My current build (head work, etc)

[BRN2RUN]

Your write-ups and photos are very interesting and informative. Very helpful. Is there any way you can show photos with arrows to define some of the terms you are using? I understand "Bowl", "intake runners", valve guides, etc, but many of the terms you used in the first few posts are in need of arrows to point out which part of the heads you are describing.

Great work with the porting. Think I understand your discussion of atomization. The air has to mix well with the fuel mist entering to get complete burns which gives the best pop in the cylinder which translates to mpg and power. Happened to look at a set of Dart (I think) heads the other day and looked at the detail inside the intake side. Noticed hundreds of tiny horizontal lines cut into the aluminum on the intake side which would obviously create some turbulence or tumbling/bouncing of the air/fuel mix that rushes past. Is it that this air bouncing past the tiny ridges creates some turbulence which forces a better mix of air and fuel coming into the cylinder?

Then, on the exhaust side, am I correct in believing that this area should have a very smooth finish to not create turbulence which would help evacuate the gases without any (or very little) turbulence?

Thanks! That's a good compliment coming from you, since you've done a crazy amount of great work on your own build.

You are correct in that the air is bouncing past those tiny ridges to mix the air and fuel better. If a surface is polished, the air flows better, but the fuel falls out of suspension by sticking to the walls and is slower than the air and it pools up before it reaches the combustion chamber. Perosonally, I think that with fuel injection that this isn't as much of a problem as in carbed engines, since the injector already sprays a fairly fine mist of fuel. But it is nice to have some roughened surfaces, just in case. The exhaust does benefit from the smooth finish, since the air fuel is mostly burned and carbon also has less of a chance to stick to the surface.

Last night, I was wondering whether to continue on with these heads.....the guy that had done the work on them before me, had opened up the bowls to the extent that they likely aren't flowing well. That's my assumption as to why the fuel was pooling up in the bowl in the picture that I posted, that because he had ground down the first valve seat angle to be flush with the bowl diameter, in that I think that there was enough velocity lost where the air/ fuel mixture had slowed down enough so that it wasn't making it into the chamber to the extent that it should be. Apparently, bowls need a venturi effect to ease the transition of air in or out.

I'll have to build the ports up a little in the throat areas with JB Weld, if i'm going to continue. The bright side is that there are some pro guys that build up certain areas with JB Weld, on purpose, like the floors of the runners or exhaust ports, to create a ramp to accelerate flow to get the velocity up. I also think that the floor of the high end runner (the right hand side of the intake runner) is too deep and that the concave here could be costing some CFM.

It looks like these heads have a five angle valve job.....do these heads have a five angle job from the factory?

 

[Markstang]

Don't use JB weld. If you get it even slightly wrong the heat will break it up and it'll fall into the cylinders. davidcseifert had a head that was ported too deep and cut into the coolant passages, it was attempted to have been repaired with jb weld. The heat cycles broke it up and ruined his engine pretty much.

 

[BRN2RUN]

I remember that thread on the other board and was wary of JB Weld of the exact reasons (I believe the "is ____ the new Delk?" was the thread title). Thanks for pointing that out, though, because it could be an issue. I was wondering, though, if the JB Weld didn't fall off because it was exposed to and ruined by the coolant......a constant stream of 192-215 ish hot water may do that, not to mention that the pressure from the coolant would attempt to take a shortcut.

JB Weld says that it is good up until 600 degrees, I believe.......not sure on their specs on tolerance to oil and coolant and fluids. Seeing as that I have an air/ oil separator and the PCV tuned to draw slightly less vacuum, I'm not getting oil through the intakes (oil/ blowby would worry me).......but something like the EGR going through the intakes, I wonder how hot it really gets in there. Do you (or anyone else? David?) if the JB Weld was blended in?

I am still wary of JB Weld in anything. But it is reassuring to know that some pro builders do intentionally build up runners to increase velocity.

Does anyone know how hot the actual bowl gets in the cylinder heads? I attempted to datalog that parameter in my Livelink "CHT" (cylinder head temperature) and it mirrored the coolant temps, so I'm not actually sure what the real temps are in the heads.

