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Are these welds factory? (4G63 head)

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Kryndon

Proven Member
944
591
Jan 10, 2014
Bulgaria, Europe
A long time ago I noticed a weird weld-looking thing right at the end of one of the head oil feed galleries that feed the camshaft. One side is fine, but the intake-side appears to have a weld there which would end up blocking oil flow to the main journal on the intake camshaft? I thought this was some sort of repair done on my head specifically by the PO, but I just saw a rebuilt head for sale and his also seems to have the same weld. Anyone got a better idea of what it is and why it's there? Pics below of my head and a different one:

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I'm changing out my valve stem seals on my '97 & it has the exact same welding. My '97 is completely stock & the engine is still all original.
 
So then this must be something to do with the casting process. Maybe that's where the air-vent was placed, the one where it lets air escape as molten aluminum is poured into the mold? Then they weld it up somehow but without blocking the channel, since it still needs to find the main journal as far as I can see?

Can't really think of anything else. I doubt these galleries are drilled out; too long and it would cause drill chatter. On the other side it's just a round nipple, and not a plug.

Maybe I'm wrong, just can't think of anything else.
 
Your guess sounds right to me but I also know nothing.

My head is completely stock as well, it's only been resurfaced and has the same weld in the corner. I also drive a 97'
 
I have a spare '98 head and it does not have this same welding. My guess is Mitsubishi had a casting problem an at least one of their production runs & the weld is a factory rework fix to avoid scrapping these heads. Funny we're all '97's with this welding. My car's production date is March 1997.
 
That makes me feel a little better about mine. I received a rebuilt head from the machine shop that had that weld on it. I figured they found a scrap core they had laying around and tried to repair it to use in my build but maybe this is a common thing? FWIW, I've never noticed welding there on any of my five other 97-99 heads.
 
Interesting. What Mello said might be the case about a specific batch having that issue. Although mine is officially a late August 1996 production car even though it's a 2GB. The head is definitely the factory one in my case. So possibly it was a late '96 to early '97? Still, that's A LOT of heads that went through before they picked up on the issue... Then again, they probably cast a couple thousand heads at the same time in the same factory and touched it up afterwards. Oh well, still interesting to learn about this. If anybody has a junked head with this same weld, can u cut thru it or drill thru it and tell us if it's hollow inside? :cry:
 
Mine is a April '96 build date for a '97 Talon. I don't recall seeing any weld spots in my head when I had it off. Unfortunately, I have no pictures to back that up.
 
This made me go look at my 2g heads. None of mine (so far) have that but I agree it has to be a factory fix for them to not scrap a shitload of castings.
I will check the other heads I have when I have time.....curious.
 
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