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Answers to a few questions about FSI brand distributors, which have automatic advance

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  • Answers to a few questions about FSI brand distributors, which have automatic advance

    Original Thread:

    FSI offers the so-called 'Zipper" dizzy as well as the 'FSI' dizzy. The Zipper looks nearly identical to the stock A dizzy, but has a fixed advance total of 28°. The springs can be changed to alter the shape of the curve, but the total cannot be changed. It is most suited, IMO, for a stock motor with a 4.2 head. In actuality, if you are running a stock 4.2 head you will not have to change anything at all.

    For a higher compression motor, such as the 5.5 or 6.0, the FSI dizzy is able to have the springs changed and the total advance reduced to between 20-23°, by use of a 'shim'. The supplied shim will get you back to about 25°, but I have developed a way to reduce further than that.
    If you run a HC head at 28° you WILL do damage.
    FSI has the different springs and the shim available.
    Personally, I feel this more sophisticated dizzy best suits those owners with an inherent understanding of what timing is all about

    You would need access to a timing light to properly set up a modified FSI.

    In my opinion FSI makes a quality product

  • #2
    This is a very timely discussion! We run a 5.5 head on new motor, F150 tranny ,and have had some issues with timing the 12 volt Zipper (installed by prior owner). We found TDC and marked the pulley, etc. and measured the 1.2" for proper advance. As some have found, the motor doesn't appear to idle well at TDC per the FS instructions but is more happy at about 3-5 deg.advanced .The degree scales available show increasing advance counterclockwise on pulley if we understand them correctly from the passenger side . When going up hills, the advance may be too much so we adjusted the rotor and or the distrib. body very slightly as these units seem very sensitive to find a sweet spot with the timing light. Perhaps it's time to get the shims and springs but not sure how to tell the difference of what's there already. Any instructions available how to do this?


    • #3
      The 28° total advance is way too much for your setup.
      I assume from your previous postings that you have decent mechanical ability. You will also need a tach.
      Before I start any discussion, it has to be made clear that the main cause of rough idling with your current setup is the advance is too much. This is assuming that everything else about the motor is properly set up; ie carb, fuel flow, good equal compression, engine not worn out,etc.
      If anyone has trouble grasping this, then I prolly cannot help them.

      All else being equal, with a properly set up engine, if there is roughness at idle or thru any part of the rpm range, then the advance is too high. We used to equate too much advance with spark knock. However, 2 things work against that former foolproof test.
      1) an A motor makes so much noise and rattle anyway
      2) most of us are older and not hearing as well as before.
      SO, in many many cases we are not perceiving knock.
      Important note, that I learned from the racers,
      rough running is an indication of too much advance. Why? Because the engine is working against itself, and will vibrate. So, ie, vibration is incipient knock. You can only appreciate this fully if you have built and tuned as many engines as George Miller and I have built.

      I have not seen a procedure written up.
      It is time consuming to do so, I might just call you on the phone.
      But first let me see if I can get some pictures of the spring and shim setup we use, and post them.
      It takes waay longer to write it up than to do it. I could have had it all done right now in the time it is taking me to write this.
      I am balls to the wall over here right now, so give me a few days and let me see what I can come up with


      • #4
        Thanks Dave; a photo will help if needed to change or adjust springs..we have a tach/ timing lights etc. The engine idles great with Allstate carb.on 100 mile motor.Spark plugs are nice clean tan. FS instructions say the Zip is fitted w/ 20 thous.springs and assume heavier springs will limit the advance, which we think is needed on steep hills.


        • tbirdtbird
          tbirdtbird commented
          Editing a comment
          last I knew the zipper had .016 springs
          The stronger springs will NOT limit the max advance, only change the shape of the curve

      • #5
        I have the FSI Zipper, Snyder 5.5 head and the F150 OD tranny (same as plyfor has). I have no idea how it was set up, as my engine builder (Ron Kelley) set up the timing on the engine. Ron is an FSI dealer and presumably knows what he's doing. I have several thousand miles on the engine set up that way and have been very satisfied with it.
        Alaskan A's
        Antique Auto Mushers of Alaska
        Model A Ford Club of America
        Model A Restorers Club
        Antique Automobile Club of America
        Mullins Owners Club


        • #6
          Ron Kelley knows exactly what he is doing. You have nothing to worry about. Every A owner should be so lucky!


