I tried to post this in What Have You Done to Your Truck Today, but it won't let me insert pictures. However, it seems to let me here so I'll just start a new thread.

Got started looking at the heads I'm going to port and, having a spare head and a powered bandsaw, here's what a cross-section at the exhaust port of a D8OE looks like: (More pictures in my Explorer album here Ford Truck Enthusiasts Forums - Gary Lewis's Album: '82 F150 Explorer)



I've pointed out where the air injection port is, and have drawn a line showing roughly where I think I need to cut back to. However, straight lines aren't that good in gas flow so the actual line should probably be a curve that approximates the bottom of the port, with the intent being to keep the volume the same.

The hole for air injection is roughly 1/4" in diameter and I'm thinking about drilling them to a standard and driving a piece of rod in to block the hole. However, there's the question of whether the rod will fall out, so another approach would be to tap the hole and run a bolt in and anchor it with high-temp Locktite. Thoughts?

Which brings me to you - I'd like your input as to what and how to document this process. I'm thinking about a set of before, during, and after pictures as well as a description of the tools I use. Further, any learnings about what didn't work will be included.

What am I missing? Your input would be appreciated.

 

Thanks for the picture, I didn't know how the AIR system worked.

Just looking at it, I don't think it really makes a difference whether or not you plug them. If you do, I think it would be much better to tap the hole and use a bolt to plug it.

 

AIR stood for Air-Injection Reaction or Reduction, IIRC. The AIR/smog pump put air into the back of the heads via a manifold, and it traveled down a passage you see as the round hole at the top of the air injection port, and thence into the exhaust port. The extra oxygen caused some of the unburned hydrocarbons to ignite in the hot exhaust gases, and helped the cat burn the rest of them when they got to it.

Oddly enough, only 3 of the 4 exhaust ports have the air injection port drilled on these heads. I don't know why - does anyone?

 

WOW! Look at that restriction!!! No wonder people remove those "bumps". Looks to be about 30% restriction, you think? Thanks Gary, for showing us that...makes much more sense now.

I've heard of removing those, but I don't think I've heard of having to plug the hole that's left. What do you know about that?

 

I'd say 30% is a reasonable guess. As for plugging them, people say it isn't needed, but if it is easy to do then why not? It would make the flow smoother (laminar) which is what you want. Nice and easy with no bumps or stubbing of toes.

 

What is your overall plan for these heads? Ford heads have more problems than just the bump, but I am not against grinding the bump out on a otherwise stock installation.

 

So what is your porting plan? Are you going for smaller passages for torque, or are you building a higher rpm breather?

 

Torque. The cam comes in from idle. The torque converter is a low-slip one. All things good for a truck that needs torque. Even using the factory intake and exhaust manifolds, but true non-cat duals from there back.

 

Here's a status update. Spent the day grinding on the cut-up head and taking pictures thereof. In the process I learned several things:

• There's no need to tap the air injection ports and plug them with a bolt since you wind up grinding almost all of the bolt out and still have a small hole at the top.
• It doesn't really take long to grind out the exhaust bumps or blend the intake's bowl
• It is easy to take too much material off the edge of the valve guide.
• The exhaust ports in the heads are too small to match the exhaust manifolds so take some cleaning up
• Taking decent pictures is more difficult than grinding!

There are several pictures in my albums here: Ford Truck Enthusiasts Forums - Gary Lewis's Album: Porting D8OE Heads And, some of those are shown below. However, I'd really like to hear from ya'll as to what you are looking for in a how-to.

Here's a view of the bump in the exhaust as seen through the valve:


Here's a view of the bump through the exhaust port:


And here's the bump ground out, as seen from the valve side:


Here's a view of the exhaust port with the gasket edges scribed:


And here's the port opened up to the scribe marks, albeit not perfectly"


Now for the intake. While it is far better in stock form than the exhaust, while here I might as well clean it up. Here's a view of the bowl before blending, showing both the blunt guide as well as a lip where the machining for the bowl ends:


Finally, here's the blended bowl showing both the guide and lip blended:

 

Lookin good Gary. Are you planning to blend the area right under the valve seats? I've just finished porting some E7's and they had alot of extra iron in that area.

Are you using stock exhaust manifolds? If I recall correctly from my research last year, gasket matching is not really recommended, but port matching is.

 

Well, I'm not sure if I'm port matching or gasket matching. As it turns out, the Felpro gaskets are a perfect match for the exhaust manifolds I'm using - which answers that question yes. So, I'm matching the ports to the gasket which matches them to the exhaust manifold. Is that bad?

As for the bowls or area under the valve seats, I am cleaning it up. Nothing major as the heads are already machined and I sure don't want to hit a seat or guide. But, I will smooth things so there are no lips, steps, etc.

Any suggestions would be appreciated.

 

I take it you`re using cast iron manifolds then and you shouldn`t have a problem. The reason I mentioned was I almost made the mistake of gasket matching my heads before I had my headers. Had I ground them out the ports wouldn`t match up very well.

Yeah, careful of those seats. I nicked mine in a couple spots, but they should be ok after lapping the valves.

 

Without blocking the AIR ports, would there be flow through that passage from port to port? Just thinking out loud.....

I would spend some time on the short side radius too.

 

Yes, there may be some flow port-to-port. But, it is only a 1/4" hole. And, the problem I had was that my taps aren't long enough to put threads all the way to the bottom (top, actually) of the hole and I can't get a bolt all the way in because of that. So, when I grind the bump out there's still the little bit of hole left at the end of the bolt.

And, that means the bolt is sorta-kinda laying in the threads of what's left of the hole, with only the back side of the bolt in there. With the heating and cooling that will occur I'm afraid it'll drop out at some point. Overall, I think I'll pass.

Yes, I'll work on the short side. But, I don't want to flatten it since the flow needs to be curving up against the top of the port so it'll continue curving as it goes into the manifolds and head down. Don't want to interrupt the flow.

 

I only mentioned the short side as it looked like you had not gone there yet.

I was thinking the "flow" through the AIR port would not be much, but just wondering if it would make a difference. Probably not, just my usual overthinking the problem self.

You can open up the port to match the back side of the valve seat cutouts. I would on the short side, and more blend it on the other side.

Also looks like you are shaping the valve guide areas. Taking away more of the guide will open area for flow, but increase rockling of the valve in the guide. Really not necessary for a torque motor.