Adventures of the Deathmobile (II)

[MtnGoat]

Tomorrow I get another reminder of why I love my job. I get to go on an all expenses paid adventure to check out some comm test sites and see if they'll work out for some stuff we need to test. This means that I get to drive around N Central Oregon, ( in the John Day region), on the clock, and get paid for mileage as the cherry on top. Touring the high desert in springtime, could be worse.

I'll be sure and take some cool pix on my way.

In the meantime, this long drive, and last weekends, has me contemplating the odd miss at high load and R's I've been getting. She pops like a leaner now and then, and sure enough with my foot all the way into it on a big grade I'll see 11's on the WO2 meter, and with each pop the meter jumps to 15+ for an instant.

Checked the fuel pump pressure, nailed at 4 psi no matter what. (electric) Checked the rear filter too, just for grins, clean. It doesn't occur at all in the morning, it runs great and pulls hard no matter how much pedal I'm using.

What I'm wondering is...could my heat shield (for the carbs) being lousy play a role? It's there, but I noticed it has none of the asbestos on the back side like it used to. I knew it was getting ratty, but now the asbestos is gone. Seems to me the float bowls getting too warm could give me some weird behavior. I have another shield around with the full backing, in pretty good condition. Wondering wether I should take 90 min tonite and swap it in before my distance run tomorrow.

[Byron510]

Is it possible that your pump volume might not be keeping up?

I don’t remember what pump you are running. But I always ran the 2L truck pump, which has a larger diameter diaphragm and can push more volume. The pressure stays the same, just higher volume.

Just a thought.

I know when I had heat sink problems on my SU's, it didn't play a part until low load and low RPM after a long run. High load and hi RPM was fine. I never did cure the problem, and went to twin DCOE’s and the problem went away – so I didn’t learn the actual fix.

Byron

[MtnGoat]

I'm running the Airtex E8016S. I pulled the hose up front and ran it, pumps pretty fast. Didn't measure it, but it filled a small cup with a solid stream at hose diameter pretty quickly. Real scientific, I know, but it seemed more than enough to keep up with gravity/Venturi action through two nozzles of much smaller diameter.

And the issue is absent when the air temp is below about 75.

[MtnGoat]

Pretty much 9 straight hours on the road. I don't remember the last time I turnèd so many corners in one day. There are a lot of stretches where the roads are so twisty that the boring sounding 55 limit makes for a pretty hairy ride in many places. The scenery surpasses epic, vast wheat fields, volcanos in the distance, canyons, meadows, weird rock formations, huge sky. Very little traffic on a weekday.

I'll post pics later. I'm thrashed.

[MtnGoat]

Headed S from Biggs on 97 starts out tight and twisty

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The high wheat fields on the road to Condon, the long sweeping curves and great pavement contribute to a sense of immensity

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The town of Fossil has a compadre for us...

dastun in fossil.jpg (203.77 KiB) Viewed 3753 times

Onward to a county road along an endless twisty valley with Sutton Mtn looming..

[MtnGoat]

I wind up going too far in the wrong direction, so this is where I turned around to head back to Fossil..

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Back at the pass, it's now snowing..

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After an insane number of twists and some white knuckle surprises between Fossil and Clarno, I wind up on the ridge W of town in time to see this...

IMG_6622sm clarno rainbow.jpg (110.74 KiB) Viewed 3752 times

After which, this was a bit of a contrast. WTF comes to mind. I can safely assert this is the only no trespassing sign I've ever not mused about passing up anyway..

biohazard.JPG (60.27 KiB) Viewed 3752 times

[MtnGoat]

I turn around from that bad juju, and find Satan's Horns looming over the road.

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Headed south between Antelope and Clarno on Cold Camp road, these vast meadows...Horse Heaven...

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Huge valleys of the same rolling, canyony terrain..carpeted in green for a couple months

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I come to this town in the center of nowhere, Ashford...separated from Hwy 97 near Madras by 17 miles of screwed up pavement wild turns and canyon running..

