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So the machine shop called today. Said I needed different rods. I am here to ask you guys your opinion. Since I am finding mixed info all over.

Bought the
Wiseco K602M975 stroker pistons
Scat 5.180" rods
Ej251 crank

This is going into the EJ22t block and having the #3 converted to #5. He says the pistons will protrude past the block. I know it will by about .014" from what I read. In that case I would run a .60" HG.

He is saying I need shorter rods. The 5.137" rods. Anyone who has done this can confirm?

Subaru rods standard length from what I have read is 5.137" which is the length of 22T and all the phase 2 rods. I believe the mixture was 2.5l crank standard rods, and the wiseco pistons you mentioned.

I have NOT done a stroker build, i'm just going off what has been read online.

Ask him if he can make 5.216" (+2MM) rods work? I have a set that may be for sale if i decide not to 2.5l my block options.

My 2 cents,

Those pistons are designed for a phase one crank/rods. I believe the phase one 2.5 cranks had 48mm rod journals vs phase 2 2.5 cranks have 52mm. Now, I don't know if the rod journal size changes the total length over a 48mm journal/5.181, and a 52mm journal/5.181.

My stroker has the phase 2 crank, and 5.137" (ej22t, ej205, ej257) rods with custom sized STi pistons.

Just quick thinking, I don't see why you couldn't run the phase 2 crank with the 5.180" Phase 1 type rods as long as they have the 52mm journals and the phase 1 forged stroker pistons. I would think the piston design compensates for the rod length, since the cranks are both 79mm stroke.

I don't have specs in front of me, but the phase 1 EJ25 rods, the phase 2 EJ25 non-turbo rods, and the phase 2 EJ25 turbo rods all have different lengths.

Those pistons need rods the length of the phase 1 EJ25 rods. Those are usually 48mm journal rods, however custom rods can always be built.

For most North American conversations ONLY the non-turbo phase 1 EJ25 (EJ25D) has 48mm journals.

The phase 2 turbo EJ25 (EJ255/EJ257) have rods the same length as all EJ20s and EJ22s. They have 52mm journals.

Phase 2 non-turbo EJ25 (EJ251/EJ253/etc) have a unique rod length and 52mm journals.

If you want to stroke an EJ22T and your using a phase 2 EJ25 crank you either need (1) custom pistons [fix compression height], (2) custom rods [phase 1 length w/phase 2 journal] or (3) play with the head gasket thickness and quench height/volume [make the other mismatches work].

I believe rod length is calculated from center of crank rod journal to center of piston wrist pin. If there is a rod with 5.181" length and 52mm rod journals, it would suffice condition #2 posted by PHyrraM above. Meaning it should serve well as the interface component between the Phase 2 2.5 crank with 52mm rod journals and Phase 1 forged piston design.

Good information. So currently this is what is happening. The machine shop guy is trying to convince me to deck the block and now shave down the pistons from 26cc to 24cc. This build is with 02 2.0 WRX heads.

Running an Ej251 crank, Ej22t block halves converted to #5 thrust, Wiesco pistons, and the Scat 5.181" rods. He is saying by his math the pistons will protrude buy 20-25 thousandths. Hmmm. Well stock protrusion is ~12 thousandths.

He had to deck the block 3 thousandths I guess. So if I were to not have him shave down the pistons. What head gasket thickness would I need? Or should I let him shave down the pistons.

Decking the block changes can timing. It is usually not done on Subaru motors.

Edit: severe typos...

Sent from my SM-N900V using Tapatalk

I was in contact with a guy on RS25.com (FujiK) because I want to do this similar setup. he told me if I were going to use all stock internals for now on 2.0l wrx heads, to use the OEM 3 layer 97-98 22E head gaskets (which is what he did.)

I believe he also used the same (or cometic equivalent) when he built hit short block

I wouldn't let anyone mess with the pistons or deck, they would be messing with too many variables that could end up biting you right square in the ass.

Going to just get the engine back and put it together and see how much the piston comes past the deck and see if I can't just make up the difference with a thicker HG

Just an FYI you can adjust the timing back from decking the block with adjustable timing belt tensioner pullies.

Crawford makes one, which I'm running and there's another company too.

http://www.crawfordperformance.com/prod ... u-engines/

http://main.experiencetherave.com/subar ... eadwork/13
http://main.experiencetherave.com/subar ... eadwork/21

All the phase 1 engines have protruding pistons, just the way they were designed. That's why they ran thicker head gaskets than the phase 2 stuff, it's all a matter of picking one that meets the requirements of your desired cr and keeping the the piston away from the head.

I would mock assemble the block like you stated in an earlier post.

To actually add to your thread, here is my set-up: EJ257 crank, BC 1.141 rods (52mm journals), Wiseco stroker pistons. Mathematically my piston is .66mm below the deck, but after mock assembly they are at .54mm below the deck. This throws the quench off a little.

Yea, the math comes out to .043 quench, 8.1-8.2:1 CR, and that's with the pistons coming out .017'' and using a .060'' head gasket. Which has basically been verified with a couple different compression calculators and things online. everything seems to come out correctly when I do some math and some different calculations I don't understand why the machine shop is trying to squeeze some more cash out.

I don't think that they are necessarily trying to get more money out of you, but more so to get you to the proper quench (squish). Quench will change how the air/fuel will combust in the chamber. Here is a link that somewhat discusses this; http://www.theoldone.com/archive/quench-area.htm

If that doesn't explain it well enough (it's a little vague) there is a bunch of data on it if you Google search it.

My build doesn't have the best quench, but I really didn't want to order custom pistons

yea, the pistons and rods were already ordered, if the specs weisco says, .017 over block and .060 hg thickness is correct it is almost setup like a stock 22t, which come out .012 over and they use .052 hg thickness. going to be mock building it and measuring the pistons over the deck anyways to double check.

I could see a shop not familiar with phase 1 stuff freaking a bit with pistons coming out of the deck. I mean it's not really that common, and of the cars I've been into engines of I can say it's the only ones I've ever witnessed first hand.