I know a little about both but what makes EDM injector nozzles better or worse than extrude honed injector nozzles for common rail injectors.

I don't know about common rail but, on my 01 cummins I used both. EDMs are much smoother and give more useable power. I ran 100 HP nozzles honed and 130 HP hot EDMs, the EDMs do a much better job specially when I run a big box like my TST drag file or even stacked. I think common rail is probably the same.

EDM is a very precise way to machine things. Electric Discharge Machining involves fabricating an electrode (or wire) then using it to "burn" features into metal. Dimensions can be controlled to within +/- 0.0001" with practice.

Extrude honing forces an abrasive slurry through a part at high pressure. It is much less controlled than EDM. Variations in alloy and heat treat affect extruding much more than EDM. It can also change the shape of the target metal unintentionally, due to flow direction.

With Extrude honing of precision parts such as injectors, I would make sure they test and "flow match" the injectors to allow for variations of the process.

This info is not based on personal usage of either type of injectors, but from inspection of machined parts using these processes. One other way to perform this type of machining would be chem-milling. You use acid to remove metal, and resist ink to control affected surfaces.

Mark @ Columbus Diesel Supply is a good one to talk to and can fill you in as they can do both. Matt

You can Always Call Don, Mike.... his number is listed on Bombers under vendor links

McRat is correct. I run an EDM practically every day (along with every other piece of machinery in the shop) burning out probes for hot nozzles in high precision injection molds that I build for the medical industry (my actual job). I am working on getting a small one for the garage. Once I get some electrode dimensions for them, I will be able to grind some up (trodes) for this purpose. I need some scrap injector nozzle tips for getting the dimensions and testing.

ooops :o

Does anyone sell EDM's for a Duramax, or has anyone ran any??

Ray, you have some.

quad?

Don't think so.

guess not

McRat is correct. I run an EDM practically every day (along with every other piece of machinery in the shop) burning out probes for hot nozzles in high precision injection molds that I build for the medical industry (my actual job). I am working on getting a small one for the garage. Once I get some electrode dimensions for them, I will be able to grind some up (trodes) for this purpose. I need some scrap injector nozzle tips for getting the dimensions and testing.
To put this in perspective, you have an injector nozzle with 7 holes at approx .006" as I understand. To EDM these holes, you will need to line up perfectly and enlarge them to a bare minimum if you want them to be manageable.

The first set that I had done were 3 holes at .012 IIRC. I think you may be able to get away with .010" and still clean up, but with that level of precision, you'll have to be spot on. These yielded a bit more gain than I wanted so I swapped them with a guy who had all 7 holes done and was having major operational problems.

For EDM, if you were making the tips from scratch, you'd have an easier time of it from my perspective.

Extrude hone will remove very little metal, and is more like a porting/polishing job removing burrs left from the EDM. The hole size is enlarged very little, to get a substantial flow increase.

Eric, Ray's are extruded.

To put this in perspective, you have an injector nozzle with 7 holes at approx .006" as I understand. To EDM these holes, you will need to line up perfectly and enlarge them to a bare minimum if you want them to be manageable.

The first set that I had done were 3 holes at .012 IIRC. I think you may be able to get away with .010" and still clean up, but with that level of precision, you'll have to be spot on. These yielded a bit more gain than I wanted so I swapped them with a guy who had all 7 holes done and was having major operational problems.

For EDM, if you were making the tips from scratch, you'd have an easier time of it from my perspective.

Extrude hone will remove very little metal, and is more like a porting/polishing job removing burrs left from the EDM. The hole size is enlarged very little, to get a substantial flow increase.

Eric, Ray's are extruded.

Just a thought...

You might be better off just making more .006" dia holes than trying to line up if you want easy repeatable units. Math would be simple, and atomization would be better than bigger holes.

If you opened 3 holes to .012", you over doubled the total area of the injector holes.

By adding 3 .006 holes instead, you would only increase the area by just over 40%

If someone opened up all seven to .01 or .012, they would be HUGE!!

To put this in perspective, you have an injector nozzle with 7 holes at approx .006" as I understand. To EDM these holes, you will need to line up perfectly and enlarge them to a bare minimum if you want them to be manageable.
Yep. You drill them 1/2 degree off in any of the 3 diminsions and you just trashed your nozzle. Also, how do you know your re-drill is perfectly concentric with the original?


For EDM, if you were making the tips from scratch, you'd have an easier time of it from my perspective.
:ro) :ro) :ro) :ro) :ro) :ro)


Extrude hone will remove very little metal, and is more like a porting/polishing job removing burrs left from the EDM. The hole size is enlarged very little, to get a substantial flow increase.
Bosch actually "extrude-hones" every seat-hole nozzle when they make it. They call it "hydro-machining" though. Same idea, it removes burrs, polished things up a bit, and applies a small chamfer to the inside edge of the spray holes.

The "right" way to do bigger flow nozzles is to drill them right the first time (when they are made)

Though the EDM is a more if not the most economical method for producing the tiny holes. The bore surface itself can be irregular when compaired to the dimensions of the hole. These tiny flaws *can* cause cavitation errosion within the nozzle ports and wear out the nozzle very quickly. Controlling the quality of the bore surface has proven to be a very difficult task.

The good side of the irregular surface is that it improves atomazation of the fuel.

EDM followed by a slurry honing process is, if I read the papers correctly, what has been done to reduce the injector nozzle issues from cavitation errosion, but it is far from perfect. Read a piece about EDM followed by Laser honing recently. Looks promising.

