Classic R #27 Build - Final Assembly - Part 3

I've been wiring the fuse and relay panels and it's taking quite a long time to complete. Nevertheless I've been able to wire two of the three panels and I hope to complete the last one next weekend. I had to stop because I ran out of printable heat shrink tubing.


Here are a couple of work in progress pictures. These connectors are temporarily tied together and will be secure to a plate that will sit above the panel.


These are the power and ground feeds to the panels. They're roughly routed but need to be secured and laced.

I also did a bit of work to tidy up the long wiring that comes with the gauges. Pictures to follow.

In other news the brake lines seem to be under control for the most part. I might try to mount the radiator before the weekend is out.

-Dave

Electrical work continues on #27. Last weekend I fabricated the top cover for the fuse/relay panel. There are still some wires and connectors to install and they're shipping this week from Prowireusa.


The top cover is an aluminum plate with a slot running across the middle. Wiring emerges through the slot and will be secured to the plate.


Test fit on the car. I may have to trim the corner off to clear the scuttle but it's not a huge amount of work.

.050 aluminum sheet arrived in the mail on Monday so I can begin fabricating the PCM mounting bracket. I'm keen to see that installed so I can put power on it and interrogate it using the OBD2 port.

Some lucky but talented soul will benefit from your thorough documentation of your high standards of craftsmanship.

Took a long break over the winter from working on the Classic R and this spring I've been concentrating on some long running carburetor problems with the MGB which hopefully I've sorted out. In March I acquired a 1966 SWB Land Rover Series 2A. Getting that up and running and roadworthy have consumed a lot of time. This weekend though I found the time to resume wiring operations on the Classic R. Hopefully will squeeze a bit more in today.

Over the winter I added TIG welding and CNC plasma cutting capabilities to the workshop. Looking forward to trying them out on the remaining fabrication tasks.

welding? smart. I did too (MIG anyway). No plasma yet. But I'm getting there.

Well, hope you find the time to finish.

Thanks Ted. The CNC plasma's going to get used today hopefully.

I spent a day working on positioning the PCM under the scuttle. I made up a cardboard template, cut it out and folded it to check the fit in the space, then transferred the measurements off it into Fusion 360 which I'm using for CAD. If time permits today I'll cut and fold this and see how I like it. Stay tuned.

A solid day today on #27.


Here's the PCM bracket, cut out of 16 ga mild steel, folded and (hastily) painted. Turned out ok.


The PCM fits through the hole in the top. I used the four cover screws to attach it to the bracket. The connectors emerge through the hole in the side. There's clearance between the scuttle and this whole assembly to accommodate the engine harness that came with the kit. Speaking of the harness, I made a couple of changes. First I eliminated the fuse block, running the four pink wires directly back to the custom fuse panel. I also eliminated the fuel pump relay, using the relay on the custom panel instead.


I roughed in the engine harness, routing it through the transmission tunnel and into the engine bay, then made the changes to integrate it into my custom harness.


With an OBD2 monitor hooked up and with power applied, the PCM seems responsive and I was able to connect to it. I can hear the fuel pump relay engage when I turn on the ignition as it tries to pressurize the fuel system. The fuel pump's not connected yet; that's a job for tomorrow.


It's the first time I've had power on the PCM so I'm somewhat relieved that it at least powers up.

Made some more progress today. The fuel pump and fuel gauge are both wired in and the pump runs when the ignition is switched on. I also got a fair bit of the dash wired. The instruments now have power to them, the voltmeter and needle lighting are wired as is the headlamp switch.



It's a small step but it feels like progress.





This view of the fuse panel was taken from underneath the dash, looking upward from the passenger seat area. It will fill up more as I wire in additional circuits. Had to order more ISO 280 relays from Waytek Wire as I've run out. It seems to be hard to find these at the local parts store.

Haha, brilliant as usual. these are the stone tablets for some bright young person building a show piece kit in the near future. could be me in my next lifetime.

Onward!



Finished up the remaining powder coating tasks today, starting with the cooling fan brackets.



Got the fan mounted but somewhere along the way I'd lost the radiator mounting bolts so had to run out and get some more.



Also did the throttle pedal and the pedestal.



Began reassembly of the cooling system. I hadn't noticed before but the thermostat is asymmetrical and that affects the alignment of my custom water neck.



Radiator top hose installed and routed as before.



Another view looking towards the front of the car.

I'm happy to have completed the powder coating tasks as they're really a chore.

A lot of tidying up yesterday in the transmission tunnel area. Wire routing in this area is a bit of a challenge because it's hard to see and get access to.




I secured the fuel line, hooked up the vehicle speed sensor and wired the reverse light switch. The reverse light switch uses a 2 pin Delphi weatherpack connector which I had on hand, with the correct crimp tool. The VSS connector on the engine harness hooked right up and it is intended to drive the PCM directly. However this raises the question of what signal to use to drive the speedometer.



The PCM notes describe a Vehicle Speed Signal output pin, pin 55 on C1. From reading around the interweb I think this is an open collector signal. Preemptively I ordered a couple of dozen pins from Mouser, part number 829-12084913, in case I need to tap this signal off the PCM.



The schematic doesn't provide any clues to the signal driver type but I've seen another picture elsewhere that shows this as open collector so I'm going to assume it is. It will require a 10K pullup resistor to +12V.



Speedhut's installation notes don't say a lot either other than that the input will tolerate a 1V to 100V input signal at up to 250K pulses per mile. It's possible that there's a pullup already inside the gauge and I'll have to ask Speedhut for guidance on that, or try to measure it externally.

EDIT: found what I needed at the Speedhut website speedometer FAQs. The VSS output from the PCM is indeed open collector and requires an external pullup resistor.