quote Originally posted by White 84 SE: for me and this porting project I will stick with the refinement of the stock 84 head and the additions of the Singh Grooves.

Sigh.

What aspect do you consider "refined"? There's no CFD work behind that head, it shrouds the valves, and the ports are obstructed. The later years abandoned the swirlport and made the most power.


84-86 head = anchor.
If you don't believe me, talk to Lloyde (yes, the FastFieros guy) Besides the accusations of notorious business practices that I can neither confirm nor deny, he also has a lot of Iron Duke work on his resume that he doesn't really talk about.

quote Originally posted by KurtAKX: Sigh. What aspect do you consider "refined"? There's no CFD work behind that head, it shrouds the valves, and the ports are obstructed. The later years abandoned the swirlport and made the most power. 84-86 head = anchor. If you don't believe me, talk to Lloyde (yes, the FastFieros guy) Besides the accusations of notorious business practices that I can neither confirm nor deny, he also has a lot of Iron Duke work on his resume that he doesn't really talk about.

Ha Ha Ha!! What I meant was that I would continue blending (refining) the stock head and adding those Singh Grooves. It's not that I dont believe you. It is pretty clear that the 81-83 heads flowed better and just adding the TBI improved upon the 1983 Duke. Your mentioning that the later heads abandoned the swirl design? That is quite telling. I will be in the area tomorrow so I will call the junkyard to see if they have any 81-83 Dukes. Before I go, do the later heads fit the 84 block I wonder?
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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

[This message has been edited by White 84 SE (edited 11-01-2010).]

A little more thought on the idea of head swapping. As I understand it the Swirl Port design is actually BETTER for low end torque and fuel economy than traditional 2 valve per cylinder heads but actively limits high RPM air flow. So, after thinking more about it I realize that for the daily driver 4 cylinder low rpm torque and fuel economy trumps high rpm performance. Best might be swapping in an 4 valve per cylinder engine which would keep velocities up and yet have better high RPM flow as well. Something like an Ecotec or a Cosworth 16 valve head. For better pickup and fuel economy out of an 84 Duke engine I think the simple blending, port matching, 3 angle valve seat job, and Singh Grooves are optimal for the stock head. For above 3500 RPM performance looks like an 82, 83, 87, 88 head swap would be ideal. I DO think that swapping in a non swirl port head can unlock the engine so with more work it can be taken up to the 150 HP range, but that will need high RPM to get. Perhaps setting the idle at 1500 RPM and changing gears at 3000 could make for a punchy little Duke. Such a Duke would have more to give with a non Swirl Port head and I think could rival a stock V6 in time slips and HP ratings also it would be lighter.

These are just "coffee thoughts" from a novice mind you. As for me, I will keep to the original idea of improving the stock head using virtually cost free mods.

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

Interesting tidbit about vortec heads I read, maybe it pertains to your situation.

"To bring any older small-block up to the specifications of a Vortec engine is not difficult. The differences between the block, crankcase, rods, and pistons were minor between the '95-and-earlier engines and the Vortec engines. The main difference is in the new Vortec cylinder heads and intake manifold and the dramatic increase in power provided by them.

Although it has always been possible to increase the horsepower of any small-block engine with larger intake ports, low-speed torque has always suffered as a result. This is not a good idea for a production truck engine. The cylinder heads designed by GM engineers for the Vortec engines provide increased horsepower and increased torque.The name Vortec comes from the vortex that is created by the air/fuel mixture as it enters the cylinder. This refers to a swirl induced by the shape of the intake port and combustion chamber. The swirling air/fuel mixture increases burn efficiency by actively pushing itself into the flame, created by the spark plug, instead of waiting for the flame to travel across the combustion chamber to ignite a stagnant air/fuel mixture."
http://www.customclassictru...ock_chevy/index.html

