Hi guys - I know many of you around here have cummins or other diesels in these trucks, and many of those trucks are 60's and 70's - so someone has to have done this...

I was looking at my in cab tank last night and wondering what all would have to be done to use it with the cummins.

In taking out/getting rid of the old charcoal canister/breather line I followed it back up the tank and thought that might work well as a return line.

Anybody used the in-cab tank for a diesel swap?


Also - I know this is kind of a moronic question but I have no clue how many gallons the in cab tank in my 74 holds as I never filled the whole thing and it's been years since I filled any of my other 70's trucks... How many gallons is the in-cab tank?

 

the tank should be in the 20 gallons range, it might be better to start with a new incab tank just because i am sure you will have to do osme cutting and welding if for nothing else a supply or return line and i wouldnt want to be welding on a tank that once held gas, you will also have to clean it out.

 

I was planning on taking the tank out and cleaning it out before using, but my supply line would be the same as the stock supply line, and I was planning on using the line that comes in the tank for the charcoal canister as my return line.

 

The canister line is the vent line isn't it?

That would leave you without a vent, guess you could use a vented cap.

-Enjoy
fh : )_~

 

"T"ing in a vent is easy. Well, easier than tapping a new line for the return. I was just wondering if anybody else had any other concerns I should know about.

 

How would you T in a vent??

-Enjoy
fh : )_~

 

On the low pressure return line that drop into the top of the tank

 

I'm not sure that would be a good idea, That might turn out to be a disaster... Bi-directional flow.

There are shops that will clean the tank and braze in additional bungs.

Not me ... I'm to chicken! I've seen the results of it going bad!

What about tapping into the filler neck for the return.

-Enjoy
fh : )_~

 

You have a good point. That is why I was asking if anyone else had done this - to see what they did.

IF I were to "tap" into the fill - I'd probably just T into the breather line on the fill neck. This would not have the same "bi-directional" flow as my other idea because the return line would not be in use while the vent line was (while fillin the truck)

Any thoughts on that one?


As for shops cleaning the tank and brazing on new bungs - around here they seem to charge more than it's worth to me. Maybe I'm just cheap Ok - there is no maybe needed

 

Yea, You probably could buy a new tank for what they would charge to do that today... Especially in SoCal.

It does have a filler vent??
Then using the Canister line doesn't seem like such a bad idea without a T, The tank will still be vented via the filler vent.

Is the filler pipe part of the tank?
If it's not, remove it and you could braze a bung in it. Closer to the tank the better.

I personally am not liking the idea of any T in a vent line for the return...

-Enjoy
fh : )_~

 

1961/77 F Series Trucks: There were five different in-cab fuel tanks.

The same tanks were used for Gas or Diesel.

1961/69: The in-cab fuel tank was 17.5 gallons.

This 17.5 gallon in-cab fuel tank (C1TZ-9002-H) was replaced by Ford in 1970 with a 1970 (1970/72) 19.5 gallon tank (DOTZ-9002-A) for use as a service part replacement.

There were two different fuel tanks used 1970/72, because in CA, all 1970/72 F100's had the Evaporative Emission system installed.

The in-cab tanks (with or without Evap. Emission) used 1973/77 are different than were used in previous years.

The 19.5 gallon non Evap Emission tank (DOTZ9002A) used 1961/72, has been reproduced by Blue Oval Truck Parts.

 

I'll take some pics tonight to clarify, but there is the little side tube/line off the filler neck that goes from the top of the tank to the side of the filler neck. So it is not really vented to the outside - but rahter to itself. I could still T into this and use that for a vent and the old vent for the return.

Both the stock supply and vent lines are on top of the tank and looked to be NPT bungs.

In all actuality my gas cap is probably worn out/loose enough that it would "breathe" enought to be a vent line


The old plan was to use the stock dodge tank. After a little looking/measuring and realizing it wouldn't fit, that plan changed to throwing the stock dodge tank in the bed and plumbing it until I build a custom aluminum or steel tank. Then, after looking at the stock, in-cab tank just recently I thought I might use it for a while, and then add on a secondary tank only if I need more capacity. This could get tricky with return line valves (had lookied at using 2 of the in floor tank selector valves) and sender wiring...

 

The non Evaporative Emission in-cab fuel tanks are not vented, the gas or diesel fuel caps are.

You must use a vented fuel cap with the non vented tank...or the tank could collapse.

For gasoline engines, Ford used the same vented fuel caps from 1948 thru 1977.

The original fuel cap was painted body color, a chrome version was available at the parts counter.

The chrome fuel cap: B6TZ9030A (Motorcraft FC23) is still available from Ford, and from autoparts stores.

Today, this cap is supplied to Ford by Stant.

 

Thanks for chiming in N.D. My 74 was originally ordered here in LA if remember correctly, so I would think that the tank would be the Calif. emissions version - IF it is still the stock/original tank after all these years.

Are there any diagrams in your old books, or is it just part numbers? I'd like to see the difference in 1) the with/without evap. emissions version of the tanks, and 2) the way they ran the return lines on the diesels.

Maybe it's time for some picture/diagram hunting?
I would think the diesel versions using these in-cab tanks would be the F-650 or so?

*edit* - N.D. you seem to have edited your above post a bit, and added more info. It looks as if I just need to hunt for a vented fuel cap now???

 

I just edited in the vented gas cap info.

I edit A LOT. It's a good idea to read my posts again after the FTE one hour editing time limit expires!

You are welcome to come on by and look in my parts catalogs...which are the exact same ones the dealers use. The catalogs have any diagram you'd like to see.

I don't know if Theodore Robins Ford in Costa Mesa still has the 1973/79 FORD LIGHT TRUCK PARTS CATALOG...or not.

If your DSO code is 71 (SoCal) or 72 (NorCal), the truck was sold new in CA.

btw: Blue Oval Truck Parts is located in Anaheim.