This is a summary of the sources of technical information, and some practical hints on routinely made modifications. There is much that is not here (believe it or not!). In particular no attempt is made to duplicate the information contained in the original workshop manual, or the commercially available manuals which are based upon it. That invaluable source of information about maintaining the standard vehicle should be consulted first in case of problems with the A30/35.
The most useful sources of technical information are the original Driver's Handbook, for general driving and routine servicing information, and the original Workshop Manual, for major jobs. Publishers such as Haynes also published Workshop manuals in their series, and in most cases they are based directly on the original Workshop Manual. Copies of the Workshop Manual can often be found in Autojumbles, as well as from suppliers listed under 'Books'. Most queries about standard vehicles can be answered by these sources. BMC also published parts lists, now available only at Autojumbles, which can be useful for identifying parts at Autojumbles, but their usefulness is now very limited: few original parts can now be found at Autojumbles, and the supply of those parts that are unique to A30/35s is now in the hands of specialist suppliers.
In addition to these sources, the technical data contained in the various contemporary road tests ("Austin A30 & A35 Superprofile" by Kim Henson, published by Haynes (1985) and Austin A30 & A35 1951-1962(sic) by R M Clarke and published by Brooklands Books (undated, early 1980s), both contain a wide selection of these), and more detailed articles written by technical magazines for the trade. A number of these articles have been reproduced in Spotlight over the last few years (see index below). On engines, the book by David Vizard "Tuning BL's A-series Engine" (Haynes) is outstanding. For the history of the cars Post-war Baby Austins A30-A35-A40 by Barney Sharratt, published by Osprey Publishing Company (1988), is without equal.
The club's Spotlight magazine, and occasionally the Newsletter/Sidelights, has featured technical articles written by Club members which cover most of the technical problems not covered in more "official" publications. Although most of these magazines are out of print, older members may still have copies. The following is a selective index of useful articles from Club magazines from Spring 1980 - the most important are marked with an asterisk*. Further details and assistance may be obtained in the first instance from your Local Area Group, or, failing that, from the Technical Information Officer (please phone rather than write) or the Spares Coordinator as appropriate.
While every effort is made to ensure that technical information is accurate, all the information given in Club magazines or by Club officials or members is given on a "without prejudice" basis: no liability can be accepted by the Austin A30 A35 Owners Club or its officials for any loss, injury or death arising from its use.
Aircleaner, anti-icing A1982 p8, S1987 p70
A30 Dinky Toy S1990 p59-63
Alternator fitting S1985 p18-19*
AS3 S1990 p9
The following mechanical modifications are frequently made to A30/35s. They
can be made using normal car maintenance hand tools unless fabrication of
parts is indicated.
WARNING If the performance of the vehicle is increased, the brakes
and handling MUST be improved to match. Any modification which affects
performance MUST be notified to your Insurers, as they may refuse to pay
in the event of a claim. Note that most "Agreed Value" Insurance schemes
apply only to standard unmodified vehicles.
General The A-series engine has been used in all small BMC, BL etc
cars since the 1950's, and mechanical parts can often be substituted. In
increasing order of dissimilarity the cars are: Austin A40, Austin Healey
Sprite, MG Midget, Morris Minor, Mini, 1100/1300, Allegro, Marina 1300, Ital
1.3, Metro. Transverse engined cars generally offer less than in-line models.
Steering: (A1990 p30-39: this article largely takes in all the earlier
material) There are no satisfactory substitutes: the A40 steering box can
be made to fit but is not a direct swap (A1980 p26, A1990 p35). Most steering
vagueness is the result of wear following a lack of lubricant, or incorrect
adjustment. The tight point of the steering box should be in the straight-ahead
position. If it is not, an A40 MkII adjustable draglink can be used on the
steering box side of the car and adjusted together with the crosstube until
the tight point is central. (S1984 p24)
Suspension (S1984 p26-33) Front springs, shockabsorbers, wishbones
and rubber suspension bushes from Midgets, Sprites and A40's all fit. (Do
not use the trunnions from any other car.) Fit all these in pairs: the rates
and lengths of the springs differ - Midget/Sprite ones are shorter and stiffer
and give better handling. Front shockabsorbers (S1987 p49-50) may vary in
their adjustment - uprated ones are sold for Midgets. (25% Uprated Midget
standard height front springs with 30% uprated Midget front shock absorbers
are excellent on a road car with otherwise standard suspension.) Telescopic
shockabsorbers can be fitted (S1980 p32-33) but this requires fabricated
mounts and is not recommended. The wishbones for Midgets and A40 MkII have
extra bracing and are stronger than those on the A30/35. The spring pan centres
used must be the same type on both sides of the car - the scalloped Midget
type has a centre 1/2" higher than the square-based A30/35 type. The Midget
type should be fitted if the brakes are improved as they reduce dive under
heavy braking. The handling can be improved by removing the rear antiroll
bar and fitting one from a Midget or A40 at the front (the latter has to
be bent to fit). The mounting points for the rollbar have to be fabricated
and the attachment points reinforced; the later type of wishbones should
be also be fitted. Rear springs are covered in A1990 p24-25: A40 springs
are the wrong length. It is possible to fit Midget springs, but this is not
recommended: the rates differ, and the rubber bushes are a different size.
