The chronicles of Lou, '70 F350 dually Cummins project

[48prerunner]

Didn't see your truck at Carlisle guess I looked in the wrong spot. At least you got up on the level, I was on that side hill with the mustang on the way up there, cursed that hill every trip back to the car, but the weather was GREAT! and a front bumper for truck ($25 not counting the tape measure purchase) fit in the mustang .

[Ranchero50]

Yeah, I was on top of the hill in the gravel by the back gate, 2nd row from the fence. I probably walked past your car as there were some oddball classes on the side hill ('94 and up modified 6 cyl. mustangs, etc.). The Carlisle folks really need to get their act together and keep stuff together by year across the makes. There were new Mustangs scattered everywhere, same for the '60's and '70's stuff. Completely unorganized compared to years past. When we got there I told my boy that if they stuck us on the side of that hill that I would park somewhere else. I won't pay to put another car on the show field. Oh well.

I did see your bumper, it's a little nicer than mine and the chrome guys were charging $30 for a core so I almost bought it so I could get a rechromed one for @ $230 or $270. I was kind of bummed about the whole thing, didn't even get an event T shirt. I did get one with my renewal to Blue Oval Trucks.

Anyway, spent some time with the truck today. Worked last night, slept from 9-1 today so thing did not go as smoothly as they could have. As you can see from the pictures I worked in the gravel with jack stands so that was 2 strikes against things going well. I turned down some 1.5" aluminum tubing to 3" long and had bought a bunch of 5" 3/8" bolts to install the box to the bed. My line up work didn't turn out too well, I just winged the hole location and really should have plotted it out on the box and frames. The back of the box rubbed the leaf spring mount bolt the first time I hung it.


After trying to get as much clearance as possible I ended up with more overhang than I wanted on the front edge. I think I'm going to extend the bed forward a couple inches so it should look OK once finished.


The welding didn't turn out too bad.


Overall I'm happy with the work. I did find that my local Lowe's does not carry the key sets so I have that search to do. I did go ahead and fill it with the tarp and tie downs. There's even enough room to stand a gallon jug of antifreeze in the box. We took it for a ride and the box survived the trip.

Yesterday I did finally order my color swap LED for the cargo lamp.

[Ranchero50]

Today I fitted another prox and got the tach working. I also rotated the AFC pin a bit and it really woke up the engine but now it smoke if I get on it too low in the RPM band.

One cool thing is I'm putting along at 1200 rpm at 50 mph, 1600 at 70.

[Ranchero50]

Here's a post I started on one of the diesel forums about my tach setup...

OK, so for everyone who doesn't have the stock tachometer installed on their truck, here is a brief description of how I was able to use an industrial proximity sensor to drive an aftermarket tachometer. As with any modification, only work within your limits and understanding. I hope this is helpful.

First, the theory... Most aftermarket tachometers hook their sense wire to the negative coil post. The voltage at the point is low while the points are closed, then goes high when the points open and the coil fires the spark plug. As diesel guys we need to substitute a switched signal for the tachometer to read that is in time with the crank. Fortunately the Cummins crank has two machined recesses that we can use as a trigger for our tachometer. So, two timing points per revolution x two revolutions for a four stroke engine means that with the stock balancer we can set up our tachometer for a four cylinder car and use the balancer to drive it.

Second, the parts... Industrial proximity sensors are used dang near everywhere in industry, as such they are readily available, usually for little cost on the surplus or Chinese eBay markets. Proximity sensors can be configured several different ways and can be confusing to buy. Using the balancer as a trigger with the two recesses, we want a prox that has a low output when energized that goes high when it reads the machined recess in the crank.

In my case I ended up with a 12mm diameter PNP N/O prox. PNP means the prox's output is low when energized (N) and high when it is not energized (P). The N/O means the signal wire is normally open. Some tachs don't care as long as they see the trigger switch. This is where cheap proxes come in handy as it may take more than one to get yours working.



This is a picture of the bracket I made for mine.


Some concerns for the prox install are I wanted the prox and wires out of the fans air stream and supported to avoid fatigue. I also wanted my bracket to be strong enough to handle getting hit be belt strands if the belt ever decided to fail. I also wanted to be able to easily remove the bracket for belt replacement.

The bracket... My bracket was simply a short length of 3/16" thick steel I had in the shop. I bent it in my vise with a hammer. I drilled a 1/2" hole 2-1/8" from the back of one leg for the 12mm prox and a 5/16" hole 1-5/8" for the 8mm timing cover bolt.

Wiring... Wiring is very simple. Just hook the brown prox wire to your switched 12v and the blue wire to ground. The black wire will go to your 'tach' wire, usually the green wire on the tachometer. I chose to run my prox wire to join my tach wiring under the dash and tied everything together there.

Note in the picture above that once wired, you only want the prox close enough to the balancer for the indicator light to light steady. You want the indicator light to go out when the recess is in front of the prox. If the prox is too far or too close it will not read correctly and your tach will not work correctly.



Once installed I routed the wires through some tubing and secured it to the oil pan bolts. My prox uses a removable wire which may become a liability to corrosion.

This is my tach...


