s'ko Posted May 1, 2007 Share Posted May 1, 2007 MUHAHAHAHAHAHA..... Ok so I killed my EJ18 in my BRAT. I have lined up another EJ18 that I am going to put in but now that gives me EJ engine parts to play with. So..... here is my theory. EJ25 short block, EJ18 heads, EJ20 pistons and a 2mm head gasket. this should give me 10.88:1 CR. Now it's seeing if the EJ18 heads will bolt to the block. BTW here is another excel calculator for Compression ratios on an EJ motors. Values are in mm. The EJ-CR docs are some info regarding EJ engines. BW EJ-CR1.doc ej-cr2.doc Quote Link to comment Share on other sites More sharing options...
Snowman Posted May 1, 2007 Share Posted May 1, 2007 Now it's seeing if the EJ18 heads will bolt to the block. How about the intake manifold? I'm assuming there is some combination that will work, but it might take some experimentation. That would be SIIIICK! Quote Link to comment Share on other sites More sharing options...
s'ko Posted May 1, 2007 Author Share Posted May 1, 2007 Still working on the variables and the measurements. The intake might have to be bolted to an adapter of some sort. The way I figure it. I have the EJ18 heads (as long as they are not damaged) I have a way of getting 2.0 rods for cheap or free, I am getting a 2005 2.5 short block for $140.00 (as long as the cylinder walls are not FUBAR) So 'lego'ing this thing together would probably cost me around $500.00 if I get new pistons. If I have to do machine work to the block and stuff then it will probably be in the 1k range or so. But it would be worth it. Would this work w/just the stock ECU, or would I have to go with engine and fuel management computers? BW Quote Link to comment Share on other sites More sharing options...
Zefy Posted May 1, 2007 Share Posted May 1, 2007 putting ej22 heads on an ej25 block is a common motor build... it pushes the CR up to about 10.8:1 if i remember correctly... your plan would probably work fine... the only issue i can see is if the ej18 heads can flow enough for the ej25... although they are probably similar or even identical to ej22 heads... if you use the ej18 heads then use the ej18 intake manifold... and the heads should be fine on the block because (i'm assuming) you're using an RS block (please be phase 2) which is an open deck block... Quote Link to comment Share on other sites More sharing options...
Snowman Posted May 1, 2007 Share Posted May 1, 2007 Are you running the EJ18 computer right now? I would think that you'd get much better performance running an EJ22 or EJ25 management system. I'm sure the EJ18 setup would be able to run it, but I doubt it would make anywhere close to max power. I've been told that the EJ22 computer is set up more for top end, while the EJ25 computers are set up for more torque and low end. (A friend of mine put EJ22 management on his EJ25 and said it lost some torque but hauled rump roast in the top end.) So if you want a screamer, put EJ22 management on it, or if you want a stump-puller, go with an EJ25 computer. Quote Link to comment Share on other sites More sharing options...
simple monkey Posted May 1, 2007 Share Posted May 1, 2007 ej22 heads on the ej25 block would yield 11.5:1, and would be a much better set up. the ej25 block will starve for air with the ej18 heads. ej22 heads have much bigger ports and bigger combustion chambers for better performance. if you plan on keeping the ej18 heads, i would suggest putting an ej22 shortblock in there. there are a couple people on nasioc.com who have tried it and liked the results. also, isn't the bore of the ej25 too large for the ej18 heads to fit? i know some of the coolant passages dont match up as well. good luck on the build. Quote Link to comment Share on other sites More sharing options...
ShawnW Posted May 8, 2007 Share Posted May 8, 2007 MUHAHAHAHAHAHA..... Ok so I killed my EJ18 in my BRAT. I have lined up another EJ18 that I am going to put in but now that gives me EJ engine parts to play with. So..... here is my theory. EJ25 short block' date=' EJ18 heads, EJ20 pistons and a 2mm head gasket. this should give me 10.88:1 CR. Now it's seeing if the EJ18 heads will bolt to the block. That'd yield 0 compression. BTW here is another excel calculator for Compression ratios on an EJ motors. Values are in mm. The EJ-CR docs are some info regarding EJ engines. BW[/quote'] I think you have a piece backward somewhere here. You say you are going to put 2.0 pistons in a 2.5 shortblock but thats 92MM pistons in a 99.5MM block. That's 0 compression. Ej18's dont have a knock sensor. Thats the biggest gain of the 2.2/2.5 engines. Ultimate Engine would be 2003 or newer SOHC 2.5 block with 95 2.2 heads and the ej18 roller rockers and cams with a delta cam grind. Even more reliable would be a 2.2 block with high compression pistons instead. Above someone referenced getting Ej20 rods for free/cheap. They are the same rods as a 1.8/2.2. Quote Link to comment Share on other sites More sharing options...
