The Diesel Garage banner

Porting & polishing diesel heads

79K views 97 replies 7 participants last post by  Fahlin Racing 
#1 ·
Being that I am a rook in the world of porting/head modification, I would like some input on working diesel heads if that is no trouble. Please chime in wether you have a large amount or small amount of experience, everything helps!:thumbsup

One thing diesels do not have traveling through the intake tract with the air is fuel like carbureted gasoline/alky engines do. So there is no worry about puddling & wet flow what-so-ever in the diesel world (YES!!). Which, in my eyes makes me want to polish the intake runners (like the exhausts) and take down (and shape) any potential "turbulence producers" if you will. But havent chatted about it with others yet.

How many have ported diesel heads in here with postive results??? Little or big, improvements are always needed/desired. I came across one thread the other day (can't remember the title - I was skimming through) where one mentioned that a certain head you couldn't reach most of the intake port for doing this. Which brings up more questions.

All "classes" involved here -> Light - medium - heavy duty

Which heads are the pain-in-the-rear to even try to improve??
AND
Which would be easier to improve??

Thanks,
Jim
 
See less See more
#56 · (Edited)
Yeah, he writes some interesting stuff. There are others out there to follow, but, you also have to watch for the junk tips as well. Verify what anyone says or has written before it goes into any sort of head. Jumping back for a second to our flow within the port, non-turbocharged vs turbocharged engines, our flow area will be roughly in the same portion of the port, in a general sense of putting it of course.

Here is the intake of the 7.3L IDI once again. I have highlighted the valve boss area in both the intake & exhaust. From the factory has some decent size to the valve's guide boss. I believe there is enough meat there to shape it more aerodynamically and hopefully produce more stable flow within the bowl area and not jepordize the strength to keep the valve operating in the position its supposed to. The boss doesn't seem to have much of a gradual slope into the roof of the port. Relieving the severity of this angle creates the better flow path into and through this part of the bowl area. The arrows I have used indicate the point of each side of our valve boss comes into the bowl. Could doing some material removal & radius work in these two areas benefit?


Seeing the exhaust valve guide boss in a highlighted picture as well, you can see the obvious. Going into and out of the cylinder, there will most likely be a generation of vorticies or 'turbulence' if there is immediate changes or of the like in the path. If we improve our exhaust flow starting at the face of the valve, between the valve curtain and seat along the short and long radius, around the valve guide boss. This brings us back to the thought of scavenging of our cylinder. Improved flow should decrease cylinder contamination from reversion on this end. If things flow well up to the turbocharger's capacity, reversion will be reduced without needing to test an tune anti-reversion techniques. There will be reversion on the intake side from the higher cylinder pressure compared to intake tract pressure. Intake air contamination may be reduced as well only if the back-flow characteristics are good. Flowing heads backwards can tell how easily reversion will be.


Looking down into, you can't see too much as far as good definition of the view of the exhaust boss, maybe it was the quality of the camera. Anyways, you could call the shadowed area the top of our boss from how the picture is taken. Again, any head you can do the same basic shaping and clean up as long as your port does not become 'out of shape' compared to how the port itself came.


Since we improve flow stability and capacity through porting (increase in velocities and CFM too) and cleaning up casting imperfections, we produce a stronger swirl action too. Now if you look at the 6.9, 7.3, Cummins 5.9 12V mills you see that the valves are positioned in the center of our cylinder/chamber. Since 2 valve cylinder heads influence swirl naturally, its best to maintain mixture motion in the center area which the valve positions and the piston crown influence this. I hope to get some ported pictures of something on here in the near future.
 
#57 ·
Update, I have not been able to get some heads yet to work with, I will try to by the end of the summer but I am not holding my breath. its been a busy year so far but I will get something up! Sorry for the delay guys and gals!
 
#58 ·
Update, I managed to get some Duramax heads today, and a buddy is going to ship me one of my 7.3L N/A heads at some point in the near future, so there will be somethin' soon! I plan on getting some silicone molding material so we can see the port shape and imperfections out of the head too.
 
#59 ·
For those wanting something to chew on until I get my mold silicone (hopefully in a week or two, maybe), here is the 2011 Duramax head view of the firedeck and closer view of the intake valve bowls. Just so everyone knows I will be grinding and cutting this head apart to see what everything looks like inside the 'outer' part of the casting along with testing the porting limits.





I would say on thing wrong, the position of the glowplug is not centered bwteen the valves the best so going to a larger intake valve or exhaust will only IMO create interference not only in physical proximity but allow more cracking possibilities due to material removal. I could be wrong in some way but that is how I am viewing it.
 