IMG_6642sm road to ashford.jpg (186.4 KiB) Viewed 3752 times

Up on top and turned for home, a last shot of the Oregon outback...yeah I came over those in the distance, on dirt

IMG_6633sm - ashford road.jpg (157.94 KiB) Viewed 3752 times

[MtnGoat]

Ran north on 97 to Bakeoven Road, then used that as the back way to Maupin. Climbed up out of yet another canyon (Maupin's at the bottom straddling the Deschutes), in time to catch Mt Hood putting on the last of it's show..

IMG_6644sm hood sunset.jpg (74.07 KiB) Viewed 3752 times

And now it's time to make for home, the sign says how far

IMG_6650sm 97 and home.jpg (112.54 KiB) Viewed 3752 times

9 hours, some photo and gas stops. half a box of cigars, full bag of taco doritos, two gatorades, 4 grateful dead tapes, one bitchin' Datsun

[Byron510]

Great photo write up - and you got paid to do the trip Awesome!

Great to see your car in use like this. Bet the renewed suspension was a nice touch for the drive.

Thanks for sharing.

Byron

[MtnGoat]

My gosh yes the new parts were essential. So much more stability and control, making the twisty roads into fun instead of a battle

[MtnGoat]

I ran across this catalog while surfing, it has all sorts of suspension add ons from stupid (long u-bolts and blocks for lowering, twist in spring extenders) to useful, including the coilovers I used to have.
http://www.sup-auto.com/assets/rideeffex2.pdf

I wasn't particularly impressed with the additional load handling of the built in coilovers I installed in the rear. The moderate load I had on the camping trip two weeks ago resulted in the back of the car lower than it had been with a heavy load using the old add ons.

[bertvorgon]

Love your trip pictures!

[MtnGoat]

Thanks Bert, it was quite a fun drive.

Been pondering on my high load miss some more. The trip was an ideal chance to pay attention to what was going on, with lots of hills and generally cool temps. What I learned is that the miss still does occur when cold, but is less noticeable. When it did arrive it was always on long grades. And if there was a level stretch before hand, it seemed to take 10-15 secs to maximize, where if it was one steep grade right after another, it was instant. This seems to lead to the starvation/flow volume interpretation.

The pump sure seemed to pump a crap ton of volume to me, I don't know how much an L20 at full throttle with dual 38s can drink, but I have a hard time imagining it's more than I saw pump into my container! On the other hand, there's the miss.

It's annoying because up to that point this mill is running as good as it ever has. Smooth and strong, hard pulling...until that point is reached on a long hill where the miss begins. Which is super annoying, because with my power to weight and willingness to wrap it out on a long mtn pass, I want folks seeing that Ratsun sticker on the rear passenger side window blowing right by them, smoothly.

[MtnGoat]

Here's the spec table for these pumps

E8016S pump specs.png (54.68 KiB) Viewed 3707 times

30 GPH sure ought to do it!

Perhaps my pressure is dropping at max flow or something? Not sure how to think about this. When I'm pumping into a container I can't measure the pressure, and when I'm running it into the carbs I get the pressure but can't measure the flow.

And I already checked the rear filter and the front one is spotless.

Maybe one of the slightly higher pressure, higher flow units and then run it through a pressure regulator?

[bertvorgon]

Plug gap not too big? Just a thought, as when you are on a hill, the load goes up as the throttle is open more, even though you may not be accelerating hard.

Only other thing I can think of is the fuel line BIG enough? I once ran into a VOLUME issue, lots of pressure, but, as load went up, the line restricted the amount of fuel and the float bowl level would drop.

Which also makes me want to check the needle and seat size.

In re-reading your post, considering the TIME factor before it starts to miss, I am thinking fuel issue in the float bowl. It's dropping and starting to lean out. That is EXACTLY what happened to me, off like Jack the bear at the start of a hill, then my car would just die at the top, that is when I determined it was a fuel line size issue. I up graded to 3/8 fuel line, problem solved.