Spatial Challenge

Before even thinking about installing batteries, the available space needed to be sized up. Substantial free volume was created in the motor bay with the removal of the gas engine and related apparatus, and a fair amount of new space opened up with the removal of the gas tank from the front of the car. The puzzle is to fit 36 prismatic lithium iron phosphate cells in that space.

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The first thing I needed was a physical representation of a lithium cell I could play with. Using some reliable dimensions for the CALB 180AH cells currently on my shopping list, I carved a dummy cell out of the packing foam that came with the AC50 motor. Battery placement is a spatial riddle, and the fake foam cell allowed me to physically visualize the form and fit of the battery pack. It became immediately obvious where a battery would and wouldn’t fit.

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Next I diagrammed the engine compartment and fuel tank bay, measuring and recording all possible dimensions on the drawings. As you can see just above, the fuel bay is a more complicated space, with many curves and bumps. I translated those numbers into an accurate computer model of the usable area in each space using DraftSight. At that point I could create computer models of the batteries and tinker with their placement and position. Although there was only one fake foam battery, I could now play with 36 virtual batteries and be confident of their exact dimensions and fit.

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After dividing the pack evenly on each side of the AC motor, while trying to cram as many cells as possible into the space, it was inevitable that no more than 24 would fit in the motor bay. Granted, there are many examples on the interwebs of a greater number being stuffed into the same area on a 914, but those are smaller batteries with a lesser amp-hour rating. Cells with a rating of 180 AH or greater begin to grow in size. I could have placed a few cells over the motor, but instead gave the battery pack a low profile to preserve room for the rain tray, the controller and other electronics, as well as maintain a low center of gravity. The placement of batteries on the right side will be a mirror image of the green cells on the left. The black filled area across the top is unusable because of the backward slope of the firewall. The two filled areas at the sides are where the rear axle swing arms jut into the engine compartment.

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The remaining 12 batteries will fit into the fuel tank bay and trunk thusly. My original hope was to keep the front trunk completely free, but that won’t be possible with batteries this size.  The next generation of batteries will likely be smaller and lighter, and the small rack for four cells in the front trunk can be removed. The blue filled box in the upper left is the planned location of the ceramic core heater box. The black filled objects are the fan box drain tube and the steering column. The black flared horizontal line is the wall dividing the fuel bay from the front trunk.

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The end result of the drafting diagrams were precise dimensions that could be checked against real-world volumes. An exact footprint of each battery pack was cut from cardboard using measurements from the drafting files, and then test-fit in each space. The foam cell could then be used to check vertical clearance, which is not accounted for in the 2D drafting files.

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Here is the footprint of the forward battery pack, straddling the fuel bay and front trunk. Notice how a perfect little cubby is left for the ceramic core heater box, as if it were designed for that exact spot. I call that magic. The next step is to choose and gather the raw material, take it to a metal fabrication shop along with the footprint templates, and have just the battery rack bases welded together. Fun is happening.

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Scaling Mount Motor

Time to tackle the motor mount. My understanding is that collar-type mounts cannot be used with the AC50 because they could warp the motor case, so instead an L-bracket mount is bolted to the motor end face. I had originally fabricated one based on RR’s 914 bracket for his AC50 motor, assuming my adapter alignment would be the same. No such luck – His ElectoAuto adapter allows positioning of the motor to any degree, but my CanEV adapter offsets the motor mounting holes by exactly 13.7 degrees. According to Randy at CanEV, this accommodates ADC and WarP DC motors, which both have a threaded lifting lug on their cases at that same offset. Unfortunately, this obsoleted my prefabricated motor mounting bracket, because drilling new offset holes would only allow room for two mounting points, which didn’t seem strong enough. After all, this bracket carries the combined forward weight of the motor and transaxle. Another revelation from HPEV was that the AC50 motor itself has an approximate 45 degree offset between the mounting holes on the drive side and encoder side of the case, where the motor mount will be attached. The approximate aspect adds some complication, which I will soon explain.

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Back at the drawing board, I fiddled with Google SketchUp to see if I could design the motor mount and produce a usable CAD file. If I could nail the exact measurements, then M&K Metal could plasma cut my piece from quarter inch steel plate, make the precise 90 degree bend, and the motor mount would bolt right in without complaint. That would be supercool. HPEV confirmed the offset between the threaded holes on the drive end and encoder end of the motor is within a few clicks of 45 degrees, so adding the transaxle adapter offset of 13.7 gives a total of approximately 58.7 degrees. The design on the upper left has slotted holes to allow for a plus or minus 5 degree variation from exact hole placement. The design on the right wishfully assumes any variation will be forgiven by a 1/16 inch larger bolt hole. Crossing fingers and wishing hard. This SketchUp Pro trial version outputs CAD files in both .dwg and .dxf format, which I emailed to Ron at M&K Metal. He imported them into his plasma cutter from a thumb-drive, and ran the job. It’s like a huge computer vector plotter that writes with superheated gas on metal. Just watching it in operation gave me a million ideas. Click HERE to see a clip of the plasma cutter in action.