Tyres (A1983 p20-24) Radial tyres improve road-holding. Use 145x13
in place of 5.20x13 (saloon), 155x13 in place of 5.60x13 (van), with tyre
pressures 4 psi greater than that recommended for cross-plies - eg: for saloons
F 24psi, R 24psi(2 up), 27psi(full load).
Brakes (A1991 p 62-86: this covers all the earlier articles) The front
brakes are small, with cylinders prone to seizure if the car is left standing:
silicone brake fluid can help, but should only be introduced into completely
new components as this fluid is more searching than normal fluid, probably
because no seal of rust is formed! The larger 8" drum brakes from the Austin
A40 MkII bolt directly onto the A30/35 stub axles. Morris Minor backplates
will NOT fit directly onto the stub axles. Midget front disc brakes can be
fitted directly if taken with the stub axle and kingpin. Fit with the callipers
at the front and use Mini hoses to connect to the existing pipework. (Warning:
when disc brakes are fitted, it is vital to check the brake fluid level
frequently. The level falls as the disc pads wear, and the reserve of brake
fluid in the standard master cylinder is small. When disc brakes are fitted
in conjunction with the standard A30/35 master cylinder the master cylinder
should be modified. The small rubber valve cup in the metal valve body at
the far end of the master cylinder should have a small but visible hole made
in the rubber valve cup in line with one of the holes in the metal valve
body so that there is no residual pressure in the system with the brakes
off.(A1990 p84 or 1988 p17) Hydraulic rear brakes from the A40 MkII or Midget
can be fitted, but require new pipework and a fabricated handbrake linkage:
this modification is probably more trouble than it is worth as the mechanical
brakes in good condition are very effective and give an especially good
handbrake. Master cylinder substitutions are possible but are not simple.
A servo of the independent type can be fitted - Lockheed supply a kit with
instructions, but as the servo ought to operate on all the brakes to retain
the correct brake balance, one of the exits from the master cylinder must
be blocked - a bleed nipple is suitable.
Engine Exchanges (A1982 p30-33)
Cooling system The standard cooling system is over designed, and if
it is in good condition it is satisfactory for cooling all but the most highly
tuned engines, but electric fans can be an advantage to reduce power loss
(S1989 p42-44). With tuned engines, a radiator reconditioner can install
a high efficiency matrix.
Ignition. Apart from distributers, which have different advance
characteristics from car to car, ignition parts can be substituted between
A-series engines. Coils must be the 12V non-ballasted type. Terminals may
differ.
Carburettors, manifolds, exhausts
Gearboxes & clutch: (S1982 p30-33) A30 can use Series II Minor
gearbox with A35 Propshaft, but no other type. However A35 internals can
be fitted (no machining required) to give closer ratios (S1982p36-37). Ribbed
boxes can be modified to fit with existing gearlever, using Series II Minor
rear cover and A35 propshaft (machining required). Although it has been done
quite often, cutting the transmission tunnel to use the remote gearlever
gearboxes with A35 propshaft is NOT recommended: unless done properly using
a tunnel from an A35, the structural integrity and safety of the car can
be compromised. Because of a lack of internal clearance, smooth gearboxes
can be used only with 803/948cc flywheels and clutches, and should use a
thin engine backplate (803/948cc type). All A35's can be fitted with the
'ribbed' gearboxes used with 850/1100/1275cc engines (Marina gearboxes are
no use), but should then use a thick engine backplate (850/1100/1275cc type).
The gearlever must be the one for the gearbox (S1989 p44). Ribbed gearboxes
can be used with any clutch, but the clutch release bearing must be the type
for the clutch fitted (the offsets differ). Note that the front cover and
clutch operating lever on ribbed boxes is different from that on smooth boxes.
