Sunflowers

The next morning in Davis we enjoyed a wonderful breakfast - poached eggs made by George Hines using a form he had made in the GreenBotics shop the evening before.  Fabulous! 

Morgan, Marc's mom, recommended Joey and I stock up on some provisions for our trip at the Davis farmer's market.  I have such a wonderful memory of visiting the Davis farmer's market when I was young with my aunt and unsuccessfully spitting cherry pits into the side streets.  It was hilarious, the stand owners even commented on how bad of a cherry pit spitter I was.  

At the market, we saw a cornicopia of fruits and veggies.  It was tough to decide what to get, but we decided on carrots, cherries, honey, and tamales for dinner.  The bunch of carrots were rainbow colors!  There were yellow, orange, red, and purple carrots!  

Davis felt like a little bucolic paradise. In front of Marc's house was a bunch of giant sunflowers. 

That day Cedric and George we off to fly airplanes at the Davis airport.  George had flown up from the bay area in a Citabria, and Cedric was going to be flying his home-built airplane.  They were going to do some aerobatics - loops and rolls. 

Fun fact: Citabria is aerobatic spelled backwards, well kind of: Airbatic

Marc and his brother Will and some of his friends were headed over to the shop to fly some RC airplanes, and to test out the drone they had built.  

Joey and I also headed to the shop to work on the van.  We were going to do some aerobatics ourselves.  Or at least burn as much gas. 

It was sweet working at the shop with airplanes zooming overhead - the RC and full size - we got buzzed a few times.   It was also amazing working around the gang, the enthusiasm for fixing stuff and making cool things was contagious.  

Okay - the van.  So we decided, since we were still having problems on the highway that this would be our best chance to try and sort out the highway/hill problem.  

We did a few road tests.  We wanted to eliminate the idea that the transmission was causing our problems.  If it was the transmission we'd not be able to go above 55 no matter how we accelerated.  If it was a fuel system problem, we guessed that stepping on the gas to 55 (like going on an on-ramp) was about as long as it took to empty the fuel bowls in the carburetor. If we accelerated more slowly, the pump might be able to keep up and the fuel bowls wouldn't empty and we'd be able to go faster. 

We did a few road tests, and when we accelerated more slowly - the van had some more juice after 55, a bit after that we started getting the starving symptoms.  When we floored it we got our classic symptoms around 55.  Sort of a shudder and "lug-lug-lug" sound from the engine. It was great the shop is on a county road with not much traffic.  There was a whole field of sunflowers too. 

We got back to the shop and decided to do a flow rate test.  The flow rate before getting to the engine is supposed to be about 16 oz in 10 seconds.  We measured 10 oz in 10 seconds. We repeated the test with the same result.  Something was constricting the flow upstream of the fuel pump.  

Joey would like me to clarify that the first fuel pump he installed actually met the specifications listed in the manual.  You see the fuel flow rate is listed two different ways.  First it is listed at 25 gal/hr then somewhere else the flow rate is listed to be 16 oz in 10 seconds.  If you do the math, the second flow rate is about double the first flow rate.  The first pump we installed was rated at 25 gal/hr.  The second one we installed is rated at 72 gal/hr.  

Okay. 

Upstream in the fuel system is an inline fuel filter (that Joey had recently replaced), the custom fuel tank, and the tank sender unit - a filter and a pump that has long since burnt out.   We figured our problem was the sender unit.  

We would need to drop the fuel tank, remove whatever was broken, and then re-install the fuel tank.  The first problem is that our fuel tank was about 3/4 full.  The second problem is that our custom fuel tank is huge.  In fact we didn't even know the real capacity - Joey guessed about 32 gallons. 

Thanks to Marc we scrounged up about 17 gallons worth of gas cans.  We had one 5 gallon gas can.  Joey heroically disconnected the tank drain and began filling the gas cans one by one.  I scrambled to position cans for him when he needed a new one, and lugged the full ones out of the way and out of the sun.  We filled up the 22 gallons of cans. The tank did not seem like it was getting empty. 

I ran and grabbed our 5 gallon all-purpose bucket, and an empty water jug.  Joey filled those up while I gave a Will's car 5 gallons of gas.  In the end we emptied 33 gallons from the fuel tank.  I suppose it's a 40 gallon tank.   Joey was covered in a fine mist of gasoline. 

Now for the hard part, lowering the gas tank.  Joey had done this once before on his own.  That seems unbelievable to me considering how hard it was for the two of us to get the job done.  Again, thanks GreenBotics for loaning us a car jack! 

Under the van we disconnected electrical connections, fuel lines, and loosened the metal straps holding up the tank.  Slowly, we lowered the behemoth. Okay, so it kind of crashed on the ground. 

At this point we removed the tank sender unit to check it out.  It looked like a custom job, the unit was mainly hose clamps with a bit of rubber and steel tube mixed in.  It looked like the old electric pump was sending gas through just fine - it was the filter that was the culprit.  Whoever assembled the sender unit used some rubbery sealant over some of the screws on the pump.  This stuff had partially dissolved and was coating the outside of the filter. It was black.  We poured some water over the filter to see if anything passed through it - no luck.  We poured water into the filter, and it just sat inside there with no place else to go. 

Well, we already had an inline filter, so we could get rid of this one.  Removing the filter and the old pump made it so the fuel line did not reach the bottom of the tank. 

Cedric suggested we use some of his aircraft fuel line and put a little weight at the end of it to keep the line at the bottom of the tank.  This is what you do in a fuel tank in an airplane.  So if you go upside down, you are still sucking gas from the "bottom" of the tank.  Awesome, aircraft-grade parts for the van! 

Joey got to work machining a custom aluminum weight for the fuel tank fuel line.  I spent the time installing a tachometer in the van.  This is important because we distrust the transmission and suspect some of the friction discs to slip in high-torque conditions.   I also installed a primer switch for the electric fuel pump so we could prime the carburetor in cold starting conditions. 

After Joey machined the custom aluminum fuel line weight and installed the new aircraft grade fuel line, we did another flow test.  The flow rate doubled. We were now seeing 18 oz per 10 seconds of flow rate. Woo-hoo!  Now the van can guzzle fuel to its heart's content. 

Eventually the van was all buttoned up.  We re-installed the fuel tank, the fuel lines, and the fuel level gage.   We did another road test, and the van passed with flying colors - we could not induce the starving "Lug Lug Lug" sounds we had been experiencing.  We were not entirely convinced since Davis is flat as a pancake. We would get the real test driving up to Lake Tahoe, our next destination. 

It was later than we expected, and we would not make it to Tahoe that evening.  I called my cousin Jeff and asked if we could stay with him in Sacramento.  Thanks so much Jeff and Uncle Paul for hosting us that evening.  We were a sight to behold I'm sure, and smelled like gasoline.