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Technical Tech Week: Make a PowerGen fit your 3 carb Flathead

Discussion in 'The Hokey Ass Message Board' started by cretin, May 8, 2021.

  1. cretin
    Joined: Oct 10, 2006
    Posts: 2,967


    Hey guys. One of the things I have always wanted to change since buying my roadster is the alternator. We all know a big old alternator hanging right up top of a flathead kinda ruins the traditional look. Something had to be done.
    I plan to run a hood on this car from time to time, and I do not want to mess with the hood sides at all, so I did not want to switch to a side mount alternator/generator.

    I took some measurements and decided I'd be able to fit the PowerMaster shorty flathead PowerGen with a little bit of modification.

    Now, let me preface this by saying that I know I have access to tools that many of you may not, so my method may not be a viable solution for many. However, hopefully you can still enjoy this thread, and get something out of it. It is still certainly possible to modify a PowerGen to fit without the tools used here, and I will touch on that in the thread.

    The first step of course is to acquire the PowerGen. Put in an order and once I got it, I started measuring again, and removed the rear cover.


    My original plan was to just cut the nub off the rear cover and make something to fill the hole that you can see using the photo above, that would be left. That would be the option for people without access to the machining equipment I end up using. Then you can get creative on filling the hole.
    Since, I do have the ability to machine parts, and the rear cover really just needed to be flat, I decided to machine a new rear cover.
    I'm keeping the design simple. Just make a cover with the basics, cut out what isn't needed, and fill those cut out areas with mesh. So, I got a disc of aluminum, found center, and marked out my first cuts.



    After I cut my first dimension, I cut in a small groove so that when I cut the mesh for the piece, I can cut it slightly oversize, and it will sit securely in the groove. It's a little tough to see it in the following photo, but I tried. After that, I cut the step that indexes the cover in the case.

    Then I marked out my first cut on the face of the cover, and made the cuts.
    (There is an extra line marked because I changed my mind on the diameter of the center.)



    Next, I needed to put a radius on the outer diameter of the cover. Since this is just aesthetic, I did this by hand on the lathe, using files, sandpaper, and scotchbrite. Then, I laid out the important stuff like the the mounting bolts, and charging stud, then the cut lines for the windows that will be cut out. I drilled the holes for the mounting bolts, and charging studs, and checked the fit.


    Once I knew it fit, it was time to cut out the windows. I like to drill holes in the corners of the windows first. This gives me an easy start and stop, and also for situations like this where I don't have an endmill with the right radius that I want in the corners of the windows. I drilled the holes, and then set up the cover on the Mill with the rotary table to start cutting out the windows.

    Here I have the outer cuts done.

    Then I made the inner cuts.

    I then made the straight cuts to finish cutting out the windows, and countersunk the mounting holes. After some cleanup on the bench by hand, this is what we have.


    With the cover made, it was time to cut the mesh to fill the windows. Later I will most likely swap the mesh to brass mesh, but this is all I had at the time. I also machined a new insulating bushing for the charging post, as I prefer the black over the red.

    I hit the cover on the polisher. Here is a before and after of the rear covers.

    So, this isn't actually a completed project because Since I don't have a garage back again, I had to do it at the shop rather than at home. Once I got back home and tried to install it, I discovered that I need to machine the PowerGen mount a little bit to fit it to my intake. I also need a bit smaller of a belt. However, I was able to mock it up.
    It is certainly close to the front carb, but it should just fit.
    In the event that it touches, there still is some room to machine a bit more off the rear cover, and I also have some room to machine off the case if I choose that instead.

    Here are a couple before photos of the alternator installed.

    PowerGen mocked up. Very close as stated, but it fits and it's better than the alternator!

    Once I'm able to machine the mount and get this thing mounted for real, I will update this thread, and show if I made any more modifications or not.

    Hope this was helpful and you enjoyed it!
  2. loudbang
    Joined: Jul 23, 2013
    Posts: 38,655


  3. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,171

    from Quincy, IL

    Yep........First Class!!

    cretin and loudbang like this.
  4. Fortunateson
    Joined: Apr 30, 2012
    Posts: 4,274


    Very nice and I prefer the generator look but you still have an alternator! LOL
    cretin and loudbang like this.

  5. brading
    Joined: Sep 9, 2019
    Posts: 436


    You certainly have made a nice job of the endplate. Think you might be getting a few calls for one.
    cretin likes this.
  6. rod1
    Joined: Jan 18, 2009
    Posts: 944


    Always fun to watch.Clean Job.
    cretin likes this.
  7. cretin
    Joined: Oct 10, 2006
    Posts: 2,967


    Yup, but a much better looking one.
    loudbang likes this.
  8. v8flat44
    Joined: Nov 13, 2017
    Posts: 859


    All of the sudden, I WANT ANOTHER F L A T H E A D !!!!! Nice job !
    cretin likes this.
  9. Tman
    Joined: Mar 2, 2001
    Posts: 34,917


    Great job! Looks very slick and better than the old Alt. FWIW, a few of us HAMBers sent original to Eric at Powergen when they were developing these. I sent a couple GM ones to help the cause and got a new flathead gen/alt in return for my trouble. It is on a pals roadster.
    loudbang and cretin like this.
  10. Gahrajmahal
    Joined: Oct 14, 2008
    Posts: 440


    Way to break down the explanation. Looks great!
    loudbang and cretin like this.
  11. Garpo
    Joined: Jul 16, 2016
    Posts: 240


    And to finish... A coat of satin black?
    loudbang likes this.
  12. cretin
    Joined: Oct 10, 2006
    Posts: 2,967


    Nope, going to keep it as another shiny thing I won’t want to clean.

    Sent from my iPhone using H.A.M.B.
    loudbang and kidcampbell71 like this.
  13. Fortunateson
    Joined: Apr 30, 2012
    Posts: 4,274


    No doubt about it!
    cretin likes this.
  14. cretin
    Joined: Oct 10, 2006
    Posts: 2,967


    Man, Life sure got in the way of wrapping this project up.
    I had planned to finish it up on Friday, and update this thread with the finished product.
    However, I got in an accident in the roadster on the way to the shop.
    The accident was caused by my engine throwing a rod and locking up, so there really isn't a reason to finish the project now. Hopefully there is enough info in this thread for anyone wanting to do it.

    You can read more about the accident here in post #97 if you are interested.
    loudbang likes this.

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