Urba Centurion Update - (Kubota diesel, 100+ MPG in mixed driving - Fall 2012 on)

[changzuki]

Originally Posted by ME_Andy

You've done so much but there's a lot more you could do. I bet you could hit 300mpg if you had $10k and a year to work on Centurion. Off the top of my head, you could go with LED bulbs, Lexan windshield, aluminum driveshaft...

Good call - You're touching on a couple of things I can speak to:
- All exterior lighting (less the headlamps) are leds:
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- The aluminum driveshaft was a consideration but with Centurion it presents a few hurdles (which is primarily why I don't have one installed.) Unlike UltArc's aerostang (which I think does have an aluminum driveshaft - citation needed from UltArc!) Centurion would need a collapsible two-piece driveshaft. The transmission has a fixed output flange unlike some of the newer transmissions which simply allow the driveshaft to slide in-and-out. Removing a "one piece driveshaft" from Centurion would be a very time consuming and frustrating task. As with all Spitfires, the driveshaft runs right along the top of the center x-style frame, meaning, to remove it you cannot go downward with it (like you could with the Aerostang) - you must come up through the top (center console in this case.) Centurion's trasnsmission and rear differential are in fixed positions, so the driveshaft must collapse to disconnect from those components, and then quite a bit more to do the limbo to pull it up-and-out.
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The second problem is, although an aluminum driveshaft is lighter it's also usually larger in diameter... If you could see how tight the stock Spitfire driveshaft is fitted partially between the X-style frame, it would probably scare you. So unless an aluminum driveshaft is only marginally bigger around, it may not fit...
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The third issue here was wanting to keep my options open to the larger transmission/overdrive swap... This requires a different (shorter driveshaft) as well as different driveshaft flanges at each end... Had I been successful with the aluminum driveshaft pre-Green Grand Prix (straight four-speed), it would be collecting dust post-Green Grand Prix (along with the other 4 driveshafts) due to the four-speed/overdrive combo...

This was one area that has merit - I just gave up.

~CrazyJerry

[BobS]

Dear Jerry
Glad you caught that techical component typo at 5:20 am. It's good not to leave typos.
I think I may have finally figured who you are chasing down - it's that 376 mpg Shell Opel up in Tacoma, isn't it? Am I right? If so, go gettum, guy.

[changzuki]

Originally Posted by ME_Andy

You've done so much but there's a lot more you could do. I bet you could hit 300mpg if you had $10k and a year to work on Centurion. Off the top of my head, you could go with LED bulbs, Lexan windshield, aluminum driveshaft...

ME_Andy, I missed part of your post (this is what happens when thy reading glasses are nowhere to be found)...
Comment here about a lexan windshield: I believe this unfortunately would disqualify Centurion from driving to, and entering in, The Green Grand Prix. Side windows and rear hatch are ok to use lexan.

~CrazyJerry

Approx: 14 wpm and stuck there....

[changzuki]

Originally Posted by BobS

Dear Jerry
Glad you caught that techical component typo at 5:20 am. It's good not to leave typos.
I think I may have finally figured who you are chasing down - it's that 376 mpg Shell Opel up in Tacoma, isn't it? Am I right? If so, go gettum, guy.

Dear Bob
The 376mpg 1959 Opel is truly an inspirational and heartwarming story the whole family can enjoy.

But, comparing each story, Centurion's "bar" was higher all the way around so there's really no chase, just two different goals.
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~CrazyJerry

[changzuki]

Lugging the replacement transmission into the "cave" to get a better look at it is the next step.
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The story I was given is the transmission "is" a good working unit and the only issues with it have only been related to the electrical side of the overdrive engagement. It certainly "looks" decent on the outside.
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The oil was drained prior to shipping so unless there was any residual inside, there wouldn't be much to go on. The two covers over the four-speed looked like standard bolt-on pieces. Their removal is pretty straightforward:
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Fist the small cover. This gives access to release the shift rail and then the larger cover can come off:
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Now the larger cover:
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A closer look does show some wear on the first gear synchro. The original 1966 transmission was a non-sychro in first gear, and I learned decades ago how double clutch and/or use second gear's synchro, so this was not an issue.
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There is an oil pickup screen on the bottom side of the overdrive unit. This linked photo shows it very well:
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A little dirty but not bad. The tray magnet is also a little "silty" but not bad..
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At this point, I'm thinking maybe any other issues will be minimal... that is until I tried to mount my 1966 bellhousing to the 1980 four-speed....
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Oh, no, here we go again!
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~CrazyJerry

[changzuki]

