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Competition from the MG SA and MG WA

Cecil Kimber never permitted either his MG SA or WA models to be road tested by The Motor or by The Autocar so we can only extrapolate figures from the power, torque and weight of the cars.

Fortunately we do have an Autocar road test for the Wolseley 18-80 which used the same engine as the MG SA and had similar running gear. The Wolseley was slightly lighter than the SA but was probably slightly less aerodynamic. Also we do have a contemporary acceleration test figure from an SA owner who achieved  0 - 50 mph in 14 seconds based on the dashboard speedo reading.

Michael Sedgewick in "Cars of the Thirties" claimed that the WA could out run the SS Jaguar 2½litre and give the SS Jaguar 3½litre a run for its money. I suspect that the large P100 headlamps did cause the SS to be less aerodynamic than the MGs so it is possible that the WA might have out run the SS  2½litre although with 10 bhp less I suspect the WA would not be ahead by much.

Looking at the power and torque ratios it seems rather unlikely that either MG would better the SS Jaguar 2½litre in acceleration.

The estimates of MG top speed are taken from the BHP Required graph and using the curve for the SS100 which has a much lower frontal area than the SS Jaguar saloons. As a check we also have a measured top speed of 76mph for a 1½litre MG tourer with its hood up which probably had similar windage to the SA and WA. The tourer achieved this with 54bhp which does follow the SS100 curve reasonably well.

 

    Wolseley 18-80   MG SA  SS Jaguar 2½litre  MG WA
Power to weight ratio  52.5 bhp / ton  51.8 bhp / ton  63.7 bhp / ton  58.7 bhp / ton
Torque to weight ratio  74.7 lb-ft / ton  73.7 lb-ft / ton  83 lb-ft / ton  75.4 lb-ft / ton
 0 to 30 mph   6.7 secs  ~ 6.7 secs  4.7 secs  ~5.1 secs
 0 to 50 mph   15.3 secs  ~ 15.3 secs  10.6 secs  ~11.6 secs
 0 to 60 mph   24.4 secs  ~ 24.4 secs  17.0 secs  ~18.7 secs
 Weight  29 cwt 36 lbs  29 cwt 77 lbs  32 cwt  32 cwt 41lbs
 Top Speed  75 mph  ~85 mph  87 mph  ~92 mph
 Price  £320  £389  £395  £442

The figures for the MGs in the table are simply extrapolations.

The chassis layouts are very similar. The MG has a slightly longer wheelbase at 10' 3" as against 10' in the Jaguar and the engine and gearbox are perhaps an inch or two further back but I don't know if this would be sufficient to give any handling advantage.

Travelling in the  MG SA




The interior of the SA is significantly smaller than the all steel Jaguars perhaps more akin to the coach built SS Jaguars. The seats are very comfortable and the level of wind noise from around the windscreen and side windows appears less than in the Jaguars. The level of engine noise is fairly similar but the transmission sounds much more vintage, especially as second gear is also straight cut.

Driving Impressions

At the end of this page you can see some experiences in restoring MG SA GRB988. This car is now on the road and I can start to add driving impressions.

In June 1938 and November 1939 Laurence Pomeroy wrote in The Motor his ownership experiences over 20,000 miles and 47,000 miles respectively in a Tickford SA. He clearly enjoyed owning the car but with one or two reservations. Ride comfort and braking were commented on favourably and these certainly mirrored my first impressions but what really surprised me on first acquaintance was the nature of the steering. The SS Jaguar, that is the obvious basis of comparison for me, is heavy at parking speeds but commendably light at speed such that it turns into corners with very little effort and has good castor action to return you to a straight line when you let go the wheel.  The SA takes 2½ turns lock to lock for a 40' turning circle whilst the Jaguar has slightly higher geared steering at 2¼ turns lock to lock for a 40' turning circle. I had expected the SA to perform in similar fashion to the Jaguar if perhaps with slightly lighter steering. In fact the SA steering is very heavy at all speeds and does not possess strong castor action.

The steering in GRB could be  turned easily lock to lock with one finger when the front wheels were jacked off the road surface and yes, the king pins had been greased and the steering box filled with gear oil. I did wonder if there was something wrong with it but reading Laurence Pomperoy's articles I see that he too was less than impressed by the steering and had fitted "the latest type of Bishop steering gear, using roller bearings and other changes in design" "This is by the way, a special fitting as the standard steering is rather too heavy for my liking, although completely free from road shock. With the high efficiency gear one can definitely feel the road on the hand, but this is something I am willing to accept." "it is not a car to flick through roundabouts at 50 mph,"

The lack of castor made me wonder whether we could improve the steering by increasing the castor angle. We have now done this and transformed the car. It now returns to straight ahead if you let go the wheel and it doesn't wander as it had previously. The steering also appears lighter around the straight ahead region and the car is much more pleasant to drive.

Although Pomeroy doesn't specifically criticise the gearbox he does comment that he generally starts in second gear, a procedure that no doubt contributed to the premature failure of his clutch. The car certainly has very good low down torque and possibly due to a fairly heavy flywheel is almost impossible to stall at take-off but first gear is a bit of a stump puller and the lack of any synchromesh in second makes for rather slow upward changes. The heavy flywheel does make for very easy double declutching though.

In terms of performance the SA is very noticeably slower in acceleration than the 2½ litre Jaguar but this is hardly surprising given the figures in the performance table.  See also: Jaguar and the Gas Meter

I haven't been able to gauge the handling so far but the ride is certainly no worse than the cart spring Jaguars.

Appearance

The SA is an elegant car but there are some aspects of its lines that to my eyes just don't work. If you look at the relationship between the windscreen and side windows then nothing appears to line up and the front doors look as if they have dropped. Compare the same aspect in the Jaguar and things appear much more harmonious.

