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Guest Message by DevFuse

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Porting Polishing Heads

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6 replies to this topic

#1 Gravityman



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  • Goldsboro

Posted 09 February 2005 - 12:27 AM

Hey Subaru Freaks A little help please

Is it wise to grind down and polish the small fins/grooves in the oil and coolant holes in the head and the cyl block for better flow or should I just mabe polish them for better cooling properties and use them as a heat sink? I was thinking grind and polish the oil holes and just polish the coolant side. What do you think?

Grind Smooth and polish


Polish only?

~~Todays trivia~~~

Polish~ to shine Polish~ relating to Poland
Does this mean Polocks are pro polishers?? Or did they invent polish???

#2 bushbasher


    exhaust fume addict

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Posted 09 February 2005 - 12:34 AM

sounds like a waste of time to me. Oil and water dont flow through the heads at high velocity, so a little flash here and there isnt a big deal. A good oil pump, water pump, and rad are more than capable of cooling the motor.

#3 idosubaru


    Elite Master of the Subaru

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Posted 09 February 2005 - 12:34 AM

in porting and polishing material that i've read it suggests to grind metal cast flashing from the coolant ports (though like just mentioned, i don't see why). never seen mention of oil passages being touched while doing head work. if you're talking about the large passages at the bottom of the head then smooth away, that is just drain back into the oil pan anyway i think so grinding something smooth won't matter there. i'm getting ready to start working on some XT6 heads as well. just got two junk heads to practice on. how did it go?

one thing i don't like is the intake gaskets seem to be almost smaller than the actual intake openings. i'd like the intake gaskets to be larger so i can open the intake passages up some. any good way to *cut* the intake gasket to make it larger? i'm cautious about doing this, i want the gasket to remain nice and clean when i bolt it on.

have you noticed this scott?

#4 Gravityman



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  • Goldsboro

Posted 09 February 2005 - 12:45 AM

"any good way to *cut* the intake gasket to make it larger? i'm cautious about doing this, i want the gasket to remain nice and clean when i bolt it on. "

I imagine if there isn't a "sealant ridge" on the gasket you probably could. If there is a seal mabe an anabolic sealant or what ever the seal says you can use can use might work. I would imagine the best way to go is just grind the heads to match the gasket perfectly or as close as you can get. This will increase flow and lower any flow resistance. You can do this to your intake an exhaust also. As far as cutting the gasket Mabe call the company "Felpro" or whoever and ask them if it is safe to do and let me know. The intake should be fine to cut i would imagine.

#5 GLCraig



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Posted 09 February 2005 - 12:55 AM

I would not do either. The roughness in the oil and coolant passageways helps to create turbulent fluid flow which is better for convection heat transfer.

#6 scrapdaddytatum


    the subaru surgeon

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Posted 09 February 2005 - 01:16 AM

i agree with the last post, i polished my returns only slightly, the port should only be to match, dont screw with the head gasket much, use a leather punch to trim it if neccesary, use mechanics die to get your marks, and as a final precasion use spray on copper seal on the gasket if you have to modify it, for better coolant flow you can consider shaving your water pump to crete tighter tolerences but this is a tricky process and took me two mills to get it right on my motor, you can buy a high flo oil pump, thats a great precation, but when ever porting intake passages remember that some twisting turbulance is good, i allways try to give my porting a rifled effect to cuase better fual mix, and remember that the factory exhuast manifolds suck and should be worked a little too, better yet make a manifold and port the ************ out of the exhuast ports, this makes a big difference, dont know about the xt6 head but on the ea82t its helps

#7 Gravityman



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Posted 09 February 2005 - 01:58 AM

I would imagine it would be fine to leave the single side exhaust port alone but port the side that siameases the two exhausts together. This is in regards to the xt6.

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