I may still avoid the intake JB Weld in the intake. Doing it on the exhaust may be a better idea, since if there's any breakup of it, it will just go into the exhaust (cats may get ruined, but not the end of the world). The fuel pooling up in the intake bowl is bugging me, though, because there's not enough velocity......if the JB Weld is still not advisable, I'll scrap these heads and make another attempt probably with brand new ones from Ford.

 

[dstaff]

Most "pros" do not use JB Weld... They would use an epoxy like MarineTech or Splashzone. The exhaust temps in the port can reach 1000+ degrees F, so no epoxy will survive that environment. I would make an educated guess that average temperatures in the intake ports would fall somewhere between what your ECT and IAT sensors are seeing, with more heat naturally being near the valve head since it's exposed to combustion on the other side. The general rule for intake throats is 88-90% of the valve diameter. If you think yours have been cut too big, you can always go to a bigger valve to bring the throat percentage back down.

 

[BRN2RUN]

That's good to know, dstaff! As far as "pros" are concerned, there's some guys online that have posted their work, but i'm not sure how many real world builds they've had. Your info helps. I saw some JB Weld "High Heat" that says it's good up to 800 psi and continuous heat up to 450 degrees fahrenheit. Like you say, the area exposed to the combustion area (even after the burn) is going to be very hot, so the continued environment of heat would wear it down.

My calculations of the valve diameter to the bowl throat is 89.4 percent (42mm divided by 47mm). What do you think? They went right flush with the first cut of the valve seat out of the bowl.

Is the valve to throat calculation the same with the exhaust side, too? The sizing is 31.5 throat diameter to 37mm valve size, which is 85.1 percent (correct?).

 

[Markstang]

it's not heat that breaks the jb weld, it's the thermal stress from heating up and cooling down. JB weld is not aluminum like your heads. they don't hav ethe same metallurgical properties and expand and contract at different rates. If you want to add material you're going to have to have it welded on. That way you get a more complete melding of the two materials.

 

[6 Shooter]

Have seen JB weld used on lower intake runners when the EGR ports are removed. Personally, would not trust that setup. Like Mark said, there is heat expansion then cooling on shut down repeatedly. Any chunks breaking off and being sucked into the heads will surely beat the piston tops and probably damage rings in the process. I broke some sparkplug ceramics using the wrong plugs in the past. It does damage and loss of compression where ever digested in the motor.

 

[BRN2RUN]

That's great advice Mark! The expansion of the different substances would, you would think, eventually separate.

Six Shooter, i'd taken a different picture and had put some (crude) artwork and descriptions in it to explain things a bit better. Excuse my MS paint skills. This is the area where i'd seen a bunch of fuel pooling up in the bowls. The roughened rotary rasp texture, i'm not sure exactly what grit it is, but it is probably a sub-60 grit, since these are quite a bit rougher than the 60 grit texture that i'd surrounded it with. The other picture is below, where you can see some brown residue (unburnt fuel), which is likely costing the previous design some power in the form of fuel energy, as the fuel was not entirely making it out of the bowl. I'm hoping that the polished higher rpm runner (which doesn't have the fuel going through it) eventually slams up against the bowl where the fuel meets up with it from the low end torque runner, and has enough of a fine mist. If you look closer, the fine brown mist appears to be quite fine almost to the valve guide area, but it really needs some help in the runner right before it enters the combustion chamber. This is where, i'm thinking, that the air/ fuel needs to be slowed down enough. It's not enough of an area to drastically slow down the air (ie: in the runners), but it's hopefully a large enough of an effective area to roughen the texture where it's needed, the most.

 

[BRN2RUN]

Have seen JB weld used on lower intake runners when the EGR ports are removed. Personally, would not trust that setup. Like Mark said, there is heat expansion then cooling on shut down repeatedly. Any chunks breaking off and being sucked into the heads will surely beat the piston tops and probably damage rings in the process. I broke some sparkplug ceramics using the wrong plugs in the past. It does damage and loss of compression where ever digested in the motor.

Great points. There was a point where I felt like removing the EGR bungs, and then filling that area in with JB Weld and then drilling the EGR hole again (you'd get the smooth surface in the lower intake, but with a still functional EGR), but had wondered if the JB Weld would break off.