86BRATMAN Posted May 8, 2007 Share Posted May 8, 2007 95 EJ22 heads have roller rockers already. Is there a difference between the ej18's rockers that make them better? Quote Link to comment Share on other sites More sharing options...
s'ko Posted May 8, 2007 Author Share Posted May 8, 2007 I think you have a piece backward somewhere here. You say you are going to put 2.0 pistons in a 2.5 shortblock but thats 92MM pistons in a 99.5MM block. That's 0 compression. Ej18's dont have a knock sensor. Thats the biggest gain of the 2.2/2.5 engines. Ultimate Engine would be 2003 or newer SOHC 2.5 block with 95 2.2 heads and the ej18 roller rockers and cams with a delta cam grind. Even more reliable would be a 2.2 block with high compression pistons instead. Above someone referenced getting Ej20 rods for free/cheap. They are the same rods as a 1.8/2.2. I would be using the 2.5 pistons. I have since thought about the project and I will be doing a standard EJ25 shortblock w/EJ22 heads. Lots of guys at nasioc have done this. May possibly take the EJ22 Shortblock and bolt up the EJ18 heads to the just for laughs and giggles. Thanks all for the input. BW Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted May 8, 2007 Share Posted May 8, 2007 I'm building the same EJ25 with 95 EJ22 heads. I've got two blocks, I think the one I'll be using is out of a 99 automatic forester, and I'll be using the crank, rods and pistons out of a 1997 outback, and the heads off of a 1992 legacy with the cam and roller rockers out of the set of 95 heads that have burned valves. Oh, and I have new Subaru piston rings. The 1997 block will have to be bored out to be made useful, it's too pitted to be honed. I'll have to buy oversized pistons. Then, I'll make another engine using the SOHC 2.5 heads off of the forester block. Quote Link to comment Share on other sites More sharing options...
Storm Posted June 1, 2007 Share Posted June 1, 2007 Bumping this back up to let y'all know that I'm working with Cometic Gasket to develop a custom headgasket for the EJ25/EJ22 hybrid. I need to get them an EJ22 gasket to confirm the coolant passages are different and have them apply that pattern to the EJ25 gasket so folks don't have to modify theirs. If any of you have old OEM EJ22 gaskets, please PM or email me. I threw all of mine out already. Thanks, Jay Storm Quote Link to comment Share on other sites More sharing options...
s'ko Posted June 1, 2007 Author Share Posted June 1, 2007 Bumping this back up to let y'all know that I'm working with Cometic Gasket to develop a custom headgasket for the EJ25/EJ22 hybrid. I need to get them an EJ22 gasket to confirm the coolant passages are different and have them apply that pattern to the EJ25 gasket so folks don't have to modify theirs. If any of you have old OEM EJ22 gaskets, please PM or email me. I threw all of mine out already. Thanks, Jay Storm Talk to Garage Tuning in Anaheim 714-288-2887. They should have a bunch or at least access to some in the future. Tell em Bosco sent you. BW Quote Link to comment Share on other sites More sharing options...
Storm Posted June 1, 2007 Share Posted June 1, 2007 Looks like I got PM'd with a set of OEM type. Once I get a PN for these "hybrid" gaskets...I'll post it up!!! BTW...here's a link to a franken-wagon having too much fun in the dirt with his phase II EJ25 and 98 EJ22E heads..... http://video.google.com/videoplay?docid=124045791458671801 Thanks all, Jay Quote Link to comment Share on other sites More sharing options...
Zefy Posted June 1, 2007 Share Posted June 1, 2007 Bumping this back up to let y'all know that I'm working with Cometic Gasket to develop a custom headgasket for the EJ25/EJ22 hybrid. I need to get them an EJ22 gasket to confirm the coolant passages are different and have them apply that pattern to the EJ25 gasket so folks don't have to modify theirs. If any of you have old OEM EJ22 gaskets, please PM or email me. I threw all of mine out already. Thanks, Jay Storm i have a set off the motor i'm rebuilding but i'm kinda far away...:-\ i could clean them up then scan one of em into the comp then send it to you? you print it off... all good! Quote Link to comment Share on other sites More sharing options...
Storm Posted June 2, 2007 Share Posted June 2, 2007 That just might work!!! Thanks! Jay i have a set off the motor i'm rebuilding but i'm kinda far away...:-\ i could clean them up then scan one of em into the comp then send it to you? you print it off... all good! Quote Link to comment Share on other sites More sharing options...
A DOG Posted September 17, 2010 Share Posted September 17, 2010 Bringing this thread back from the dead. I am doing this swap now. EJ25 block with EJ18 heads and EJ18 tranny. I am ordering up aftermarket parts tonight. Can i use the EJ22 lightweight flywheel and stage 1 clutch with the EJ18 tranny mated to the EJ25 block? Quote Link to comment Share on other sites More sharing options...
Gloyale Posted September 20, 2010 Share Posted September 20, 2010 ej22 heads on the ej25 block would yield 11.5:1, and would be a much better set up. the ej25 block will starve for air with the ej18 heads. ej22 heads have much bigger ports and bigger combustion chambers for better performance. Where aare you getting this? There are no visible differences in the EJ18 and EJ22 heads. Certainly not "much larger" anything (larger combustion chamber would lower compression:rolleyes:" Quote Link to comment Share on other sites More sharing options...
Gloyale Posted September 20, 2010 Share Posted September 20, 2010 MUHAHAHAHAHAHA..... Ok so I killed my EJ18 in my BRAT. I have lined up another EJ18 that I am going to put in but now that gives me EJ engine parts to play with. So..... here is my theory. EJ25 short block' date=' EJ18 heads, EJ20 pistons and a 2mm head gasket. this should give me 10.88:1 CR. Uh......might have a bit of excessive side clearance with EJ20 pistons in a EJ25 block. Like several mm extra, I don't think the rings will seat:lol: Quote Link to comment Share on other sites More sharing options...
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