quote Originally posted by 2.5: Interesting tidbit about vortec heads I read, maybe it pertains to your situation. "To bring any older small-block up to the specifications of a Vortec engine is not difficult. The differences between the block, crankcase, rods, and pistons were minor between the '95-and-earlier engines and the Vortec engines. The main difference is in the new Vortec cylinder heads and intake manifold and the dramatic increase in power provided by them. Although it has always been possible to increase the horsepower of any small-block engine with larger intake ports, low-speed torque has always suffered as a result. This is not a good idea for a production truck engine. The cylinder heads designed by GM engineers for the Vortec engines provide increased horsepower and increased torque.The name Vortec comes from the vortex that is created by the air/fuel mixture as it enters the cylinder. This refers to a swirl induced by the shape of the intake port and combustion chamber. The swirling air/fuel mixture increases burn efficiency by actively pushing itself into the flame, created by the spark plug, instead of waiting for the flame to travel across the combustion chamber to ignite a stagnant air/fuel mixture." http://www.customclassictru...ock_chevy/index.html

Interesting, I too read tha article but did not consider the Vortech head as an option. It sounds very similar to swapping a SD head on there which I hear is also possible. Got me thinking though. It may be possible to grind the face of intake side head at an angle...so that it is thinner at the top than bottom....follow? A compensating bolt holes on the manifold might work and the manifold would set a little higher but the angle into the chamber would be reduced. It is a long shot at best. I checked and the roofs of the Duke head are about a 1/16th of an inch. Certainly cant raise the roof on a stock head.

Honestly, I am a believer in the swirl port idea. Did they get it right with the 84-86 Duke head....probably not but I am enthusiastic about the concept. Perhaps a further development of the swirl idea would be a very small turbo together with a swirl port head. I think both of these would be in line with the original Fiero concept. So something like a T25 or maybe even smaller would get the higher (3500-4500) RPM flow going in a way that seems a natural aftermarket outgrowth.

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

I have been reading Vizards articles about porting heads and get the idea that the swirl port head design was a kind of answer to the short comings of the traditional designs. The swirl port design introduces a ramp which reduces the angle into the chamber just as raising the roof might. It also has curving rather than direct port passages which are aimed to work with the natural flow better than the standard design. This is also a mod Vizard offers for regular heads by removing material to create a semi swirl port design. The chamber design also works to direct fuel past the spark and then back into the spark for better fuel utilization. The real problem I see is that the end result is best for low RPM efficiency at the expense of high RPM efficiency.

The real bottleneck in this stock 84 head to me seems to be in the throat/bowl area. Here we have some oversized guide bosses and the swirl port ramp. The fuel wraps around the guide boss as it travels toward the the valve. I bet simply opening up the throat a mil all around and skinnying up the boss a mil all around will be the best way to approach the problem. More than this and I suspect velocities would decrease to a point where fuel suspension may be affected adversely.

Well, that is the end of my researches on this and I will get to grinding right away....Yay..

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

OK finally got that pic of what I figure would be a good Singh Groove applied to the Duke head....


Each groove points directly at the spark plug and are intended not to disrupt the swirled flow during the intake stage. Used only a triangular file to get those grooves...pretty easy and quick. The idea is to get some ignited fuel to fill a "shielded" area of the chamber during the expansion stage. I see it as a kind of expansion stroke scavenging via spreading the ignited fuel to the far"corner" of the chamber faster. I feel doing this will ignite some fuel that would exit the chamber unused or expanding AS it exits. The result of a smoother quieter engine with a little more power and responsiveness as reported by others who have tried this would make sense if fuel were effectively scavenged with the Sing Grooves.
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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

[This message has been edited by White 84 SE (edited 11-06-2010).]

tear drop the guides ,knife edge towards the comming fuel mixture
Vortex ?? noway
the best duke heads are the latest model fantastic
an 88 duke engine with the 91 S10 head & upgraded ECM will give super performance ,in a slightly lightened no A/C notchie you would stay with a V6 to 30mph,mayby 45 with a great one
The Chevy Lumina a 3250 pound car came with a duke, 110 horse power,135 torque ..

quote Originally posted by uhlanstan: tear drop the guides ,knife edge towards the comming fuel mixture Vortex ?? noway the best duke heads are the latest model fantastic an 88 duke engine with the 91 S10 head & upgraded ECM will give super performance ,in a slightly lightened no A/C notchie you would stay with a V6 to 30mph,mayby 45 with a great one The Chevy Lumina a 3250 pound car came with a duke, 110 horse power,135 torque ..

