1974 TVR 2500M driver restoration

Certainly should have enough seat time to get everything well sorted by then!

TVR Scott said:

CoolHandMoss said:

I'm down for the get together. Dallas Texas in October 2028? 

That might give me enough time to finish my car.

Though that date was very specific.  Some event you have in mind?

Oh not at all. I just think Dallas is rather centric and 5 years 'might' give me enough time if things go well! Also, October is a good month for travel. 

Well I'm in Milwaukee, WI so Dallas is almost as far from me as it gets. Not saying it's not doable...

Still plugging away over here. Haven't done much since bringing it home from the painter. One of the reasons why was a great birthday trip to Kentucky for a weekend of Bourbon sampling. Nothing starts off your weekend like 4 drams of whiskey all 120 proof or better at 11 AM. We did 3 distilleries Saturday, 3 Sunday and drove back on Monday. The highlight was probably touring Buffalo Trace's facility. It's everything you probably think of in a historic whiskey distillery. I'll bring some to our collective TVR release party! 2025?

Back to the TVR content-

With the car back in the garage I started fitting the bumpers. I bought the stainless steel reproductions that are available from various sources. As far as I can tell they're all made by the same supplier in Vietnam. They appear to be high quality and well made. They will ask you when you purchase what specific year/model the bumpers are going on as some have a flat end and some come to a more tapered termination. The one problem with them is the mounting holes are nowhere near where they need to be, at least for a 1974 M series. Ah, the joys of rebuilding a hand-built car...

What I ended up doing was mounting them where I thought they should go using a bolt through one hole plus tape to hold the bumper up, and then marking where the new hole should be drilled in the bumper bracket. Then I drilled a new hole in the bracket and am having a shop weld in new captive nuts. If you look up a Youtube channel called D3Sshooter he has a good video on this which I shamelessly stole the idea from.

I've also been spending time on the trim pieces that cover the transition from vinyl roof to paint. They needed some clean-up to their appearance. So I went at them with 200 grit sand paper and worked up to 2000. Sanding purely by hand left a somewhat unclean impression from the end of each stroke, so I ended up putting the DA in a vice and worked the piece over it. That left a more consistent finish.

Getting to them to fit the car was the trickier bit. When I removed them there were these small slotted screws with flat sides to the heads so they would fit in the channel of the trim piece.

I could not find anything that matched that. The proper installation method would be some sort of rivet that goes into the body and the trim piece snaps down over, but I could not find anything like that to suit. Triumph did use and various places like Moss sell body trim rivets, but the ones I bought to try out were much too large to use with this trim piece. So my solution was to use brass counter sunk screws (8-32 thread if I recall) and grind the heads down to fit in the trim slot. Doing so required opening up a section of the slot to fit the screw into, and from there you can slide the screw to the position that matches up with the hole in the body. With all the screws installed in the trim you can press the trim piece down onto the body. From there I used a rubber-bonded washer to trim and keep as much water out as possible, and a lock nut to secure.

That's the aft section. Trickier still is the section closer to the seating area where the wheel wells and headliner interfere. I had enough room to get my hands up behind the headliner to secure most of the studs so that obstacle was mostly just an annoyance. The wheel wells create a situation where the screws will go through into the body but there's not enough roof to secure it with any sort of hardware from the inside. Since these ares were mostly not under tension and I was able to secure the screws on either side of them, I felt comfortable using a Christmas tree type nylon fastener to push into the hole. Just trim the head to suit the slot like I did the screws.

All in all I'm not overly excited about the methods I had to resort to, but the desired results were achieved and I believe it should be permanent enough and reasonable serviceable in the future should anything need taking apart some some reason.

So, it's coming along and the more pieces I get installed the more it looks like a real car again, in turn making me more excited to keep finishing it up. I've got the front/side indicators installed recently as well. I currently have the headlights and taillights disassembled on the bench (kitchen table) cleaning up what I can and replacing what I can't. I installed some dynamat foam on the transmission tunnel and passenger firewall (exhaust on that side) to keep as much of the heat out. We also made a real start with the electrical system this part weekend. Battery holder and battery, plus the main power and grounds to the starter installed. Made some decisions on how to implement the rest of the harness. This will be the biggest focus for the next phase of the restoration.

Looks great!

Was your headliner in good shape or did you have to get it redone?

