1966 Triumph 2000->2500->4000

[BiTurbo228]

Right! Rack mounts.

After a bit of measuring and cleaning up some 5mm sheet the previous occupant had left in the garden I could start mocking bits up. Cad template turned into this:

Spent a lot of time measuring the location of the rack relative to the now-flipped centre of the crossmember. It wound up being 98mm from the upper face closest to the rack to the outermost point of the centre rack tube, in case anyone's thinking of doing the same thing.

Bolt another bit on the bottom of the rack and clamp the rack in place like so:

Bit of welding and grinding and we end up with this:

I'll clean up the welds in the centre as soon as I work out what I've done with my carbide burrs...

On the other side I had to move the repurposed mounts a little outboard as the bolts fouled on the turret of the rack, but other than that it was the same thing again.

...and we end up with this

Saves maybe 20mm of clearance over the old mounts, which hang well down below the rack.

Next step was to see if my measurements were anywhere near right and it fits underneath the engine. Did a bit of repair work on the mounting surfaces where I'd mistakenly clearenced them where I didn't need to:

...did a bit more clearancing of the sump...

...and bunged it all in there!

It fits, but it's tight!

In a pleasant surprise, it's not actually the lowest point on the car at the moment. The bottom of the rack is spot on 2mm higher than the bottom of the sump:

This probably means that the engine mount rubbers have compressed more than I'd thought, which is a good thing. Pending bonnet clearance I might be able to shim them up a bit and sneak another couple of mm clearance above the rack.

But still, great success! 

Edited March 15, 2023 by BiTurbo228

[Nick Jones]

Jeez…. That might even be snugger than a Vitesse rack!

[BiTurbo228]

Haha yeah I was inspired by how little clearance Triumph seem to think is necessary for the small chassis cars

[Nick Jones]

When the Vitesse gets even more uncivilized than usual in NVH terms, it tends to mean that the engine mounts have sagged to the point where the sump is beginning to lean on the rack and indicates the need for another shim or two 

[BiTurbo228]

Right! Long time no post. Turns out that although having a kid is nowhere near as all-consuming as I'd expected, it does still have an impact. Lots done, but in lots of short spurts and not a great deal of big stuff ticked off just yet. Still, getting there slowly.

The main project has been the front suspension, starting with the struts.

Turns out it had Koni inserts!

Completely shot mind, so I don't mind having bought a set of GAZ adjustables.

Slightly sketchy test of the springs showed they were 157lb/in, which fits pretty well with the 160lb/in stock rate online.

Stripped the struts down with the truly wonderful angle grinder paint removal discs. First time I've use them and they're brilliant.

Bought a set of 2.25" coilover conversion kits from RallyDesign just down the road, and a set of 200lb springs. These match the existing aftermarket springs you can get for T2000s, but gives me a bit of an easier time switching around ride heights and different spring rates if need be.

Turns out the GAZ struts are about an inch shorter than standard T2000 struts. Typically people shim them up with spacers dropped into the bottom of the shock, so I've ordered a pair of [url=https://www.ebay.co.uk/itm/193181861987?var=493371873671]15mm long 46mm alloy spacer tubes[/url] with a 20mm centre hole. They fit nice and snugly down the strut tube and should locate the bottom of the insert nicely.

I've also tested out some de-rusting acid solution from Bilt Hamber on all the various front suspension gubbins, which took a while on some of the more corroded bits but worked a treat. That's all currently with a local zinc platers being made all shiny

Meanwhile I've painted the lower control arms and subframe. Can recommend Bilt Hamber epoxy mastic as a chassis paint. Seems much better than the POR-15 I've been using previously, which works well when it's gone off slightly but out of the pot it runs off edges leaving them exposed far too readily.

Next up is a set of camber adjustable strut tops from a TR7. You can get these in the right bore for T2000 struts, though I've had to drill out the bottom of the spacer to 19mm for 3mm depth or so to give enough threads poking out the top for me to be comfortable with them. I'll also need to make up a spacer so the spring pan will sit on a proper shoulder in droop, for which I'll need the lathe up and running.