On Edit:

Went looking for some more info and found this

http://www.extrudehone.com/superpulse.html

Guess it is closer than I thought.

Didn't realize how small we were dealing with. Anyone sitting on the fence undecided about the second filter should follow this topic. Washing the nozzles out with poorly filtered fuel is not just a possibility, it is probably. It took a lot of research and development to come up with a seven hole pattern. I would think that is one thing to leave alone. Later! Frank

The hole size is fairly critical to good atomazation. The smaller, the better. The number of holes makes up the flow rate. Better results would be had with increasing the number of holes, but keeping them small. The catch is where to put the new holes in an existing nozzle unless you add 7 and spread them evenly. That would be some HUGE flow.

Yep.
The "right" way to do bigger flow nozzles is to drill them right the first time (when they are made)

Yeah, I bought a set of "power plus" nozzles with supposed bigger holes, had them installed on a set of injectors and tested. While they were very high quality, the flow was right at stock. No small investment to have them assembled/tested either. Still waiting for some truly improved flow units...

The hole size is fairly critical to good atomazation. The smaller, the better. The number of holes makes up the flow rate. Better results would be had with increasing the number of holes, but keeping them small.
Not necccesarily. Too small and the mixing isn't as good- you get O2 "depletion zones" where the fog is too thick, and at higher boost the smaller droplets don't penetrate as far into the combustion chamber.

For example, when Dodge upped the 3rd gen torque to 600 and hp to 325, they went from 7 small holes to 5 bigger holes- all to reduce emissions.

Yeah, I bought a set of "power plus" nozzles with supposed bigger holes, had them installed on a set of injectors and tested. While they were very high quality, the flow was right at stock. No small investment to have them assembled/tested either. Still waiting for some truly improved flow units...
Working on it...;)

Sucks there is so much work to change the LB7 injectors. LLY, on the other hand...:ro)

Not necccesarily. Too small and the mixing isn't as good- you get O2 "depletion zones" where the fog is too thick, and at higher boost the smaller droplets don't penetrate as far into the combustion chamber.
What your saying is contrary to what I have been reading, but may be true. Lots of money being spent on pattern and chamber design research. Story changes every month it seems.



For example, when Dodge upped the 3rd gen torque to 600 and hp to 325, they went from 7 small holes to 5 bigger holes- all to reduce emissions. IIRC, it was a rate of combustion issue. Too fast and localized high temps generating overly high NOx. I'll see if I can find that paper again. I don't follow the Cummins engines as closely anymore since I don't drive a big truck any more.

you find the answer I will install injectors all day....

If I knew the answer, I would be rich. I don't, and have the bank account to prove it. I've enjoyed following some of the work that has been done in the last 10 years to improve diesels, and other motors as well.

Almost everything I have read and heard about is a compromise. Power vs economy, economy vs pollution, Pollution vs Power. Can't seem to have it all.

you find the answer I will install injectors all day....
What answer??:confused:

Atomization is the proper term. Back in 06 while serving in the Navy I rebuilt and tested 6-71 injectors for proper atomization. We had a Plexiglas cylinder to actually watch the injector spray pattern. Don't know how you are going to check it with the HP we are running. Later! Frank

We own the most ultimatly versatile vehicles on the face of this plant that I know of. With a few flips of some switches, we can go from a faily economic (for its size) and low emissions vehicle that pumps out a modest 300hp and is an exellent vacation or work vehicle platform, to a FIRE SNORTRING, BLACK SOOT POLLUTING, CRAPY FUEL MILEAGED BEAST, ready for the highest HP or track times any one could ever imagine to be resonably possible for a everyday driver, passenger truck. We have some time to figure out what the injectors will be able to use and like. We are a group of approximately 1/16% on the face of this planet that gets to enjoy such playful toys. How lucky we truly are. What a wonderful world.

"Back in 06"

Glad you still have your driver's license and can see the road ):h

96 maybee.........9 and 0 are real close

The Cummins in 03-04 actually had an 8 hole nozzle. They recently ( in 04.5 600 ftlb engine ) went to a 5 hole nozzle. This was to combat the shorter duration injection times ( to get more injected in less unit time ) and be able to add addtional injection events per cycle. The spraying angle was tightened up to insure a good liquid length to the combustion bowl wall on the first and last events. Liquid length and jet wall impact is used extensively to atomize fuel parcels in heavy duty engines.

A stock injector should never be EDM modified. It cant be done with enough precision.

A new and properly designed nozzle is the only way to go. Or extrude honing the stock nozzle the proper way.

Don~

Actually it was 66. Just making a little joke that most are to young to understand. Later! Frank

Well I should keep my mouth shut!! ;)

I finally got a look at an LB7 injector tip... EEKKK!!!

The holes appear to be .165mm (165 microns) or 0.0065 inches in dia. You can barely see them with the unaided eye. Lining up an EDM electrode to the existing holes would certainly be an adventure.

You descibed the kind of work I do every day. Toolmakers are a dieing breed. Surgeons at waiters pay. Only difference is Medical Surgeons get to bury their mistakes.

Yeah, but a scrap $100,000 tool is still worth $1/lb.

Corpses have terrible resale.

If you need the angle of incidence or anything, let me know. I'm going to use a more precise way to measure the dia as well, and verify the LLY uses the same dia.

Just get yourself some dental floss and some polishing compound http://www.dieselplace.com/forum/images/smilies/hihi.gif

www.fredflintstoneinjectors.com

http://www.dieselplace.com/forum/images/smilies/biggrin.gif

Toolmakers are a dieing breed.

):h