#60 ·
Here is a piece from Jim Mcfarland in chapter of a racing book taking into consideration of equalling out the ports pressure distribution through the runner when flow is occurring.
Whether the "working fluid" is air or air and fuel, air tends to follow the shortest geometrical path between two points of pressure difference. In areas where pressure is skewed to one side of the path to another, low pressure opposite these areas tends to encourage air/fuel seperation or low pressure instability. Intake and exhaust port dimensioning (or modification) should include consideration of these basic features, attempting to keep pressure distribution as uniform as possible across each port section.
Regardless of the shape, as long as the port surface has nothing more than micro-vortex generation, the airflow boundary layer, our cylinder filling will proceed in the right direction. As we enlarge our port, we decrease flow velocity some, in turn we increase the port's flow to a higher rpm level. If we can lighten rotating masses and further improve rpm capability the use of the larger port will become apparent. However we must still take into consideration the proximity of the water ports in the head as well.
 
#61 ·
Here is a process that Burgess & Gollan state in their book for porting.
1.Carbide use (cutting down large areas quicker)
2.Mounted point (stones)
3.Fan grinding
4.Flapping, restores proper finish for fuel suspension and air flow boundary layer.
5.Hand finish if needed w/ emry cloth
 
#62 ·
Since its taking longer than I would like to get molding silicone for the port molds, I plan to start out by taking a hole-saw and cut out the intake manifold mating flange and grind away what is in the way so we can see wall thickness once I get the drill press set up, however my boss seems to be taking his time on ordering more arbors for the hole-saws we stock, but that is what I plan on doing first then make some port molds of both intake and exhaust.
 
#63 ·
So I've decided to hold off on the hole-saw for now. But here is some pictures of the intake ports that I will start on soon. My idea of combining the two ports to make one to a certain length into the runners then they split. Feed the high rpm breathing requirements :D

Looking from the exhaust side




For this port project I plan on using a runner cut from a SBC head to make things a little easier. My idea is to be able to feed the cylinder more efficiently at higher rpms, there may be some filling in addtion to shape the internal of the runner once I get everything in place and welded. I hope to find a reputable flow bench near me to test the port when I am finished. I will also be doing regular porting, i am just doing the port reconstruction just to do it and hopefully learn more and more. Being that you want to match the valves to the port, I will just use the stockers until I flow test the port. Then we can maybe jump into bigger valves if possible and see what the flow difference may be if it goes better or if it screws it all up. But thats what the R&D is for :rock

Feel free to voice what you think of my idea on the single runner dividing into 2 as they approach the valves.
 
#64 · (Edited)
To everyone I applogize for the misleading post of #59, I was told I was buying a set of Duramax heads. I didn't get Duramax heads, they decided to give me POWERSTROKE 6.0L heads and NOT tell me!!!! I am new to still identifying the makers myself on this light duty diesel engine world, forgive me guys/gals. From what I am told Duramax heads have ONLY come in Aluminum castings, not iron.

PlainredTruck, or any other moderator PLEASE CHANGE POST #59 from 2011 Duramax head TO ''2003 Powerstoke 6.0L head'' when either of you are able!!!

Any ways, you Powerstroke fans, I should be digging into the first one this weekend!!!
 
#65 ·
Ok, 6.0L Powerstroke heads investigation, I started out with a regular grinder to take as much out of the center as I could before I started with the stones.

Here is the removed divider after about 1 hour and 20 or so minutes. The port wall thickness in these heads seems to be around 1/8 to 3/16ths of an inch.

With the red arrow I am indicating that this runner (the shortest of the two) has more of a corner than a completely round runner like its partner. The runner/ports are mirrior to each cylinder so each (viewing from the intake manifold side) will have this on the left intake runner. With these heads we have 1 shorter and 1 longer set of intakes which pretty much tells you the valve placement is rotated about 90 degrees compared to a head with a single or dual equal length runners.

Now here I got a picture or how narrow the sight is going straight to the valve. I used my work light so we can see the position of the valve bowls.

Here is a shot of the right side intake runner, notice the runner wall surface texture, thats majority through the entire runner, expect it in each set of runners per cylinder.


Enjoy :rock
 
#66 ·
6.0L Powerstroke head

Here is a picture of the firedeck of one cylinder, the intake bowl in the upper left is the closest to the intake manifold. If you look into the bowl you see a similarity to the bowls designed to specifically produce swirl. Notice the other (right) has nothing like it. Also notice the 'chamfered' portion of the intake valve pocket circumference on each intake pocket. If you look at the exhausts, like Wekiwa mentioned earlier on the bowls for these heads are restrictive.

This next picture, I haven't entirely ground away the deck between the two coolant passages, after glancing after I took some material out there could be a small passage to the right of the portion I did grind. I will update this later on. The arrow showing you the path of flow, from the above picture you see what the bowl looks like.
 
