Where Engineering Meets Coachbuilding

In a few days’ time, I hope to have completed the restoration of my TC, apart from a few out of sight jobs which will be cleared over the winter, so I was pleased to accept the Editor’s invitation to record my thoughts on what was involved in a frame up restoration. But rather than provide a detailed chronology of the work involved, which others have already done far better than I could, I wanted to delve into the more philosophical aspects of this job.

This was my 4th restoration but first MG, so I had a good idea of what was involved; the others were cars of the 60s, Lotus and Brabham, but this time I wanted something older both for its aesthetic appeal and to experience a previous era of car design and manufacture. I probably get as much enjoyment from a restoration as driving the finished article, so in August 2014 I purchased TC2628 in need of….. well everything!

For me, engineering is where components are designed and then produced to detail drawings, where tight tolerances ensure each part is identical allowing for ease of assembly and interchangeability. That is basically true for the whole of the rolling chassis with only the gearbox layshaft and differential requiring selective assembly to accommodate tolerance stack. So, the rolling chassis can follow a normal restoration approach of strip, clean, inspect, repair and refinish the surface or replace before the fun part of reassembly can begin. A big Meccano set where the principal tools required are spanners and sockets.

If most who take on such projects are engineers at heart then this part should be pretty straightforward and is generally achieved. I placed particular importance on, and effort into, chassis and axle alignment, balanced spring rates, geometry and poly bushes; I wanted the car to drive well. By contrast the remainder of the car is coach built, a very different approach where components were of course still designed but cut to patterns to be adjusted at the assembly stage to enable them to fit to each other.

The result is elegant, functional, more or less symmetrical but unique. Here nothing quite fits at the start but a good coachbuilder brings them together in the end to achieve the required shape, fit or clearance. Perhaps this is why some restorations stall at this point, I think it is important to realise what you can achieve yourself and what will need to be sub-contracted to those of greater skill.

This is why I ordered a new assembled ash frame from Enrique Llinares, 14 months later it would be in the last batch he made before retirement. I panelled it myself in Aluminium except for the scuttle, fortunately this very difficult to produce panel was easily salvageable. The front wings were replaced with new but the original rear ones were worth repairing, their profile was correct and they were a matching pair.

Trim and paint, like the ash frame, were left to the experts, but with the plywood panels provided to me before they were trimmed so I could adjust them to fit the tub and doors. Not as simple as it sounds, they need to be cut under size to allow for leather being wrapped around the edges and to control by how much the piping along the top edge protrudes, for me not a lot.

I think the prize for the worst job must go to floorboards; mine made from scratch must have been in and out 30 times for initial fit, gearbox clearance, machining underneath with a router to clear parts of the body irons and body mounting bolts, to fit the heat shield, trim the outer edges again to clear the now installed side trim, pedal clearance, master cylinder hole. I eventually worked out that the outer edge sits on the body iron, the inner edge with the addition of the mysterious narrow strip, shown on Michael Sherrell’s drawing, on the prop shaft tunnel flange whilst the centre has clearance above the top of the chassis.

The TC is a very elegant car; the styling department (probably smaller than those of today’s car industry) did a great job where every panel plays its part, particularly the running boards. Mine were beyond saving, but it was worth the hours spent reducing the width of an original pair of TA ones to preserve their gently curving line from the front wings.

Likewise, the battered front splash apron. I repaired mine by cutting out the damaged areas and making and inserting repair sections for the rivet bumps and rolled front edge.

Front splash apron repair section.

My main sources of information were Michael Sherrell’s TCs Forever! Doug Pelton’s From The Frame Up technical tips and TTT 2 articles. However, one important job which I could find little information about was tub position on the chassis. I settled on central side to side which is easily measured and for the fore/aft position, I supported the chassis on stands so the rear axle was sitting on the droop stops, its forward most position. Then I slid the tub forwards until there was just enough clearance at the front of the tyre to be able to remove a rear wheel (see pic). That way you can get the wheels off (important!) and when the car is at its normal ride height the rear wheel sits correctly in the arch.

Actually, I struggled to get the tub far enough forward and whilst not quite at the end of the travel in the body slots, I had to extend the slots in the ramp plate support brackets where they bolt to the chassis.

From day one originality was an important consideration, but with two exceptions; drivability and colour. I was restoring this car to be driven and enjoyed a lot (I hope) so I was happy to fit a VW steering box, substantial drop arm, high ratio final drive and indicators.

And, as I did not like any of the standard colours, a unique dark green paint for which I have the mixing formula, poppy red leather throughout because there is no matching vinyl, and birds eye maple veneer for the dashboard courtesy of Enrique Llinares.

Birds Eye Maple, very Art Deco, lovely.

Trimming the rear quarters in leather was a challenge, at the third attempt I stayed with the FTFU video but undercut the hood tacking strips to accommodate the thicker folds of the leather. The interior was completed with dark green wool carpets bound in Poppy hide.

Wood undercut to accommodate leather folds, new Triumph Bonneville indicators

Dark Green wool carpets and Poppy hide

The painter made such a good job of the inner rear wheel arches; he thought they were visible, that for the moment I have decided to leave them that way.

Body coloured inner arches, hidem nails still accessible just in case.

Would I do it again? Not sure, repetition is boring but I have now accumulated a lot of knowledge that would make it so much easier and quicker next time. I think the answer is perhaps if it was a TB, but it might end up as a lightweight race replica being used on the road, same colour, white race number roundels and cycle wings. Bob Lyell

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