In reply to TVR Scott :

Thanks! The headliner is totally new. Andrew Gray sells patterns conveniently.

ViperT4 said:

In reply to TVR Scott :

Thanks! The headliner is totally new. Andrew Gray sells patterns conveniently.

Oh cool!  I didn't know that.

Did you make the whole thing yourself?

Edit:  Looks like Andrew Gray sells them already sewn and ready for install.  Is that what you did?

TVR Scott said:

Oh cool!  I didn't know that.

Did you make the whole thing yourself?

Edit:  Looks like Andrew Gray sells them already sewn and ready for install.  Is that what you did?

They were definitely cut, but I think the upholstery shop did the sewing around the bows in the roof which it hangs from. I really just took it all to the shop with some pictures of how it was originally and they did the rest. You'll notice in my pictures that the headliner stops partway down the A-pillars. This is how they were from the factory and how Gray's supplies them. If you're going to order from him try and get extra material to cover that part. They're going to be able to use some of the fabric cut out from the sun roof to do that on mine but I was mostly lucky on that account.

Yesterday's theme was "you win some, you lose some."

New inner and outer gaskets for the taillights plus the rubber seal for the license plate lamp came in and those were successfully rebuilt. Doing similar work on the headlight assemblies, but the outer trim rings Moss sent me were either just the wrong pieces or are substantially different than my OEM pieces so I wasn't able to complete those. We're still figuring out a solution there.

More substantially, I got the pedal assembly mounted to the body, which for me is big because that had to happen before a lot of other items like the steering column and brake/clutch masters can go in. I put the brake booster and master in, which is not bad other than one bolt which took me 25 minutes lying up-side-down in the footwell to try and get a nut on that stud. With that in I was able to determine that an angled spacer will in fact be needed for the fluid reservoir to clear the hood, and that the aluminum piece for a TR6 I bought is far too thick. So I get to lay in the footwell a few more times to remove and install as many times as it takes to get it all to fit well. I bought a sheet of 1/2" x 6" x 24" ABS plastic which should get delivered today. I should be able to make all of the window lever/steering column brace/brake booster spacers made from that in the near future. 

All of this is happening in parallel with making progress on the wiring harness. Most of the progress initially has been mental, i.e. making final decisions on locations of splices, layout and the like. But I'm preparing to start making actual connections pretty soon here.

Another round of updates from the garage. Quickly, I got the last bit of front end trim installed on the car. The bumpers came back from having the new mounting nuts welded on and they went on the car without much of a fuss. The headlight outer trim has been its own mini-saga. The ones on the car were technically serviceable but beat up enough that I preferred to get new ones if I could for the amount of effort and expense being put into the car in general. I bought a replacement set from Moss and despite being mostly universal (besides the type of fastening clip at the bottom) did not fit well around my headlight buckets no matter what I did. The rear lip on the TR6 trim are larger than what was on my old ones and they never sat right or tightly.

The rings I could best tell that were similar were from classic Minis. I ordered one set from a vendor in early December only to find out they weren't in stock and wouldn't ship for 2 weeks. Two weeks came and went and still nothing so I canceled that order and finally got a set from Wild Child Classic Cars, which came in a few days so shout out to them. They seem to fit well enough without any play but we'll have to see if that remains to be the case once the car starts seeing some miles.

I have to say, I really like how the front end of this car is coming together. The bonnet fitment still needs to be adjusted but I'm quite please with the direction I've gone with the car cosmetically.

I also got the sun roof reinstalled. I won't say too much about it because I don't think the others doing M cars here are keeping theirs. It was pretty straightforward, just a matter of taking your time and ensuring everything fit well before doing the final riveting. I added what is essentially plumber's putty to the front and rear frames to hopefully keep any water from sneaking in. I think the factory only used it in the rear. The side frames are so snug to the headliner and vinyl roof that I don't think there's a chance of anything coming in that way.

One tip I would tell anyone who is going to keep their sun roof is you may want to consider running the headliner fabric around the bottom half of the front sunroof frame. The frame at the front is two pieces, one upper and one lower, that are riveted together with the roof in the middle. The standard installation is over the headliner, but that leaves a big gap between the frame and the roof if you're ever looking form the front (see last picture). I confirmed by looking at pictures of unrestored cars that this is how it was done originally, but I don't think it looks very nice. I think it would be much better if one were to wrap the headliner fabric around the lower part of the frame  and then up into the "sandwich" between that and the upper frame. Too late for me and really just a cosmetic thing, but something others may want to take note of.