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Seeing the perfection of the shapes and buttery smoothness of the cut edges was really impressive. Then we discovered the mounting holes were slightly larger than expected. Further inspection revealed all other dimensions were scaled up by about 10 percent. Back at his computer, Ron opened my CAD files in a free program called DraftSight, and confirmed all the measurements were off. Somehow, the SketchUp output to CAD introduced a scaling error, and the cutter had simply followed those bad directions impeccably. It was on me to figure it out.

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First I went into the SketchUp Model Info pane and switched the Units from Architectural to Fractional, increasing the precision to 1/64. Then I exported an AutoCAD 2010 DWG file and opened it in DraftSight for Mac OSX, shown above. Ron’s business relies on DraftSight, and it speaks a language his system understands, so I was satisfied when it reported the dimensions were good. After resending the file to Ron, he confirmed the dimensions and ran the job free of charge. That small token of generosity made my week, and I left with perfectly rendered motor mounts in hand.

.Just to show the precision of the plasma cutter, the first set of brackets on the right were accidentally scaled 10.1 percent larger due to an output error in Google SketchUp, and yet they are perfectly proportioned. The second set on the left were scaled and cut to the correct size.

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A test fit was very encouraging and underscored the precision of the plasma cutter. The motor mount with unslotted holes fit flawlessly on the end of the motor, but did not provide the offset needed for the bracket to sit level on the crossmember. This proved that crossing fingers is statistically effective only some of the time.  On the other hand, the mount with slotted holes allowed enough play for the bracket to level itself before tightening down all the bolts. To prep for permanent installation, the working mount was buffed with a wire wheel, and given a few coats of etching primer and appliance epoxy black for protection.

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Here’s a shot of the final install. Notice the 1/2 inch collars used as spacers between the bracket and motor, which provide a gap for the encoder and temperature sensor wires to pass under the mounting bracket. That gap is needed because the white temperature sensor wire emerges from the motor end face itself (visible in the picture at the very top). I was careful to add the spacer thickness to the inner dimension for the bend, and am glad I actually measured them: They are sold as half-inch, but are actually 7/16 inches thick. Alas, the short distance to perfection is infinite.

All told, the fabricated mount cost me less than buying an off-the-shelf bracket, which would have needed modification for the offset anyhow. I’ve also gained a rudimentary knowledge of both Google SketchUp and DraftSight, a working CAD file of the motor mount, and a really fun experience with a plasma cutter. Something tells me my plasma cutting days are not over.

** Note of celebration – This was my 100th blog post!

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Linkage Jerry

If removing all of the linkages is one of the first steps in dissembling the car, then putting them back is one of the last. It’s exciting knowing that the car is closer to completion. Above is a shot of the clutch and speedometer cables installed. A zip-tie around both cables provided added support for the speedo cable, which must stretch from the firewall to the furthest end of the transaxle.

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On the other side of the transaxle is the shift linkage. A brush, a rag, and a couple blasts of degreaser removed decades of grime from the accordion boot, cover, and band clasp. No more will the splatter of motor oil defile its friendly plastic finish.

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The rain tray is an important item that was also installed today. It hugs the underside of the motor bay deck lid, and funnels rain away from the sensitive motor compartment. It originally prevented water from fouling the ignition and carburetion systems, but now it will protect the LiFePO4 batteries and BMS (battery management system). The depth of the rain tray subtracts from the headroom afforded the batteries, but its stock design is so useful that I am committed to keeping it.  I’ll make room. The batteries are best positioned lower in the motor bay anyhow.

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These funnels collect runoff from the rain tray and direct it down to the street. My lovely wife calls it “car piddle.”  She’s so cute.

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Mating Game

The transaxle is now refurbished and shiny, and the grand moment of coupling it to the AC50 electric drive motor has arrived. I just received two essential items from East Bay Conversions: the hub and the adapter plate. The hub is used to mount the clutch and flywheel to the AC50 electric motor. The custom adapter will then mate the motor to the Porsche transaxle.

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The hub is from Canadian EV, and is custom machined to exactly fit the electric motor shaft with a square key. A nice design feature seats the hub flush against the motor front bearing, eliminating any possible wobble, and sparing the locking screws from the forces of the clutch.

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The red forged aluminum adapter matches the motor mounting holes to the bolt pattern of the 914 transaxle, and must be installed on the motor before the flywheel is mounted.

A Word on Flywheels

In an internal combustion engine, the cylinders are timed to fire in succession, like a galloping horse. This creates sequential bursts of angular torque that must be smoothed out for the engine to run evenly.  The inertia of the flywheel’s spinning mass does exactly that, evening out the rotation of the crankshaft. But an electric motor already has a very regular and smooth power profile, making the flywheel irrelevant and literally dead weight. Because the flywheel’s mass resists the motor’s effort to accelerate the car, valuable electrons are wasted. A general rule of thumb states that each pound of flywheel weight is the equivalent of an extra 100 lbs of car weight. For more on this subject, UUC Motorwerks has an in-depth explanation.