          • #7
            OK, this thread has triggered a lot of questions and PMs and such.

            I am not sure that I can word this properly, and I surely mean to offend no one, so bear with me, I'll try my best.
            There are certain facts of mechanical life that cannot be avoided, and what I am gonna sum up here, again, is a combined knowledge base of an Model A racer I happen to know, Dave Gerrold, an outstanding engine builder, and my own personal experience as an engine builder of many varied Marques of cars over at least a 45 year career. Oh, and add to that the knowledge of Mel Mallory, former partner with JD at FSI, who sadly died about a year ago.

            You need some decent mechanical experience and especially experience with tinkering around with engine timing on a bunch of different cars, to get on board the train. Experience only with timing a model A will not help, because it is timed so very differently than any other car. And, for a stock motor, with a 4.2 head, the timing could not be simpler.
            BUT toss on a HC head and everything you just learned goes out the window.

            1. Stock (4.2 CR) timing max should be about 28-30°. The Zipper comes with 28° built in, and CANNOT be changed
            2. Timing max on a 5.5 head is 23°
            3. Timing max on a 6.0 head is 21°
            4. the springs inside a centrifugal dizzy such as are any made by FSI do NOT change the max timing; they only change the rate of advance, ie the timing curve. Please google this "timing curve" for additional reading if this is not something you are familiar with
            5. I was asked about the police head with 5.2 compression, and I have no direct experience here. However, extrapolating from the other heads I would think that 25° would be a place to start for the max timing
            6. The higher the compression of the head, the more the timing has to be decreased from stock
            7. FSI corp. also offers the so-called FSI dizzy. It comes with advance at about 28°. A 'shim' supplied by JD at FSI can be used to limit the max advance to 25°, and another spring combination they have available can be used to change the curve. Please note that changing the curve is NOT the same as limiting the max advance. You will be using 2 dissimilar springs to change the curve, you want the max to kick in more slowly
            8. To get the max advance down below 25°, I specially make my own custom 'shims'.
            They are time consuming to make and I do not sell them, you would have to make your own. Really not that hard, just tedious. I make them from .030 stainless sheet metal, but you could use aluminum, which is what JD's are made of. Per Mel, a thickness of .030 is the exact thickness you want.

            Over the years there have only been about 10% of the people that have contacted me that I could help. The others could not let go of their myths and misunderstandings, and I told them they needed to talk to someone other than me for advice. Please note, there are many many people who will jump at the chance to offer advice. So, the very next question should be, what are their qualifications?

            I am so very sorry if any of this sounds high-handed, since that is not my intention. I can only play the game according to the rules of science and fact. If there are other rules going on, I am out of the game.

            By the way, max timing settings more than shown above WILL do engine damage

            I will try to get up some pix soon, but I have some huge family obligations right now


            • George Miller
              George Miller commented
              Editing a comment
              Very good and true. On your 10/% you are doing better than me.

          • #8
            Tbird thank you, after having built race engines and dealing with folks who want to know or think they know I appreciate where you are coming from and as you said the springs will only alter the auto advance characteristics and cannot limit the amount of advance. I will look into this distributor later this evening trying to get everything buttoned up outside for winter cause I will be roosting in the shop tomorrow. Mitch there is a lot of good tips and stuff on this site and this could be a great tech section thread when finished. Dave I was thinking in the ball park of 24-25 degrees since the B head is a little less compression ratio. There is a lot of good info here about what is out there.


            • #9
              Chief, I agree with you. I think I would get the off-the-shelf shim from JD and expect you to be fine at 25°


              • #10
                At what rpm is the timing max on these? This depends on the spring strength, correct?

                The NuRex unit,says it will provide 10 to 12 degrees per thousand RPM. What are the thoughts on this unit?

