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It is very interesting to follow this thread by the way. Ever think of installing a RallyBobCam in your shop so we can watch all of the action live? Just kidding, sort of.
You can always spend a week or 3 browsing through Bob's Flickr page.
 

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Discussion Starter · #183 ·
Took me a while to find the stuff, but I dug out a differential cover I previously modified to work with a Watt’s linkage.

With even more difficulty, I found the raw components to build the Watt’s link pivot bar.

I didn’t weld the pivot parts together, as my current intent is simply to mock up the differential cover and pivot bar. I need to design a body mount for the upper crossbar of the Watt’s link system. I’ll be using the standard panhard bar body bracket for the lower crossbar of the Watt’s link system.

Today I cut out and bent up some steel gussets for the outside of the torque tube. At 9:00, 12:00, and 3:00 o’clock, I’m using 14 gauge steel for gussets. The lowermost gusset at 6:00 o’clock is made from 11 gauge steel. I’m not planning on rallying this car (maybe rallycross…maybe), but I’m building it as if I would be. It is a potential failure point on higher HP cars that are driven hard. I doubt I’ll ever put more than 250 hp into this car, but you never know. I will also be sleeving the inner torque tube shaft (a VERY common failure point), and using studs to secure the torque tube to the differential. Loose bolts here are one of the biggest causes of TT shaft splines and differential barrel spline failures.

After bending and fitting the steel gussets, they were fully welded in place.

Since I had the welder out, I ran a few beads of silicone bronze at the TT mounting points. These looked pretty good, but I’ve had these tear out before from rust. Just another 3 minutes of work, and then they’re basically bulletproof.
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Discussion Starter · #185 ·
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Discussion Starter · #186 ·
Haven’t really worked on the car for a couple of days. But today I did bolt up the other 1” wheel spacers and fitted all 4 wheels and tires.
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On a different note, today on Facebook somebody posted a pic of his 1974 Ascona from back in the day. His car was EXACTLY like the first Opel I ever got a ride in back in 1982. That was 40 years ago…

My good friend John drove his mom’s 1974 burgundy Ascona with white pinstripes. I first got a ride in it in 1982, and drove it in 1983 a few times. That car always punched above its weight class. It wasn’t fast, but boy could you drive it fast. It is 100% responsible for my lifelong addiction to the Opel marque
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My good friend John drove his mom’s 1974 burgundy Ascona with white pinstripes. I first got a ride in it in 1982, and drove it in 1983 a few times. That car always punched above its weight class. It wasn’t fast, but boy could you drive it fast. It is 100% responsible for my lifelong addiction to the Opel marque
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Bob that is better than some other types of addictions. As I have so often told my wife Morgan Fairchild! Yeah, that's the ticket.
 

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Discussion Starter · #188 ·
Didn’t take many photos today. I got in a few small boxes of mostly small (but expensive) parts. Pretty much all the parts are plumbing bits, for both the brake system and the fuel system. There’s also a few ARP fasteners for the torque tube. I’ll take photos of that stuff tomorrow.

As you may recall, this car will potentially go back and forth between carbureted NA engine, EFI turbo, carbureted turbo, and carbureted with nitrous oxide.

In order to enable this, the fuel system has to be able to handle the fuel demands of anything I throw at it. I’ve designed the system to allow fuel pump swaps to be made easily. I will be running 3/8” copper-nickel fuel feed lines, 3/8” copper-nickel fuel return lines, high pressure 3/8” (-6AN) flexible hoses, and the ability to regulate fuel pressure for the task at hand.

Here is the setup that allows for the use of a Weber (or Webers). My carbureted fuel pump is rated at 7 psi max, in case I want to run a Holley carburetor or if I want to run nitrous oxide, which requires about 6 psi fuel pressure for proper fuel enrichment.

I already had a Purolator-style pressure regulator, and a 15 psi pressure gauge. I needed to put these items in line with the 3/8” Earl’s Vapor Guard fuel line I’ll be using. Now I can regulate pressure down to roughly 3 psi for optimal Weber performance.
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Discussion Starter · #189 · (Edited)
Continued from yesterday. Here are the Earl’s Vapor Guard fittings threaded onto the fuel pressure regulator and gauge.
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Here are the bulkhead fittings I’ll be using to pass thru the floor pan and the firewall.
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Below we have a mock-up of the fuel pickup line off the gas tank feeding the fuel pump, and then the outlet off the fuel pump. The EFI fuel sender unit has a 12 mm (.472”) tube size. I’ll be brazing on a -8AN steel fitting, allowing -8AN hose to be used (1/2” ID) for the pump inlet. It’s not really necessary on the low pressure pump, but it’s good to have for the EFI pump.
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Moving on, these are the replacement fasteners I’ll be using to secure the torque tube to the differential. I hate the OEM metric serrated bolts, they always seem to strip out and they often loosen up. I could use normal 12.9 grade socket cap screws, but I also hate rust!

In order to prevent rust AND match the tensile strength of the OEM fasteners, I went with stainless ARP studs and nuts. The 12-point nuts allow for better tightening. However they are VERY pricey.
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Here’s some of the fittings I got for the brake lines. More bulkhead fittings and tube nuts, plus a 10 psi residual pressure check valve for use with the aftermarket master cylinder I’ll be fitting. This works with the rear drum brakes to keep the brake shoe spring hardware from fully retracting the shoes and creating longer pedal travel. Master cylinders for disc brakes don’t have this internal feature.
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Discussion Starter · #190 · (Edited)
More brake plumbing stuff. I wanted to convert all the brake lines from 45° inverted double flares, to AN 37° single flares. For most items, this is easily done.