One EV solution is to marry the motor shaft directly to the transmission drive shaft, eliminating the flywheel and clutch altogether. A gas engine needs a clutch to shift gears, but an EV has full torque available at all motor speeds, and can be left in 2nd or 3rd gear for all driving requirements – except reverse. But because shifting in or out of reverse usually happens at a standstill, and more importantly because electric motors don’t idle, reverse doesn”t require a clutch. I almost talked myself into removing it, but the clutch stays because I want the option of using 5th gear on the open highway, and 1st gear on Fargo Street. How else will anybody know how fast an electric Porsche will go, or how steep it will climb?

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Deciding to keep my flywheel and clutch didn’t help with the rotational inertia problem. The racing crowd addresses the issue with lightweight racing flywheels, which are very expensive. A common and thriftier method is removing unwanted mass from the existing flywheel. This sounded like a good idea, so I turned to RIMCO in Santa Ana. They are experts in air-cooled engines, and routinely lighten stock flywheels. They threw my flywheel on their lathe and removed the unneeded starter teeth, as well as another 5 lbs, reducing it from 17 to 11 lbs. That’s an equivalent of 600 lbs of vehicle weight, according to the formula. They then precision balanced it, of course.

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Here is the lightened flywheel, mounted on the motor.  Notice the missing starter teeth ring.  Installing the flywheel was not any different than installing on the gas engine, except that without the starter teeth, it required other means to lock the flywheel while torquing down the mounting bolts. I threaded a couple clutch mounting bolts into the flywheel and used a breaker bar against them as a stop lever.

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While the flywheel was being lightened, RIMCO determined the clutch pressure plate and disc still had a good amount of life in them, so I am reusing them here. A pilot tool helped align the clutch disc while bolting the pressure plate onto the flywheel. Here you can see the motor and transaxle engaged in their mating dance, with the axle shaft preparing to dock into the splined collar in the clutch disc. It’s a love story.

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And that is how EV babies are made.  The white three-phase main wires on the right were later rotated to the top of the motor, where the terminals were more accessible, and where there would be less interference with the future battery racks. This involved removing the flywheel and turning the motor 90 degrees on the adapter, so that the transaxle side of the adapter kept the same orientation.

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Installing the coupled pair in the car was much easier than yanking the stock gas engine and tranny. Due in no small part to my buddy Steve dropping by to lend a hand and some unfailing common sense. The AC50 has a much smaller footprint and profile than the stock gas engine, making it much easier to maneuver. First the whole assembly is positioned level on the floor jack and rolled under the car into position. Even though my jackstands were at maximum height, we had to angle the bell housing in through the rear wheel well. The jack was raised so the rear transaxle mounting feet just reached the brackets on the undercarriage, and then rolled slightly backward so the transaxle docked with the mounting bolts. I medium-tightened them just to hold position for the meantime. Then the jack was raised just enough to allow the lower cross-member to be installed under the motor. The motor’s end will rest on a small block of wood until the L-bracket is fabricated.

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The CV joints needed a good once-over before going back in the car. I stumbled on an excellent YouTube video showing the teardown, inspection and reassembly of 914 CV joints, which motivated me to roll up my sleeves. I took each joint apart, cleaned, bagged and marked them individually to identify their position on the axles. It turns out that both left side joints were badly worn and required replacement. Auto Atlanta sells reconditioned CV joints complete with boot and bolts, but I was able to talk them into selling me just the splined joints alone. Since the right side joints were being reused, I took the video’s advice and swapped the inner and outer joints for greater longevity. Now each bearing will wear on the opposite, fresh side of the spider race. It’s possible to pull and replace the CVs without removing the stub axle, but over-torquing and breaking a flange bolt forced me to remove it anyway, so I could extract the broken end. I had added peace-of-mind watching the axle-side CV flanges seat properly over the roll pins, which is impossible to see with the stub axle installed.

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Now that everything is in correct position, I torqued down the motor cross-member and transmission mounting bolts. Next up is refabrication of the motor mount L-bracket. Can’t wait to spit out a CAD file for the plasma cutter!

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Getting in Gear

When I bought my roller, the health of the transaxle was unknown. There was no point marrying it to the electric motor, riding solely on faith that it wouldn’t fail. A transaxle is a complex affair with a myriad of moving parts, and the only way to know its condition is to crack it open. I am not the expert for that, and so I didn’t expect to cut any corners. My choices were to ship my transaxle to somebody like Dr. Evil on the 914World forums for rebuilding, or purchase a rebuilt transaxle outright from places like California Motor Sports or Cog’s Cogs.

