Project Austin ‘Special’: Planned Mechanical Upgrades

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– Posted on February 15, 2022

In the previous installment we unveiled the bodywork modifications converting the Austin from a doughy four door into a slightly less-so business coupe-style two door. This time around the drive-line plans are revealed. While I would like to upgrade from the modest performance of a stock Austin A40 Somerset, this will be more a cruiser rather than a tire shredding hot rod; something in the vein of elevated performance that would have been somewhat believable in its time period.

source – https://www.flickr.com/photos/47676646@N08/31727123944/

On the suspension side, the A40 is similar in concept to the later MG A or B. Front suspension is lever shocks with A-arms and coil springs. Out back there is a live rear axle suspended by leaf springs. The axle is roughly the same (narrow) width. It seems reasonable to update the suspension a few decades with MG B components. MG parts are cheap and plentiful, which is not the case for the Austin. The Austin frame is fully boxed and rather beefy, especially given the A40’s modest 42hp. Crucially, it already fits the car’s body, so I will be keeping it.

 

On the steering side of things, the pieces I most wanted to upgrade was the steering box and linkage. It sits right behind the bumper which means any front collision is likely going to push  the steering column directly into the driver’s chest. While others have come up with often obscure combinations of other Austin and MG components to replace the drums with discs, this still leaves the potentially stabby steering intact. It also reportedly gives a roughly 1.5″ suspension drop. I wanted a more serviceable front suspension and brakes, with a safer steering linkage location. The MG B was again the obvious candidate as it is similar in concept but better overall.

I was able to find a complete MG B front suspension assembly for sale. This will give me rack and pinion steering, disc brakes as well as easy parts availability. Crucially, it is the correct width as many other potential donors would have be narrowed significantly. I am hoping to modify the frame in some way so that I can bolt in the whole assembly. That way the suspension will act and behave as if its still in a MG with no funky geometry. Comparing to the diagram above it is obvious that the front cross member is going to have to be altered to fit the steering rack and anti-roll bar.

If MG B suspension is good for the front why not the rear too? This makes sense to me and should be a reasonably easy swap. Again, the axle width looked about right so I bought an axle with a set of springs and driveshaft as well. I will have to see if the A40 or MG B springs make more sense to use. I suspect the spring perches will have to be moved a little bit either way.

Changing the suspension means a change in wheel bolt pattern so the Austin wheels will no longer fit without adapters. So why not upgrade the wheels as well? I received a set of 14″ MG B “rotostyle” wheels with my rear axle as the seller would not separate them but they do not really fit the vibe or era of the car as well as looking a little small. Ideally I wanted something closer to the 16″ stock wheel size. On the plus side, the MG B runs a more common 4×4.5″ bolt pattern, so that opens up other options, but many are 13-14″ in size as well. I did find these Nissan Sentra steel rims with worn out snow tires cheaply in the desired 16″ size with the correct bolt pattern. Being a front wheel drive wheel the offset might prove to be a problem however. Perhaps a spacer might work.

I do think they might look somewhat similar to a MG A Dunlop wheel with a lick of paint. If you do not see it then you probably just need to squint harder.

Now that we have our suspension plans sorted–in purchase if not installation–it was time to think engines. The engine bay in the Somerset is quite small, especially in length. The A40 (mostly Devons and Dorsets) based dragsters often have their firewalls hacked up to stuff a V8 in there. I was not willing to go that far so I went on the hunt for something physically small and with a reasonable horsepower upgrade. The smart thing would be to find a complete, rusty and running MG B as a complete donor. For some reason my wife did not want a second rusty car filling the garage for months on end so I was left to source the components separately, the hard way. This left the door open for a little more power than a MG B engine can give. Perhaps a five speed gearbox for more relaxed highway travel.

The candidates I considered were;

  • Chevrolet 2.8L V6 from S10, Camaro, etc. This is a very compact engine with reasonable power and torque. Its a well known swap into MG Bs and there is even an A40 pickup locally with one. It looked like a tight but do-able swap.
  • MG B 1.8L four cylinder. Modest power but probably the great ease of swap. Stock transmission only has four forward speeds unless a pricey overdrive unit is found.
  • Datsun L-series four cylinder. My friend Rod has one with a five speed gearbox and all the accessories he was willing to give me. It was seized but a few others were available semi-locally to combine with his bits to make a cheap complete runner. Adding a Weber carburetor 32/36 would likely make a reasonably powerful and reliable power plant.

In the end I went with none of these. I was browsing the online classified ads as one does and came across an ad for a Toyota 20R with a brand new Weber carburetor listed for little more than the cost of the Weber itself. It also came with a beefy five speed gearbox. While no high revving monster, it would provide plenty of low end torque. I figured the 20R puts out as much power as a highly tuned MG B engine without the hassle of having a highly tuned engine, so it will hopefully suit the overall vision for the car as a conceivable high performance period “what if”. A drive to Calgary and it was mine.

The seller was an exceptionally nice gentleman who was swapping a more performance oriented engine into his 1977 Toyota Celica.

Because of this I was able to snag not just the engine and gearbox but also a front cross-member, drive-shaft and aftermarket header. The engine relieved itself of a bit of coolant in the back of my wife’s truck during transit. Luckily, I was able to clean that up before she noticed. As tradition seems to dictate, I was unloading at night.

It might be just a four cylinder engine but it is physically quite large as I realized when it sat near the Austin. I think it will just fit but it is going to be a bit of a tighter squeeze than I anticipated. The 2.2-liter (2189-cc) overhead-cam engine made 96hp and 120 lb-ft from the factory but with the header and Weber it is probably just a little above that. Let’s call it between 2.5-3x what a stock A40 would have had. An A40 Somerset would have weighed 300 lbs less than the Celica it came out of so performance should be a slightly better than in its previous host, at least in a straight line. On the topic of weight, I am guesstimating I should come in around the 2,200 lbs or less, which about the same as stock. Some items on the A40 were crazy heavy, like the radiator, and it will lose some weight with a more modern unit. I would likely gain a few back with the beefier MG B rear axle.

The electrical system of the Austin mostly does not exist anymore. There was a fuse box and the remains of the occasional bit of wire. The fabric wrap on the wiring loom remnants had mostly been eaten away. If I had been smart I would gone with the single MG B donor which would have included an electrical system but since I was sourcing individual bits I needed wiring. One can wire a car from scratch or use an aftermarket kit for this purpose, but the kits are not inexpensive, especially given the unfavourable Canadian to US dollar exchange rate. I did luck out on a local person selling one of these kits for a fraction of the cost of new. Given the cost of wire it is likely a cheaper option than creating my own wiring loom.

As perhaps an interesting side note I thought I would give some indication of scale by showing it next to my 2017 Mazda MX-5. The Mazda is a little more forward but the overall length is within a handful of inches.

Austin vs Mazda
Wheelbase:   92.5″      90.9″
Length:       158.5″      154.1″
Width:          63.0″       68.1″

As the car sits now, I have shell that is progressing to where I want it to be. I also have the majority of the big mechanical building blocks. I am still missing some smaller bits like a steering column, heater box, radiator, gauges, etc. Updates will likely be slow from here, but I will provide progress reports as significant milestones happen.

Project Austin Special Series:

Project Austin ‘Special’: Acquisition of a 1952 Austin A40 Somerset

Project Austin ‘Special’: Assessment of the Car

Project Austin ‘Special’: Four Becomes Two

Project Austin ‘Special’: Planned Mechanical Upgrades

Project Austin ‘Special’: Rear Suspension Upgrade