Sometimes, You Eat the Bear...Sometimes, the Bear Eats You!

Hello Gray Ghost Fans!

It's been a busy couple of weeks since my last post.  We've seen so much rain that you can almost hear everything growing.  That means that there is no time for doing anything truck related.  Except for gathering parts!  In that regard, I've been collecting fuel system components.  You wouldn't think that there'd be too many, but there are a ton of bits and pieces.  Anyway, I've got a notional layout in my mind and some of the parts to make it work.  So, with a day off, it was time to get out in the garage.

First thing I had to do was to assemble the gas gauge sending unit and then attach it to the gas tank.  As usual, nothing comes easy, but it is what it is.  The gauges that I bought and installed

use the modern ohm range to drive the gas gauge.  Originally, Chevrolet used 0 ohms for empty and 30 ohms for full.  It stayed that way for decades.  Then, in the 60's or 70's the changed it to 0 ohms for empty and 90 ohms for full.  Then it stayed that way for more decades.  Now, it seems to be an SAE standard to use 240 ohms as empty and 33 ohms as full.  Anyway, the gauges came with the proper sending unit.  So what's the problem?  The sending unit did not have a fuel pickup tube integrated into it.  That meant that I could use the original Chevy method of drawing fuel from the bottom of the tank (and the new gas tank does have a provision to do that) or I could use the better method of drawing fuel from the top of the tank and get a different sending unit.  Well...long story short, I found one sending unit that would work.  Just one.  Once again, what's the problem?  Nothing really, except that when you get a "universal" part, you know you'll have to adapt it to your project.  So that's what I set off to do this morning.  The first part of the instructions were clear and I had to layout dimensions, based off of measurements from my tank.  The layout lines look like this:

Right away, I figured out what they were trying to get me to do.  Top of tank, bottom of tank, fuel reserve when the gauge reads empty.  The center line is where you put the rheostat and the float pivots from there.

Once again, since this is a universal part, I have to adapt it to my needs and the instructions told me exactly what to do.  The resulting modification looked like this:

Here you can tell that there will always be some gas in the bottom of the tank that I won't be able to suck up, but that is good!  That's where the sediment will collect, so I don't want to draw that gas up the tube anyway.  That is the primary reason why I went for the top fuel outlet, versus the bottom outlet which is correct for my year of truck.  To be fair to me, though, top draw was used by Chevy the very next year....

Next it was time to attach the float the the rheostat.  Once again, the instructions were good enough to get me close on the first try.  However, I think that there was a typo.  I'll explain in a moment.  To get close, you use the same drawing and put the float arm over the bracket that will eventually hold it.  Then you align the top of the float with the top (full) line on the page and mark where the float arm covers the hole in the bracket.  Add another 3/16" and make a 90 degree bend in the rod "in the same direction as the bend by the float".  This is where I think they made a mistake.  I think they meant 90 degree bend that was 90 degrees different from the bend by the float.  The reason that I think this is that making the bend per the instructions (as I did) puts the float arm end in the way of the set screw that attaches to that hole!  Anyway, a little grinding with the Dremel to angle the end of the rod to allow for some contact with the set screw and I think it will work.  Final assemble looked like this:

I included the close up of the set screw and lock nut to show you that the set screw uses a 3/32" hex to tighten it down onto the rod!  Small, but effective once I took some meat off of the rod.

Now, I know what you're thinking.  Not much else to tell, right Gray Ghost?  Well, not so much.  So far, I'd been eating the bear.  Now, he gets a bite of me.  Somehow, I have to fish that mass of sending unit/float arm through the hole in the top of my gas tank.  The instructions that came with the sending unit tell me that the hole must be 1 7/8" in diameter (mine was 1 3/4") or I could notch out areas to allow it to fit.  Good grief!  The last thing that I want to do is cut on my brand new gas tank!  What to do?  Suck it up and get out the Dremel and grinding wheels.  My thought here is to use the smallest grinder that I could, in the hopes of doing some "precision" work and not destroy my new tank.  Once again, very long story short I managed to make just enough room for the sending unit.  Finally, right?  Nope!  So here's where things really come off of the rails.  The instructions tell you to loosen the rheostat and slide it to the bottom of the pickup tube.  Then, angle the float so it fits into the tiny opening (it barely fits!) then rotate everything so that the rheostat can be inserted into the tank next.  OK, but what about that float hitting the side of the tank?  Oh yeah!  That's a thing!  It seems like there may be some play in the arm (I'm guessing if that's the case accuracy of the gauge will be affected) but the arm goes in and so does the rheostat.  Now, you have to "clock" the rheostat/float unit so that it will move up and down inside the tank without hitting the side and align the screw holes on the top of the sending unit.  Once you have done that, you have to tighten the screws on the rheostat to lock it into place!  Oh yeah, don't forget to set it to the right height...!  Dagnabit!  Ok, deep breath, we'll get through this.  Rheostat locked down, screw holes aligned, ground wire attached to one of the screws, time to tighten it down!  What the?!?

Well Gray Ghost fans, either there is a manufacturing tolerance issue or one of the manufactures used metric measurements instead of English, but those screw holes do NOT line up!

You've got to be kidding me!  Nope, not even a little.  I had been using the cork gasket that came with the sending unit, so I still had the rubber gasket that came with the tank.  When I laid the rubber gasket over the top of the screws that were in the sending unit, I could see that they were off.

At this point, I was drained.  Today was one of the hottest days so far this year.  I'm a desk jockey and not used to the heat.  Once this became clear, it was time for me to call it a day.

So, the plan of attack is to come back when rested and rehydrated and drill out those holes using the rubber gasket as a template.  From there, I should be able to mount the sending unit onto the tank and finally get to putting the tank into the truck.

I had no clue that today would turn out the way that it did.  OY!

That's all for now...I need a nap...and to regrow some backside where the bear took a bite!