                I don't know what happened to the thread I started yesterday on this subject, all I can think is I fat fingered a delete. If I have that option. Sorry about that.


                • tbirdtbird
                  tbirdtbird commented
                  Editing a comment
                  I have mega family obligations right now and will be off line for the next 5 days at least

              • #11
                I have the adjustable FSI distributor in mine. Like the others I have a 7:1 Winfield head .100 over bore a Stipe 340 cam and an F150 trans. I got the advance to work good in cruise mode by changing the springs and welding up the slot that sets the amount of advance. To climb hills, I was advised by Mel at FSI to remove the screw that holds the plate in position and machine a slot where the hole was. I then replace the screw but leave it a little loose. It is held in place with some locktite. The original timing arm is then attached to the plate. I then set the base timing with the lever all the way down. This is my normal running position. To climb hills I can lift the arm and retard the timing about 5°. This is enough to keep it from knocking under a heavy load. My timing is roughly 10° advanced at low speed and 25° at full speed.
                1930 Sport Coupe, 1965 Lotus Elan


                • #12
                  Bettlesr, your explanation sounds consistent w/ info from JD concerning the springs. Do you know what springs you changed to: 16, 20, 26 thous.? The larger springs will evidently slow the advance and the springs can be mixed according to JD. Do you set your timing at 0 deg. TDC first with the lever all the way up, then use a timing light to get smooth idle?


                  • #13
                    Dave, Gods speed with resolving your family problems in the best way possible!

                    I too would like to know what I would need to do to keep my NuRex centrifugal advance system with putting the B head on my engine. I have time and will wait until you have resolved the problems and have a clear head.

                    You wana look waaay far up da road and plan yer route because the brakes are far more of a suggestion than a command!


                    • #14
                      I set my advance to 10° with the lever all the way down using a timing light and then played with the springs and slot width to get a max of 25° at 2000 rpm. I had a bunch of Chevy springs left over from my Corvette and used them. The engine idles well at 350 to 400 rpm. I am still playing with the jets on my Weber 32/36 carb. Still slightly lean just before the secondary barrel opens.
                      1930 Sport Coupe, 1965 Lotus Elan


                      • #15
                        bettlesr, thanks. Do you know what your advance reading is at with the lever all the way up? This would help since I'm not at the point to make the upper plate movable. I want to deal with the springs and try to get the advance modified if possible. Mine likes to idle at about 3- 5 deg. beyond TDC at around 450 rpm due to the hc head and carb mixture. What did you due to the slot width, i.e., is that the slot you enlarged at the plate hole or elsewhere?


                        • #16
                          The hole for the screw that holds the upper plate in place is the one I slotted. Not sure what my timing is with the lever full up. Next nice day I will check it against the timing light. You can't make the slot too long as you are cutting across the width of the arm and it isn't all that wide.
                          1930 Sport Coupe, 1965 Lotus Elan


                          • #17
                            My latest engine has a 5.5 head on it, a cam modified to close to B specs (don't know exactly) and a down draught carburetor. I realise the standard 28 deg advance is too much and in the past, I have set the timing 6 or 8 deg after TDC. That, I figure has the timing with a 28 deg distributor at full advance the same as one limited to 20-22 deg. I believe that 20-22 deg is pretty right for a motor like this. That has worked well in the past but this engine vibrates some at low speed and smooths right out at higher speeds. From earlier posts here, I'm thinking it might be timing related. Your thought would be very much appreciated.
                            Oh yes, it also has a counter balanced crank running in inserted bearings.
                            FWIW, I did 160 miles at about 50-55 mph yesterday and was very happy with it at highway speed.


                            • BNCHIEF
                              BNCHIEF commented
                              Editing a comment
                              Greynomad my engine is pretty close to what you have, my car idles perfectlt with the zenith i am about to put a weber on it however so i will see what that does. I am wondering do you get any advance at idle with this set at 6-8 deg atdc I am wondering if that and carb adjustment might not contribute since the engine smooths out at speed.