 

[dstaff]

If you're at 89%, I would leave it alone and not worry about it. I've heard where some pretty smart cylinder head people tend to like 86-88% on the exhaust side, so I wouldn't be too concerned about 85% on a lower output engine like ours. The big thing on the exhaust side is that there is a smooth transition from the seat to the port with preferably a radius cut underneath the 45 degree seat.

 

[BRN2RUN]

If you're at 89%, I would leave it alone and not worry about it. I've heard where some pretty smart cylinder head people tend to like 86-88% on the exhaust side, so I wouldn't be too concerned about 85% on a lower output engine like ours. The big thing on the exhaust side is that there is a smooth transition from the seat to the port with preferably a radius cut underneath the 45 degree seat.

That is reassuring to know. I've spent a ton of time on these heads already, and the bowl diameter had me thinking that the previous guy had hogged out too much already.

Do you know if these are 5 angle jobs from the factory? I'm not an expert, but from the angles that I see, they look like 5 angles. If so, I would have had no idea.....that's cool.

 

[BRN2RUN]

Here's my throtttle body port/ polish, and upper/ lower intake manifolds that i'd done last year. Along with some FelPro gaskets (gasket matched), there's no leaks or anything. The throttle body opening, i'd softened some harder angles and lines. I have no idea why that square opening is right below the mouth of the TB......maybe some sort of idle. It was gasket matched along with a 1/2" phenolic intake spacer from VAP.

The high end (circle) runners seemed to naturally take to a shape of a bell of a trumpet (based on the shape of the runner), whereas the lower end rpm/ torque runners seemed to naturally take to a full gasket match diameter.

 

[6 Shooter]

"I have no idea why that square opening is right below the mouth of the TB......maybe some sort of idle."

That rectangular opening below the throttle body air opening is a channel for the idle air. The idle air is routed pre-throttle blade, through the idle air controller, then the outlet is post throttle blade inside the intake.

BTW, in the past when seriously porting the 99-04 lower intake, had difficulty getting runner sizes equal from one runner to the next. Did not have access to a CNC machine or bench flow machine. So, I used various sizes of deep sockets to drop down into a runner. Found the largest socket that would fall down the hole the deepest. Measured the height of what did not go down into the runner. Then, using the same socket and measurement of what did not go down into the hole, went to the next runner and dropped the socket into the hole. If it did not drop down to the same depth, more porting inside the runner was needed. Etc.

 

[BRN2RUN]

That's pretty much the same way I did my lower intake--got to a certain length that my grinding bits would reach, and took off an equal amount of material, going in a circular motion. Thankfully, the lower intake runners are not too long, so it's fairly easy to get at most of the runner. I found that for the intakes (and the intake ports on the heads), going in a circular motion is best, because going length-wise seems to just mirror the unevenness of the casting. I find that it's easier, also, to get a more even amount of material taken off that way.

 

[6 Shooter]

Speaking of tools for porting and getting inside the runners, look at these, the ones I sometimes used for finish work. rotary files from Northern Tool + Equipment Think the shafts are about 6" in length. Northern also sells an extender (6" and maybe 9") which adds length to how far one can get down a runner. Uses two allen set screws to hold the rotary file.

For more aggressive aluminum removal, I primarily used the ball nosed file. Could have also used the round nosed and flame shaped files at the time, but the round nosed one did the best. Aluminum Cut Carbide Rotary Files

All my work was done with a standard 3/8" variable speed hand drill.

 

[BRN2RUN]

You'd done some really good work on your own build! With the longer carbide burrs/ files, how did you get a finer finish further down the runner? What i'd done on the upper intake, is take off as much as I could reach with the grinding bits, and then take my finger and go in with some sandpaper and then contour it further into the runner, as far as I could get in with my finger (this is starting to take on an almost dirty tone ). It seemed to work pretty well, and at least the major casting flaws/ finish was taken out of the runners.

With the upper intake, the fudge factor, to me, was the upper part of the runner, anyways (where it comes out of the upper part of the manifold), and like your photos and work shows when you cut it open, the runner shapes coming out of the top of the manifold are kind of weird shaped. I suspected that sort of shape (potato/ oval), just based on the casting shapes of the ports and openings in the manifolds, but you'd confirmed it.

