Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

Porting/Polishing


  • Please log in to reply
11 replies to this topic

#1 TurboSPFI

TurboSPFI

    Banned

  • Banned
  • 374 posts

Posted 13 June 2005 - 06:56 PM

I've never ported or polished anything and was wondering if there were any certain processes to follow when doing this.

been considering P/P my turbo and heads

also, what kind of "grind bits" work best? do i need multiple? how bout carbide burrs? i know they can take alot off quickly, but that might be the issue?

how bout P/P my VF2? bore out the wastegate? anything?

thanks

#2 MilesFox

MilesFox

    Catch this Fox!

  • Members
  • 10,423 posts
  • Madison/Milwaukee, WI

Posted 13 June 2005 - 08:06 PM

i use a dremel with the flex extension, i will use one of the metal blade type bits to get my shape, and follow thru wuth stones. be careful as stones will clog up, so use light to moderate pressure and a medium rpm under load. finish up with the sanding drum

i like to use the cylindrical stones for most of the work and the cone stones for tighter splaces. when selecting stones read the details on the back of the package to pick the best one for aluminum, as the stones come in different textures and colors depending on their intended application

#3 NoahDL88

NoahDL88

    Elite Master of Cookies

  • Members
  • 4,264 posts
  • Everett, WA, USA

Posted 13 June 2005 - 08:44 PM

metal bits made for ally won't clog nearly as easily as those for steel, they will have bigger spaces between the flutes.

having my engine machining certificate, I should warn you that you need to be extra careflul when poring by hand without a flow bench. if you take off too much in any one area you can severly reduce velocity and loose a dramatic amount of power, my .02 would tell you that you should just smooth up the ports with a sand paper type cylinder or cone. just try to smooth out the transitions and don't get too carried away, bigger isn't always better, especially on these motors.

If you're gonna port and polish, you should get a 3 angle valve job with some bigger valves, that would be your biggest restriction.

As far as the turbo, i'd leave it alone and get a bigger one, ask WJM which one he's using, that would be a good start.

#4 erik litchy

erik litchy

    Leadfoot

  • Members
  • 1,090 posts
  • Peoria IL

Posted 13 June 2005 - 09:54 PM

on my non turbo heads there wasnt really any areas that really needed lots of materail removal. the worst part being the exhaust where it transitions to a cylinder. the intake side all there was really was bowl work, and the exhaust bowl area, to gain flow id have to add materail not remove it. the casting is quite odd under the valve seats there.

#5 4WDFrenzy

4WDFrenzy

    Certified Subaru Nut

  • Members
  • 857 posts

Posted 13 June 2005 - 09:54 PM

I used a set of die grinding stones that I bought at Wal-Mart for like $10. They worked great. I also used them with the cheap $18 corded drill that I bought there as well and mine turned out great.

If you are going to use a Dremel though, buy a Dremel brand tungsten carbide bit for it. It works well, but you have to be extremely careful when applying hand pressure to it as it will cut into the cast iron very quickly. And if you aren't careful, it may cut deeper into it than you may have wanted.

As far as porting & polishing the turbo, make the inlet to the exhaust snail rounded and tapered, like a funnel or the bell of a trumpet. In theory, the funnel shape will decrease the turbulence often occurs in this area and it should aid in the responsiveness of you turbocharger as well. I would also advise removing the compressor snail and go over the inlet, inside(as much as you can reach),and outlet with 2000grit sandpaper. The best thing to do though is to send the compressor snail out to be bored. This will allow the turbo to move a bit more air under boost and also increase compressor efficiency a tad. I hope this helps.

#6 gravelRX

gravelRX

    Driven with both feet.

  • Members
  • 885 posts
  • Roanoke, VA

Posted 13 June 2005 - 09:56 PM

Well timed post.:) I was just asking about this in my up pipe fab post.

Jay

#7 TurboSPFI

TurboSPFI

    Banned

  • Banned
  • 374 posts

Posted 14 June 2005 - 03:53 PM

is there anything else we need to know?

dremel sounds too easy for porting and polishing

#8 BoostedBalls

BoostedBalls

    Subaru Fanatic!

  • Members
  • 444 posts
  • Cornelius, OR

Posted 14 June 2005 - 04:11 PM

be careful using stones on nonferrus metals! They clog, then heat up, expand and POW pieces everywhere!

You can use the small fluted carbide bits on aluminum without clogging issues if you use a special wax/grease for the tip, also makes smooth cuts. If you use the large fluted carbide bits for port work, I hope you have a real firm grip and a very steady hand!

As far as porting the turbine housings- I would only knock the casting slag off the surface and open the inlet enough to match the up pipe so you won't have a recuction step.

Here's a good article on porting your turbine housing http://www.gnttype.o.../turboport.html

-Chuck-

#9 lagwagon

lagwagon

    USMB is life!

  • Members
  • 157 posts

Posted 14 June 2005 - 06:24 PM

I p&p my heads when i rebuild my ea-82. I use a flexible dremmel with the metal bit. I just removed the casting marks on both intake and exhaust sides. But I only polished the exhaust side. From what I was told there is a bumpy texture to the walls of the intake side. this helps mix the air with the fuel so don't polish this side. By polishing the exhaust side it is a lot harder for carbon to stick to it. Also make sure your gaskets match up well and don't leave a little lip inside.

#10 archemitis

archemitis

    guy smiley

  • Members
  • 3,554 posts
  • the big minnie

Posted 15 June 2005 - 08:42 AM

when i do harley heads, i use the bits made for aluminum. they dont clog, but they do take out a huge amount of metal at once. they make the chips fly, and if you get even a little out of controll, you dig a big hole.

when im doin little heads like these(where hitting a water jacket is a big deal), i use the cheap conical bits made for steel. they clog up, but are more forgiving if you slip.

realisticaly you should take the valves out and sharpen the valve guides, and enlarge the port a bit around it(the guide). and you should have your valves recut with at least 4 angles, as i think subaru used 2 or 3 maybe.

or a safer bet for a first timer. just use sanding rolls, and clean it up alot.

for the guys doin it without taking the valves out... make sure all of that sand and aluminum is outta there before you cram it down into the cylinder.

you can get as much as 10% hp from a good flow job, from what i've seen.

#11 TurboSPFI

TurboSPFI

    Banned

  • Banned
  • 374 posts

Posted 15 June 2005 - 03:55 PM

10 hp?! *runs to start porting/polish!* :slobber:

#12 Vanislru

Vanislru

    Durka Durka!

  • Members
  • 791 posts
  • Cumberland, BC

Posted 15 June 2005 - 03:57 PM

is there anything else we need to know?

dremel sounds too easy for porting and polishing

I've done several turbo's and a dremels fine. For any of the turbo's that our cars came with all you really need to do is the side the exhaust enters in from the header. Feel inside and you'll find a lip abou 3/4 " in. Grind it smooth and around the passage into the wastegate if you have any boost creep prob's. Removing that lip is where any efficiency gains will be had. Don't worry about the compressor side.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users