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In the end I decided to rebuild with Werks II Motorsports in Burbank, a dedicated Porsche racing and full machine shop. Staying local allowed me to culture a valuable personal relationship and tap into a resource just a short drive from my home. If anything goes wrong, they are near and can set it immediately right.

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I got to know Galen and Tony, whose bread and butter is prepping Porsche cars for the racing circuit. It was obvious Galen knew his way around a Porsche transaxle from our first conversation. It was a good sign they were often busy late into the night, preparing multiple cars for weekend races at Willow Springs. I also felt good about the relative cleanliness and organization of the bench areas.

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Because Werks II is a full machine shop, they happily offered to help with any fabrication for my EV conversion. One item I immediately needed was the AC50 motor mount, which supports the end of the motor not mated to the transaxle. For this purpose I had brought a piece of beefy 90 degree aluminum plate that I scouted at M&K Metal. The shot above shows Galen cutting a 5 inch hole in the mounting bracket that will bolt flush on the end of the motor casing. I also brought an additional steel piece that Galen dubbed overkill, assuring me the aluminum would handle a 747 engine.

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After cracking open the transaxle and having a look-see, Galen gave me a list of parts needing replacement, and the reasons why. One of the bearing cages was cracked, and many of the gear teeth and syncros were badly worn. Shown above are all of the bad components that were replaced. Among them are two large bearings, four gear syncros, two shift sleeves, the first gear teeth, the throwout bearing, and various washers and bushings. He was able to save some money by using good used parts saved from other rebuilds.

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During this process the case had been put through an ultrasonic cleaner, which removed any remaining grease and gunk that I missed at the car wash. But since it hadn’t been media blasted, the magnesium case looked dull and homely. Despite Galen’s advice to leave it au naturel, I masked it off and applied a light coat of metallic spray paint. No harm, and now it looks like a new transaxle.

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The end of the motor that is not mated to the transaxle receives the newly fabricated aluminum mounting bracket. These 1/2 inch mounting bolts were the first non-metric hardware used in this project. The holes for the adapter plate on the drive side of the motor are also American threaded. Shout out Richard Rodriguez for the AC50 motor mount template. Now I wait for the adapter and hub to arrive from East Bay Conversions, and then the motor gets married to the tranny and goes in the car!

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**UPDATE**

As clean and beautiful as the aluminum motor mount is above, it will not work with the Canadian Electric Vehicles adapter, because the adapter mounting holes are offset by 13.7 degrees. Randy at CanEV tells me that these adapters were designed primarily for ADC and WarP motors, which have a threaded lifting lug on the case, offset by that exact amount. If I redrill new offset holes in the motor mount, there will only be room left for two, rather than three attachment points. It’s either back to the machine shop, or wait a week till CanEV produces their new L-bracket end mounts. Drat.

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Motor Purchase

Today was a major milestone. I left the house at 6am for Ontario, CA to pick up my motor from HPEV, aka High Performance Electric Vehicle Systems. The HPEV website recounts their legacy, starting in the early ’60s as a small company that rewound fried washing machine motors, and then branching into golf cart and other industrial motors. Today, their motors power the all-electric Wheego Whip, the Trexa M9, and numerous EV conversions by knuckleheads like me. I purchased my package at a modest discount as a member of the V is for Voltage forums, and then picked it up from HPEV myself to save on shipping.

When I arrived, Bill Ritchie, the shop manager, invited me inside to check out their operation. I enjoyed hanging for a short while with the guys at the winding table, just one of the steps in the assembly of several different motor models.

Bill explained that the raw wire has a resin coating, and after the windings are complete and assembled in the stator cases, they are dipped in a solution and then oven-baked. This activates the resin and fuses the windings into a solid epoxy mass.

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In the shop, there are pallets of lithium batteries designated for various projects. This is the Voltronics standard 3.2 volt, 180 amp/hour cell, identical to what I will be using for my traction pack. A total of 36 cells will provide a combined 115.2 DC volts that will be fed to the controller to drive the motor.

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Here is the Curtis 1238R-7601 650amp controller that will do all of the heavy lifting. Its function is to invert the direct current to alternating current, and then shape the AC sine wave to provide a custom torque curve for the specific vehicle. The ability to shape that wave is why AC drives can be programmed to behave much the same as the original gas engine. HPEV is currently working on a more powerful AC motor that will pair with the coming higher voltage Curtis controller. It’s exciting to know that development and innovation is driving this industry forward.

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Here’s a look at the BMS (battery management system) that HPEV is using in their electric Jetta project. If I remember correctly, Bill said this was the Flux Power system. The above nine modules each manage four lithium cells. Some research will be required to arrive at the exact BMS that will fit my budget. Some leaders in the conversion field point to evidence that a BMS can ironically cause more cell failure than not using any BMS at all. That’s scary, since the BMS is designed to safeguard one of the biggest investments in an electric vehicle.