                            • Greynomad
                              Greynomad commented
                              Editing a comment
                              BNCHIEF, I get no advance at idle, which is what I would expect. Good thought though. As for carb adjustment, this motor is fitted with the same one as my others (a locally made Stromberg as used on Holdens from 1948 till about 1963) and they run fine. I'm probably being a little too picky because I could live with the vibration. On the other hand, if something can be improved, I say "Why not?"

                            • BNCHIEF
                              BNCHIEF commented
                              Editing a comment
                              Yeah the low speed vibration is a little strange, probably some goofy little thing when you find it, good luck.

                          • #18
                            Not to confuse things but i have a fsi zipper I assume you are talking about a regular fsi distributor, the shims Tbird talked about and after talking to JD are for the fsi distributor and will allow you to reduce the maximum advance by 5 degrees the zipper is a whole different matter. Hope that helps some.


                            • #19
                              BNchief is correct; the Zipper can't seem to be advance- adjusted easily which has been our issue; think I'll pull it and install modern points distrb. for now until we can figure it out. It's great on start up and on flat terrain, but under load up steep hills, it needs some attention.


                              • BNCHIEF
                                BNCHIEF commented
                                Editing a comment
                                Plyfor I am working on a way to be able to alter that, gonna be a little while however.

                            • #20
                              Not to offend anyone, but we pulled the Zipper in favor of modern points/ rebuilt stock dizzy--12 volt neg . ground. Set timing with a light bulb to the points arm and ground with lash removed. Took about 3 tries and the motor has never idled better. Set the point gap to .019 for the 5.5 head to get better retard. We had to rewire for the 12 volt coil: coil + lead to terminal box, coil - lead to ignition switch. Also, we tried the Nurex timing tool from cam to cap. Wasn't as accurate as the test lamp but that may be case specific.


                              • Mitch
                                Mitch commented
                                Editing a comment
                                As mentioned many times the nurex wrench gets you close but not on the money

                              • BNCHIEF
                                BNCHIEF commented
                                Editing a comment
                                Plyfor I got mine going great with my zipper fixed it so maximum advance is 25 degrees, I am also running a weber carburetor and my car idles beautifully. My plugs are gapped at 40, engine does not ping 87 octane no ethanol gas. 180 thermostat with 1/4" hole. car runs at 180 as well. temp is important to get good combustion.

                              • BNCHIEF
                                BNCHIEF commented
                                Editing a comment
                                By the way plyfor your not going to offend anyone it is your car and your money and what works best and makes you happy that is the bottom line. The nurex wrench is a ballpark tool and great for a place to start or a complete novice for guys who really know what they are doing no. I use it to get a quick point to start from.

                            • #21
                              Tbird, thank you for starting this thread. Very informative. I also have a FSI Zipper, 5.5 head, larger intakes, and a bgrind. I was having issues in changing the timing.


                              • Mitch
                                Mitch commented
                                Editing a comment
                                I agree Dave provided us with expert proven information

                                I thank him too

                            • #22
                              Chief, if i recall you had the police head, 5.2 compression? What did you do to the zipper to dial it back to 25°?

                              No ping is nice; it must also run smoothly with no vibration through all rpm ranges to know it is not over advanced. Vibration comes just a hair before ping happens


                              • #23
                                I took some metal tubing and brazed it in the slots where the weights reach full advance I then went to my neighbor and used an end mill to machine this back and kept playing with it until i got it right if I get my hands on another advance I have thought about using a set screw w/blue loctite and drilling thru the advance base so the screw would limit the advance and it would be adjustable. I know exactly what you are talking about remember Tbird I am also running a weber downdraft.


                                • #24
                                  FS told me they eliminated the small positioning dowel into the head to reduce the $50 added distrib. body casting costs., also allowing the ability for the entire distr. to be rotated very slightly. Even that wouldn't get the retard down enough. Also, BN chiefs comment about the thermostat leads into another discussion about originality vs. more operational improvements. Our recent rebuild eng. never goes above 150 or 160 deg. without it and there doesn't appear to be a thread consensus what is "best". With an F150 4 speed, we can down shift easily but couldn't get the knock removed on hills with the Zipper. Perhaps the other FS distr. combo is more forgiving.


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