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Old 10-07-2022, 11:32 AM   #1
BlackFighter
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Default What are the half moons for?

So I tried searching on NASIOC and online, but can not find any explanation what the half moons in the heads are designed for. At first I thought it was to release high build up of pressure in the heads in case of a emergency, if that's even possible. Hans them being made out of rubber/plastic, but if that's the case than won't using the billet ones a bad idea? Any explanation why Subaru put them in there? Was it for aluminum expansion?
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Old 10-07-2022, 11:58 AM   #2
wobbletop
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It's so they can line hone for the camshafts during manufacture.
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Old 10-07-2022, 12:29 PM   #3
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Ahh man, I'm retarded. That makes perfect sense. Mod can close this thread. Thanks
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Old 10-07-2022, 12:44 PM   #4
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BUT!!! it also gets more interesting. The newer EJ heads do not have half moon cutouts. So something, somewhere at some point in time changed and they do not use the same technique that they used to.
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Old 10-07-2022, 02:23 PM   #5
BlackFighter
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Quote:
BUT!!! it also gets more interesting. The newer EJ heads do not have half moon cutouts. So something, somewhere at some point in time changed and they do not use the same technique that they used to.
You talking about the "W" heads? ya like you said, I see they don't have half moons. I guess they go through the AVCS now.
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Old 10-07-2022, 02:23 PM   #6
BlackFighter
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Quote:
BUT!!! it also gets more interesting. The newer EJ heads do not have half moon cutouts. So something, somewhere at some point in time changed and they do not use the same technique that they used to.
You talking about the "W" heads? ya like you said, I see they don't have half moons. I guess they go through the AVCS now.
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