DIY Port and Polish For Miscellaneous Subaru Parts

I figured I'd start a thread and share the experience I've acquired on DIY porting and polishing of miscellaneous subaru parts. First thing I'm going to say is I'm not a professional and never have done any P&P work until my subaru rebuild so please take everything I say and post as a novice just sharing what I've learned with the community.

I will start the thread with the minimal tools requires listed below.

1)Either an air powered die grinder or a electric rotary tool that you can control the speed on. P.S. you can use a router speed control to control a single speed electric rotary tool.

2) A good set of carbide deburring bits.

3) A port and polish sanding kit.

4) A set of sanding flapper wheels.

5) A vise

6) Lubrication WD40 works.

7) Fine grit sand papers.

8) Polishing Compound.

9) Dykem, permanent marker, spray paint and scribe.

10) Safety Gear consisting of safety glasses, gloves and respiratory protection.
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The second main thing I'm going to point out is porting and polishing can lead to expensive mistakes. I'd personally leave headwork to the professionals or at least wait till you get experienced enough by practicing on other subaru parts. Even after you get your confidence level up I would only suggest an intake gasket port match and runner clean up. I've also been informed that gasket matching the subaru heads exhaust ports to tne exhaust gaskets usually is a terrible ideal by several reputable engine builders just FYI.

Another thing you need to consider is how much softer aluminum is compared to cast iron. A carbide deburring bit can trash an aluminum part very quickly so you might want to learn on a cast iron part first till you get a good feel for the tools and bits.

A good way to look at porting and polishing is to look at an engine as an air pump. What I mean by that is you want to make the air flow easily by gasket matching intake and exhaust components and by smoothing out rough castings or extra material left from the casting process.



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Re: DIY Port & Polish For Miscellaneous Subaru Parts

Excluding the heads this is a list of parts you can DIY port and polish. Please take note some of these might be just a quick casting clean up and need minimal work.

1) Throttle Body
2) TMIC Y Pipe
3) Intake Manifold
4) TGV Housings
5) Exhaust Manifold Components
6) Up Pipe
7) Turbo
8) Down Pipe

As I said in my previous comment think of the engine as an air pump and all your trying to do is make it easy for air to flow thru it with minimal removal of material. Please always be aware of how your altering the flow of the air when your doing your porting.



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Re: DIY Port & Polish For Miscellaneous Subaru Parts

Throttle Body before and after pics.

This can and should be done with out carbide deburring bits and just done with the porting wheels. I will be honest with you when I started it with the carbide deburring bits I had to take a beer break to relieve my anxiety then go back with just the sanding bits.

The goal was to remove the ledge inside the throttle body and to shape it like a funnel with a knife edge on the rim of the TB. I taped the throttle bodies butterfly to protect is and to also prevent shavings from going in to the shaft bearings. Another key thing is to not grind where the butterfly seals against the TB cylinder.
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Re: DIY Port & Polish For Miscellaneous Subaru Parts

Sti TMIC Y Pipe.

The gaskets were a match for the intercooler ports so I just gasket matched the y pipe ports that bolt to the TMIC to the gasket.

The goal for the portion of the y pipe that connects to the turbo hose was to make it a funnel and knife edge it as well.

I was actually shocked on how much material actually was removed when I did this P&P.
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Re: DIY Port & Polish For Miscellaneous Subaru Parts

Turbo Exhaust Housing.

Gasket matched the up pipe gasket to the housing while making it a funnel shape since this is what I've seen done on several turbo porting jobs. I also took the turbo DP gasket and matched that gasket to the housing but my before pics some how got lost. The waste gate passage was cleaned up as well to help avoid any boost creep.
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Re: DIY Port & Polish For Miscellaneous Subaru Parts

Long Runner impreza 2.5i intake manifold gasket matched to the phenolic spacers.
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Re: DIY Port & Polish For Miscellaneous Subaru Parts

I will be porting and polishing a sti intake manifold, a set of TGV housings, an exhaust manifold and the intake side of the turbo housing. The pics and updates will be posted in this thread. Please feel free to add any porting & polishing projects you have going on.

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Re: DIY Port & Polish For Miscellaneous Subaru Parts

This is awesome. I need to do this to my exhaust manifold and y- pipe so I'm glad you did this post


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Re: DIY Port & Polish For Miscellaneous Subaru Parts

This is awesome. I need to do this to my exhaust manifold and y- pipe so I'm glad you did this post


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Thanks I just wanted to share with the community about what I've learned so far. I will say any non Rambo person should be able to do mild port and polishing if they take their time. I'll also do some more updates on random stuff that I will be porting.


Now only if the title of the thread didn't get messed up from my phone smoking rocks. Can A mod fix the title thread?

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Re: DIY Port & Polish For Miscellaneous Subaru Parts

They should be able too change it no problem


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So I finally disassembled the VF48 turbo all in was kind enough to give me to practice porting on and this is the results of the compressor housing.

Take not I could easily spend a couple more hours of time polishing it which I will do if I decide to rebuild it.

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These photos aren't really photos of porting but more of a visual to compare the size difference of the 05 sti, 2006 2.5i and a later model 2.5 NA intake manifold.

PS the 2006 2.5i manifold lost about a pound and a half of aluminum from the shaving process.

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Grinder34

Track Monkey
They look like something from HL2 video games! A pound and a half! That's a lot of porting/polishing!
 
They look like something from HL2 video games! A pound and a half! That's a lot of porting/polishing!
I was actually shocked by how much was removed during the shaving process. After comparing the two manifolds to each other and noticing that the newer model manifold doesn't have the extra ribs on the underside of the manifold runners like the older model does I'll be removing them since I want as much clearance as possible under the manifold. I will also say the 06 na 2.5i manifold plenum looks larger then the later model as well.

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MCScoobaru

New member
I ported and polished my heads during my build. I used the scrap heads from my previous motor to practice. The only problem I ran into was porting the exhaust side I ground through the little channels in the casting on the bottom side of the port. Not a water jacket but the void space on the casting. Thankfully I?m a welder and I just welded it up. It didn?t warp the head or anything. Don?t get me wrong. It was a major pain in the ass!! But I got it done. Also. They?re are 2 types of carbide bits. Ones meant for ferrous metals which you have pictured. And ones for nonferrous metals. I included a picture. But the nonferrous are what you want. The soft aluminum clogs up the cutting edges of the ferrous close tooth bits. Also. I have pictured is a cross buff. They?re great to use instead of the sand paper flapper. These give it a mirror finish. When you rub you finger down the ports you can?t even tell it?s metal. I?d suggest using those.
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Batmobile_Engage

Squirrel Meat Aficionado.
Staff member
Congratulations [MENTION=2822]Doppelganger[/MENTION]. This great thread is now a STICKY!
 
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