ArdWrknTrk Posted March 3 Share Posted March 3 Is this one similar to the school bus muffler you have ? https://www.amazon.com/Walker-21533-Quiet-Flow-Stainless-Muffler/dp/B001DR7VTC#customerReviews That thing has rolled seams, like a can of beans. The one I bought was 14-15 Ga and has domed ends welded on. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 3 Share Posted March 3 That thing has rolled seams, like a can of beans. The one I bought was 14-15 Ga and has domed ends welded on. This one is all welded stainless steel. It doesn't have rolled edges to rot out. Dual 2 1/2 in 3" out, 22" long. https://www.bearriverconverters.store/products/jones-mf2588-muffler-no-stock Link to comment Share on other sites More sharing options...
viven44 Posted March 3 Author Share Posted March 3 This one is all welded stainless steel. It doesn't have rolled edges to rot out. Dual 2 1/2 in 3" out, 22" long. https://www.bearriverconverters.store/products/jones-mf2588-muffler-no-stock Thanks! Looks like a high quality product. Only possible concern I have is that it claims to have a "a deep aggressive sound". I'm after OEM sound (as best as aftermarket can provide). Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 3 Share Posted March 3 Thanks! Looks like a high quality product. Only possible concern I have is that it claims to have a "a deep aggressive sound". I'm after OEM sound (as best as aftermarket can provide). At a good price. It's big enough that it shouldn't get loud unless you really get in it. 😉 Link to comment Share on other sites More sharing options...
viven44 Posted March 4 Author Share Posted March 4 At a good price. It's big enough that it shouldn't get loud unless you really get in it. 😉 Wanted to share an area of weakness on the dentsides. There is definitely more metal on these trucks but whatever plastic they used didn’t last as well as the bullnose ones. Maybe why Ford felt comfortable using more plastic on the bullnose as they had made it better. For instance when I pulled the gauge cluster this is all I recovered ! Fortunately LMC sells the backing plastic for $39 so it was easy to fix After painting needles with fluorescent paint and adding LEDs we are back in business I tested the oil pressure gauge, and coolant gauge using the short to ground method. Fuel gauge seems to work. Is there a quick and easy test for the charging gauge (unable to start the vehicle without exhaust currently) ? The wiring is same as a bullnose .. if I plugged in a battery tender type charger would that cause the gauge to go to C ? I’ll probably try tomorrow. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 4 Share Posted March 4 Wanted to share an area of weakness on the dentsides. There is definitely more metal on these trucks but whatever plastic they used didn’t last as well as the bullnose ones. Maybe why Ford felt comfortable using more plastic on the bullnose as they had made it better. For instance when I pulled the gauge cluster this is all I recovered ! Fortunately LMC sells the backing plastic for $39 so it was easy to fix After painting needles with fluorescent paint and adding LEDs we are back in business I tested the oil pressure gauge, and coolant gauge using the short to ground method. Fuel gauge seems to work. Is there a quick and easy test for the charging gauge (unable to start the vehicle without exhaust currently) ? The wiring is same as a bullnose .. if I plugged in a battery tender type charger would that cause the gauge to go to C ? I’ll probably try tomorrow. I think the flex circuit is available from a number of vendors, today... The ammeter is only showing the drop across the shunt. And the shunt necessarily has to pass all the current that goes into the cab (through the switched & unswitched fuse links. They never worked well. That's why CCI converts them to a voltmeter. Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 4 Share Posted March 4 Wanted to share an area of weakness on the dentsides. There is definitely more metal on these trucks but whatever plastic they used didn’t last as well as the bullnose ones. Maybe why Ford felt comfortable using more plastic on the bullnose as they had made it better. For instance when I pulled the gauge cluster this is all I recovered ! Fortunately LMC sells the backing plastic for $39 so it was easy to fix After painting needles with fluorescent paint and adding LEDs we are back in business I tested the oil pressure gauge, and coolant gauge using the short to ground method. Fuel gauge seems to work. Is there a quick and easy test for the charging gauge (unable to start the vehicle without exhaust currently) ? The wiring is same as a bullnose .. if I plugged in a battery tender type charger would that cause the gauge to go to C ? I’ll probably try tomorrow. Looking good, Vivek. As for testing the ammeter, Jim is right that it just sees the voltage drop across the shunt, which is pretty small. Here's the result of testing I did on 4 different Bullnose ammeters to swing them to full scale in each direction as well as the calculated resistance of the meter itself: Link to comment Share on other sites More sharing options...