#68 ·
After thinking about somethings brought to my attention, the sizes of each style of cylinder head port, in this case a N/A head versus the Powerstroke, are we more worried with a overall MASS being trapped with less concern of air speed as long as its enough to hopefully complete a cylinder with enough usable air? Forced induction is obviously pushed into the cylinder for the most part IMO, if the cylinder pressure becomes above the intake tract pressure you will have reversion if the camshaft has not completed its intake cycle. As far as runner design and direct or indirect injection designs, will this dictate how our designed port/runner layout will turn out? Could the runner be sized to adequately fill the cylinder with atleast the minimum 'lbs of air' requirement to produce the desired power by pushing the 'air velocity' topic to the back and again point to a MASS flow concern that is more important, again in the direct or indirect injection dry flow system that is present.

Either application we like a lot of weight in terms of quantity of air ingested, however the only way we can improve this is by shaping our runners and 'straightening' the flow path producing a more efficient run to the cylinder. After scraping the carbon from the 6.0L's EGR deposits I see the runners are more square than they are at the intake manifold mating plane, which they are circle.

Since the N/A 7.3L head has a large bend to it and larger bowl with a larger valve being 2-valve per cylinder. Plus the swirl-chamber, could this swirl chamber be the reason such a big port works well? The less we bend and twist our flow from the intake manifold to the intake valve we keep flow effciency up, now this is where I go back to the thought of MASS important versus velocity importance that was brought into view by another gearhead I had spoke with.

Anyone else have a thought on this?

With newer turbocharged heads, 2 runners for the intake, is this just a large runner design split in two? Why is it that way? Certainly isn't for desigining advantages from my view, more complex casting for starters.

Just a reminder of what is needed to think about during a project...
Intake design
Intake runner design
Intake runner layout
Intake runner volume
Intake convergent side
Intake valve seat/throat/area (shape)
Intake valve shape
Intake valve pocket in the firedeck or divergent side of the valve
Airflow reaction once its past the intake valve head into the cylinder(I think this has some say into the final cylinder filling because we have a moving floor (piston) with a dish ect.

I will soon be posting some valve areas of the 7.3L N/A and 6.0Ls I posted earlier from calculations in Harold Bettes book Engine Airflow
 
#69 ·
Here is a picture of where I want to cut and install the roof and do the same for the floor on the underside with some obvious internal shaping.
 
#70 ·
Here is the valve area calc out of Engine Airflow from Harold Bettes.
Area of the Valve = (Dia. squared x 0.7854) - (dia. squared x 0.7854)

Notice I typed a capitol D and lower case as well like how the book has it printed. The capitol D represents you major diameter and the lower case d represents the valve stem diameter. Answer is in square inches.

Example:
7.3L N/A
(1.877 squared (D) x 0.7854) - (.370 squared (d) x 0.7854) = effective valve area
(3.5231 x 0.7854 ) - ( 0.1369 x 0.7854)
2.7670 - .1075 = 2.6596 square inches of effective intake valve area
 
#72 ·
Alright, finally bought up some epoxy to reconstruct the port. I bought it, the 2 quart kit, through Reher-Morrision Racing engines for $85.00 + shp. This stuff won't do exhaust ports from what I am told. Reminding those, I bought this epoxy because I don't have access to a welder readily so I chose this route. It is warming up outside so it will be easier to pick a day soon to heat the garage up and apply the epoxy. Hopefully sooner than later.
 
#73 · (Edited)
Little more information here from Mr Vizard again regarding valve inclination, I stated somthing along these lines earlier in the thread with a drawing but I seen this in David Vizard's newest book, How to port & flow test cylinder heads. He even shows you what you need to build a budget flowbench as well. Check it out.

"The more poorly the turn into the valve throat area is, the smaller the valve appears to the port, and therefore the port needs to be smaller in cross section to keep a lesser amount of air up to speed for inertial ramming of the cylinder. As the port inclination becomes steeper, it is able to utilize the valve better and the valve appears to the port to be bigger; hence a bigger port is optional."
I may be able to goop up the head within a week or two and start shaping the ports and move onto the bowl area on these 6.0L heads then get them to the flowbench within a month amongst all my other chores!

Added: with the ports and almost any diesel engine that is common the runners are flat-planed. If you look at a Perkins intake runner, i wish I would remember the engine, but any ways I will see if I can post pictures of how inclined those runners are.
 
#74 · (Edited)
Runner Inclination example

Here is the cylinder head I was able to get some pictures of. Perkins 6 cylinder.



Protractor applied to show how much angle this head's intake runners have.




