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Technical Fuel injector Fab

Discussion in 'The Hokey Ass Message Board' started by HemiRambler, Feb 23, 2019.

  1. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    IMG_1692.JPG IMG_1702.JPG IMG_1706.JPG IMG_1720.JPG IMG_1733.JPG IMG_1736.JPG IMG_1742.JPG It's been a while since I posted last - I guess I'm pretty overdue. So for your entertainment I give you my latest folly a DIY fuel injector for my dragster. Nothing earth shattering - just a project I've wanted to do for a long time. A super low profile 4 port with a Scott inspired top. I'm sure it's been done before, but this one is mine. We'll all have to wait and see if I can pull this off. (I hope so because I'm already planning on an 8 port)
     
    Last edited: May 7, 2019
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  2. yellow dog
    Joined: Oct 15, 2011
    Posts: 398

    yellow dog
    Member
    from san diego

    Nice!!! Impressive work. I still remember how bad my port alignment was for the Enderle in my avatar
    back in the 60's
     
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  3. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    Thanks Yellow Dog! I'm trying to be as precise as I can. I was hoping there'd be a little more interest and perhaps some first hand experience - it'd be nice to discuss the pros/cons of different seating angles - everyone seems to talk about 7 degrees but ocassionally I see less than that mentioned - I will start with 7 knowing I can always change it later if I have to. I've also seen a comment or two about offset throttle shafts to assist in self closing. My initial thought was centered (no offset). I looked at a Holley throttle plate and the primarys were centered while the secondaries were offset. I'll peek at a couple of injectors before I machine those holes. I am leaning on possibly using teflon on the shafts, but honestly haven't ruled out bronze bushings yet. Talked with a machinist friend and had an interesting discussion on machining the throttle shafts - that's gonna be fun I think. I guess I am getting ahead of myself.
     
    Last edited: Feb 26, 2019
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  4. I made an injector years ago for a blown alky car. I wanted to make the butterflys the same size as the throttle bores.That didn't turn out to be such a good idea. I copied the barrel valve ratio from an Enderle bird catcher as a starting point. This unit had 2 huge butterflys. With the vacuum that a good blower will pull, that proved to be less than wise. All the injectors I had were equipped with brass bushings. You may find out why. :) Have fun with your project.
     
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  5. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,210

    drtrcrV-8
    Member

    Yellow dog: I'm following your project as I've been considering a similar project on a large 4cyl. As far as throttle bodies, have you thought about selecting a more or less "optimum" butterfly size & spending some time at your local "pull-a-part" looking at the smaller late model OT cars for throttle bodies that could be readily adapted to your project? The precision fit available would be a lot easier to adapt, as opposed to "re-inventing the wheel", & fabricating linkage to synchronize the butterfly/"brain" openings shouldn't be that difficult( just like "synchronizing" any other mechanical injector unit as far as I can figure?)
     
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  6. 402BOSSMAN
    Joined: Jul 26, 2015
    Posts: 321

    402BOSSMAN
    Member

    Nice start, how do you plan to drill for the shaft? What bore size will this be? I'm a big fan of people making chips on a mill, I'll be following along!
     
  7. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    402BOSSMAN -Nice avatar BTW. My plan is to center drill with a mini right angle head, followed by a drill undersized and then I will fashion a long .375 reamer to do all holes in one shot. I haven't decided on under cutting the shaft for teflon strips like a holley carb or bushing the housing with bronze. I bored the holes to 3.000" - I'm planning on making the butterflies 2.996" -7deg. Everything subject to change as I learn more.
     
  8. dreracecar
    Joined: Aug 27, 2009
    Posts: 2,869

    dreracecar
    Member
    from so-cal

    When you send in an injector back to Enderle to be refurbished, they machine the throttle shaft bore for needle-roller bearings. Don't get too/so precise, they are sloppy for a reason---Enviroment. Carbs need to be sealed because they rely on vacuum to draw the fuel thru it, Injection has the pump feeding the engine so the injector is just an air valve.
     
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  9. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    Dreracecar, That's a goood point. I wasn't thinking telfon to be super tight - I was considering what might be easier to fab. On that same note - I had previously looked up some thin roller bearings at mcMaster-Carr and made note that they are .562 for a .375 shaft - which I made sure I had room for - just in case. Now you got me to thinking maybe I should consider just going straight to the roller bearing! Thanks for sharing your thoughts. My experience with roller bearings is that the shaft needs proper hardness to prevent damage. I doubt the loads here would render that a concern. I made a last minute change where I moved the bore centerlines to resemble a Hilborn - I did this as an insurance policy IF I couldn't fab a shaft I'd just buy one. Now I'm second guessing that, but it's to late - in for a nickle in for a dollar. :)
     
