracks. maybe i'm just not doing it right. the engine ran well when i pulled it but i didn't think to do a comp check. i don't really know how much the guy overheated it - neither does he for that matter, he said the temp gauge was all over the place. i don't want to hotrod the engine. if i don't just end up selling it i'll use it to replace the 2.2 in my wife's legacy while i go to town on it doing anything i can to up the mileage. after that i'll probably sell the 2.5 anyways which is why i don't want to bother tearing it down. i can get a set of 95 ej22 heads in good shape for $120 but i need to know if they'll bolt up and how they'll affect the engine. I don't think a "frankenmotor" can run regular gas. It's something like 10:1 compression ratio or higher. (I suppose you COULD run regular gas, but the knock sensor would pull timing, thus reducing MPG & power.) Nathan Link to comment Share on other sites More sharing options...
Gloyale Posted June 2, 2008 Share Posted June 2, 2008 I don't think a "frankenmotor" can run regular gas. It's something like 10:1 compression ratio or higher. (I suppose you COULD run regular gas, but the knock sensor would pull timing, thus reducing MPG & power.) Nathan Naaahhhh.... they run fine. Very popular set-up for Sandrails. 2.5 block, 2.2 heads. Run 89 or 92 octane if you get any pinging. Link to comment Share on other sites More sharing options...
hankosolder2 Posted June 3, 2008 Share Posted June 3, 2008 Naaahhhh.... they run fine. Very popular set-up for Sandrails. 2.5 block, 2.2 heads. Run 89 or 92 octane if you get any pinging. To be clear, I was just speculating, based on the high CR, not on any actual experience. I could be dead wrong. On the other hand, you are suggesting upgrading to premium fuels in the event of pinging...if you're getting pinging, the ECU has already pulled the timing back as far as it can- not good. Nathan. Link to comment Share on other sites More sharing options...
mountaingoatgruff Posted June 3, 2008 Author Share Posted June 3, 2008 so any 2.2 heads are going to raise the cr? will using 2.2 heads on a 2.5 block reduce the likelyhood of hg failure? anyone have any experience with arp head studs on a stock 2.5 dohc? are they available and do they help reduce long term failure? i know its an aluminum block and you can only put so much pressure on it's threads and i'd guess they'd be pretty pricey so i'm asking more for curiosity than intent. Link to comment Share on other sites More sharing options...
idosubaru Posted June 3, 2008 Share Posted June 3, 2008 will using 2.2 heads on a 2.5 block reduce the likelyhood of hg failure?no, but doing a proper head gasket job should give you plenty of reassurance. i'd blame the blocks more than the heads, but there are entire threads devoted to "why" EJ25 head gaskets fail you can read more there. the blocks are where the majority of the material has been removed to allow for larger pistons, not the heads. use the newer head gaskets...although i've seen some claims that there is no "new" or "updated" head gasket. Link to comment Share on other sites More sharing options...
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