This is the first posting to see if PIP will cooperate.

I did alot of research and asked alot of questions and here is what I know and what I did.

Arn

First off, the heads are designed for emissions.

The exhaust bowls have "ledges" to heat up and burn off unburned fuel. In other words, choke the engine.

Second, the exhaust runners are choked off 25% by a bump that is directly beside the sparkplug well.

The intakes are not even in volume or runner width.

What to do?

Arn

I'm just trying to remember off the top of my head, but I think I read somewhere that the bump in the exhaust port should be left in there. It was actually proven to flow more air with it left. Maybe someone else can chime in here and verify what I read or I'm just nuts.

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Buy a fiero, become a mechanic

The bump that flows more is on the intake.

You can experiment this way. Take a tube and blow through it. then create the same bump top to bottom, 1/4 of the volume of the tube with tape and some paper.

Blow again. More pressure right?

The bump on the intake splits the air flow to allow the air to go around the valve stem and create a swirl in the chamber.

No such action in the exhaust side. Notice how I nicked the intake bump when I was grinding. I could have done better.

Hope this explains a bit.

Arn

Hey Arn,
Looks like you got em done. My computor took a dirt nap and I had to go to the library to read e-mails.
I am sorry I did not get a chance to reply to the e-mail you sent. I didn't want you to think I was ignoring you.
You have pretty much done what I would have suggested anyway.
There is one thing I would suggest on the exhaust ports and that would be to get a cross buff set from Standard Abrasives and use those to polish the exhaust ports. The cross buffs will give a much smoother surface than the flap wheels do. In reality though you are probably smooth enough.
Any ideas when it will be back together?
Richey

I'm hoping to have the engine in the car and have it home by May.

I have to do some body/paint work as well.

Thanks for the encouragement and the advice Richey.

Arn

PS. I got a couple of compressed paper dremel bits from Oscar and they seem to be 'putting the shine' on those exhaust runners rather well.

[This message has been edited by Arns85GT (edited 03-12-2005).]

This is good info! It's especially helpful, since I plan on doing some port work in the near future.

While I have not ground on my 2.8 heads--it runs just fine, so far--I spent a weekend in grinding on my Dodge 360 heads. The exhaust ports looked pretty much like your first photo, and I assumed these were just 'poor' castings. It was very gritty, dirty, and rewarding.

I agree it doesn't take much in the way of equipment, or time (hey--we mechanic--for fun!!), to improve head performance dramatically, since factory castings/parts are, if nothing else, of highly variable quality. ( Fiero exhaust headers, exhibit #1). I would encourage anyone with the tools, time, interest, etc., to go for it.

My 360 really pulls. I built it to haul my boat, and it probably puts out about 275 HP (40 over stock), with the torque coming on about the time the secondaries open up at 3500 rpm+. But man, does it burn fuel!! These head mods are not for economy engines!! These engines are more 'efficient' at moving air thru the engine, every rpm. And all that air includes fuel. Be prepared to pay at the pump for the power, whether you use it or not!!

Disclaimer: I'm thinking about sending my entire intake system--TB, both intake manifolds-- to Darrell Morse next summer for a 'little' work--well, $500 worth. And I've been told they'll fit on a 3.4 short block. : )

Arn,

Great information, keep up the great work.

quote Originally posted by Arns85GT: PS. I got a couple of compressed paper dremel bits from Oscar and they seem to be 'putting the shine' on those exhaust runners rather well.

Well, here is the result of giving up about an hour with the compressed paper dremel head.

This compares to the flap wheel result.

So, it has been double cut carbide burr - single cut carbide burr or medium grind wheel - 120 grit dremel drum sander - 120 grit flap wheel -then compressed paper dremel wheel.

I am happy with the result. Thanks for the bits and tips to Rubyredfiero

Arn

quote Originally posted by Arns85GT: The bump that flows more is on the intake. You can experiment this way. Take a tube and blow through it. then create the same bump top to bottom, 1/4 of the volume of the tube with tape and some paper. Blow again. More pressure right? The bump on the intake splits the air flow to allow the air to go around the valve stem and create a swirl in the chamber. No such action in the exhaust side. Notice how I nicked the intake bump when I was grinding. I could have done better. Hope this explains a bit. Arn

Gotcha. I knew there was a bump that was important somewhere, didn't know if it was intake or exhaust. Thanks for clearing that up.

Well, the heads are with the machinist, and he tells me the job I did looks good. That is gratifying for a first attempt.

Here is a better pic of the middle exhaust valve bowl.

See the knob and the restriction? This was particularly satisfying to take out as you can see above.

Arn

[This message has been edited by Arns85GT (edited 03-14-2005).]

thats some good looking work, Arns

Thanks for the compliment.