Positively, the boltholes for the strut line up nicely with the slightest tickle of a file. Maybe half a mm per hole which should help keep them in the right position. The OD is too big to fit though, so that's another lathe job...

Lastly, because you can never have too many things dismantled all at once, I've pulled the rear suspension off as well ready for the BMW diff swap

Hopefully will be getting some bits built back up again soon!

Oh, also, before I go and spend £240 on a PI fuel tank, do I remember correctly that the PI saloon tanks have an integral swirl pot/sump? If so I'll grab one, but if not then I'll just use the tank I have already with an external swirl pot of some variety.

[Escadrille Ecosse]

Progress is progress. Good stuff.

And congratulations on your firstborn. It's quite an experience.

With two of you and just one of 'them' the situation is fairly evenly matched once you get the basic hang of things.

Once number 2 arrives then you need to be prepared to be outnumbered

[Nick Jones]

11 hours ago, BiTurbo228 said:

do I remember correctly that the PI saloon tanks have an integral swirl pot/sump

It’s more of an internal “cat dish” iirc. 

[BiTurbo228]

@Escadrille Ecosse Haha yeah it feels like we've got it somewhat under control at the moment. No sure how well we'd cope if we also had a 4yr old to deal with! 

@Nick Jones Gotcha, so probably not worth £240 when I'd likely have to have a sump/swirl pot of some variety anyway.

 

Oh, also, I don't suppose anyone's played about with MGF calipers before. I'm looking at a disc brake conversion and I reckon I've found a solution for a disc that doesn't need machining to fit the rear end (Hyundai Coupe Mk1 with a 76-70mm spigot ring adapter). Next step is to work out the caliper mounting bracket. I've got a pair of MGF calipers knocking around somewhere but do you think I can find them?! 

Main thing I can't seem to find online is the distance of the lug holes radially from the centrepoint, or from the outside of the disc.

[BiTurbo228]

Next few bits and pieces progressed, in my usual scattergun approach 

First off was a bit of de-rusting on the diff mount. Dragged the subframe assembly out of the car and pulled the mount off:

I've bought a bottle of deox c acid rust removal stuff from Bilt Hamber and made it up in a bin. Wonderful stuff! Goes to show how wire wheeling heavily rusted parts still doesn't quite get all the rust out:

Also managed to pick up an E36 compact subframe for £20 and liberated the diff mount:

Next up was sorting the pedal box. Welding the bias bar into the pedal worked perfectly, but the threaded rod on the master cylinders wasn't quite long enough to reach. What I really need is some 5/16ths threaded, 1-1.25" long hex standoff nuts, but they're not a common fastener it would seem. Ended up tapping some tube and screwing that on using a piece of threaded rod, which gets it all connected while I source some proper hardware.

If I can find a source for the right standoff nuts I might look at getting a batch of the adapter plates made in 6082 aluminium with helicoiled studs. I've done some rough quoting and would probably be looking at £50 each for a batch of 5, or £40 for a batch of 10. Not sure how many takers there would be though, seeing as it would only really fit saloons and stags.

The next thing I've been pottering along with is a rear disc conversion. There's been about half a dozen different approaches for TR6s all using a caliper mounting plate that sandwiches between the hub and the trailing arm like so:

http://www.britishv8.org/Articles/Images-V17-1/TR6-Rear-Disc-Brakes-CB.jpg

All of them have used discs that needed machining, and often custom handbrake cables. Using the brake disc catalogue I've put together I found that a 258mm Hyundai Coupe disc and a 76mm-70mm spigot ring would work pretty well.

 

I've picked up a set of MGF calipers, which very nearly fit perfectly just bolted to a flat plate on the back of the hubs, but are out by 2mm.

First iteration of the design had two plasma-cut plates, a caliper mount and a spacer. This would increase the track by 9.5mm each side though, so I switched to a machined plate that looks a little like this:

That only increases the track by 7.5mm a side which is more likely to be within the range of plunge for both the UJ and CV driveshafts.