 

[dstaff]

You can buy 6-8 inch long sanding roll mandrels from Summit if you need an extended reach for finish polishing.

 

[6 Shooter]

You'd done some really good work on your own build! With the longer carbide burrs/ files, how did you get a finer finish further down the runner?

Northern sells little flapper wheels at the store near me. US Forge 888 Flap Wheel, 2-Inch by 1-Inch 60 Grit - Power Sander Accessories - Amazon.com About $2+ each and come in various sizes and grits. Very handy.

The 5 file kit from Northern for $30 will produce some very fine surfaces as the teeth on the files are very short. When using a small amount of pressure, the filed surface would look like it was hit with 80-100 grit.

Have also used a tootsie roll rotary file. It is basically like a twisted drill bit on the end with adheasived backed sand paper rolled on the ends which slowly disintegrates while rotating. The screwed on rolls come in various grits, with 60 being the most commonly used. http://www.grainger.com/search?sear...02231&ef_id=UxjE-QAABEwzkWbY:20141225000924:s

mandrel Cartridge Rolls products - Grainger Industrial Supply

 

[BRN2RUN]

Some good options there. I've found that the best success for a fine finish is to use 150 grit sandpaper, and then 400 grit. It exposes the flaws in the grinding, where there was places that the burrs or grinding bits had taken a bit more off. It's probably overkill, but i'd done a 400 grit finish on the high RPM runner and it took quite a while to get all the grinding flaws out of there (ie: from a 80-100 ish finish). I'm using diamond tipped 150 grit bits and it still leaves too rough of a finish for me.....any grinding method seems to be just a bit too rough for the exhaust ports, where I dont want any smaller grinding lines. I'm going to keep the exhaust ports a bit smaller than the gaskets/ headers (to prevent air reversion) but i'm going to have the smoothest finish possible in the exhaust ports.

The good thing about the split intake ports is that one could assume that you could polish the high rpm port up and gain some significant flow/ velocity at higher rpms, without having to worry about fuel atomization (until the bowl, which has been roughened). As you can see in the picture, the right low rpm/ low torque runner has the fuel injector and a roughened finish is probably beneficial for atomization (of note, i'm not finished the low rpm runner, but you get the idea). What I think i'll do is remove yet more of the casting flaws and contour the overall shape in the low rpm runner, so that the shape is better, but then make sure that a roughened finish is still there. There's also an area (in yellow) where I suspect some flow/ velocity could be gained before the air/ fuel mixture, that might benefit from a polished finish. The lower angle by the injector, i'd rounded that off more, so that (in theory, one would think), low rpm vacuum would help promote a better mixture (?) since air travels the fastest along the top of the runner (the bottom in this picture), and might be more likely to send more air to mix with the fuel (?) as it might have less of a ramp effect to jump over or bypass the injector entrance area.

The bonus of not being able to really reach the injector area to grind or polish down, is that the roughened surface likely gives some good atomization right into the head.

Using a swivel light that can cast shading into the runner, I think, is a good idea, since one gets a better perspective on how rough the finish is with the smaller grinding marks.

Does anyone have any insight about the fuel injector area in the runner? Remove a bit more material to smooth out the overall shape?

I also wasn't satisfied with the valve guide height in the exhaust port, so i'd ground it down flush with the surrounding area. The valve guides are pretty long in these heads, so I think that it shouldn't weaken the valves (esp. at higher rpm's) or have side loading on them, but if anyone thinks they're ground down too much, feel free to weigh in. I tried to keep the general shape of the valve boss area, without grinding down that hump too much, as I think that the "V" shape of the taper should keep the velocity high. These are not the end port shapes (need a gasket to do that), but they will only be enlarged slightly. The finish needs to be redone in the exhaust port too.....the slight grinding marks will likely still attract carbon and build up.