Interestingly the original design drawing by James Wignall doesn't show the same downward slope of the front door. Perhaps it was altered to give a less upright appearance.

 All in all an interesting car and more from the early thirties than the late thirties.

But who got there first?



As an aside: since we are looking at the SA dashboard (in colour) above it might be worth mentioning some of its features.
Both the speedometer and rev. counter are, in fact "chronometric
" which involves a slightly more complex mechanism than the aluminium disc and spinning magnets found in the Jaguars. They are also quite intriguing to watch as they click up or down at fixed time intervals when speed or revs change.

The thing that looks very like an owl's eye cigar lighter above the steering column is in fact a 30 mph warning lamp. This detects the speed via a switch within the speedometer body.



The little red and black terminals in the centre of the instrument panel offer the possibility of running all sorts of electrical accessories. The only limit on what can be powered is the current rating of the wiring harness as these terminals run straight to the battery without a fuse
!

 

Customer Loyalty

Since writing the above I've had the opportunity to read more and gain more first hand experience of the MG SA and have come across some interesting and some trivial information.

I guess the first thing that amused me was the obvious displeasure of some MG owners at the upstart company of SS Cars Ltd. and this even in recent times:

"Many car companies of those days had taken the same economical path to update their engines, by converting a current sv unit to ohv. SS Jaguar did this with David Blacks (sic) 'Standard ' six cylinder sv, using it as an ohv in their SS90 and SS100, real 'hairdressers' cars."

Unlike with the pre-war MG saloons, Cecil Kimber did permit the motoring press to perform proper road tests on MG two seaters. The TAs and TBs were nice fun cars to drive but I don't think many commentators would rate their performance highly against the substantially more powerful SS90 (even in sv form) let alone the 100.

What is clear is that the MG company went out of their way to attract the type of owner who would perform almost all his or her own maintenance and repairs. Perhaps it is this closer relationship between company and owner that has instilled an almost religious devotion in the latter? Whilst SS Cars did produce quite helpful Instruction Books those for the SS Jaguars were hardly an invitation to anything more than routine maintenance and as far as I know no factory Service Manual ever existed until after the war.

In sharp contrast the "Instruction Manual for the MG Two-Litre" could be easily mistaken for a comprehensive workshop manual. That was certainly my first impression although reading on, it soon became clear that this was so comprehensive because it was instructing the home mechanic to perform tasks normally in the province of the professional. To give you a small example here is just a couple of paragraphs from the many that make up the electrical section:

"When the dipper switch is turned the connection to the blue wire is broken, and instead a connection is made between the blue and white wire which feeds the switch and the other terminal. To this are attached two red and yellow wires which carry current direct to the two passlights.

These two circuits are completed through the bodies of the lamps to the bumper bar, and thence, through two flat steel strips which bridge the silentbocs on which the bumper bar is carried, to the frame (earth).
"



Looking at some of the mechanical sections of the Instruction Manual there are many similarities in the construction of the big MG to that of the SS Jaguar. Engine similarities are perhaps not too surprising given that both evolved from earlier side valve designs. The SS Jaguar used valve timing of 16,56,56,16 which by virtue of its symmetry led to very simple installation of the timing gears and chain. The MG SA in common with other MGs of the period used 11,59,56,24 which made installation slightly more demanding and certainly worthy of comprehensive description, especially if you turned the starting handle a little too far!

"It will be noticed that the timing chain has two white links, and each of the sprockets has a tooth marked "T". Between the white links are twelve black ones on one side of the chain and fifteen black links on the other. The camshaft is correctly timed when each of the "T"-marked teeth is in a white link with the shorter black portion of the chain uppermost. The twelve black and two white links are clearly shown in illustration No. 28, which shows one white link of the chain engaged with the "T"-marked tooth of the camshaft sprocket, while the "T"-marked tooth of the crankshaft sprocket has left the other white link, twelve black links behind the first one."

This is all commendably clear when you look at illustration No. 28 but woe betide the unwary who don't read the next paragraph!

"Owing to the fact that the total number of links in the timing chain is a prime number, the engine must be turned fifty-eight times before the links and marked teeth come back to this position again."



Looking at articles in "The Motor" and "The Autocar" the SS Jaguar was first introduced on 24th September 1935 and the MG SA only a few days later, on the 4th October. The two cars were clearly aimed at the same market. The MG being priced at £389 and the Jaguar at £385 but due to their differing heritage the MG started out on the back foot and despite various small changes and a major upgrade as the MG WA they never really gained a march on the Jaguar.



The SA started its life with an engine of 2062 cc as against the 2664 cc in the Jaguar giving the latter a nearly 30 bhp advantage in a car that weighed the same. The Jaguar did get bigger and heavier in 1938 when coachbuilt construction gave way to all steel but despite a couple of capacity increases the SA was always inferior in power to weight ratio. The introduction of the WA did improve matters for MG but this car had also gained size and weight and was still at a disadvantage in power to weight ratio relative to the 2½ litre Jaguar. It had also risen in price to £442 puting it very close to the even more powerful 3½ litre Jaguar which could be had for £445.

Other facets of the MG design heritage also conspired against it. The SS Jaguar started life with a gearbox with synchromesh on the top three ratios driven through a dry plate clutch. In contrast the SA inherited a totally crash gearbox with straight cut teeth on both first and second and driven through an oil bath cork faced clutch of a design that dated back to the early 1920s. Whilst the SA did later get synchromesh on third and top gears it was only in 1938 that a dry clutch and second gear synchro was available and that only on the more expensive WA.

The big MGs are nice cars but the more I read, the more I can understand the attitude of some MG devotees towards the SS Jaguar.


 

MG SA GRB 988

Click on the picture for some reports of restoration work.

 


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