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Here’s a batch of AC50 cases waiting for the next phase of their assembly. This is the exact model that will power my 914. One configuration is sold as the AC50-1, which includes a tail shaft that can be used to drive various accessories, like a tachometer sender or an air-conditioning pump. However, Bill explained that the Curtis controller had a built-in tach signal output, and that there were better ways to install air-conditioning. He also explained that the extra shaft length could cause clearance problems, such as they encountered in their 911 conversion. With that assurance, he issued me the AC50 model without the tail shaft.

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My visit to HPEV was one of the high points of this project. Bill Ritchie is a great guy, offering me all of the insight and advice needed to make this a successful EV conversion. I left feeling inspired that this industry has a great future ahead, and with a trust in the quality of the components I was buying. That’s Bill sending me off with my new EV drive system. I can hardly wait to begin the install.

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Rocker Roll

My original black plastic scuff plates and inner carpet strip were worn, cracked, and generally pretty beaten up, so I replaced them with durable new aluminum versions that will make a great impression every time the doors open. To install, I removed the door weather strip so the upper rivet mounting holes were accessible, and the scuff plate could be pushed snug against the door pinchweld lip. There is a lot of chatter on the 914 forums about which type of rivets are original, and which are better.  A call to Auto Atlanta confirmed that Porsche originally used aluminum rivets for the scuff plates and rocker covers on some early 914 models, and then switched to white or black plastic rivets to allow easy removal of the covers for cleaning and maintenance. I don’t anticipate ever removing the scuff plates, so I used aluminum rivets which better match the finish. Once the top of the scuff plate was fastened in place, the weatherstrip could be replaced snugly over the pinchweld, covering the rivets.

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The inner carpet strip was installed next. To start, I peeled the carpet away from the rearmost part of the sill to find the first mounting screw hole, and then used a small jewelers screwdriver to poke a matching hole in the carpet. Using that hole as an anchor point, the strip can be laid on top of the carpet and used as a template to locate and punch through to the rest of the screw holes. They are marked in gold ink on the carpet above.

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The inner aluminum strip actually overlays the clasp of the weatherstripping, both holding it in place and protecting it from shoe traffic. It’s fastened in place with machine screws rather than rivets, and I used stainless to sidestep any future rust issues. The bottom edge of the outer scuff plate will be riveted in place after the rocker panel covers are installed.

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Rocker Panel Covers

Even though the original steel rocker panel covers were in great shape and had been soda-blasted and primed along with the rest of the car, I decided to replace them with fiberglass replicas to completely eliminate corrosion. I sold my original steel rocker covers to the guy that bought my steel wheels. You will soon see why I regretted that decision.

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A test fit over the rocker panels revealed the passenger side alignment was good, but the driver side needed some finesse with a file to enlarge the trailing side of the jack point hole by about a quarter inch, after which it cleared.  The image above shows the filed edges on the right side of the jacking hole.

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The fiberglass rocker covers came without mounting holes, and required some fitting and drilling. I used a jeweler screwdriver to scratch drilling spots in the fiberglass that aligned with the existing holes in the door sill. First I drilled the upper mounting holes, and then drilled the holes for the front and rear fender well mounting points.

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Unfortunately, with the cover’s upper edge flush against the door sill, the lower edge of the cover would not reach the three mounting holes on the underside of the rocker panel. The picture above and two immediately below show the misalignment of the cover’s template holes with the actual mounting holes on the car.  This was true for all three holes on both sides.

No matter how much force I applied, the fiberglass would not flex enough to cover the lower holes. Even if I drew the upper edge away from the door sill, there was still not enough play to cover the lower holes, and the shortfall was merely transferred to the top. If you notice in all three pictures, the bottom edge of the rocker panel cover is not even touching the car. Disappointing and frustrating.

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After mucking with them a while longer, I discovered the inside surface of the covers were contacting the three vertical braces on each rocker panel, preventing them from falling completely home. Grinding away a portion of the braces was unacceptable, like removing toes to make the glass slipper fit. The aftermarket fiberglass valances weren’t this much trouble! I expected some minor finessing – not a disappointing hassle with no positive outcome.

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Rather than waste more time and money, my solution was to return to stock original covers and use other methods to seal and protect them. I was able to pick up a couple online for about the same amount I sold mine for, although they still needed stripping and refinishing. In the meantime, a cursory test fit proved my sanity. They seated perfectly, and all the holes lined up.

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The used rocker panel covers had a fair amount of surface rust, so I took them to Safe-Way in Culver City to have them sandblasted. Unlike baking soda, sand will leave microscopic pits in the metal. But since these covers are mounted low on the car and are generally painted flat black, their finish is less critical. Besides, I wasn’t driving way out to Upland just to have these two covers soda-blasted.  Safe-Way was nearby, and this was a great opportunity to lose my sandblasting virginity.