Edit: If you look at a set of 6.0L Powerstroke heads there is a mixture of the two layouts. At the runner/intake plane opening is elevated compared to the firedeck plane. As the runner moves towards the valve bowl there is a fuel supply passage it must go under at which this point the rest becomes flat-planed to the bowl, in addtion to moving over towards the front of the engine and the other runner moving towards the rear of the engine creating a real pain to get in and shape. Even with air flow taking the shortest route to the cylinder, aka the peak pressure point at the head of our flow will not always stay in the center of thr runner all the way to the valve, the directional changes within the port create longer (even though minute in size) distances.
 
#75 · (Edited)
Alright, sorry for the images not showing, I didn't realize they would not show up if I move them in photobucket. Here the are again.
The ones showing the runner inclination of a Perkins 6 cylinder.




Current progress once again on my Ford Powerstroke heads.










Again, sorry for the inconvience I wouldn't have moved them if I knew I would have to repost them.
 
#76 ·
Looking at the very last picture in post #75 (above) see notice the shape, remember the shape at the intake mating flange? they are complete circles and transform to that shape until the intake bowls. Also looking at each picture each runner is at a different level as they proceed to the bowl so they don't make a flat even floor or roof side to side which will be needing some contouring once I am able with the cartridge rolls and the flapping wheel when I have decided to finish the surfaces.
 
#77 ·
So far everything I have done is cut and rough in things with stones. One thing I learned is let the stone do the cutting/grinding, you put too much pressure on them you will split them. My big Milwaukee grinder is nice, but, I would like to have a smaller one for the more minute areas. I know Goodson sells them, if I remember right Harbor Freight may sell a a narrow long neck grinder however I am not sure how well they hold up. Maybe somebody can chime in on if they have this grinder from Harbor Freight. Makita Has one I believe too.

Once I get the epoxy cut down to what I want to start shaping, I will be using a steel rotary file I have. Then I will be moving to cartridge rolls of sand paper. The grit I have at the moment I will have to get back to you on. Remember you can buy short shank and long shank stones, rotary files etc. This first picture below I cleaned up the areas with some sand paper prior to filling.





After the Splash zone epoxy is mixed up it looks like a dark ugly green. Maybe this is where the 'green death' comes from lol. The 2 part epoxy starts out one black and the other a yellow. Mix until its a solid color then MAKE SURE you apply within reasonable time.
 
#78 ·
Started to take the splash zone epoxy down with a steel rotary file in my grinder. What I did before I applied the epoxy is filled the runners with some paper & plastic and whatever I had close that was easy to remove to keep from filling each runner too much when pushing the epoxy into place.
 
#79 ·
This is a more roughed in of the port. I have some cartridge roll usage to still do but I will using the flapper wheel soon. As you see I have used two red lines to show the runner position between each in this area of the ports. The right side sits higher than the left as you leave the intake mating flange where they are starting our equal in position. The Blue arrow I have indicated the corner again that the runners have more pronounced in different areas. I will test in another port how much if needed to even take out before it becomes a smooth swooping radii and then drill thru to see how much is left in the runner wall thickness.


With the purple arrow in the center at the runner divider I am pointing out the shape it is now, its an acute sharp edged angle which will create a separation of flow making the flow in that area be less efficient. Vortex generation in the flow path (other than micro-turbulence needed for flow attachment for adhesion to the walls) is our enemy.

The stones I have been using I believe are 80grit, the cartridge rolls right now are 80 grit to get rid of the small dips you can see in the picture. Each time I do some grinding I use my finger to feel the runner. Once you feel a spot you need to grinder more, MAKE SURE you think about how far you will be pushing your grinder in if you have a tapered or odd shaped bit to cut the material down. If you don't, you will feel a dip when you should be feeling a smooth flat/contoured area. Its takes practice, lots of practice like the gurus say, its an art in porting. If you can work a grinder smoothly you should be fine but going through the motions with your motor-skills, hand & eye coordination is key too along with the by-feel when you can't see as I stated previously.
 
#80 ·
Here is a picture, favoring the left intake runner. Notice at this angle you can see the right side is appearing larger, IMO this can act as a partial funnel as well as provide a straighter path to the valve (airflow takes the shortest route possible) as I will point out in a future picture. If we view the right runner the left runner appears larger. Both have a straighter path than before. If you look back at the earlier 6.0L runner pictures you can only see a narrow area to the valve because the runners go towards the valve and then move out away from each other.


When thinking, keep in mind the peak of the pressure front of flow will change positions as it moves through the port going to the cylinder, flow is quickest at the center of the runner because of less friction being present unlike the flow next to the wall surface which is slower. Check the link out for an example .
http://www-mdp.eng.cam.ac.uk/web/li...mal_dvd_only/aero/fprops/pipeflow/node10.html
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top