Here's hoping it performs equally as well as it looks.

Arn

quote Originally posted by Arns85GT: Thanks for the compliment. Here's hoping it performs equally as well as it looks. Arn

well, does it? how'd it turn out?

Well Pyrthian,

If you're out for the Grand Bend cruise this Saturday, you can see for yourself.

I don't know if the jetting is quite perfect, but, when I start it, the lamp in the master bedroom rattles. You know, like when a jet flies a little too low?

At idle you can hear the air hitting the bottom of the T joint in the exhaust. Kind of a Pam-Pam-Pam metal sound. That sound disappears at about 1000 rpm and it settles into a nice roar.

When I get on the throttle, I have to respect the clutch for now so I haven't dumped it, but it pulls real strong to 6000 rpm.

I tried a pass on the freeway from 100 kph to 140 kph and it got there before I got by the car in front. I expect it is better than it was.

Arn

quote Originally posted by Arns85GT: Well Pyrthian, If you're out for the Grand Bend cruise this Saturday, you can see for yourself.

unfortunatly, I'm just getting started on replacing my trans. split the case on my 4-spd muncie
but, maybe I'll take out the family sedan, and take the wifey camping at the Pinery, and sneak out to meet you all.
I miss the Grand Bend cruise every year....
seems I'm always doing something to my car in the early season....cradle dropping is a yearly event in my garage...ARG!

quote Originally posted by Arns85GT: If you examine the cross sections at various points, you will discover a trumpet effect. What I did was try to keep that effect. A gradual openning up to a round pipe going into the valve.

You mean tapering down to the valve like a funnel?
Increasing cross section as you go toward the valve will slow the charge down and reduce low RPM torque.

quote Originally posted by Will: You mean tapering down to the valve like a funnel? Increasing cross section as you go toward the valve will slow the charge down and reduce low RPM torque.

That is not the way it is Will. The bowl is bigger than the runner. The runner flares out to match the bowl size. The air swirls before it moves down to the valve openning. It is a trumpet shape, sort of. When you port, you first hog out your bowl. You smooth the sides down about an inch and smooth out the walls to create clean air flow. You then blend the bowl to the runner.

This way, you keep everything proportional. The runner creates air speed because it is smaller than the bowl. The cylinder is way bigger than both of them, so the suction at the valve empties the bowl, hopefully in an even manner so the air is pulled more or less evenly around the valve. The runner creates the speed, and the bowl finalizes the mix.

I hope this explains.

Arn

[This message has been edited by Arns85GT (edited 05-27-2005).]

This is my first try with really porting heads. These heads are broaken and I will get new pair tomorrow. What do you think of my work?

intake:

exhaust:

Should intake vane be round or sharp? In pictures it is sharp.

Great job and looks like a great deal of work went into this.

[This message has been edited by typhoon (edited 12-12-2005).]

Nice contours. You have uneven surface on the exhaust bowl wall, but you are close. It looks like you can take more out of the sides of both bowls for sure. I can't tell from the pics, but you need a smooth transition from the intake walls to the bowl walls. The bowl should drop right off, right below the valve seat, and have a clean, smooth run to the bottom. (Don't nick your valve seats though)

Also, the exhaust bowl should be shiny smooth. The closer to glass the better. The reason I was told, is that carbon doesn't stick to the smooth surface and the air doesn't tumble on the smooth surface for quicker evacuation.

You will want to polish the intake bowl as well.

You're well on your way for the good set to be real nice. Nice accomplishment.

Arn

Project was finished couple of months ago but now I have some results. I think I have leaking injector, it would be best to replace them all.

0-100 km/h (~0-60 mph) with 2.8 auto (TH125)

before: 9,5-10,0 s
now: 7,3 s

http://spad.sytes.net/temp/kiihtyvyys.gif

Work done: "ported" heads, ported stock manifolds, matched intake and Edelbrock performer cam (204/124 deg @ 050). ECM should be pretty stock with disabled EGR. Things to correct are that TPS will never go above 85% and fuel maps are a bit lean. I don't think it's a good idea to correct them before replacing injectors. Not a bad result, I think.

Nice to hear Spad. Sorry though, I can't get your pics to come up on my system. Any chance you can PIP them?

Arn

edit:
Pictures are when the heads came from machinery shop, final touch was given with Dremel-copy and stone tool.

[This message has been edited by spad (edited 05-12-2006).]

Your work looks pretty good. Just to recap...The exhaust SHOULD be polished. The Intake SHOULD NOT be polished. The reason being, if the intake ports are polished it leads to "puddling" of gas, which is bad. You want a little bit of roughness to keep the air/gas turbulent to improve atomization.