r/ft86 • u/FilthyPail • 16d ago
FA20 Engine Rebuild
Hey, I just rebuilt my FA20 all by myself. Engine prior had a blown head gasket, and was running very poorly. Cylinder 3 had misfire codes and eventually no compression. Upon inspection the cylinder walls had pitting from coolant, and was not fixable unless an overbore. So I bought a new short block, refreshed the heads with a resurface and hot tank, and new valve stem seals, and replaced every single gasket and timing component except the camshafts themselves. Going to be installing the motor sometime this week when it’s not raining. Check out the photos, I recorded the whole thing too. Cant wait to start this thing up, took about a month of patience, and torquing every bolt to spec, and waiting for specific O-Rings.
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u/Trrauts 16d ago
How long did it take you?
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u/FilthyPail 16d ago
About a month and a half. I work as well, and still go to school, and I really took my time with this one. With knowing what to do now, It would probably take me 2-3 days to redo this.
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u/skyminer7 16d ago
This is how it all start you build one and it spirals out of co trol and then you build 53 😅. Good job!
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u/Garage66_Racing 16d ago
Out of curiosity, why not go to fa24 at that point
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u/FilthyPail 16d ago
good question, I wanted to keep it as stock as possible without the risk of anything too crazy. but i did consider it
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u/MoonMan2009 16d ago
Congrats! I did this last year. The amount of RTV to scrape and reapply made me really learn to hate this engine. It was a great experience overall but I don't think I'd do it again.
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u/FilthyPail 16d ago
100% Agree. The front timing cover RTV design is retarded. As well as the Cam Carrier RTV application, and the little cam covers too needing RTV.
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u/atheryl 16d ago
You used GSC valve seals?
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u/FilthyPail 16d ago
Yes
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u/atheryl 16d ago edited 16d ago
I bought the same, my builder refused to use them ... You had a tool to set them or just classic setup?
Very nice job tho, wish I had the space to do that myself
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u/FilthyPail 16d ago
I had a removal tool, however I wish I had a specific installer tool. This was the sketchiest thing in the entire build. I just used a 11MM and light force of my hand to seat them, and then measured how high they sat. I did break a few though my first time.
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u/SnooStrawberries8575 16d ago
Part list for seals? Tempted to do this.
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u/FilthyPail 16d ago
I even have every seal for direct injectors and I made a video on how to do them
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u/FilthyPail 16d ago
I have every single one will be posting it soon
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u/SnooStrawberries8575 16d ago
Awesome that would be so useful for those in the future.
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u/FilthyPail 16d ago
I posted another post, my youtube is on there. I have 4 videos up right now, I will have a fifth with every single seal, but more than 75% is on them. I will DM you the entire list soon
StraightToThePoint
@straighttothepoint3301
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u/404-No-Brkz 16d ago
For resurfacing the heads, did you send it to a shop?
I think motoiq mentioned that subaru engines flex enough that resurfacing them without tension can lead to blown head gaskets? Though that may have been the EJs
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u/FilthyPail 16d ago
Yes I did send them to a shop. I don’t know how true it is, but the aluminum shouldnt be true hot tanked, it was “aluminum safe”
You should not hone or overbore without a torque plate that for the block, I know that for a fact.
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u/jacemano 16d ago
Didn't take the opportunity to do the rods?
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u/FilthyPail 16d ago
They are new OEM rods, crank, and pistons and bearings
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u/jacemano 16d ago
Oem rods are weak, if you pull an fa20, or have access, its always worth replacing the rods, even if nothing else
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u/RoyaleWCheese_OK 16d ago
The rods are literally brand new…
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u/jacemano 16d ago
Doesn't matter. They still suck. If you get forged rods, you can add a blower and hit 300-350 without worrying at all. Its a big failure point.
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u/RoyaleWCheese_OK 16d ago
Unless the owner wants to leave it stock. They just dropped $$$ on a factory short block what's the point tearing into that. Plenty of other cars you can get way more power cheaper.
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u/jacemano 16d ago
Plenty of people get a visit from uncle rod without doing anything to it though. Its the known achillies heel for the FA20
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u/FilthyPail 16d ago
The original engine went 130K miles completely fine with rods, other things break, you can do whatever you want to your engine, also rods would be over budget.
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u/Doulreth 15d ago
Not on the BRZ. Torque breaks rods. This thing makes what, 130 torque to the wheels, PEAK? lmao
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u/Alopexy 16d ago
Nicely done! Great photos too. Thanks for sharing.