Your right on the tear drop no-no. The swirling fuel wraps around the valve guide in this design. I figure skinnying up the entire boss will allow more fuel to pass and keep the swirl.

Also, notice that the intake boss is about 3/8th" longer than the exhaust ones. This is to accommodate the swirl but I wonder if it need be so tall.
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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

[This message has been edited by White 84 SE (edited 11-06-2010).]

KEEP the tall,, you can shape mild vocano style..
the RPMs you want,, the stock crank will not take,, keep the porting mild, smooth her out ,just basic stuff ,clean it up
your thinking is for engines that can turn 6000 RPM
..The super duty was build because this was about the worst engine in the GM line up to modify,, turbos sent many duke Fiero,s to the bone yard the duke would not take the added RPM! KAPOW

quote Originally posted by uhlanstan: KEEP the tall,, you can shape mild vocano style.. the RPMs you want,, the stock crank will not take,, keep the porting mild, smooth her out ,just basic stuff ,clean it up your thinking is for engines that can turn 6000 RPM ..The super duty was build because this was about the worst engine in the GM line up to modify,, turbos sent many duke Fiero,s to the bone yard the duke would not take the added RPM! KAPOW

Yeah....an apex on those bosses could do the trick and keep the flow running round the boss as designed.

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

quote Originally posted by uhlanstan: KEEP the tall,, you can shape mild vocano style.. the RPMs you want,, the stock crank will not take,, keep the porting mild, smooth her out ,just basic stuff ,clean it up your thinking is for engines that can turn 6000 RPM ..The super duty was build because this was about the worst engine in the GM line up to modify,, turbos sent many duke Fiero,s to the bone yard the duke would not take the added RPM! KAPOW

You must be talking turbo use on a Duke. I was thinking a very small turbo would be best. One that has to scroll up at 3,000- 3,500 RPM. I honestly have yet to seriously look into turbos at all.

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

Uh Ohhhhh...

looks like I spotted a crack...exhaust valve seat.....
Hey Kurt you still there? What do ya think just swap in an 87-88 head? They are improved for flow but do they fit? The crack was probably there a while and I hadnt noticed any problems before disassembly. It probably has not gotten far enough to cause any leakages. I am certain if I simply reinstall it it will buy me running around time...maybe even an entire year but it is just a matter of time.



see it there...valve seat... about 12 oclock...... bummer

[This message has been edited by White 84 SE (edited 11-10-2010).]

quote Originally posted by White 84 SE: Uh Ohhhhh... looks like I spotted a crack...exhaust valve seat..... Hey Kurt you still there? What do ya think just swap in an 87-88 head? They are improved for flow but do they fit? The crack was probably there a while and I hadnt noticed any problems before disassembly. It probably has not gotten far enough to cause any leakages. I am certain if I simply reinstall it it will buy me running around time...maybe even an entire year but it is just a matter of time. see it there...valve seat... about 12 oclock...... bummer

The whole reason behind my interest in the 552 and 702 heads used prior to 1984 is that the stock intake fits them, unlike the 87+ heads. If you want to see what I'm talking about without going to the trouble of buying whole 'nuther head, just buy yourself an 87 Fiero intake gasket and try and line it up to your stock intake.

That may not be such a great loss though. If you believe in Singh grooves (and that's a big if) it seems they should be connected to the quench pad areas in the chamber. The piston is dished in the area where you cut the groove, effectively leaving no quench in the area you filed. Also, let me see if I can get a pic up here shortly that will change your mind about filing on the chambers and making them more likely to crack.

Edit...