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Here’s what they looked like when they came back.  The surface is dull and has a texture similar to 800 grade emery cloth. Although the rust was completely gone, it had left rough areas where it had chewed at the surface. I hit those patches first with a couple coats of Rust-Oleum Rust Reformer.

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In order to take the tooth down on the entire outer surface, I applied a couple coats of etching primer and sanded lightly to a smooth finish. Then I applied a few coats of satin black to the outer surface of the covers, and some rubberized undercoating on the inside.

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One issue that evaded bodywork was this hole in the driver side rocker panel, just behind the front fender well. I could take it back to Manny and insist he fix it, or I could take it to a nearby body shop.  Either way, the whole car would need to be towed, and I didn’t want to upend my workspace and workflow. So I decided to patch it myself, as I have done many times before. It was a minor hole on a surface that is exposed on both sides, so I decided fiberglass would be fine if it were properly sealed when done. First I masked and sprayed rust reformer and undercoating inside the hole from all angles, being careful not to clog the drain port where the rocker panel meets the floor pan. When dry, I ground the outside of the hole down to bare metal at a half-inch radius.

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Then I prepared a fiberglass patch that perfectly covered the entire bare metal area, mixed a small amount of resin and applied it over the hole. After curing, I shot some Rust Reformer onto the backside of the fiberglass patch through the adjacent drain port using one of those skinny red plastic hoses. After drying, I followed it with a couple blasts of rubberized undercoating directly into the drain port.

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And viola – rocker covers completely installed and fitting perfectly without any further hassle.  I especially regret selling my original covers, since I usually retain all the original parts until the new ones are installed and working. My opinion of replacement fiberglass body parts has tilted toward greater suspicion. They are not subject to factory standards, and will require a fair amount of noodling and fudging to make them fit (if at all).

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Teeniana

Vintage "fake" Porsche 914 commercial

While waiting for my used rocker panel covers to return from sandblasting, I’ve been digging into Porsche 914 history. Aside from the general quest to convert a classic car from gas to electric, there are reasons I was drawn to the 914. First off, it was an overlooked underdog in its day, never getting the respect it deserved. It has been called the Rodney Dangerfield of sports cars. Because the 914 was produced in partnership with Volkswagen, it was regarded as a bastard child – the runt of the Porsche litter that didn’t merit the same esteem as the rest of the fleet. As such, they can be had for much less than other classic Porsche cars, and they perk right up with a little love and attention. Click on the image above and tell me this 914 vintage-style commercial doesn’t just make you giddy with nostalgia.

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Original 914 Ad - "..for the fun of it."

Porsche and Volkwagen’s involvement dates back to the founding of VW, when Porsche was contracted by the German government in 1937 to design a “peoples’ car,” the volks-wagen. This began a long relationship that gave Porsche responsibility for most of Volkswagen’s developmental work. That contract was to conclude in the early ’70′s with the production of the 914. Porsche saw this as a way to boost their sales by entering the mid-level sports car market, while Volkswagen was looking for a new flagship to anticipate the discontinuation of the Karmann Ghia. Unfortunately, when VW CEO Heinz Nordoff died in 1968, the manufacturing, marketing and sales of the 914 were thrown into contention, resulting in mismanagement, cost overruns, and the early demise of the 6-cylinder version of the car. Despite bad press and poor initial reviews of the 4-cylinder model, it struggled forward and eventually gained a modest but devoted following. The design of the 914 is fairly basic, with obvious similarities to the Karmann Ghia and Beetle, with most spare parts easy to find even today. Click the image above to read a complete history of the Porsche 914 from Classic Motorsports magazine, and click here for the Wiki entry.

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Race practice in a 914 at the Targa Florio

Despite its fitful birth, the 914 got favorable marks from the racing community, where both 4 and 6-cylinders models challenged the reputation of Triumph and Datsun, garnering several SCCA and IMSA trophies in the early ’70s, including a Daytona win in ’71.  Many features contributed to its racing success, including the rigid body, all-independent Porsche suspension, excellent handling and comfort, all-wheel disc brakes, and 5 speed transmission. The 914 was also used as a practice car for the Targa Florio, an endurance race on the public roads of Sicily, where drivers tore through narrow streets of small villages at frightening speeds, and each lap was 43 miles. The above clip from 1970 shows British driver Brian Redman practicing the course in a 914, as he narrowly misses horse carts, buses, trucks and pedestrians.  I’m sure the Targa Florio was a grave hazard to Sicilian villagers during the weeks leading up to the race.

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AltCar Expo 2011

It’s hard to believe an entire year has gone by since the last AltCar Expo at the Santa Monica Civic Auditorium. It was pretty low key as always, but there were plenty of enthusiasts lining up for free test drives of several electric vehicle models, including the Nissan Leaf, the Mitsubishi “i,” and the Chevrolet Volt.

My only real mission this year was to get a close look at the new industry standard charging receptacles and plugs. Inductive paddles were long used to charge vehicles, but energy losses and heat generation were the Achilles heel that made direct connections more effective and efficient.  As the standard changes, entire businesses have formed around locating and replacing old paddle chargers with the new plugs.