My tach I found on eBay a couple years ago. It's a 0-4000 rpm electric tach out of a Blue Bird bus. It has the selector switch for 4/6/8 cylinders and has a nice retro look in my '71 F-350. The housing I made out of scrap electrical tubing that I welded, machined, sanded and painted with a semi gloss clear coat to give it a brushed look.



So, hopefully this will help some other members get tachs on their trucks and help understand what RPM's their engines are doing interesting things at.

[Ranchero50]

Oh yeah, got my cargo lamp switchback LED installed finally. It's pretty worthless during the day as a CHMSL but does a good job at night. I did paint the white part of the inside of the lamp bright aluminum and that helped a lot.

[Ranchero50]

Thursday evening shot of the truck and boat getting ready to go to the river after suffering through getting the trailer lights to work with the truck lights while being sleep deprived...


Ok, after a goo nights rest today I decided to start extending the front of the bed. The bed extension will serve three purposes. One, it'll close up the gap between the bed deck and the stacks. Two, it'll allow me to move the tool boxes forward a couple inches for tire clearance and three, it'll allow me to make a cool headache rack.









I also spent some time today welding shut most of the bolt holes in the deck.

[Ranchero50]

First top of tank to top of tank resulted in 17 mpg running mostly interstate or loaded.

I did get my first tree July 4th, a 45' mutt that was storm blown over. Lowered the back of the truck 4" once loaded. On the trip home one of the rear bearings was making noise. Drove the truck to work Sunday and once I got it home, both rear hubs were warmer than they should be so I pulled the wheels off and all the lugs were too loose. I pulled the axle and the bearings look old and gunked up. The hubs are pretty tight as well so I'm looking for new bearings to do a rebuild on it.

[Ranchero50]

Friday I got some new sneakers for the back and then hauled dad's boat to the river.

[Ranchero50]

Still getting 17-18 mpg with a lot of interstate and hauling / towing use.

[Ranchero50]

So, I was a bit bored last night looking at the truck and decided to pull the stock air horn off and see what the inside measured...



Yeah, 2.1" diameter for the inlet. Area of a circle is 2rx3.14 or 2.1 / 2 = 1.05 x 1.05 x 3.14 = 3.46 square inches. My 2.5" OD tubing has a 2.38" ID which gives 4.44 square inches. Which means the stock air horn inlet flows a minimum of 77% less than the pipes feeding it.


The bottom is better, 1.75 x 2.5 = 4.37 square inches but it runs directly into the heater grid...


Welp, this is what I came up with as a replacement. A chunk of 2.5" mandrel bent exhaust U pipe from Summit racing welded to a chunk of 1/4" plate I had floating around the shop. The plate I bored and drilled in my mill but it could be done simply with a drill press or even by hand with enough patience. I did use a die grinder to clean up the inside where I had some weld penetration. So for a couple hours tinkering I should get 28% more air flow to the engine.


Some Rustoleum gloss black makes it look nice and with the extra height I can see what I'm doing when tinkering with the fuel system.


In other news, the truck is still averaging 18mpg and running well other than still drawing some air in the fuel lines.

[Ranchero50]

So, here we are, another year gone by. Truck currently has 65,890 miles on it, or at least some of it does

Been using it as a truck, dragging stuff around and hauling lots more stuff. Over the holidays my buddy gifted me the dump mechanism that I had taken from a '75 C3500 and put on a '90 W350. Now it's on a '70 F350. The hydraulic station is Italian, not sure what vintage but the parts are still available. I still need to wire the cab once I figure out where to put the switch. I've run out of real estate where the rest of the switches are. I also need to get my brake controller mounted so I feel something custom is coming.





Overall the truck has performed admirably and gotten a good many thumbs up from drivers as well as some guy doing a paparazzi attack at Long John Silvers a couple months ago. Mileage is still around 17-18 and I have a short list of leaks to address up front with the fuel system. I've also noticed that the trucks runs a whole lot more effortlessly once it's warm though so far I haven't had any trouble starting it on sub 30` days without the heater grid hooked up or it plugged in.

[Ranchero50]

Mechanism was salvaged from a '75 Chevy, then installed in a '90 Dodge and finally found it's way into my '70 F-350. Hydraulic station is fully electric. Main contactor to drive the pump and solenoids for up and down.


I used a starter solenoid for the contactor. It takes about ten seconds to lift. It was cold enough yesterday that I had trouble getting the heat shrink to shrink.


Mounted the switch next to the headlamp switch. I turned a little 3/4" aluminum bezel to match the other switch bezel's profile and glued a black cap on so it would look 'stock'. Yeah, that white stuff on the floor is salt stains. Trying to avoid that with the truck.


Now I need to remount my side box and then install my brake controller. Side box did not like hanging from the bed, have some cracks to weld together.

[Ranchero50]

Picked up a load of dirty crush and run today, truck weighs 6060 lbs with half a tank of fuel. I was surprised it was that light.

Dump bed raised enough to make it easier to remove the load but not high enough for it to self dump with the diamond plate. Didn't have any trouble lifting the 2 tons of stone though my back isn't happy about it after spreading it out.

[wndsofchng06]

Love this truck!! Glad to see you using it as a truck too.

[Hiroshi]

Awesome project Ranchero50!
I want a cummins 6bt in my truck too, learned a lot reading this thread.

Where can I find this emblem?