A little while back I bought a sheet of 1/2" ABS plastic off Amazon and cut it up into tall the spacers I need. This goes back to the brake booster discussion from earlier. I still don't believe my original spacer was tapered, but regardless the master cylinder reservoir now hits the hood when it's closed. Nick Kennedy on the TVRCCNA page advised me that he made a spacer and ended up using a taper of 7/16" (5/8" wide at the top and 3/16" wide at the bottom). Since my material was only 1/2" wide to begin with that made it a little tricky as I'd only end up with 1/16" of material at the bottom. But I just went slowly on a band saw and it came out alright. Someone with a fancy new 3d printer could probably be much more precise

With that spacer in place the booster/master assembly were able to go on that they are close but do clear the hood. Clutch slave and pedal assembly also went on since I was working in that space and I like to lay upside down in a footwell as little as possible.

You can see the rubber gaskets I cut out of 1/8" rubber sheet I bought from China (Amazon).

Spacers for the steering colum bracket are doubled up. This could seemingly be adjusted for whatever fitment or steering wheel placement is necessary just by bending the sheet metal bracket as needed but I just replicated what came out of the car.

And finally, I've been focusing a lot recently on the wiring even if I haven't been putting that much activity towards it. The effort's mostly been around planning layout and making sure I understand all of the nuances before going in making connections. But I've now actually started cutting my wire and making connections and this is where the majority of my efforts will be focused until it's finished. I don't know that I'll post in that much detail about it as I think it'll be fairly monotonous, but I'll try to remember to post things like adding a hidden wideband O2 sensor, getting my radio and amps hooked up, etc.

For those of you that I sent that wiring planning Excel file earlier on I've made a handful of significant changes now that my understanding of all the components has improved. It was still valuable as an exercise to begin to plan things out but shouldn't be used as a bible by any means. I've taken that and along with my adjustments draw up a schematic which is about 95% final. From that I intend to make a 2.0 version plus diagrams of individual circuits that I can reference in the future. I can reshare once that's all completed. In the meantime, here's what I've decided to do.

My schematic. This was very helpful for me in taking the individual runs of wire I listed in the Excel file and putting them physically where they're going to be in the vehicle. This let me plan out where my splices are actually going to take place, how many wires need to pass through the firewall etc. Plus now I have a roadmap to work from as I'm making the harness and an easy way to keep track of what I've done. Showing here not because it's anything pretty, but because others may want to steal this practice.

From looking at the TR6 diagram I am referencing, a significant amount, if not the majority, of circuits in the original harness were unfused. The ones that were fused were all done on a total of 4 fuses. I thought this could be improved on, so I'm running two fuse boxes with 12 fuses each. Some will be that's more I can use if I need to down the road, and at least mentally it lets me bracket things to keep track of everything. I'll have one fuse box in the engine bay and one in the interior of the vehicle. Generally that's being broken down into switched and unswitched circuits, with the fuse box in the engine bay being for unswitched.

Rather than running all the current through the ignition switch I'm running all of the high current items through relays and just using the unswitched feed in the ignition to trigger the relays via the dashboard switches. I have a power distribution block to connect to the battery positive terminal which will directly feed the engine side fuse box, and those fused wires will run into the passenger footwell to feed the relays. Some will go back out form there, otherws will go to inter components like the rear window defroster, heater fan motor, etc.

Here's the power block and engine side fuse box.

For the interior fuse box and relays I made little mounts out of the abs plastic I used for the spacers and used adhesive to glue them to the inside of the body in the passenger footwell. I cut some shallow channels in them so that my adhesive would have more to bite onto.

So these circuits will all be switched. They'll be powered by one of the large gauge wires coming from the ignition switch and generally are powering the lower current components like gauges and just the switches switches for some of the high current items. It also has a bunch of ground lugs so I can run most of the interior component grounds there and then out via a bigger wire to the chassis. I'm not doing anything exotic or especially skillful here, just trying to focus on making it safe, practical and serviceable as much as possible.

