Blog Entry #22 September 24, 2013 – Conquering Tioga Pass on the way to Yosemite National Park

The morning of Tuesday, September 24th was filled with a combination of excitement and apprehension; for me anyway.  Jean continued with her undaunted faith and trust in our ability to meet any challenge.  My concern was based on our pervious evening’s “sampling” of the Tioga Road leading to the east entrance to Yosemite National Park.  The eastern end of Tioga Road contains a 5 mile stretch of steep grade ultimately taking one through Tioga Pass at an elevation of 9,943 feet.  We had gained enough mountain climbing experience on this trip to recognize the challenges to our horsepower-challenged fully loaded station wagon (72 advertized horsepower).

We left our lodging earlier than usual, as we wanted to take advantage of the cool morning air to help keep the Jeep from overheating on the long climb (I usually let Jean sleep in until 8 am while I am up at 5 am to work on the blogs).  At 9:30 am while Jean was paying the breakfast tab, I was across the street topping off the gas tank, oil and water; and getting the business card of the local car towing service – just in case.


Sunrise on Mono Lake, California the morning of our departure to Yosemite National Park

So off we went westward toward the eastern entrance to Yosemite National Park, some 12 miles up the Tioga Road (“up” being the operative word).  So technically, we have 5 forward gears to work with.  Starting with the highest torque (lowest top speed) gear we have 1st gear, 2nd gear, 2nd gear with overdrive, 3rd gear, and 3rd gear with overdrive.  Sounds complicated; however, we seldom use 2nd gear with overdrive and the overdrive engagement in 3rd gear is generally “automatic” being based on vehicle speed.

OK, so now we are sitting at the entrance to entrance to the Tioga Road looking at a sign that said something like “not advised for commercial vehicles towing trailers” (commercial vehicles towing trailers out-climb us all the time).  So we do our preflight check: oil pressure – good; engine temperature – good; generator charging – good; brakes – OK (as good as they get); seat belts – secured; doors – locked (sort of); and off we go.

Tioga Road starts off with a steep grade, but levels off enough for us to get all the way up to 3rd with OD (at 40mph!).  Then, we hit the 5 mile continual grade to 9,900 feet.  Starting to lose speed – shift back to 3rd without OD (36mph).  That lasted for a few moments until the speed drops to 28mph at which point we drop back to 2nd gear without OD and continue the next 4.5 miles at between 25 and 28mph; when called for, pulling on to the right shoulder to let those show-offs with their new-fangled modern cars wiz by; and while continually scanning the gauges for any sign of impending trouble.

We are running at nearly full engine power with manifold vacuum at around 3 in Hg (close to full throttle).  The water temperature slowly rises to about 210F and stabilizes.  This is significantly higher than our usual 180F, but still tolerable (we hit 235F climbing in Rocky Mountain National Park a month earlier).  Oil pressure stabilizes at 30psi which is sufficient to maintain lubrication and cooling of internal engine components.  One thing that we do not have to watch as we negotiate the winding road is the speedometer.  No chance that we are going to exceed any speed limits any time soon.

Faster than imagined earlier we make it over the top of the pass at nearly 10,000 feet and drive on to the eastern entrance to Yosemite National Park, running surprising well considering our carbureted engine, unlike modern computed controlled fuel injected engines, has no means of compensating for the thinner air at this altitude.

Side note:  One thing that some of we old car drivers (that is drivers of old cars) dream of is the day when a solar flare sends an electro/magnetic pulse to the Earth that wipes out the solid state ignition systems ubiquitous on all modern cars – leaving us old car folks to carry on the task of handling transportation for the foreseeable future. Not true (the dreaming part), but with our strong dependence on solid state devices, it is something to think about.


The east entrance to Yosemite National Park on September 23, 2013 (notice the snow)

9-24-2013 Ascending Tioga Pass from the East toward Yosemite National Park

9-24-2103 Completing the Ascent of the Tioga Pass toward Yosemite National Park

Blog Entry #21 September 21 to 23, 2013 – Mono Lake & June Lake Loop
Blog Entry #23 September 24 to 25, 2013 - Yosemite National Park