(They are not quite interchangeable in pairs - the front covers use slightly
different locating stud positions but can be made to fit by drilling and
tapping.) Ribbed box levers are 'higher geared' so that clutch operation
is likely to be even more "in and out" than it usually is with the standard
linkage. (Clutch judder in reverse with the standard clutch and accelerator
linkages is almost incurable.) Most ribbed box levers are intended for hydraulic
operation, and the lever will have to be modified (welding) for mechanical
operation. Conversion to hydraulic operation (S1985 p20-21, A1985 p38) is
possible but not easy.
Back Axles: (S1981 p30) MG Midget back axles can be made to fit (welding),
but not recommended. Midget halfshafts (disc wheel type) fit the A30/35 casing
- and are stronger - use with high power engines. A40 Mk II and Minor are
too long. Many gear ratios are available, but note that those with ratios
higher than 4.55 (std A35) do not normally have the oil filler hole in the
differential carrier casing. Either fill through the breather hole (do not
overfill) or make a filling hole in the rear of the axle casing at the same
height as the original filling hole (braze or weld into the casing a drain
plug and hole from discarded back axle). Ratios available: 5.13 (early 803),
4.88 (later 803, 850), 4.55 (948), 4.22 (1098 & early 1275), 3.9 (later
1275), 3.73 (1500cc Midget, Riley 1.5, Wolseley 1500). Ratios one either
side of the engine size given can be used, lower for acceleration, higher
for relaxed cruising and economy.
Front Seat Belts (A1988 p18-20) Pre-1965 cars are not required to
have seat-belts, but if fitted they must work, and be either 3 point or diagonal
only. The difficulty is making adequate mounting points that are in positions
which ensure the belt works correctly and which are also strong enough. Anybody
fitting seat belts must satisfy himself that his mounting point design will
accommodate the very large forces (well over a ton on each mounting point)
which occur in an accident, and that the belt will not slip off the user
or strangle him. Static belts can be fitted relatively easily to 2-door saloons,
with the best place for the upper attachment being under the rear side window,
preferably 11" back from the door opening. (This ensures that the belt does
not slip off the shoulder and the user will not twist round the belt too
much as he moves forward in an accident. Unfortunately many belts are not
long enough to allow the attachment point to be so far back. Inertia reel
belts cannot be fitted in this location, as the reel must be directly below
the upper mounting point.) The other points are attached to the floor or
transmission tunnel (depending on the design of the stalk or belt). All these
mounting points MUST be reinforced - the upper one requires a long bar under
the length of the window. A30s with seats that fold forward cannot use belts
with stalks, as there is no room for them. For A35 2-door saloons only, the
upper belt attachment can be to the door pillar, taking the bolt through
to the outside of the car, or the retaining nut can be welded to a long bar,
and the belt screwed to it through the inner side of the door pillar.
Rear seat belts (A1988 p18-20) A30/A35s are not required to have rear
seat belt fitted. Inertia belts and 3 point belts are unsuitable for saloons.
Static lap belts can be fitted to saloons and vans by having one end down
the side of the seat and bolted through the wheel arch. Reinforce the area
on the outside, and put the bolt as far into the corner between the back
and seat as possible. The other end should be fastened through the seat pan
(again reinforced) under the opposite side seat, as far to the rear of the
pan as possible, just where the bulge starts above the differential. Fitting
inertia rear seat belts to a van or countryman would require the use of the
kind of inertia belts which are fitted to the rear of the Metro or other
hatchbacks. The van side would need to be substantially strengthened. The
lower mounting belt points are similar to those for lap belts.
Child Seats (A1988 p18-20) Fitting normal child seats can do a lot
of damage to the upholstery and is now unnecessary, because it is now possible
to get seats which will work with normal seat belts. These new seat belts
can be taken out of the car quickly when not needed and used as a seat for
the child. he Britax child seat for 1-4 years can be used very satisfactorily
with a 3 point front static belt in the front seat. This seat can be used
in the back of a saloon, held down by a static lap belt, but is less easy
to secure firmly. A large piece of thick felt is needed under and behind
the seat to stop the rear frame going down the gap between the squab and
the back. Because the rear seat squab is very narrow from front to rear,
a further strap is often needed to go round the ALREADY TIGHTENED belt and
the front rail of the seat to prevent the seat slipping off the front of
the seat in normal use.
Electrical etc
All material on this site is copyright, with all rights reserved
Whilst great care is taken to ensure that the technical information and advice
offered is of the highest standard, neither the author, nor The Austin
A30/A35 Owners Club, or the Officers of the Austin A30/A35 Club accept
any liability at law for any death, injury or loss whatsoever arising from
the use of advice contained in this article.