Again, happy to produce a batch if people are interested (after I've tested it works of course!). Looking like £150-200 a pair for those in hard anodised 6082 ally, again depending on batch volume. Would be interested to know if anyone fancies a set. Should work a-ok on saloons and stags. Will need to test for TR4 IRS', TR5s and TR6s as the bumpstop is in exactly the wrong place.

Also happy to share CAD files if they want to make a pair themselves, but commissioning them individually does work out more expensive.

Edited July 6, 2023 by BiTurbo228

[Nick Jones]

Interesting….

I thought the usual approach was to use the complete E30/E36 compact/Z3 rear with driveshafts, brakes and all?

[BiTurbo228]

Ah yes I'd forgotten about that approach! I was put off by the heavy steel trailing arms. Stronger I'm sure, but considering people have put American V8s and at least one turbocharged cossie engine through TR6 trailing arms I'm not sure that additional strength is required.

Would undoubtedly have been much cheaper though...

Edited July 6, 2023 by BiTurbo228

[BiTurbo228]

Also, I've yet to come across a BMW handbrake that could stop a stiff breeze from just pushing the car merrily along. I've experienced an E30, 2 E36s, an E39, 3 E46s, 2 E92s and an F30 and as far as I can tell they've all functioned by pressing soft cheese against the disc and hoping that stopped the car 

[BiTurbo228]

Next step was to sort out the diff mounting. First job was to make a jig to keep everything in the right place once dismantled.

Then some careful tracing of the BMW diff backplate bolt pattern and transposing the Triumph mount holes to it at the right height to get the output flanges in roughly the same position.

Bit of drilling:

Then scanning a copy to cut out clearance and mark that out too.

Choppy choppy:

https://live.staticflickr.com/65535/53046276685_11d808271d_b.jpg

All fits neatly which was surprising 

Then it came to bolting it up to the frame, where it turns out my eyeballed 'height of output flanges to bottom of diff' measurement of ~4.5" was a little out.

BMW diff pinion is sitting 35mm below the bottom of the subframe by a good 35mm. I reckon I can sneak 20-25mm of height without compromising the rear diff mount frame. Just a shame as I'd already cut it pretty much plumb on!

On the positive side, my Hyundai disc/MGF caliper setup appears to fit fine in the 14" steels I have

[Nick Jones]

Definitely doing it the hard way….. Why not use at least the centre section of the BMW beam?

[Escadrille Ecosse]

21 minutes ago, Nick Jones said:

Definitely doing it the hard way….. Why not use at least the centre section of the BMW beam?

Yeah. Might be simpler going over this again rather than moving the problem to the front subframe. 

You weren't going to get another 35mm out of that rear beam 

[BiTurbo228]

Do you mean the centre section of the front beam or the rear diff mount? As far as I can tell the BMW rear mount is just some tabs attached to the chassis rather than a beam of any variety. I suppose you could use them and just weld tabs to the chassis. Didn't think of that!

If you meant the front beam subframe thing then I've got the upper centre section of that cut out already, which I'll use. I didn't want to use the whole centre section as to get the prop out I'll need to be able to drop the rear end down and pull it out backwards over the chassis cross-beam I've added in up front. Ordinarily that'd be fine.

Definitely not 35mm left in the rear beam though! A quick measure suggests that 25mm might be pushing it a little too far, but 20-22mm might be doable. I can deal with 15mm of the diff poking out down below the subframe. I've got worse ground clearance issues up front!

[Nick Jones]

Centre section of the front beam…..

[Escadrille Ecosse]

3 hours ago, BiTurbo228 said:

I can deal with 15mm of the diff poking out down below the subframe. I've got worse ground clearance issues up front!

[BiTurbo228]

7 hours ago, Nick Jones said:

Centre section of the front beam…..

Ah, I've chopped off the bits I think I can use. It was a little crusty anyway so I wasn't 100% convinced how sound it would be to re-use without at least some mucking about with (it was only £50!)

Quote

I can deal with 15mm of the diff poking out down below the subframe. I've got worse ground clearance issues up front!

The more I've thought about it tonight, the less happy I am with losing 15mm of clearance. Or rather, if it was just 15mm I'd be fine but it's 15mm of diff flange which translates to nearly 30mm of diff as the casing pokes out below the flange. Seeing as I've made a fair amount of effort to maximise ground clearance at the front I should probably try a bit harder at the back.

