ERIPs B-Series " ets even better
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Tim Blakemore_grows to like nis new study in blue with e Cummins ocharged 250 engine now offered as an option. Pictures by Dick Ross
ERF'S B-SERIES has undergone two major changes since CM last tested one in November 1978: the cab interior has been revised and the Cummins turbocharged 250 engine is now offered as an option. After three days of testing the latest day-cab tractive unit fitted with the NT240, my view is that both drivers and operators should be pleased with the modifications.
The first noticeable difference inside the cab is the colour scheme, which is now in shades of blue. I was somewhat daunted at first to find so much of the interior finished in the cOlour including cab fascia, roof and door panels, seats, engine cover and even the grab handles and steering wheel.
felt grateful that I wasn't inside the sleeper cab (which, of course, has a blue bunk).
However, I soon overcame my initial impression after a few hours behind the wheel; I had to admit that the new interior does, in fact, provide a very pleasant working environment.
It's practical, too, because the colour is dark enough to make it fairly easy to keep clean.
Underneath the cab, the Cummins NT240 engine has the turbocharger mounted centrally on the offside and a pipe runs over the top of the engine to the inlet manifold on the nearside. This doesn't present a problem for the ER F cab which is mounted low and has a relatively high engine cover intrusion anyway.
The Ho!set turbocharger, exhaust manifold and air crossover, as well as the exhaust silencer, are components shared Nith the E-Series engines. Most Df the engine's components, in:luding cylinder block, heads, Distons, valves, water pump, oil :ooler and alternator are identi:al to those of the naturally )spirated NHC250, while the amshaft differs only in the iming disposition of its cam obes.
With maximum torque in
:reased dramatically to 058Nm (780 lb ft) net at 300rpm compared with the .1HOs figure of 895Nm (660 lb t) at 1500rpm, the "Big :am's" con rods, vibration amper and fillet-hardened ran kshaft are used to cope with le inevitably higher firing ressures. The turbocharged ngine is approximately 18kg 140 lb) heavier than is naturly aspirated predecessor.
With a Fuller RT095-0-9A :irkstall hub reduction rear axle,
nd 273 litre (60 gal) fuel tank, or test tractive unit weighed in t just over 6 tons (6250 kg with five gallons of fuel and no driver).
The first part of the first day of each CM test is spent at the Motor Industry Research Association (MIRA) proving ground near Nuneaton where the vehicle undergoes specific operations such as hill restarts, brake performance and acceleration.
When we tried the acceleration runs with the B-Series, we encountered an unusual problem with the clutch that caused it to slip badly when we reached fourth or fifth gear. The first time it happened, I thought we would have to abandon the test because we could get very little drive; but after bleeding the clutch slave cylinder of air, everything returned to normal.
Off we went again down the one-mile straight, only to be halted again by clutch slip when we reached fifth gear.
This time the fault cured itself, but we agreed with ERF that the best course of action would be to forego the acceleration test temporarily (since it was obviously rapid gear changing that caused the problem), make a short detour from our road route to the Sandbach factory, and change the clutch.
We were stilt able to check fuel consumption over the nor mai route because the tractive unit was fitted with a very useful JPS flowmeter with a digital display in the cab and a "hold" facility.
The air servo assistance unit (soon to be a standard fitment) for the hydraulic clutch was also changed since it could have been defective. It took less than two hours at Sun Works to change clutch centre places, pressure plate and servo unit, which must say a lot for the accessibility of the gearbox on the ERF chassis.
I learned later that the fault did lie in the servo which, I believe, was unable to exhaust air quickly enough during very fast double-declutching. The constant-mesh Fuller gearbox, in fact, allowed fast changes to be made without doubledeclutching.
Eaton has established an enviable reputation with its 600and 900-Series twin countershaft units which have now captured over 70 per cent of thE UK heavy-vehicle gearbox mar. ket. It is surprising how thE various different installation: affect the "feel" of thE gearchange. in the ERF I founc it slightly notchy — not quite good as in the Foden or Ford.
With the exception of thE almost horizontal row of war fling lights (which were difficul to see), all other instrument! and controls in the B-Series cat were particularly well placed The individual heater control: for driver and passenger havi been relocated, as have the si• rocker switches previously fitter on top of the dashboard. In thi straight-ahead position the nev steering wheel with its twi acutely angled spokes gave completely unobstructed viev of the instrument panel.
ERF's reason for mountini the warning lights horizontally i that they are intended as secondary warning, the first ir dication of a malfunction bein given by the two "idiot" light mounted one each side of th tachograph.
These flash when the parkin brake is applied and will also d so if a fault — such as lo engine-oil pressure or no batter charge — occurs while drivinc The driver should then look z the warning lights to find 01 what the problem is. I think pe haps it would be better simply mount the lights in a more easi' visible position.
.Optional ratio
A new optional diff ratio 1 4.64:1 has recently becorr available for B-Series tractk units and fitted to our test vehicle with the Cummins engine governed at 1900rpm, maximum geared road speed was 106km/h (66mph).
Motorway running at the maximum legal speed was achieved at a comfortable 1750rpm, and on M6 and M74 northbound we obtained fuel consumption figures of better than 8mpg.
However, the combination was not so well suited to 40mph running because at that speed the engine was turning at only 1150rprn. Consequently, even a slight uphill gradient required a change down to eighth (direct).
Even allowing for the highergeared rear axle, which is necessary to maintain a similar road speed with the lower-speed engine, the tractive effort, compared to the NHC 250, is better by about 9 per cent. In practice this meant that fewer gearchanges were needed than I would have expected with the naturally aspirated 14-litre en gine. The exhaust note too was different with a distinctive tone, accompanied by a slight vibration, at the maximum torque speed of 1300rpm.
Comfortable cab
A high level of comfort is provided by the SP Mk 2 cab and obviously much thought has gone into the improvements. Fixed quarter lights are used so that the weight on the window winding mechanisms is kept to a minimum and also to allow the windows to be opened in wet weather without water rushing in.
The mirrors are set forward out of the most turbulent area in an attempt to keep them clean, and I found that this does help, although is not 100 per cent effective. Judging by the number of ribbons we see tied to the mirrors of various vehicles, this is the most effective method of keeping them clean.
The three wipers were able to keep a large area of the screen and the heater, demister and fresh-air vents were very effective.
However, an intermittent wipe facility would be a worthwhile addition.
Summary
ERF's unique cab-construction method of a steel frame overlaid with SMC (sheet moulding compound) has now been accepted by a large number of operators, as a drive down any motorway will confirm. The most recent changes to the cab are not purely cosmetic, but have improved driver comfort a good deal.
I had my doubts about the interior colour scheme at first, but by the end of the three-day test I had grown to like it. I was certainly impressed by the Sandbach company's attention to detail in the cab design.
It was expected that the fuel consumption with the turbo 250 would not match that of E290-powered machines, but then the initial cost is considerably less.
List price of the tractive unit as tested (including fifth-wheel installation at £435, rear wings at £80, and fog spot lamps at £57) is £23,322.