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  10. dreracecar
    Joined: Aug 27, 2009
    Posts: 2,869

    dreracecar
    Member
    from so-cal

    I sent my "Hat" in to be re-furbished , the shaft was worn out where it came into contact with the alu due to friction/rubbing. Load is sooooo minimal that shaft hardness isn't a consideration because you are not spinning the shaft XXX rpm, a little spray contact cleaner and a squirt of WD40--- no grease because it will collect dirt. Boreing for the shaft is going to be difficult without tooling in the bores to support the drill bit and keeping it straight. Also consider buying the shaft, its a lot of involved work for money (around $100)
     
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  11. 41rodderz
    Joined: Sep 27, 2010
    Posts: 3,316

    41rodderz
    Member
    from Oregon

    I will be watching with both eyes wide open :cool:. This what I love , home grown tech.
     
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  12. cederholm
    Joined: May 6, 2006
    Posts: 1,608

    cederholm
    ALLIANCE MEMBER

    Nice! Machine work is cool.

    ~ Carl
     
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  13. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    IMG_1769.JPG IMG_1774.JPG So I started on the throttle shaft. Using a stubby center drill I spotted each hole and then went back and thru drilled each one using a standard bit that I shortened. So at the moment the thru holes are 3/16" simply because that was the size my right angle head is set up for. I moved the quill for each hole only because I have a digital readout on it which I still used with a stop. I think that ought to be OK. Next I gotta either modify a cutter or maybe make a small adapter - we'll see. I think nows the time to spot check to see how centered I am!
     
    Last edited: May 7, 2019
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  14. RichFox
    Joined: Dec 3, 2006
    Posts: 9,818

    RichFox
    ALLIANCE MEMBER

    chips.002.JPG
    This would not work for a blower. Maybe the shaft and butterflies. It is very much for sale by a motivated seller. 4 holer only.As I remember 2 5/8 opening. Bells are separate. chips.0014.JPG
     
    Last edited: Feb 26, 2019
  15. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,210

    drtrcrV-8
    Member

    Thanks RICHFOX. I'm SLOOOWLY working on a 3.7 MerCruiser (1/2 a 460 Ford) so I need to use separate, (non-Siamese) intake ports, & being "Terminally Cheap", thought about using "P-N-P" sourced FI throttle bodies of about 2-1/2" to 3" dia. as a starting point, to, if nothing else, avoid the accuracy needed to machine the "new" throttle bodies from scratch. I figured it'd be a whole bunch easier to drill/tap 4 small mounting holes for each donor unit(as well as one hole for the injector nozzle), & worry more about linkage, a much easier task, unless I'm missing something? Your thoughts?
     
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  16. RichFox
    Joined: Dec 3, 2006
    Posts: 9,818

    RichFox
    ALLIANCE MEMBER

    Made several of them using SOHC 4.6 Ford throttle bodies. Sealed ball bearings on the shafts. Millions made. I have several that I could be talked out of. DSCN8335.JPG
     

    Attached Files:

  17. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,210

    drtrcrV-8
    Member

    Figured you'd get it!! Not ready yet, but working out the ideas in my head first, so thanks!! I've still got that "A-A" to finish before I move on, so I'll be a while before I'm ready to start the 4 banger(although I'm using a nearly "stock" one in the truck.)
     
  18. 402BOSSMAN
    Joined: Jul 26, 2015
    Posts: 321

    402BOSSMAN
    Member

    I've been in a similar boat as you many times before. I'll share what I know. My experience comes from Gene Adams (who worked for Hilborn for 20 years) and the folks at Hilborn. The shaft itself will need to be hard chromed after you machine it. You can run it in the aluminum body with a few thou clearance or you could also bronze bush or bearing the ends, your call. The blade to bore clearance is typically .005-.006 and I believe the blades are machined on a 5° angle? The biggest thing is getting the bore sizes of the body within .001 of each other. I hold tolerances of .0005 on my setup as its very rigid both boring and holding. I am able to take 3/16" of a cut in one pass. The other portion is fixturing to machine the shafts. You need support on each side of the cut when you drill and ream. As you know it can drift the further you go so that fixture keeps things in line better. Gene Adams gave me all of his fixtures to "pass the torch" as he knows my dedication and passion for this sort of thing. Hope some of these details will help you.
    IMG_20181005_123009_234.jpg
    IMG_20181005_163306_066.jpg
    IMG_20170914_202137_506.jpg
    IMG_20180330_071231_802.jpg
     
  19. RichFox
    Joined: Dec 3, 2006
    Posts: 9,818

    RichFox
    ALLIANCE MEMBER

    This is a very quick and dirty baby bug catcher I made to run on a Nissan V6 in Jack Costella's streamliner. Actually worked well enough to get the F/FS record in 2000. When I was making the throttle plate I noticed how far open the plates were on my real Hilborn injector at idle. Realized there was no reason to get serious about it sealing the the bore. It's never going to be closed anyway. Close is good enough. upload_2019-2-27_8-31-46.jpeg
     
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  20. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    Nick, That was very helpful. Much appreciated. Is there any chance you can share a pic of your extended drill/reamer?? Thanks.
     
