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Discussion Starter #1
Someone should send me their old, unused 3k/stealth heads so I can port and polish them. I've got all the cartridges, pads, etc, and I wanna try porting/polishing something, but I need something to try on.

So, anyone got some old heads sitting around?

.jon
 

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The Armor All Tire Mod
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I just recently ported and polished my intake manifold, and im waitin to put it back together. ill let ya know when im done what hapened
 

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Discussion Starter #3
Did u use this?
http://www.sa-motorsports.com/diyport.htm

I've got a dremmel and almost all the necessary attachments, and it doesn't look to hard. I'm gonna do my intake manifold next weekend (haven't ordered the gaskets yet). I'm gonna port match my plenum to it as well. Hopefully if I can get good at it, i can do it for the 3si guys at some ridiculiously low price :)

Got any tips for me? All I need is the plenum gasket and intake manifold gasket, correct?

.jon
 

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Hey Jon,

My spare (old) engine is in the back yard on a stand - obviously it has the heads on it. Aluminum is not too forgiving when you're learning, but if you think you can do a nice job on them (remember they do have to be workable) I would consider sending them. Let me know what you think - private e-mail is ok @ [email protected]

Rick
 

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Kevin - don't sell something you might need - believe me if what happened to Brainfood happens to me, I'll be happy I have my old heads.

How's the new VR purchase going - anything new on getting it there?

BTW did the photos I sent actually get there ok - I never heard back from you.
 

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Wrenchmonkey #839
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Dremmel will not work

jon3k said:
...I've got a dremmel and almost all the necessary attachments, and it doesn't look to hard......
....
Got any tips for me? All I need is the plenum gasket and intake manifold gasket, correct?

.jon
A dremmel does not have enough torque to do any serious porting.
You need an air grinder or a heavy duty electric grinder made for porting.

I ported the heads on my 69 cutlass and it is a lot of work.
I did not do much porting on my VR-4 heads because it is easy to
do more harm than good.

Gasket matching for performance is not worth any power if you
are just matching the gaskets.
For example if your intake runner is 2" in diameter and the
plenum is 2" in diameter what good does it do to port the
gasket area to 2 1/4"?:confused:

What you want is smooth flow going INTO the engine.
Joe Mondello (A oldsmobile Porting expert) suggests putting a
piece of cardboard between the two ported surfaces then bolt
them together and take them apart. Use the upstream imprint
as a guide to port the down stream part. That way when air is
flowing through the intake there is now edge to create a
disturbance. You don't care if there is an edge when flowing
backwards.

After giving all of this porting advice I examined my, intake to
plenum to heads to exhaust manifold joints. The only restriction I
saw was the exhaust manifolds. I ported these lightly but you
can't get too crazy of you will go through the manifold walls.

Picture of ported forward exhaust manifold:



Picture of ported rear exhaust manifold:

 

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Discussion Starter #8
Doh!

Just read the FAQ on sa-motorsports.com, they definatly advise against a dremmel. Looks like I really do need an air die grinder. I think I've got a friend I can borrow one from. How much do they normally run ($$$)? Any brand recommendations?

Thanks for all the info - looks like I've still got a lot to learn.

.jon
 

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High Boozemaster
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when porting your plenum & lower intake manifolds, aren't they supposed to be the same diameter all the way through, not just bigger at the ends where you can reach with a grinder? isn't that why people get thier's extrude honed?

thats just what i heard, i dont know if any of this matters or not
 

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Wrenchmonkey #839
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Exactly

mitsu3kgt311 said:
when porting your plenum & lower intake manifolds, aren't they supposed to be the same diameter all the way through, not just bigger at the ends where you can reach with a grinder? isn't that why people get thier's extrude honed?

thats just what i heard, i dont know if any of this matters or not
Note: my air grinder was $20 at Lowe's but my air compressor was $350 at Sears. The ginder was an complete air hog but it worked.

The theory behind gasket matching came from old time big 3 auto maker's poor build quality. On my 71 Lemans I could look down the intake manifold and see a 1/8" overlap with the heads, so the intake was 2" diameter(guess?) the head has 2" in diameter but the joint between them was only 1 7/8" in diameter because the 2 runners did not line up, creating a restriction. If you matched the heads and the intake to the gasket then the joint might be oversized a little but the restriction is gone.

When I tore my VR-4 engine apart the runners were extremely well matched. The biggest overlap I saw was around 1/64" except for the exhaust manifols were the overlap was closer to 1/8". I ported my exhaust manifolds and left everthing else alone.

Horsepower gains from home porting ??? who knows, it is always a good idea to remove restrictions but my engine did not have many. My butt dyno tells me it is worth 1/2 HP between 4700-5100 RPM:D But thats just a guess:D

John Monnin
 

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I've done quite a bit of porting and polishing. I've done several heads and a ton of intakes. A smooth surface must be maintained at all times. So after your done experimenting make sure to use a very fine bit to clean up with. Then use a polishing bit to finish. Gasket matching for a smooth transition will yield minor gains. Most of the HP gains are done at the bottle neck just prior to the valve. However, your better off staying stock then going to large. You actually lose power if the port is to big. One way to figure out how much to open the port is to use the diameter of the valve. You get the most gains between 88% and 91% of the valve diameter. But be very careful not to hit an oil or water jacket. You can weaken the wall just enough for a leak but yet it will be unseen to the naked eye.

I have jacked up my share of heads. Be careful and have fun with it. Patience is key...

WD
 

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stuff

I might of missed this but Im fixin to polish everthing. What polish to use. And this is probably a dumb ? but can you use Mothers polish on the engine?
 

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Discussion Starter #14
Re: stuff

3GTERY said:
I might of missed this but Im fixin to polish everthing. What polish to use. And this is probably a dumb ? but can you use Mothers polish on the engine?
Mothers polish would only be the last step.

Polishing metal is done by using a grinder and very abbrasive pads. You start with a really rough grit and work your way down to a small grit, and a mirror finish.

Check this out:
http://www.sa-motorsports.com/diyport.htm

.jon
 
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