viven44 Posted March 4 Author Share Posted March 4 Looking good, Vivek. As for testing the ammeter, Jim is right that it just sees the voltage drop across the shunt, which is pretty small. Here's the result of testing I did on 4 different Bullnose ammeters to swing them to full scale in each direction as well as the calculated resistance of the meter itself: Thanks Jim and Gary! I was able to observe functionality this morning but testing the "discharge" side of things. I saw the wiring diagrams for the 78. With the key-off, I noticed the shunt would see current draw if I turned on the Hazard lights, which it did, just did a micro-peg onto the discharge side. On the Bullnose trucks, once should similarly see a peg to discharge side if headlight switch was turned on with the key off. This is a quick and easy way to test the ammeter and see if it works. I found the shunt wire, it is absolutely massive gauge wire. Wonder if it can also support a 3G level current draw?? Fuse Link G is the shunt On the table below, I don't think i'm following what was done. Was the ammeter out of the truck and did you apply the voltages directly to it? Also why are the voltages 1/100th of the actual voltage ? Is that to keep from frying things ? That makes me think the Shunt is about 100 times lower resistance than the Ammeter itself. Link to comment Share on other sites More sharing options...
viven44 Posted March 4 Author Share Posted March 4 I think the flex circuit is available from a number of vendors, today... The ammeter is only showing the drop across the shunt. And the shunt necessarily has to pass all the current that goes into the cab (through the switched & unswitched fuse links. They never worked well. That's why CCI converts them to a voltmeter. Remarkably the original flex circuit survived as I think it’s made up of Polyimide type material. What disintegrated is the backing case itself which supports the flex circuit. Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 4 Share Posted March 4 Thanks Jim and Gary! I was able to observe functionality this morning but testing the "discharge" side of things. I saw the wiring diagrams for the 78. With the key-off, I noticed the shunt would see current draw if I turned on the Hazard lights, which it did, just did a micro-peg onto the discharge side. On the Bullnose trucks, once should similarly see a peg to discharge side if headlight switch was turned on with the key off. This is a quick and easy way to test the ammeter and see if it works. I found the shunt wire, it is absolutely massive gauge wire. Wonder if it can also support a 3G level current draw?? Fuse Link G is the shunt On the table below, I don't think i'm following what was done. Was the ammeter out of the truck and did you apply the voltages directly to it? Also why are the voltages 1/100th of the actual voltage ? Is that to keep from frying things ? That makes me think the Shunt is about 100 times lower resistance than the Ammeter itself. I had 4 different ammeters on the bench to test. I hooked my lab power supply up with a DVM measuring voltage and another measuring current. On gauge #1 when the voltage got to .125v in the positive direction the gauge was at full scale and pulling .75 amps. And when I reversed the voltage the gauge was at full scale at .147v and was pulling .88A. As for the shunt, the largest alternator the Bullnose trucks came with could put out 70A from what I read, although Jim and I've debated this and he's pointed out that there were 100A 1G alternators available. But most of the documentation I have suggests 70A was the max used in the pickups & Broncos and, if so, the shunt was probably sized for that. I probably have an intact shunt around here some place and ought to run a test some day to see how hot it gets at various amounts of current and we'd know - for that one shunt. But my here's some math: P = I * V so let's assume the shunt is sized such that it'll drop .132v (the average of my 8 full-scale readings) @ 70A and you have 9.27 watts. So if you put in a 130A 3G alternator you'll see 18 watts in a piece of wire maybe a foot long? Link to comment Share on other sites More sharing options...
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