more of the same

 

moving on, extending it a bit, knocking down the ridge just created, before it gets too big to smoothly blend later.

 

 

In the above pic, I'm beginning to move down one side. In this instance, it's the more open side, but sometimes I do the tight side first. Follow your whims in the future, but for now, follow me. You should be in the same port as me, especially if this is your very first one ever.

 

The idea here is to keep the tip from gouging a trench, but be shaping the base of the boss. You must control which way you're applying pressure. In the above pic, the motion is somewhere between sweeping and stroking. still using medium tool speed and medium-slow hand speed. too slow on either will create problems. too fast on either, you might bend the shaft of the tool, but that's not a big deal. just put it on full speed, and bump the burr end of the shaft against some stationary wood until it's nearly right again. It still happens to me after all these years.

now it's more of a sweeping motion, going around the trailing edge a bit.

 

now toward the side, more of a stroking motion.

 

 

What more can I type, at this point? So, moving on...

 

there, it's obvious that the shape isn't yet right, but it looked better in the previous pics. Perspective and lighting both make huge differences, but since we're not very far along yet, no big deal. Remember, believe your fingertips. If it feels bad, it probably is.

 

Blend that nasty bump away, don't just grind on it. Here you see it smoothing out. Not gone yet, but going.
By the way, I really did do that on purpose, just to teach you. Do try to avoid creating bumps. If you can't see it, fine, because if you ever do create one, then you'll remember that I did cover it. I do recall my own early days of porting.
Moving on..

A little blending on the near end of the guide. You're not trying to create a bowl here, and you don't want air to stagnate here. In the coming pics, you'll see better. That's why you're going through all these posts before starting on your heads. (Right?)

 

here I jumped up and started blending the 75-degree cut. Even the great Serdi cutters can't do good 90-degree cuts, Sunnen cutters can't even do clean 75s. Anyway, you're making your own 90-degree cut, parallel to the valve stem, but not removing all of the 75. Leave about 1/8" of 75 showing, because you'll be polishing later.

 

now i began plunging on the tight side. Try to not remove metal from the wall, try to remove metal from the guide boss only. You won't succeed, I still don't. But try. However, do not break through the guide to the valve area. That means more profit for the machine shop. And worse flow for you.

 

 

just notice the shaping. This is a very informative pic when you have your own head right in front of you. Some of these pics just don't have much value unless you do have your Vortec head between you and these pics.

more work on the tight side

 

more of the same, just slightly different perspective

 

now time to do some more grinding, still mostly a stroking motion:

 

a little more was done, not just another perspective.

 

 

compared to post 167, you can see how the shaping was extended toward the bowl, the second pic in post 168 being more than the first pic in post 168. Look at those 3 pics in quick succession.
this next one is just a different camera angle:

 

dunno why I took 3 pics of that, but here ya go:

 

now I jumped up to work on the wall where the stock 75 failed to blend smoothly. You really do have to remove quite a lot of iron. Nt much depth, but much area. You kind of have to keep extending the work toward the headers.
I took a bunch more pics in there, the total was 70 pics, but it just does not show up, so rely on feel.There should be NOTHING resisting your finger sliding toward the headers. No angles, no bumps. and don't go deep, the walls aren't all that thick. Not scary thin, but don't get crazy.
At the sharpest edge, your MAXIMUM depth is 1/8". 1/2" out from there, it's about 1/16", but you should be able to get a good shape only removing half that much.

 

nm

 

Now, for the first time so far in this sequence, I changed the lighting, as will be obvious. I also used the polishing to help me check for any tiny issues. Unfortunately, I failed to see the big picture, as we'll see later, but no harm done, just extra work. These belong to my friend, so he's not paying my labor anyway.

 

see the issue directly left of the guide itself? that needs more attention before calling it done. But I do these things since you probably will. You need to see that these horrors (to you) can be cleaned up without hurting the end result.

 

what that white spot is is light through the spark plug hole. The point of the pic is how difficult it still is to see the short turn. I'm not doing it yet, because the more the rest of the port gets polished, the better this will show up, as the pics will show.

 

a bit of that polishing, and I saw a problem, not seen earlier because I was too distracted by all the getting of good pics.

 

I did my fixing through the header end, and that's why there are gouges on the boss. Good thing the boss wasn't final-ground yet, even though it was polished earlier. All that darkness to the left of the gouges, that's where I did most of the fixing. But it was necessary to do it this way...

 

but skipping around, here we see that the short turn isn't really visible yet from the header end, either.

 

but there's no grinding to do in the header end, from the gasket face, to about 1.5" in. so just polish it shiny. Do not even think of gasket matching. It won't help flow, and it'll reduce the anti-reversion effect. Anti-reversion is good, whether manifolds or headers, whether turbocharged or not.

 

here's the top view of that fixing and those gouges. Also notice the V under the guide. That V is a good thing.

 

and another camera position.

 

this is a bit more grinding, the gouges are going away, not gone yet.

 

note all the imperfections remaining. Most of which I polish away. Polishing removes metal slower and more evenly than grinding, even with a worn-dull burr, but can make it difficult to tell if you helped things.

 

yes, I was turning the head a lot. Good exercise. A little polishing showed the gouge not entirely gone yet.

 

again I'm jumping around. Now there's more light getting to the short turn.

 

so I polished it before fixing it. With Vortecs, this generally isn't a problem. Remember, minimal pressure, meduim tool speed, medium hand speed, and long, sweeping hand motion.

 

skip this pic. it's no help.

 

then a little light grinding, starting with that 90 I discussed earlier.

 

this is the untouched adjacent port, showing the sharp edge you're grinding.

 

after it feels like a radius, polish it to make sure.

 

this doesn't look right to me. The overall shape. More heavy polishing required.

 

from here it's barely visible, and I'm not gonna point it out, but the idea is a big, smooth radius. Like a Pringles potato chip, only smaller and smoother, and with a metallic flavor.

 

I see a couple of mini-ridges that must go. They're to either side.

 

here I see 5 problems. Sorry to seem mysterious, but I'm building up to something.

 

nm

 

now the problem is obvious.
To get the sweeping radius that matches the valve seems fairly easy, but here's evidence that even that can go wrong, even for experienced pros. And you cannot understand it until you do it.
By this point, you might be ready. The secret to polishing short turns is difficult to describe, and hard to show, especially without an experienced helper.

 

First, adjust your tool so that only 1/2" of the shaft is in the tool. You want the roll to have all the reach it can get. Use a fresh roll for each short turn.
Now, there's a lot of blind faith required because you can't see the contact point. A mirror tends to confuse most guys who try it.
Now, before applying air, or electricity, practice with the tool off. The idea is ti start with the tool as far in as the shaft allows, and work your way out, still using sweeping motions, in such a way that you get every tiny bit, and don't miss anything, but don't create any ridges, angles, or edges.
Actually doing it isn't that difficult. But on your first one, keep your tool speed medium, and your hand-speed medium-fast, but your pressure very light. And plan on doing it 4 times. First from the header end, then from the valve end, then header, then valve. The final result doesn't need to be glass-smooth in texture, but it does need great shape. Pringles.

 

this is a virgin port, for reference.

 

and this looks wrong, so...

 

and..so check it from somewhere else:

and realize you forgot to finish that part.