The rear wheel cylinders were a bit more involved. They are 10 mm x 1.00 pitch inverted flares. I ordered some adapters that said they were 10 x 1.00 IFF, but clearly the end of the fitting was not going to seat in the cone within the wheel cylinder. So, measuring up a 1/8” NPT-to-3AN adapter, I realized the 1/8” NPT was just a little bit bigger than the 10 mm x 1.00 thread. In fact, it starts to thread in a few threads, so the pitch isn’t too far off.

I said, ‘what the heck’, and proceeded to disassemble the wheel cylinders. It’s not that they are crazy expensive, but they are brand new ATE 19 mm rear wheel cylinders, so I can’t just run down to NAPA to get new ones if I screw up.

I milled off the internal ‘cone’ at the bottom of the 10 mm hole with a 5/16” end mill and a drill press. Then I ran a new 1/8” NPT tap in as far as I could, followed by a modified (shorter) 1/8” NPT tap that takes the thread diameter out a bit further before bottoming out.
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The end result is a 1/8” NPT-to-3AN adapter that threads directly into the wheel cylinder. Then I just need to bend up the 3/16” copper nickel lines for the rear axle housing, flare them, and secure with -3AN tube nuts and tube sleeves. Almost like factory.
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Discussion Starter · #192 ·
Did nothing much today but shovel wet, heavy snow. The one exception being welding a few 6 mm bolts to the steel torque tube. These are to secure the -3AN stainless braided Teflon flexible hose feeding the rear brakes. You can see I’ve discarded the short OEM hose…and instead will run a long braided flex hose from the floorpan near the front of the torque tube pivot, all the way to the T-fitting at the rear differential cover.

That’s about it for today.
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Discussion Starter · #194 ·
Uh-oh, cabin fever! You were climbing the walls and got the urge to weld something.

🤪
Lol, not so much Gordo. I’m just trying to persuade myself to get something done on this car every day. Even if it’s one tiny thing, it’s still forward progress.
 

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Discussion Starter · #196 ·
My little something I got done today.

I previously dug out an unused Momo FIA racing seat I have had for years. It’s not a wraparound competition seat as is the norm these days, but it’s fine for hillclimbs and track days.

I will be making custom seat mounts for the Manta 400 Recaro seats that will be used for daily driver duties. I want to be able to swap out the driver’s seat rapidly for a race seat. Remove and replace four bolts and I’m done. 5 minutes or less. So it stands to reason I need to design both sets of mounts simultaneously.

The Recaro mounts are very straightforward. The Momo mounts require a little work. First of all, I’m not using rigid side mounts, but rather using bottom mount sliders. I have a set of unused competition grade sliders too, but they needed a few tweaks to work on the Momo seat.

First of all, they need to be spaced down so the release mechanism doesn’t rub the underside of the seat. I happened to have a few 1/2” thick scraps of round aluminum (slugs from hole saws) which only needed to have their center holes enlarged slightly and they were a perfect fit. Next, there was no crossbar to connect each release mechanism. A street seat would usually have a single lock/release mechanism, but the racing version requires one on each side.

Here’s how I went about doing that. I dug out a piece of thin wall chromoly tube for a connector bar, and modified as follows:
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Discussion Starter · #197 ·
Next, a little bit of welding got done.

The battery box was finally welded into place.

I then tacked together one of the main hoop baseplates, and fully welded it on my bench. Finally it got sanded down and slid back into place. I’ll hopefully do the other main hoop baseplate tomorrow. With any luck, that means I’ll be ready to bend up the main rollcage hoop soon.
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Why use sliders on the Momo race seat?
Just have bolt in mounting that fits you.
Eliminating the sliders gets rid of one more thing that can go wrong.
 

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Discussion Starter · #199 ·
Why use sliders on the Momo race seat?
Just have bolt in mounting that fits you.
Eliminating the sliders gets rid of one more thing that can go wrong.
As I said, I already own them, so why not use them?

Also, there’s the distinct possibility I’ll let other people use the car for autocross or even track days. I’m not sure if my significant other will want to, but I know her son will. And he sits appreciably closer to the wheel than I do.
 
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Discussion Starter · #200 ·
Slow day, spent most of it helping Tina take down all our Christmas stuff, box it up, and put it all away.

Then of course a bit of excitement when our furnace expansion tank failed, with the overpressure causing water to get dumped out the pressure relief valve. Luckily the service guys got here quickly and had the part in stock.

I didn’t get to do much car stuff today as a result, the one area I worked on was mounting up some aftermarket TEX mirrors to my Sportwagon. These are made in the UK and are commonly fitted to MG’s, but in the 1980’s they were super popular for 1974-1975 Opels as they are nearly identical in size and design to the originals.

I had three new driver’s side mirrors left over from my C&R days, but no new passenger side ones. I did have a used passenger side TEX mirror from one of my old cars, so I’m going to refurbish that one. New fasteners, a quick polish of the stainless steel and chrome, and scrubbing the mirror clean should do it.

The mirror’s original mount design can be improved a bit by getting rid of the sheet metal screws provided and instead using machine screws and nutcerts for a more secure attachment.

It’s not much, but progress is progress.
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