Back axles, alternative S1981 p30
Battery NLWint1985 p22, A1986 p45-47, A1988 p22
Braking System, Std S1981 p18-21*, S1983 p38, A1984
Carbs, Alternative S1982 p50*, NLWint1985 p7, A1989
p35-41*
Cooling System Fans S1989 p42-44*
Concours judging S1986 p8-9, S1987 p63
Convertible A1981 p44-45*, S1982 p22-26*,27, S1983
p14-15
Gearbox fitting A1987 p22
Gearboxes, alternative A1982 p30-33*, S1983 p38, A1985 p42, S1989
p44
Headlining renewal S1986 p11-14*
Headlining, Alternative S1981 p57
Heaters A1983 p24-26*, NLSum1987 p29*,
History of A30/35 A1981 p7-8,9-19,20-21,22-29,36-40,64-65, A1982 p20-21,
S1984 p8-17, A1984
History, individual vehicle A1990 p73-75
Insurance S1990 p56-58*
Jacking A1987 p27
Kingpins S1984 p26-33*, S1985 p22-23, A1985 p39, A1987 p33
Modified Cars - examples S1980 p6-8,9-11, S1981 p34-35,43,54-55,
A1982 p33-35,40-45, S1983 p38,52-53,54-55, A1983 p13-15, S1984
p21,
MOT A1984 p32-35*
Number plates S1990 p49
Oil filter, alternative S1991 p88
Oil pump, unsuitable A1990 p42
Paint colour codes A1983 p34-37*, S1984 p34, A1987 p30-32,
S1988 p35-36
Pickups S1983 p22-37, S1984 p42-45[chassis nos
Production figures A1984 p38
Registration numbers, lost NLWint1990/91 p4-5
Roadholding A1983 p20-21*
Road Test Articles etc S1980 p16-19, S1981 p44-45, A1981
Rust proofing S1980 p22-26*
Seat Belts A1988 p18-20*, S1989 p14*
Security A1981 p53, NLWint1987(publ Jan 1987)
"Service Data" A1984 p389-46*
Servicing S1988 p32-34
Shockabsorbers A1986 p19, S1987 p49-50*
Shockabsorbers, Tele S1980 p32-33*
Sound Control S1987 p51*
Speedometers A1986 p8-16*
Springs, road S1990 p24-25*
Steering S1984 p22-25*, A1984 p32-33,
A1990 p30-39(covers all earlier articles
Steering Box, Alternative A1980 p26, A1990 p5-36*
Structure of vehicle A1984 p14-19, A1987 p23-26*
Suspension A1980 p19-20, S1984 p26-33*, A1984 p32-33,
S1985 p22-23, A1985 p39-41,
Tips, general A1990 p43-44, S1991 p87-88
Trim S1988 p37
Towing, Towbars S1983 p42-45*, A1984 p50-51, S1990 p26*
Water leaks A1980 p20-23, A1983 p26-27
Windscreen A1980 p22-23
MODIFICATIONS AND ALTERNATIVE PARTS FOR A30/A35
The following information is believed to be accurate, but it is provided
on a "without prejudice" basis: no legal liability can be accepted by
the Club or its Officers for any loss, injury or death arising from its
use. Please report any errors, omissions or problems to the Technical
Information Officer or R H Johnston.
High power engines must not be fitted without improving the brakes and
suspension. All 'in-line' A-series engines (except Marina 1300) will fit
in A30/35's, but the rear engine plate should be chosen to match the gearbox.
Transverse engines are totally unsuitable as the blocks and crankshafts are
different. (Although Marina 1.3 engines can be modified to fit (S1986p14-15),
this is not straightforward. There are a number of difficulties: the front
and rear plates are required from a Midget (or A35 ones adapted) and the
flywheel have to be specially modified (Midget ones do not fit). A small
oil filter must be used.) Some donor engines do not have the holes cut for
the petrol pump: either drill out and tap the holes required, or fit an electric
SU fuel pump (from eg Midget or Minor). The 850,948 and 1275cc engines are
stronger than the 803 and 1098cc engines. For further details on engines
and tuning see David Vizard: "Tuning BL's A-series engine", Haynes.
Cylinder heads: (S1990 p27-29) The 803/850/948/998/1098 heads are
all interchangeable: 1098 heads have larger inlet valves than the smaller
engines. Some heads have provision for water temperature sender unit. 1275cc
heads are not directly interchangeable with the smaller engine heads.
Other engine parts: Many, such as the valve rockers and shafts, are
interchangeable, but check carefully. Pushrods, for instance, can be different
lengths. Duplex timing chains and sprockets from some 1275cc engines can
be fitted to other A-series engines, if the two setscrews each side of the
crankshaft on the front plate are countersunk (use the screws like those
that fix the brake drums). Toothed rubber belt conversions are available
from performance part stockists such as Mini Sport, but may be more trouble
than they are worth.