Since I'm not replicating exactly how the factory wiring in the ignition switch was used I took the time to map out exactly which connections had connectivity to each other in the Off, Acc, Run and Start positions. Feel free to use as you need. The large gauge brown wire on terminal 2 is the positive into the switch. The little brown wire on terminal 4 is spliced with the large brown wire so I don't bother to show separately it in my table. I do have a question on what I've named "terminal 7". It is a black green wire that is attached to the cas of the ignition switch. It's not part of the switch itself and doesn't have connectivity with any of the other switch wires. This should be for the anti-run on valve. I'm not going ot bother using one (I think it came on later TR6's, not my car), but not even sure how it works if it never sees + voltage. 

Nice progress!  Great to see it all painted and with some of the trim on.

You're so close!

Slow_M said:

You're so close!

Getting there!

Little update as I got the first of 2 relay banks wired up. We've had a cold stretch here. I think the high temp today was 1*! So wiring today became a back and forth of measuring wire length in the garage, then hurrying back inside to cut, strip, and crimp. One other thing I'm doing with my wiring that I didn't mention before is using a label maker to print where each wire connects. I'm printing on heat shrink tubing so I can attach it right to the end of each wire just to make it that much easier to keep track of things.

I hope you're really over-thinking all of this.  If not, then I'm seriously under-thinking what I have in store for me!  Looking good there, my friend!  Great to see such progress, especially since I barely get out to my garage, and what I think is cold you guys would laugh at!

Greetings Stu! Overkill may be a good description, but I'm ok with that. On the other hand this was about as simple conceptually as I could make it, so actually working on it is pretty straightforward. Doing the schematic planned everything out and made sure I understood what I was doing so it eliminates getting half way through and having to second guess myself. Essentially it allowed me to take what was, to me, a fairly nebulous concept as a whole and  break it down into achievable steps. The extra step of doing the labeling is more to make working on it in the future easier. I am doing much of wiring off of the car right now as I mentioned so it's helping in that regard as well, when I take finished assemblies back to plug them in. But who knows what'll happen in the years to come and how far I'll have to disassemble things at some point so it will only make servicing that much easier. I'm thinking of things like the all the dashboard switches, or taillight harnesses, etc.

I'm going to try and get as much done as possible today and tomorrow. If I really get after it I could probably have the entire thing wired up by Tuesday. Thursday I'm headed to Daytona Beach for the Rolex 24! Looking forwatd to seeing the new Mustang, Lamborghini, McLaren and Chevy customer Corvette GTD PRO entrants. Should lead to an exciting seasons compared to past years. I camped for the Sebring 12 hours with a friend a number of years ago and had a blast. I'm excited to take in another endurance race and get the experience of 24 hours, although I'll be headed back to our AirBNB for a few hours sleep at some point.

While I'm at it I'm curious if anyone following has had thoughts or experience on adding a 3rd brake light. That would be my ideal, but I'm struggling to think of a way to do it that wouldn't ruin the vintage aesthetic of the car. My compromise is that I'm planning to wire in one of those brake like pulser modules. It will flash the brake like 3 or 4 times when you press the brake pedal and then stay on solid until you release. I figure this will give me 95% of the effect I'm looking for without having a 3rd light that doesn't look like it belongs. But certainly open to suggestions here as I haven't seen every possible scenario of addressing this.

https://www.superbrightleds.com/brake-light-strobe-module-brake-light-strobe-module

I was thinking the other day about adding a 3rd brake light too. 

I think it could look subdued if mounted on the inside of the rear glass.  Not very noticeable when not in use.  I also am thinking of tinting that glass pretty dark, just to keep the solar gain down.

I like the blinker brake light idea, too.

I've thought about putting one on the back side of my roll bar, but haven't gone much past that.  The soft top will block it from the view of taller vehicles, but I really wouldn't want to put one on the trunk lid or under the roll bar.  That's already pretty low and would block my rear view somewhat.

   I think a 3rd brake is over-rated for most vehicles, but probably worthwhile with our little sports cars mostly because of our lower profile and subsequent lower light height.  I agree that it might be hard to add an unobtrusive third light, but a lot of the problem with older cars in general is poor light intensity.  Going with some bright, high-intensity LED brake/tail lights will go a long way toward rectifying this, and I think the pulsing brake lights could only help!  The fact that LED lights also draw far less electricity make them a win-win.