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And here it is: The business end of the mighty SAE J1772-2009 charging connector, modeled by one of the lovely Chevrolet Volt Ambassadors. There is a joke somewhere about the illusion of the plug size relative to her small hand, but it escapes me at the moment.  My simple goal was just to confirm the nomenclature and get a few pictures of the plug so I can start thinking about locating the charging port on my car.  Ideally, it will be hidden under a flip-down license plate frame, like gas caps on those big heavy American highway cruisers your grandpa used to drive.

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Here is the simplest solution for home charging.  Those dangly wires on the right run directly into an open 110 or 220 VAC breaker in your home distribution box, and the more voltage delivered to the vehicle, the faster it will charge. The J connector and bracket is installed in a convenient location near the vehicle on either the outside of the house or in the garage. This is exactly the setup I will use.  There is also a simple adapter that offers a 110 VAC standard 3-prong household plug on one side, allowing you to charge from any regular outlet.

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Here’s a look at the Nissan Leaf dual charging ports. The aforementioned J plug is on the right and handles level 1 and 2 charging, taking between 8 to 12 hours depending on the feed voltage. Since charging EV batteries requires direct current (DC), the vehicle must convert standard AC mains current to DC using the on-board rectifier included in it’s charging circuit.  Beyond 220 VAC, it is much more cost, energy, and time efficient to just deliver DC current directly to the batteries rather than converting it from AC.

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The larger Leaf receptacle on the left is the TEPCO JARI high-voltage DC charging port, which accepts 480 volts DC and will charge the battery pack in less than an hour (according to the Nissan reps).  This fast charging protocol has been developed in Japan, and is named CHAdeMO, which is an abbreviation for “CHArge for MOtion,” and otherwise a Japanese pun for cha demo ikaga desuka, meaning “How about some tea?”  Fast charging cannot easily be done at home, and these charging stations are apparently expensive, making wider adoption by commercial and municipal concerns less urgent.

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Here is an idea whose moment has come.  It’s only a matter of time before we see Automobile Club tow trucks pulling around EV mobile charging units to rescue stranded drivers.  Using the DC fast charging port, you could be juiced up in 30 minutes while you have a cup of tea with the AAA driver.  Maybe they should build a teapot into the trailer.

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This was the Nissan Leaf battery pack lecture and demonstration.  The display above shows the to-scale top-view outline of the car, and the relative position of the battery pack. I learned that the total pack voltage is about 400 VDC, and the entire battery pack is located in the chassis, which segues nicely into the next item.

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This is called the Trexa, and is one of the more interesting products shown at the AltCar Expo for a couple of reasons.  First, this is the most practical implementation of the swappable body concept that has been on automakers’ drawing boards forever.  The idea is that the volume and weight of EV batteries make it reasonable to integrate them right into the structural chassis.  In this case, the batteries are located inside the central torque tube, making for even weight distribution and very low center of gravity.  Due to the simplicity of this design, it’s easy to scale the tube and battery pack size, as well as swap vehicle bodies depending on the application or tastes of the user.  Trexa is pitching the utility and modularity of it’s product to the military market, not so much as a specific vehicle but as a multi-application platform.

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The other reason I found the Trexa so interesting is the drive-train, which looked immediately familiar. This is exactly the HPEV AC50 motor and Curtis controller that I have been eyeballing for a long time, and using as a basis for my own drive-train and traction pack design.  It’s a huge vote of confidence in the reliability of these components being used in a vehicle that is intended to take a beating.

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The only item that trumped the Trexa was a vehicle that wasn’t even being officially exhibited: this home-built solar bicycle.  The solar collectors are pulled along on a trailer, and are wired into the DC motor in the hub of the rear wheel.  I overheard the owner describing how he cruised the city for seven straight hours on an overcast day without a single pedal stroke. That’s a future I can live with.

For the curious, here’s my post on AltCar Expo 2010.

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Belt Tightening

Above is a picture of the original seat belts after receiving some TLC.  They didn’t start out looking this respectable, and they weren’t operating properly.  I considered replacing them, but a new pair of genuine 914 seat belts are currently priced from $270 to $500 per pair.  The next best option is re-manufactured replicas from Professionally Engineered Products, which includes a core charge.  There are also a few specialty aftermarket companies that sell universal 3-point retractable belts, such as SeatBeltsPlus, and RetroBelt USA. But before spending more money, I wanted to at least take a shot at restoration.  Why pass up some obvious fun?  I started by removing the two screws that held the side cover on the winding mechanism.

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To my chagrin, the cover I removed houses the coil spring.  The chaos shown above happened in less than a second. The cover bounced off the ceiling, and sitting across from me at the dining room table, the wife jumped in her chair. For future reference, the spring housing is the thinner of the two covers.  I felt the chances of correctly replacing the spring were slim, but that wasn’t enough to stop me from trying.  You’ll never know unless you take a whack at it first.

