X-ray Spec: ERA E-type

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Built to challenge the Continental GP teams, this design was flawed from the start: Keith Howard speaks to the man who sorted it out, 65 years on

English Racing Automobiles was, in more ways than one, the pre-WWII prototype of BRM. The philosophy was the same: to revive British motor racing by building cars to meet and beat the best from Europe. Key personnel were the same too: Raymond Mays, who was still a driver when ERA was founded in 1933, and designer Peter Berthon. Likewise the ability to create a car that was wonderful in some respects, but sadly crass in others.

Although earlier ERAs had proved hugely successful in European voiturette competition, the marque’s last and most ambitious model, the E-type, was intended to confront the might of Germany and Italy in grand prix racing. But it arrived too late — it did not race until 1939 — and then proved adept at tripping over itself.

Although the E-type quickly set new hill-climb and standing mile and kilometre records for its class, it fared less impressively on the circuit. At its first appearance, for the International Trophy race at Brooklands, it performed so poorly in practice that it was withdrawn. At the French Grand Prix the car was again temperamental during practice and didn’t race. On its eventual debut, at Albi, Arthur Dobson crashed while in the lead,rupturing the car’s fuel tank, and was forced to retire. Various owners continued to campaign the cars after the hostilities, but still without conspicuous success.

Just three E-types were built, designated GP1, GP2 and GP3 in recognition of their grand prix ambitions. Following a crash and subsequent fire at the Isle of Man in 1950 — caused by a driveshaft shearing and then puncturing the fuel tank — GP1 was rebuilt using a spare chassis from GP3. It is now owned, maintained and raced by Briton Duncan Ricketts. His comments over the page reinforce the view that, with a bit more forethought, the E-type might have been a formidable machine. But as he concedes: “In some ways the car is a really lovely thing, and in other ways they just got it so wrong.”

In its favour, the E-type was formidably quick in a straight line. Mercedes timed it at 172mph during practice at Reims, justifying ERA’s decision to slash the car’s frontal area and give it more flowing lines. Whereas its predecessors had a frontal area of some 13.5sq ft. the svelte E-type cut this to just 9sq ft. Power increased to 260bhp, about 20bhp more than the C, but it was improved aerodynamics that contributed most to a remarkable 62 per cent improvement in the crucial benchmark of horsepower per square foot

In one fundamental respect at least, the chassis design was right too. Today, when Fl teams spend untold sums contriving ways to lower a car’s centre of gravity by a few millimetres, it is intriguing to find that a quite different philosophy held sway at ERA.

Reid Railton had done much of the design of the initial A-type, based around an engine derived from the modified six-cylinder Riley unit that Mays had raced in 1933. It was Railton’s firm conviction that a high centre of gravity, around 20 inches above the ground, would make for a car that was more controllable at the limit. All ERAs, including the E-type, were designed accordingly.

Duncan Ricketts’ experience suggests that Railton was right “The chassis on a Riley is underslung, so it has a very low centre of gravity. Then they went to Railton and got this thing that you sit on top of! The difference — and I know because I’ve driven them — is that when you put a Riley sideways it gets to a certain point and then it just goes, and you won’t catch it. Whereas with an ERA you can virtually let the back overtake the front and still be in control.”

X- ray spec

Ricketts: “The car is very quick in a straight line, but with 19in rear wheels and I8in fronts, you can’t get it around corners anywhere near as quickly as a B-type on I6in rims; they are quite wide, so you don’t get the tyre distorting. On the bigger wheels the rim is narrower so the tyre tries to roll off. The wheels themselves are a Dunlop design in aluminium. People don’t believe it but the rims are an extruded section formed into a circle and joined. You can see the plate they riveted across the join. Of course, that puts the wheel out of balance so on the opposite side you can see the balance weights!”

The E-type’s De Dion rear suspension was a blatant copy from the Mercedes Benz WI25 and W154. “Originally the car had swing-axles and the handling was a bit hairy. Then they saw the rear of the Mercedes and thought that would be a much more sensible arrangement. “One of the distinctive Mercedes features, apart from the vertical sliding bearing in the diff casing to provide lateral location, was the divided De Dion tube that prevented it acting like a torsion bar. ERA didn’t execute it properly. ‘What happens, as I found out to my cost, is that if you put the car hard into a corner and there is a bump in the middle, the back end goes into spasm. I have a film of it — the back wheels wobble all over the place. And if you put a crowbar behind the diff casing and levered the tube away, it would bend in the middle! So I took the centre section out of the tube and made the whole thing a bearing, with bushes at both ends. It has transformed it.”