I don't have any other resource (pictures or real explanation) in how the Mustang 3.8 heads benefit from valve guide and valve guide boss design and variations on various shapes and partial removal. It would be safe to say that in theory, any impedence in the exhaust bowl would slow down flow. Below, these are someone's Super Coupe heads from SSM.....the exhaust bowl valve guide has been ground down and that hump in that area tapering from the valve guide to the surrounding area has been removed, so in the 3.8 engines, pro head guys have removed quite a bit of material. Mind you, that's also an FI engine, so it would benefit more from more on the exhaust side, but i'm also wondering if removing that much material would put more stress on the valves and have more play at higher rpm's (valve float, oiling problems, etc)? In other engines and builds, some guys leave the valve guide length alone, but taper it up the sides. As far as i've researched, the valve guides also absorb some heat from the exhaust ports, and transfer some heat energy away from the heads, and that if too much valve guide is removed, that there's oiling problems and accelerated valve guide wear.

Any thoughts, advice, experience would be appreciated.

 

[BRN2RUN]

I've been doing more research on split/ bi/ dual intake runner engines of various types, and came across this article, which explains perhaps the best:

AutoSpeed - Split Port Intake Manifolds

Tuned runner length is critical, but there's various factors like shape, size and turbulence in the runner which can affect things. The split port (or variable resistance/ pressure systems in other cars......explored by Ford on their own intake manifold runner controls from 2001-2004 on the 3.8 engine) seems to have some untapped potential, because when the 2V engines were finally getting maximized towards their potential, engine designs went to dual overhead cams with TI-VCT (twin independent variable cam timing) to intelligently monitor the intake pulses and vary the valve timing to coincide with the right amounts of air being let in at various rpms and speeds and low load versus high load situations. With the split ports, the air just takes the path of least resistance in low loads/ high vacuum situations and then takes the longer path in the high rpm's. The interesting thing is that we can see that the low end runners (the longest ones on the upper intake manifold) are longer in the beginning, but it's the high end runners that are longer in the actual head, once air is diverted that way.

Rarely discussed in engine builds is the reversion wave in the air pulses. I'm thinking that in the low end runner in these engines, the fuel injector area slows down the reversion wave (the air pulse cut off by the intake valve closing and then shooting back towards the throttle body). I'm not sure if it is an area of focus for some pro head builders, and perhaps the pulses are already tuned very well from Ford (or intentionally slowed down in the low RPM runners), but it's something to consider. I'm going to contour that area down a fair bit, so that the reversion wave has less resistance on the way back.

Some other points:

--the low end runners have more bends/ snaking in the actual head area, so one would think that the faster that the pressure wave gets rejected at the intake valve area, the quicker that it would get back to the common area in the upper intake manifold to then get sucked down into the high RPM runner. Some sort of logic would say that while the internal psi of the head would go down in the low end (ie: reducing low end torque), it would eliminate negative psi (bends, pressure, protrusions) that would make the engine respond much better, even without a cam, since the split port design is a bit of a crude TI-VCT

--how much sympathetic air/ vacuum actually makes it down the high rpm runners at lower rpms? Ford seemed to indicate that there was some air making its way down there, seeing as that the inclusion of the IMRC's would cut off any vacuum/ suction effect from the intake valve, and that the system would start drawing air in the minute that the IMRC's opened. Dyno graphs with the IMRC's tend to show that there's a little lag or hesitation time in the power band, seeing as that there's a little blip in the linearity of a dyno graph

--certain cylinders have slightly different bends in the low rpm torque runner in the heads. The upper and lower intake manifolds appear to be pretty equal, but the snaking in the heads isn't quite equal (at least to my eye). It could be due to design constraints (water jackets, etc), but equalizing the bends may make these engines more efficient

--Taurus SHO engines have a similar split port setup, though it looks like the low end runners are much longer. There are points in this build where I feel like sawing off the low end runners in my upper intake manifold, and then having some sort of removable, bolted/ hose clamped low end runner, so that I can experiment how it pulls in the low end. For example, it might be a crude Windstar upper to some effect (look at the low end--long--runners on the Windstar upper intake) and it could be a sort of variable tuning system. The SHO'S are DOHC 4 valve engines, which would warrant the long runners with more air, but for example, contrast the runners with the Windstar. The removable runners on the SHO were likely done so that people could access other parts of the engine without having to remove a bunch of things, but it created the idea with me that due to the Windstar having much longer low end runners (more of a low end torque improvement, but one that still improves a bit of peak horsepower), that there's some sort of upper intake modifications with tunable runners that could yield some decent gains, without having to experiment with Freestar/ Windstar/ F150 type of uppers/ lowers.