Rebuilding a Subaru FA20 Engine - Part 1

Watch the disassembly video first: • FA20 Complete Teardown...
In this video, I go over the first steps in rebuilding a Subaru FA20. I clean the RTV from the surfaces, install rod bearings, plastigauge the clearances, and install main bearings. Stay tuned for part 2!
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Songs Used:
ROY KNOX & CRVN - The Other Side [NCS Release]
Jack Shore & KORA - Memory Nights [NCS Release]

[@austinblackwell8331]

What size honing tool did you use? I saw you left it in the description but 89mm seems a little big for a 86mm bore. Just trying to figure out if that will be okay and is 240 grit good enough for the pistons to seal

[@allengarsee-realestateagen2743]

I’m currently working on my own fa-20 build. Any chance you could share the manual you used??

[@DaDaDo661]

How do you check for flatness on the heads?

[@notsponsored103]

Watched your first inspection after you towed it home.
Pretty good oil leak there.
Wouldn't it be reasonable to conclude that the failure was oil starvation, not a pressure problem related to factory clearances and oil specifications?
The FA platform is also a high oil consumption design even when it isn't leaking.
Regular oil level checks are critical.
I suspect running wider clearances with a modern 30 weight oil is going to make this failure more likely to happen again, not less likely.

[@NickSabella]

I do check the oil regularly in all my cars. It was the first thing I checked when the bearing spun and wasn’t low at all. The switch to 5w30 is based on a recommendation in a mightycarmods video I watched from a shop known for building these cars. I also saw some graphs on an 86 forum of much cooler oil temps on a track with 5w30. I do believe the cause was some form of oil starvation. I just don’t understand what caused it. The oil was full and the pickup tube wasn’t clogged at all. Why do you think the extra oil clearance and thicker weight would make the issue more likely?

[@notsponsored103]

@@NickSabella ok that's interesting to know that you didn't have low oil.
My reason for suggesting increasing clearances might be risky is based on the assumption that you won't be changing the oil pump to provide the necessary flow to support the change, but you know what they say about assuming.
Are the shops that recommend the oil upgrade also increasing clearances or just increasing oil viscosity without clearance adjustment to try to achieve higher pressure?
P.S. apologies for not hearing you say you checked the oil in the other video

[@NickSabella]

@@notsponsored103 the shops did not change any clearances. I did not end up changing or modifying the oil pump. Just opened it up and cleaned it out. I understand your concern that the larger clearances could lower the oil pressure. The new bearings are still technically in spec according to the service manual so I think it should be okay. I was just trying to make some sort of change since in stock form it spun a rod bearing under relatively normal driving conditions.

[@notsponsored103]

@@NickSabella cool man, I'll look forward to the next episode.
I would just add that the red line is red for a reason.
Perhaps going there regularly isn't normal for a stock engine.
When you think about where the tachometer is at peak torque in stock form, the engineer has expected you to get in the next gear long before the needle reaches the danger zone.
Race car different story.
Stay free. I'll keep watching. You got a new sub.

[@NickSabella]

@@notsponsored103 Yeah I guess I had to learn the hard way. Thanks for the sub!

[@civicgamessports6937]

With engine prices the way they are. Would it be worth it to rebuild a blown engine? (Oil changes)

[@NickSabella]

I think so. This engine kinda sucked to rebuild though. So much rtv

[@BoostedFA]

Since Toyota uses the fa20 motor, are most parts interchangeable like this? I have to rebuild my motor ASAP. Mosy likely need a crank too. I have a 18 wrx fa20..

[@NickSabella]

Everything between a brz and fr-s are interchangeable. I know the wrx and brz engines are different though. You'll have to compare part numbers to see if it matches a brz. If it fits a brz, you can buy it through Toyota to try to save money.

[@Johnnie5213]

😎👍👍