Good day and Happy New Year to you too, Jean-Paul, Sadly, I do not have any of my blocks left including the small 2-fuse fule pump fuse block used on the BBi's. I have yet to source replacement base material, as what I used originally is no longer available. Unfortunately, I cannot provide you with any time frame as to when I will have blocks available and so you will have to explore other options... either purchasing some of "Birdmans" fuse blocks (for the larger left/right blocks) or perhaps there is new stock available, or rework youyr existing blocks as a preventative measure (see my earlier response about things you can do: https://www.ferrarichat.com/forum/threads/boxer-fuse-block-upgrade.140216/page-13#post-147878584). Cheers, Sam
Dear Sam, thanks for your comprehensive answer, always a pleasure to get practical advising from yourself. As you could see on my 2 previous pics the connectors and fuse blocks are "as new" without any oxidation nor loosen connectors on tabs. So little room to improve on that side, just poor contact with these bloody conical fuses. But I take your point to mesure with my ammeter the amperage of each circuit: always good to know and mostly for both fuel pumps and radiator ventilators when on duty (any over-amp?). Otherwise I looked to Birdman's website and it looks fine even if I would have preferred your solution with flat modern fuses. For a 512BBi they supply, included, the 2 fuses central block for the fuel pumps, but the 3 plastic covers can't be fixed up to the new larger fuse blocks. Anyway, I will order to secure the situation on this weak point of the BBi. Thanks again, and regards, Jean-Paul
Good day Jean-Paul, You are most welcome! Measuring the circuits that have the high current draw is very important. Ferrari's wiring, etc was marginal at best and so drawing more current than about 1/2 the rated fuse size can be a concern. Some circuit loads can draw more current over time do to aging. The radiator fans are a good example, where the motor's electrical bits (commutator and brushes) can be an issue, but also the bushing lubrication could become gummed up, dry, etc... all of which will affect the motors efficiency and current draw. In addition to the circuit draw, measure the voltage drop across the fuses themselves. Ideally the voltage drop should be 0 Volts, but with age, oxidation, clamping force, etc the voltage drop can increase. Since the circuits can draw a reasonable current and the higher the voltage drop means the fuse will be dissipating more power which will result in heat... which if left unchecked can cause significant damage to the blocks. A picture of this is within this thread near the beginning and is from my black fuse block... and it was this that triggered me to create a suitable replacement. Cheers, Sam
Dear Sam, Indeed, I will add voltage drop survey to amperage one. I had a look to your melted fuse block!! My goodness... For mine, since new, it is OK but the main issue of high temp was reported on fuses. Since plastic nowadays, the frame of the fuse melts and shortens occurring loose of contact in the conical area. I suppose that in the 80's they were ceramic, but impossible to find now: just plastic. Anyway, definitely changing to Birdman's glass tubular fuses, I will secure the situation. For another 330GTC, the fuses are the same design, conical, but without any major issue on both fuse blocks. But in case you (or another Chatter) would know where to find these fuses with a ceramic frame, instead of fragile plastic, I would be grateful. Cheers, Jean-Paul
Good day Jean-Paul, Indeed, my original fuse block should serve as a reminder to thoroughly check, clean, rework, etc the original fuse blocks. Also, this fuse block and its condition as how I received my car. The Ferrari dealer at the time simply installed external bypass fuses for these circuits. For the longest time replacement fuse blocks were not available which no doubt forced the dealer to use the repair method that they did. As for the fuse base material... Technically it should not matter if the material is ceramic or plastic, as the voltage drop should be very, very small and so the resulting heat generated by the fuse material will also be small and so a ceramic base would not be required. The plastic base material only becomes an issue if the voltage drop across the fuse is much larger than it should be. Consequently, it is very important to periodically clean the fuse and fuse clip contacts from oxidation along with ensuring the fuse has sufficient clamping force. As to who now makes the original bullet fuses with a ceramic "frame" as you call it...Unfortunately, I have not found a manufacturer that does this, but there could be. As for the earlier Ferrari fuse block designs like the 330GTC, etc... They also suffer from the same issue as the Boxers, but less frequent. My guess is that the circuit loads are lower, but also the base fuse block material, contacts, etc are different too. All of the various components used in the fuse blocks can influence the resistance through the fuse block circuit. The higher the resistance, the more heat is generated within the fuse block and fuse, and less voltage is available to circuit. If the fuse circuit load is lower... then less heat would be generated and so the blocks could last longer with less issues. After I made my Boxer blocks, I was going to reproduce blocks for earlier Ferrari models as well using the same approach and with modern blade fuses. I acquired some older Ferrari damaged fuse blocks to review, etc. However, as time marched on and other projects arose, I never had the spare time to work on these other models. That said, I will be creating replacement fuse blocks for my 365 GT4 2+2, as these have issues similar to the Boxer, but not nearly as bad. Since the early 400 series share the same blocks as the 365 GT4 2+2, my efforts on my car will benefit 400 models too. Cheers, Sam