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  21. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    Rich - VERY neat. I would have expected a larger inlet. Thanks for sharing. I know what you mean about tolerances - especially for my application wwhere it's all gettin' stirred up in the blower anyways. In my case I'm tryn' to error on the more precise side simply because I don't have a lot of experience here. :)
     
  22. RichFox
    Joined: Dec 3, 2006
    Posts: 9,818

    RichFox
    ALLIANCE MEMBER

    21752365_1412893625454822_5632880734509967742_n.jpg
    ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,The plan as explained to me is that you take half of the displacement of your 4 stroke engine. Then take the tire circumference and final drive ratio and calculate how many revolutions you will you need to go one mile. Put those numbers together

    and that is how much air you need. Then calculate a column of air one mile long and find the height and width and that equals that number. That is the proper size of your air intake. Any larger is drag. Note size of scoop on this record holding nitro roadster
     
    Last edited: Feb 27, 2019
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  23. atch
    Joined: Sep 3, 2002
    Posts: 4,294

    atch
    Member

    Brilliant! And simple also. Although I'll never need this information it's extremely interesting.
     
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  24. RichFox
    Joined: Dec 3, 2006
    Posts: 9,818

    RichFox
    ALLIANCE MEMBER

    Here is the Flashpoint car with a Top Fuel type hat. Ran 395. And with the current Don Jackson Bonneville size hat ran 451. Of course there were several other changes. But the car was faster and more responsive to driver input with the Jackson hat. Also the Sumers Bros Goldenrod went 409 with the MoPar scoops made by AFX engineers. When they went to the Bob Herda scoops they went 425, Back to Back 1471 .jpg 13987371_1768017290082471_962519234743150165_o.jpg
     
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  25. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    IMG_1792.JPG Given my tools and comfort level (turns out that my extra long drill bits are a couple inches short) I decide to just continue on this path of step drilling - given the size of my right angle head I wanted to keep the load small - hence the reason to step drill where otherwise I'd probably go right to the size needed for reaming. Checking along as I go - this is keeping everything inline really well. Now I have to fashion some sort of long reamer! Slow, but progress is progress! I can see where a fixture would be worth the effort if doing anything other than one offs!
     
    Last edited: May 7, 2019
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  26. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 933

    19Eddy30
    Member
    from VA

    Op great machining skills , What size butterflies ?
    Is this for Blown Application ? I believe I read that low profile Can have issues caused by the vacuum of the rotors to open butterflies specially if they're big In size , Hot Rodding /Race is all about trial and error and thinking outside the box ,
    Nice job your doing
     
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  27. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,659

    Mike VV
    Member
    from SoCal

    Rich -
    For what it may be worth, the injector hat you speak of is actually a Funny Car hat than a Top Fuel hat.
    TF = tall, Funny Car = short.

    Unless...you were being very generic.

    Mike.
     
  28. RichFox
    Joined: Dec 3, 2006
    Posts: 9,818

    RichFox
    ALLIANCE MEMBER

    I'll buy that. But Bob wanted a streamliner hat.
     
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  29. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,140

    HemiRambler
    Member

    19Eddy30 Thanks! I'm using 3" butterflies. Yes Blown application - 6-71 on a 392. I do have some concerns that I could be too low and have a couple thoughts for a plan B if that proves to be a issue. Which include adding a spacer under (keep in mind it'll already be a tad taller due to a blower restraint plate under it) - also possible to add a riser to the top. I've gt some ideas for making a modular injector - but that will wait for the next one. Plus maybe another trick or two up my sleeve. :-o Like maybe adding a slight offset to the pivot. Just trying to learn as a I go. It's been a really fun project so far. I always feel like I'm learning something even when I screw up!! :)
     
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  30. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 933

    19Eddy30
    Member
    from VA

    HemiRambler , when I posted what i did ,I was al redly thinking of that if it was a problem .I have some NASCAR carb spacer's from a guy I encountered he had like 40 or so C&C , they where all with in .030 thousands of an inch in thickness , from .500 to 2.000 for Dyno pulls .I can not Believe that .030 makes that much of diffrents in power, or why not just use diffrent gasket thickness Within reason .

    HemiRambler, There a Good feeling when you creat or build somthing from yr own vision & labor. Myself I have machining equipment ,chips fly with ideals , modify and making my own parts , that's what Hot Rod's / Racing is about, trial and error !!!
    Nice machining :D
     
    Last edited: Mar 2, 2019
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