One of the ‘improvements’ over previous ERAs was the use of hydraulic brake actuation and drums with twin leading shoes. “But funnily enough they’re not as good as the B-type brakes, which had a self-wrapping system with one big shoe and one little one. The big shoe can pull away from its operating mechanism, so when you brake it tries to wrap round the drum, pushing on the little shoe. The larger you make the big shoe and the smaller you make the little one, the larger the leverage and the greater the servo effect. You’ll see when a B-type brakes for a comer that it almost goes from one side of the track to the other, because the brakes take over. You have to be very careful not to put them on too hard or they’ll lock on, but otherwise they’re brilliant.”

Originally the E-type’s gearbox was fitted with synchromesh, but Ricketts has removed it from GPI. “I had a lot of problems with it grating. You had to get the revs just right, it wasn’t pleasant, and every time I took it apart there was lots of shrapnel inside. Another problem was that once you’d stopped you couldn’t get it into gear. As you came up to the start you had to change gear on the move, before you came to a standstill. If you tried it stationary you wouldn’t get any gear except reverse — the only one without synchromesh. I tried all kinds of things but I couldn’t cure the problems. So in the end I took the synchro rings out and made up spacers to take their place. From that day forwards the gearbox has been great.”

In its pre-war form the E-type had a capacity of 1487cc, but was originally specified with a 2.2-litre version of ERA’s in-line six. “ERA was trying to compete with 3-litre cars, but could not afford a new engine so they grew the original as big as they could. But at 2.2-litres there’s so little meat between the bores that the block cracks, so I don’t believe they ever did make it 2.2. I think they were talking up the car. It was actually a 2-litre, like the engine I’ve got in GPI. It’s original, exactly as made by ERA, and was in the car in its prototype form in 1938.”

Gearsets behind the clutch and ahead of the gearbox lowered the propshaft, in order to sit the driver as low as possible. “In pre-war form the car had the dropped propshaft — not 3in below the crank, as it says in the books, but 4.5in; I’ve measured it. Post-war, ERA was trying to gain in every respect and figured the car was losing too much power through the gearing, so the propshaft was brought back into line. If you look at the bell-housing there’s a little cover — that’s where the shaft came out. At the back, ahead of the gearbox, you could do the something. Preand immediately postwar the car had a lovely cigar shape; then you suddenly see the cockpit area change and the driver sitting up out of the car.”

To put it mildly, the E-type’s steering gear was an abomination. “On the bulkhead behind the engine, three gears take the steering off to the left. There’s a reduction too. From there you have a very small-diameter shaft that runs down the side of the engine, then another two gears bring it up to the right height for the rack and pinion. So the steering is a bit remote. I always had the problem that when I went into a corner the front wheels would do one thing while I was steering the opposite way. I was always trying to catch up with where the wheels were pointing. It turned out that the shaft alongside the engine, which is nearly 3ft long, was twisting because it is too small in diameter. I’ve put in a thicker one, although space is very restricted there. It made a big improvement.”

The track-rod layout was a Horlicks. “The rack is over to one side with both track-rods at an angle. On the left the arm is much shorter and at a larger angle. When you were comering, the track-rods would pull the rack and pinion back and forwards. One day I also realised I had half an inch more lock on one wheel than the other because the steering angles were so different. So I made up a frame that bolts on to the rack’s original inner joints for the track-rods. This moves them back about two inches, so that they are now in a straight line with the steering arms, and then I made the track-rods equal lengths to this frame. That solved the different bump steer at the two wheels as well!”

In search of increased power, ERA replaced the Murray Jamieson Roots-type supercharger used previously with a Zoller vane-type blower, capable of higher boost pressure. “It wasn’t just about boost. The Zoller is more efficient— it only loses about 30 per cent of the extra power generating the pressure. With a Roots, once you get to about 16psi, every extra bhp you produce you just about lose powering the blower. I have drawings showing two different Zoller sizes. I think the smaller gave 28psi boost— the figure quoted in the books — and the bigger one perhaps 32psi.” The Zoller wasn’t reliable, however, so different options, including twostage Roots superchargers, were adopted post-war. GPI now runs a single K300 Roots.

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