Good day ScudF1, They only melt if enough heat is applied to them... Blade or ATC modern fuses are encased in plastic and they do not melt under normal or expected use. The heat generated across the fuse can be calculated by Ohm's law: Voltage (drop across the fuse in Amps) X Current through the Fuse (in Amps) will produce Watts which will be dissipated as heat. Since the circuit current is relatively fixed by design (e.g. circuit loads and number of them), any increase in the voltage drop across the fuse will increase the heat generated by the fuse. That said, using ceramic fuses would be better.... but could actually mask a circuit that has excessive current draw and/or a higher than designed fuse voltage drop. Cheers, Sam
Newer ceramic fuses have better metal tips/ends on them. The older original fuses the factory used may have the older lead or tin plating on the ends. These ends tend to corrode over time and cause voltage drop and heat as mentioned above. This heat can cause the clips that hold the fuse to loose tension, further increasing the heat. This heat then softens the plastic materials around the rivet as mentioned previously. It is a good practice to check the tightness of these fuses in their clips, and re-tighten them if loose. Also, clean the fuse tips and clips from time to time. The increased current use in the newer cars, fans, A/C, windows, etc., have far exceeded the design limits of these older ceramic fuses. Thus, replacement or periodic service is needed.
Thans to contributors for their reminder of Ohm's Law. Indeed, as Sam outlines, true ceramic fuses may hide, by resisting better to heat, excessive Amperage from the consumer or other miss-contacts. BTW, Billy, could you fwd the link to these ceramic torpedo fuses? Because I don't see see them from France on eBay. Other vendors qualify "ceramic" as generic name, whereas they are plastic. Cheers, jean-paul
https://www.ebay.com/itm/373372875953?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=TSovrppBSMu&sssrc=2349624&ssuid=JSKiA9wnSLW&var=&widget_ver=artemis&media=COPY
Dear Sam and other contributors, I come back just to tell that I changed the 3 fuse blocks of the BBi for the Birdman 308’s ones (for glass fuses). Good vendor, easy change and contributes to tighter contacts and low voltage drop. Now remains only one contact at 60 C for one fuel pump, still high but acceptable, even if amperage measured are ok. Thanks again for your advices, feel now confident, mostly for ventilators circuits! Cheers, Jean-Paul
Good day Jean-Paul, That is great that you have found a suitable solution! That said, 60C seems very warm to me. What is the current drawn through this fuse? Also, what is the voltage reading at each side of the fuse referenced to a good chassis ground? Although measuring the voltage across the fuse would provide some info, I would be interested to see the absolute voltages as well (with the absolute voltages, the voltage difference... e.g. voltage across the fuse... can be calculated. Cheers, Sam
Dear Sam, I agree with you that 60C is too high even if there is no more risk of fire/fuse melting. I had measured the amperage with my ammeter (one with clamp around the wire) for continuous current: well below 16A (fuse spec) but I don't remember the exact value, sorry. As you suggest, I will do a comprehensive measurement of A, U and report to you. But I will be away of the 512BBi for a week, and will do it afterwards. Thanks again, best regards, Jean-Paul
Good day Jean-Paul, Understood. Be aware that clamp on style DC Ammeters can be inaccurate depending on the manufacturer, but also the current magnitude (e.g. larger currents tend to be more accurate). I typically use a series ammeter and log the values over time to determine the peak current and its duration. As I mentioned very early in the thread, the Ferrari circuit testing I found that the current draw was anywhere from about 50% to 80% of the rated fuse size. If any of your circuits are close to the rated fuse size or at the fuse size itself, then something is amiss and should be investigated. Secondly, a fuse will expire over time if operated at the fuse size current. Lastly, Ferrari's choice of wiring (wire composition, stranding, diameter, insulation choice, etc) is so-so at best and so supplying current even at the rated fuse size level could be putting the original wiring and your car at risk. Cheers, Sam