Deviating from the original Centurion plans causes many self-created problems.... but whining - there's no whining here!
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Decades ago, American manufacturers had already discovered the magic of interchangeable parts. For example, Chevrolet developed it's original 1955 model year small block V8 from 265 cu in (4.3L) incrementally until it reached its peak of 400 cu in (6.6L) in 1970. With few exceptions, parts from engine to engine would interchange - pretty good.
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If this was a huge plus for racers and bone-yard pickers, then Pontiac may have been the King's delight. Their 1955 267 cu in (4.7L) V8 also grew incrementally to a whopping 455 cu in (7.5L) by 1970! With few exceptions (like the 301 and 303 V8's) nearly all parts were interchangeable to include connecting rods. The difference in block sizes were identified by small and large journal cranks (they were all considered "big blocks"). This rivaled, if not exceeded that of the small block Chevy.
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Drivetrain interchangeability was even easier as the years rolled on especially when the GM line began to standardize transmission choices.
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According to Wikipedia, Triumph Spitfire was in production from 1962-1980.

During those years Spitfires went through various changes such as engine displacement and driveline upgrades. So when mixing and matching Spitfire engines, transmissions, and rear ends, you'll need to pay attention to driveshaft lengths, mounting flange bolt patterns and thicknesses, and flange bolt sizes for axle shafts, transmission output, and differential input. What
were they thinking?
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In this section of Centurion's adventures, we are met with another challenge; swapping out a 1966 three-rail 4-speed with a 1980 single-rail 4-speed with optional overdrive. The newer, larger transmission won't mate up to the old bellhousing for a couple of reasons. One is easy to spot in the following photo:
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Ok, so all we need to do is get a bellhousing with the correct mating surface and we're gold!
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Wait - Not so fast! There's another issue too... Some of the correct bellhousings have a "scroll seal" and some have a "shaft seal" and as luck would have it, they don't appear to be straight across the board compatible. When looking for the correct one, I was presented with the following pic showing the differences between to transmission input shafts - one using a scroll seal, and the other using a shaft seal:
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As usual, the solution was simple - nothing money couldn't fix.
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Replacement bellhousing on the way couldn't arrive fast enough. In the meantime, we can inspect the pressure plate and clutch. If both are good, maybe we can remount them to the flywheel and be ahead of the game. Well, the clutch is in excellent shape along with the springs and all ten splines.... too bad new transmission has twenty splines on the input shaft.... yay.
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Top of the class - School of Hard Knocks
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~CrazyJerry
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[changzuki]

--- Back-to-the-future ---

While CrazyJerry is digging around for more of the correct pieces (clutch, bellhousing, etc), let's look ahead in time and preview a segment of an actual road test with this transmission swap!
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The test here is to see if Centurion's Kubota D850 has power enough for a normal 55mph cruise while the overdrive is engaged. RPMs at this speed are at a very nice 2150!
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Just before the 1:14 mark where the hill crests, you'll hear what sounds like the engine cutting out - it is. When the conditions are right I let off the pedal and the fuel is effectively cut to the injectors, the digital tiny tach loses its injector line pulse, and the microphone records what sounds like a plane running out of fuel.
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At roughly 1:14 into the video, the uphill grade is finally crested and you can see how easily the speed increases with no additional throttle beyond what it took to skate along at 55mph..
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To give it a little perspective, the initial uphill grade is very similar in pitch and length to the back forty at the Green Grand Prix.
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https://www.youtube.com/watch?v=T8etAClP

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~CrazyJerry

[changzuki]

It's total euphoria when the right parts are at hand and they actually fit!
With the correct 20 spline clutch, assembly can now begin.
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With clutch properly set and pressure plate torqued to the flywheel it's time to fit the rest together!
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The red arrows in the above photo indicate that victory was brief.
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For whatever reason, two of the adapter's bolt heads wouldn't clear the new (1980) bellhousing flange. The cast iron is no match for a hand grinder and the violent shower of sparks is swiftly over.....
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The area that may need an attitude adjustment is outlined below between the red forks:
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Taking into consideration all these little pain in the a$$ tweaks, plus parts finding and delivery time, a steady 60+ hr a week job, and life itself, is it any wonder it takes a very loooong time to get through a tank of fuel to generate any mpg numbers?
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Even with some testing/driving since the completion of the transmission swap, Centurion is still not ready for a fill-up..... Clack-clack-clack-clack...
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More pulse-n-glide.......
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~CrazyJerry

[changzuki]

Wow! Time flies whether you're having fun or not.
In fact, today marks an 18 year milestone - for Dottie...
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In addition to Dottie's appearances in CrazyJerry's posts over at the MirageForum and here at ecomodder in the Urba Centurion thread, below are a few memorable moments of her along the way.... She's always the life of the party - even if there isn't one!
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And lastly, a very special video:
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https://www.youtube.com/watch?v=RygP9Rfe6K0

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Happy 18th Birthday Dottie!!!!
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~CrazyJerry

[redneck]

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Dottie is off the chart...!!!

Dog Age Calculator in Human Years

Happy 88th Birthday, Dottie...



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