WATCH: How to Build a Subaru EJ Engine that won’t BLOW UP!


Time to dust off Project Bugeye WRX and start putting its new engine together. We’ll show you all the parts that will be going into our EJ20 build, along with some of the tricks and processes we use to ensure its reliability. Many will say that a rebuilt EJ is never as good as one from the factory. We don’t agree, so let’s us show you how we do it.

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  1. If you wanted an easy revving 2 liter why didn’t you start with the jdm EJ207 that revs to 8,000rpm and has a lot of hardware benefits over the EJ205. It was the base for the group N rally cars and standard in ROW STIs.

      1. Hey, I’m trying to submit a request on that page, but the Submit button seems to be broken. Clicking it only changes the color of the button, and the request doesn’t seem to go through.

  2. Very cool build! Not a lot of info out there on the 83mm strokers on 2.0L. Any machining needed on the block or heads for clearance needed. You got more info on those custom pistons. How can I get them?

  3. Hi Mike,
    I’ve been trying to get a hold of you to work with you on a quote for my Subaru, but as Dane said above, the form on the website doesn’t seem to be working. I’ve also emailed, and on social media, but haven’t ever gotten a response. I’m working on a fairly unique build, and really want your expertise on it.

    1. The link is working, we probably haven’t had time to get to all of them, we get about 5-10 a day lately and they can take some time to sort through. What is your budget and I can tell you pretty quickly if we can be your engine builders. I can tell you up front that 98% of people who want engines have no idea what they cost and we never hear from them again.

      1. ^^^
        Mike, thanks for responding. I’m in the planning phase of the engine build at the moment, which is really where I would like your help…But, at the moment I’m planning about $20K for the engine build.

          1. This engine is built to produce 3x more than the stock engine. No race engine has a warranty. If that is important, leave it stock!

  4. Hey mike, great video and technical insights. I’ve seen piston pin bores raised into oil ring lands on inline engines, but as you know on a typical Subaru build the pin is inserted through the case after the rings are installed. How do you get around this? Do you have to install the piston to the rod, and assemble it into the case halves as one? I’m trying to imagine how to compress the rings at that point. Thanks for any insight into this!

  5. I’ve read that project and appreciate the detail you guys put into those posts. What i don’t understand is how the pin enters the piston, when the oil rings are obstructing the top portion of the pin bore in the piston boss. The top of the pin is at the top of the ring groove, does the ring not block the pin from entering? Thanks for the quick reply!

    1. Ah sorry, I misunderstood your question. For the long rod engine, we have to have the piston on the rod and lower it down through the case and keep the cases split while staging it up, it’s more fiddly but possible.

  6. Do you by chance have any more detailed information on the process of installing pistons like that? How do you address the tightening the rod bolts issue? And what would need to be done once one case halve set of pistons are in the bores? If you have 2 and 4 in their borse and with rings how do you attach the other 2 rods? I guess you could bring the pistons as far down into the borse as possi le to get as much clearance as you can.

  7. Do you have links to the exact parts that you used for this build? I’m having trouble finding the right parts and I don’t want to order them wrong

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