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I removed the spring altogether, then unspooled the belt and unseated the end from the center spindle by popping it out of the slot with a small screwdriver. The holding pin slides out from the belt end loop, and the belt can then be pulled back through the slot and completely removed from the winding assembly.  This can also be done with the spring intact, as shown above.  With the belt completely unwound, wedging a screwdriver or allen wrench into the centrifugal clutch wheel will lock it so the belt can be removed.

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With the belt gone from the spindle, it can now turn freely to allow rewinding of the coil spring.  First the spring needs untangling, so that it looked like one single and perfect Goldilocks curl. That took no more than 10 minutes. Examining each end of the metal spring ribbon, it was clear that the tip with two bends attached to the center, and the side with just one bend attaches to the outer edge.  It also became obvious that the slots in the center spindle could only hold the ribbon in one orientation.  If flipped over, the center tip of the spring won’t fit the slots. So I placed the spring into the spindle, and began winding by hand using the clutch wheel.

If the spring ribbon is oriented properly, it will be winding onto the center spindle opposite to its natural curl. In other words, it will look like it is winding onto the spindle wrongside-out. The picture above shows this clearly. The natural counterflex in the ribbon also gets stronger as you wind toward the outer spiral, becoming progressively harder to wind as you proceed. This winding operation also took about 10 minutes max.

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Once the spring is wound tight and the outside end is fit into its slot in the back plate, slipping an allen wrench through the center spindle slot will keep the spring from unwinding.  Keeping the spring tightly coiled will prevent it from exploding from the spring plate, so you can free your hands to clean and replace the spring housing cover.  In restrospect, unless the spring is obviously broken, there is no need to remove the spring cover.

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With the belt liberated from the spindle, the chrome guides can be slipped off to allow washing of the fabric belts and separate cleaning of the metal. The buckle tongue is the only bit of hardware that will not fit over the belt end, and cannot be removed without unstitching the loop. Luckily, mine were in good shape and didn’t need separate attention. However, the belt guides shown on the right above had some rust that had pitted the chrome.

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Some online research led me to an old school method for removing rust from chrome: Oxalic acid, otherwise known as wood bleach.  The big hardware chain stores didn’t carry it, but a local shop stocked it alongside various wood and metal treatment products. Oxalic acid is used to lighten and even out wood discoloration, but it also attacks and breaks down rust molecules without harming chrome.

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I created a solution of about a half quart of hot water and a quarter cup of oxalic acid powder, and soaked the rusty pieces for 24 hours.  The VintageBMX blog I read suggested periodically wiping the residue from the pieces once or twice during the process.  I used a small wire brush to clean them off before returning them to the bath.  The picture above shows the white coating that forms over the entire surface of the objects.  Once the soak was done, I removed the parts and simply rinsed them with water.

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The acid did a pretty good job of breaking down the rust, which dissolved cleanly away from the chrome. Unfortunately, the oxidation had chewed deep enough into the metal to cause pitting, which would just start rusting again if not protected.  That’s why I decided to shoot the pieces with a thin coat of “chrome colored” paint, followed with a coat of heavy duty clear wheel sealant.  Letting it cure and harden for a few days will ensure a durable surface that won’t be eroded by the friction of the seat belt fabric.

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In the meantime, I decided to wash the belts. They were grimy after 37 years of use, and needed freshening up. Since the chrome buckles could not be removed from the belts, I thought maybe I could wrap them tight in a towel so they wouldn’t harm the washing machine.  Better yet, why not let the hardware hang outside the washing machine hatch, as above? That was a great idea until the spin cycle literally tied the belts into a death knot, battering the drum with a horrendous thunking until I hit emergency stop. It sounded worse than it was. But the belts were clean enough at that point, so I fired up the electric clothes iron and pressed them flat and dry between two towels.

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Reassembly of the winders benefited from reference photos, ensuring the refurbished seat belt guides were replaced in the correct order and orientation. Understandably, the factory does not wind the belt spindles as tight as possible, but with time the springs suffer from relaxation. To compensate, the spool can be wound a little tighter before attaching the belts. I wound mine to maximum tightness, backed off a half turn, and then reattached the belts. If you are adventurous, another method is to shorten the spring by clipping several inches from the end closest to the spindle center.  Good luck.

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Finally, here is the seat belt assembly mounted on the firewall behind the passenger seat.  The winder spooled out smoothly, but retracted with a bit of rattling that may disappear with use.  Some silicon spray on the centrifugal clutch wheel might help.  The belt fabric on the driver side was slightly fuzzy from wear, and offered more resistance to being retracted than the other. I misted the entire length of the belt with some ArmorAll, which made it more slippery.  After all that work, I was a little disappointed that the winders didn’t snap perfectly back to life. We’ll see if they become less temperamental after a little breaking-in. There are always options.

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