legacycentral bbs

I know that any motor will bolt into pretty much anything, But what about just shortblocks? I've got a 91 SS with a #1 rod bearing that is about to go. I'm moving to oregon in october, and I'm not sure if I want to put in an N/A motor, till I get there, or if I can swap in say, just the shortblock from an STI, but keep my heads and stock ECU? What, if any shortblocks will fit the heads properly? Gaskets? T-Belt? I hate my life....

An STi shortblock **should** work fine

An STI short block will work fine, but you will have to get a stI timing belt tensioner....I think....

If the WRX and STI tensioners are the same, you can and MUST use the legacy tensioner bracket and tensioner with the SOHC heads, or the belt will be the wrong length.

what year STi? Wont the pistons overlap the combustion dome on the head slightly?

boro wrote:what year STi? Wont the pistons overlap the combustion dome on the head slightly?

Doesn't matter. Guys have been mating 2.0l heads to those blocks since the day they were released. And I know a couple of local guys who have mated them to Ej22 heads. There's really no issue there.

It's going the other way that makes issues. In particular SOHC EJ25 heads cannot be bolted to EJ20 blocks because the bore is so much smaller that the head gasket won't seal.

so matt, Youre saying that I could essentially grab the service manual for my 91 turbo, and follow that without fail, for shortblock replacement. Has anyone done this? Will my stock EM be able to handle it? I need a new shortblock, and I want to do this as painless as possible, but I cannot find a stock 2.2t block up here in alaska.

Yeah, just do a EJ257 (STi) block...everything will bolt on up

And it will run as it is supposed to? I do have an apex'i SAFCII that I could use if I needed to richen things up a bit. It just seems to me that +.3 liters doesn't compute to the ecu.

If you are running it in stock trim (i.e. no boost increase, etc) I don't believe you would really see a problem based on displacement...

And then if you were to tune it, just keep an eye on things with a wideband

Most of the stuff that makes the engine "run" is attached to the heads or intake manifold.

If you keep your original heads and intake manifold, then yeah, the 257 shortblock should swap right in for the most part.

I believe the original knock sensor should work, and I believe the crank angle sensors swap too. Then I believe the coolant crossover pipe should change over as well, so you can use your same coolant temp sensors. Other than that, I believe everything will be the same.

You shouldn't have trouble with airflow metering since the MAF sensor know how much air is coming in. Just keep ypur boost below the threshold of maxing the MAF sensor out.

If it has the crank cog still on the 2.5 use the one from your 2.2. The newer stuff has a different tone wheel. If you dont swap them out it wont run.

If he buys just a shortblock, it shouldn't come with that wheel. As stated above he will want to use ALL the parts from his Ej22T other than the shorblock (which by definition is only the case, pistons, cylinders and things like rings and bearings).

The only compatibility issue is that the Ej257 block has an additional case breather that will hit the early style coolant crossover pipe. The solution most guys use it to either cut it up with a cutting wheel and stick a rubber corks in it OR crimp the end of it after putting some silicon sealant in there and knock it over with a mallet. One is prettier than the other, but they both serve the same purpose...

I am running a td04, and I'll have an sti turboback on it, but I'm running wastegate boost which is about 9 psi. thanks for all the info, I can't wait to get started.