I reckon something like this might do the trick:

E36 medium case rear cover. Weld a couple of mounts to the chassis and job done. It would also move the diff forward a bit as well as up, which is useful for both driveshaft alignment and prop length. Only slight concern is that people do like to shear those mounting ears off these diffs, but people do all sorts of hooligan stuff with E36s so maybe that's the root cause 

Edited July 15, 2023 by BiTurbo228

[Nick Jones]

I think the bits that break on the E36 are the brackets on the shell getting ripped out of the boot floor. The E36 diff doesn’t have the front attachment to help out….

[BiTurbo228]

A little closer examination of the E36 diff cover suggests that the mountings are a bit too far back. You'd be mounting the diff 3" into the boot.

Spent a fair while vacillating around about how whether it's better to mount it too low but in the right place fore/aft, or the right height but too far forward, before finally thinking 'I've hacked a great big hole in the floor for the gearbox, why am I concerned about a little bit of clearancing at the back?' 

So I've spaced the diff forwards by 10mm with some extra nuts and washers:

...welded an extension to the diff plate and drilled yet more holes:

...and actually put the pinion in a sensible location:

I don't actually think it'll take much clearancing of the floor at all. A little under the middle of the rear seat to get the prop high enough (not an issue if you're using the original gearbox as mine's sitting much higher), and a little expansion of this pre-existing scallop:

[Escadrille Ecosse]

1 hour ago, BiTurbo228 said:

Spent a fair while vacillating around about how whether it's better to mount it too low but in the right place fore/aft, or the right height but too far forward, before finally thinking 'I've hacked a great big hole in the floor for the gearbox, why am I concerned about a little bit of clearancing at the back?' 

Spaceframe chassis and a Silhouette bodyshell....

But where would the challenge be with that

[BiTurbo228]

17 minutes ago, Escadrille Ecosse said:

Spaceframe chassis and a Silhouette bodyshell....

But where would the challenge be with that

Haha where does modsports end and silhouette racers begin?! 

[BiTurbo228]

Been plugging away at the rear subframe. I've tried to pay attention to how the forces are fed through the subframe and eyeballed where it'll need reinforcing to resist them. This video gives a good idea of what direction cornering forces are fed into the suspension:

So, primarily it'll be using the trailing arm as a lever to push the centre of the subframe forward towards the front of the car. So, big flat plate on top. Needs to be curved to clear the prop though

It also needs to hold the diff in the right place fore-aft, so welded to the BMW diff mount I've chopped off the compact subframe:

Next thing it'll try and do when suspension forces are put into it is buckle the bent cross-plate upwards or downwards (not sure which). The diff also needs to be supported properly to stop the nose bending upwards or downwards relative to the rest of the car. So, I plated in the back section. The vertical plates will help with the buckling and diff location, and the horizontal plates hopefully feed some of the suspension forces into the diff mounts.

Lastly, with the back side being reinforced it still left the front liable to buckle upwards as it's only a single thickness of 3mm plate, so a stiffening brace went on there too:

The rear diff mount was nice and stiff vertically, but where I'd cut away a fair bit of the structure to poke the diff up through it you could wag the mounting lugs forward and backwards horizontally a little. So that got a little horizontal bracing over the top of the diff:

This still leaves the underneath of the subframe open and unreinforced, which won't be great for stiffness. However, thanks to the fact that the propshaft will need to go over the top of this box section in the middle of the car...

...I'll have to be able to drop the tail of the prop under the rear subframe to get it out.

So, I figured a bolt-on reinforcement plate on the bottom would work well. That meant a few captive nuts on both the horizontal and vertical planes:

Finally, that's all the welding sorted and I could remove the jig and the piece of beefy box section I'd welded to the bottom to keep it all true. It did go ping a little, but through all that welding had only distorted by maybe a millimetre (if that) over a 2-foot distance.

Not bad I think!

[Escadrille Ecosse]

Busy.

That looks very like it was made at the makers I have to say.