Here it is. I can't take credit for this bucket of awesomeness, but be aware, this can happen in abusive/overheat situations. I sure wouldn't be filing in a good location for a crack to start like that:

[This message has been edited by KurtAKX (edited 11-10-2010).]

Holey crap...that is like the most iron one can find in the entire engine and some guy gets a crack THERE? This is like a vision from God. Moses raised his septre and cracked that Duke head in THAT spot....insane.... Even Einstein would say that does not compute except but in extreme abuse and then it would be most likely the area to crack. It would be most vulnerable to expansion the thicker the metal.

And yeah, the Duke has these dished pistons.....those groves are less warranted than I thought. They still may have an effect but dished pistons help in getting the corners like I was not thinking of.

doah!

Sheesh, I spotted a v6....maybe that will be my big downtime project......

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

quote Originally posted by White 84 SE: Kurt regarding your project...maybe mine too Why not instead of flat top pistons go for longer connecting rods? They say the Duke rods are suspect and that way wouldnt volume and compression be increased? So like an 83 head with slightly longer rods... What are your thoughts? A bit of a stroker with more torque and HP too? Ought to be fairly easy to change out.... Can all be done with the engine in the car....I think...

The length of the rods is not going to alter the stroke

quote Originally posted by TONY_C: The length of the rods is not going to alter the stroke

Aw man.....of course not....thanks.

Now it would be a way to up compression though right?

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

quote Originally posted by White 84 SE: Kurt regarding your project...maybe mine too Why not instead of flat top pistons go for longer connecting rods? They say the Duke rods are suspect and that way wouldnt volume and compression be increased? So like an 83 head with slightly longer rods... What are your thoughts? A bit of a stroker with more torque and HP too? Ought to be fairly easy to change out.... Can all be done with the engine in the car....I think...

What rods would you use? I'm guessing you're not up to paying for custom rods. Buick V8 rods? Then you're into custom pistons.

Longer rods won't increase displacement.

What's the attractiveness to doing the work with the engine in the car, when it only takes 45 minutes to pull out with basic hand tools and a cherry picker?

Iron Duke rods are already in the 6 inch range, with a 3" stroke, you really don't need to go any longer.
If you must have aftermarket rods, get a set of small-journal 6" SBC rods and have the faces milled to make them .100" narrower. If you did something like that, I might even be interested in splitting a set with you.

quote Originally posted by KurtAKX: What rods would you use? I'm guessing you're not up to paying for custom rods. Buick V8 rods? Then you're into custom pistons. Longer rods won't increase displacement. What's the attractiveness to doing the work with the engine in the car, when it only takes 45 minutes to pull out with basic hand tools and a cherry picker? Iron Duke rods are already in the 6 inch range, with a 3" stroke, you really don't need to go any longer. If you must have aftermarket rods, get a set of small-journal 6" SBC rods and have the faces milled to make them .100" narrower. If you did something like that, I might even be interested in splitting a set with you.

I figure I am getting way over my head....
That 3800 swap is looking real good. Actually someone local is selling a 1987 fiero v6 engine for $200. I figure it will need a complete disassembly and spec check at the very least. Maybe he has the electronics....

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White

I think Kurt has it right with the flat top pistons and the 83 head swap. Better flow similar compression easy swap. For now I may take my head in to get it magnafluxed for cracks if the cost is low. Pretty sure it is cracked. Perhaps the easiest thing to do would be a head and intake swap. An 86-87 flow best for the stock fiero series. I've read they all bolt up.

Basically for this project I have found that the 87/88 heads and intake are better ported than the 84/86 can be made to be. So it's a don't waste your time scenerio. Instead swap on an 87/88 head and intake or go with an 83 head and change out the pistons to flat tops.

This approach may seem counter intuitive to the classic gear head approach which would be to do more porting to correct casting flaws and production line design limitations. These things can also be done on the later heads. As it turns out the later heads and intake manifolds were improved inherently and many design limitations overcome. I say go with a swap.

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84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White