Petrol Lead-free petrol can be used in engines which are not driven
hard, by putting one tankful of leaded petrol in the tank every fourth fill-up.
NB the use of unleaded all the time will lead to erosion of the valve seats
and expensive engine failure.(S1989 p40-41)
Zenith carburettors: (S1982 p43-50, reprinted A1989 p29-35) The 26VME
and the 26JS carburettor used on early A30's are interchangeable, but the
jets are larger in the carburettors intended for the A35. A35 26VME carburettors
will work on 803 and 850cc engines. By opening out the standard inlet manifold,
30VM and 30VIG carburettors can be fitted, but you are on your own with choice
of jet sizes, as they are sensitive to such factors as exhaust system design.
SU carburettors (S1982 p50, A1989 p35-41) are more reliable and give
more power. Single HS2 1.25" carburettors from eg: A35 vans, A40 MkII, Mini,
can be fitted complete with the manifold and airfilter (NB some Morris Minor
manifolds do not allow enough space for the carburettor). Metering Needle
sizes (using manufacturer's airfilters) are: 850/803: EB, 948: M, 1098: AN,
1275 - not recommended. The throttle linkage from the pedal will need to
be bent towards the engine so that the throttle works properly. The choke
cable can usually be persuaded to fit the SU. Single HS4 1.5" carburettor
from 1300 will fit with manifold - needle 1098: DL, 1275:DZ, but will need
a fabricated throttle cable. The 1.5" Marina carburettor and manifold will
also fit, but its exhaust manifold expects a much larger exhaust pipe. Twin
1.25" carburettors with inlet manifolds from Midget/Sprite fit, but may require
a fabricated exhaust manifold (one possibility is to cut off the inlet manifold
from a 1.25" SU combined inlet/exhaust manifold), but offer no power or other
advantage over the 1.5" carburettor. High power engines MUST have a specially
fabricated, low back-pressure exhaust system - the standard system is extremely
restrictive and will prevent the extra power being obtained, and will give
problems with oil leaks and overheating.
The difficulty with 4-door saloons is the upper mounting as the door pillar
is so far forward which makes it difficult to get the belt to lie across
the shoulder properly. I am cautious about recommending this mounting point,
the use of an inertia belt in this position can be improved by using a child
adapter belt of the type which consists of a secondary belt which goes behind
the child and ensures that the belt sits on the shoulder correctly. Belts
which take the upper strap back down to the floor at the rear of the car,
as used some open sports cars may be preferable, but will be a nuisance to
rear seat passengers. If the pillar is used as a mounting point, the attachment
is made above where the trafficator either is or would be. Remove the outer
cover or trafficator, and put a long load spreading plate along the line
of the pillar to provide additional strength and bolt only through the inner
surface of the pillar and the load spreading plate. The other mounting points
are as for the 2-door saloon.
Very late vans were fitted with front seatbelts. If you are fitting belts
to an earlier van, try to see a late van to get the positioning, and the
design of the mounting points. The upper mount was braced with a small plate
onto the van side. This can be copied. Alternatively spread the load with
a vertical bar along the line of the pillar. The position of the lower mounting
points are as for the cars.
Starters and dynamos from any vehicle with an A-series engine fit, but terminals
vary.
A-series alternators can be substituted (S1985 p18-19), using the mounting
bracket and fanbelt of the donor vehicle, BUT the electrical connections
have to be modified, eliminating the voltage regulator, and the vehicle wired
negative earth.
Bulb type headlamps can be changed for standard 7" sealed beam units, or
Quartz halogen. Use units without integral sidelights, and obtain the modern
type of plug connector if not changing the headlamp bowl. The chrome headlamp
surround is interchangeable with those on the Mini and MG Midget.
The brake and indicator light assemblies are common to many 50's cars and
some Viva vans. The bulbs are the same as most British cars up to the late
70's. The number plate light assembly is used on some models of Mini.
The brakelight pressure switch is common to most BMC and early Leyland cars.
A Unipart wiper blade and arm of modern design is available to fit A30/35
wiper spindles, using a pinchbolt. The Morris 1000 door courtesy light switch
will fit.
MG Midget heater ducting can be used on A30/35's.
Engine and other noise can be reduced by felting the underside of the bonnet,
the passenger side of the bulkhead and thickening the carpets.(S1987 p51)
Towbars can be fitted (S1983 p42-45) but this normally requires fabrication.
The "official" towbar mounting uses the fuel tank mounting bolts which in
my view is not safe.
R H Johnston Technical Information Officer
(c) R H Johnston, 1991. Material may not be published for profit
without permission.