Thanks Sam (Ohm would be your family name?). Agree on all, I felt easier to use the clamp instead of connecting a serial circuit for the Ammeter (surprisingly with this brand new ammeter, on other trials, I didn't find much difference between clamp and serial measure, so...). Let's see the survey results in a few days. Cheers, Jean-Paul
Hi Sam, I just completed some measurements on the BBi, after some minutes running idle (remember the fuse blocks have been changed for Birdman's glass fuses): Fuel pump LH: 10,8A. Voltage upstream fuse 13,7V and downstream 13,6V. So, P=146W Fuel Pump RH 10,2A . U= idem LH. So, P= 138W. Temperature with IR gun around 40 to 50°C (if meter is accurate) , but quite hot on finger for one fuse. As car was completely renovated 2 years ago, pumps are new and I feel that is slightly high amperage. But I can't find W specification for the Bosh fuel pump. Any experience? Another big and important consumers are radiator fans. Amperage for 3 fans motors measured on alimentation wire 28A (couldn't measure individually), for 3 fuses 16A downstream, which looks OK (9A per fan?) ; maybe somehow high but fuses aren't hot (say 35°C). For this amperage my Ammeter cannot be used in serie because limited to DC 10A, so clamp was used with limited accuracy. And I cramped slightly the upper female connector on alimentation since found some loose. Thanks for any comment, but, even if not perfect for fuel pumps, the situation improved vs previous torpedo fuses blocks, if not wrong. Cheers, Jean-Paul
Good day Jean-Paul, You are too kind and funny to suggest that last name having "ohms" in it ... actually my last name should be "sparks", as this tends to happen more often than not... Thank you for the additional information! Ideally you want to measure the voltage across the fuse, as this would be the most accurate. That said, something seems amiss to me. I say this, as the voltage across the one fuse is approximately 0.1V given your measurements (13.7-13.6V) and with a current of 10.8A means that the power dissipated (or consumed and emitted as heat) by the fuse is 0.1V * 10.8A = 1.08W This is not a tremendous amount and really should not be so hot that you cannot hold your finger on it, but you stated it is indeed too hot to the touch. I will need to do some bench tests to see what the temperature rise is for a glass fuse, but my gut feeling is that either your voltage or current measurements are incorrect. I will report back with my findings. Perhaps it is nothing and this it just the way it is, but it is worth checking in case there is something going on... and something that should be investigated further. As I said, Ferrari's choice of wiring is crap... and it does not take much for it to fail. Cheers, Sam
+1, but the problem may be where the voltage measurement is being made. Measuring between the two end caps of the fuse, or even the metal terminals holding the ends of the fuse, may not give the real situation. The voltage measurement should really be made between the bare wire strands entering the female spade terminal at the top of the fuse and the bare wire strands exiting the female spade terminal at the bottom of the fuse. That way it also detects any bad connection(s) between the wires and the female spade terminals, between the female spade terminals and the male spade terminal, all the connections in the fuseblock itself, and between the metal terminals of the fuseblock and the metal end terminals of the fuse. Because all of these components have good thermal conductivity to each other (even in a "poor" electrical connection situation), they all heat up a lot if there is a bad electrical connection (meaning something as small as 0.030 Ohms which isn't really very bad at all, and the device run by the fuse still works just fine) in any one of those connections.
Good day Steve, That is true... however, Jean-Paul, replaced the original blocks with those from Birdman and so the connection from the spade connector to the fuse cap is very short and a single piece of metal if I recall... but perhaps I am mistaken? More info is needed in terms of where the voltage measurements were made along with the fuse block's construction. To rule out any potential error in the DC clamp on style ammeter's current reading, I would use a precision power resistor installed in series and measure the voltage across it to determine an accurate current measurement. I have chased my tail more than a few times with erroneous meter readings and so I have learned to double check measurements if something seems a bit odd... and the high temps in this area seems really odd to me. Cheers, Sam
I wouldn't doubt his CIS fuel pump current measurements that much as 9A~10A~11A is in the right ballpark for that device, but the voltage drop (i.e, the resistance in some connection) has to be higher than the .1V (0.009 Ohms) that his initial measurement indicates to generate that temperature.
Good day Steve, Agreed. However, something is consuming power/radiating heat and the resulting voltage/current data is not agreeing with temp and empirical measurements. Cheers, Sam
Agreed, but he needs to include every connection in the voltage drop measurement (even the wires being crimped into the female spade terminals).
