Welcome to the RM Riley Technical Tips
Here you will find technical
articles on RM Rileys. Just
click on the subject heading which interests you.
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Brief History of the RM
Buying an RM Riley
If you have not owned or even driven an RM Riley before it can be
difficult to know what to expect and what to look for when viewing one.
Here we give a basic guide to help you avoid buying a lemon.
For New Owners So
you have now bought your RM Riley but are a little unsure
driving it as it is very different from your modern car. Fear not, it
will be easy to drive and the following tips may make the experience
more enjoyable and take away some of the initial worry.
There is a monthly Riley meeting in south Hampshire to which
anyone with an interest in Rileys is welcome. It is held in a
large country pub with a car park to match. If you already
have a Riley, are considering getting one or just want to talk about
them why not join us? Click on the heading for more information.
Riley RM Maintenance
All you want to know about fault find and overhauling the steering
system, the charging system, clutch, the engine bearings and much more
but were afraid to ask! Now includes the Workshop Manual, drivers
handbooks for the RME, RMF and the RMB (Export Edition) and a number
plate guide giving details of when and where a UK number plate was
issued. Just added is a special bonus of the Riley
Service Bulletins Vol.1 to Vol.4. The Notes are in
PDF format and can be printed out for ease of viewing.
Production Modifications. It is often said
in jest that Rileys did not make any two cars the same and it does seem
that there are always at least minor differences between cars.
Sometimes the differences are more than minor and parts which should
fit do not. In an attempt to unravel the puzzle here are lists of the
recorded production modifications although it is very likely that other
one-off changes crept in too.
Body Colours. Riley offered their cars in a range of colours
and the standard ones
are listed here. They would also paint a car in any colour the owner
wanted, including two tones, for an additional cost. For todays owners
this means that they are free to paint their car any colour they want.
Reference Data Using the correct needle and jet is
essential to good economy and performance. Here we give a list of the
carburetors fitted to the various Riley models along with the
appropriate needles and the needle profiles.
SU Electrical Pump
These pumps are usually very reliable but after a considerable period
of use they can become erratic often stopping until given a sharp bang.
This means that the contact points are burned and should be replaced. A
temporary fix is possible which will certainly get you home and will
probably last until you have got a repair kit and the time to do a full
pump overhaul. Usually new points and a new diaphragm will return even
the oldest pump to full working condition. In the very unlikely case
that a new pump is needed it is useful to remember that the same pump
was used on the Morris Minor.
Setting the Float
All carburetor tuning should start with getting the float level right.
Too low will give poor running while too high will give a high fuel
consumption. The method described in the Workshop Manual gives a start
point but we can do better using the method described here.
We all know that good compressions are essential but what is the best
way to check them and what can cause low results apart problems within
the engine? Here we look at some of the pitfalls that await the unwary.
RM compression ratios are quite low but can be increased either by
fitting high compression pistons or by shaving the cylinder head to
reduce the combustion chamber volume. If the engine needs a rebore and
new pistons then high compression pistons are a simple solution however
the cylinder head can be skimmed at any time without the need to remove
the pistons. If head skimming is the chosen way ahead, how much should
be removed? Here we give a table of compression ratios versus amount
Original RM pistons are no longer made and the Hepolite replacements
are very difficult to find. Alternative pistons are available both in
standard and high compression forms. Here we give data on old pistons
which might help in determining how suitable a replacement type will
Fuel gauges which do not work properly can lead to running out of
petrol or over filling the tank on the garage forecourt. Probably the
most common problem is a gauge which always reads full. Read on to see
how to diagnose the problems and hence fix them.
Oil pressures are specified in both the Workshop Manual and the Drivers
Handbooks but these are not always achieved in practice. Lower
pressures are often found but rarely seem to cause any problems other
than a worried driver. Many other makes of car run quite happily
without an oil gauge using just a warning light which comes on at a
very low pressure. So how important is oil pressure and does it matter
if the reading shown on the gauge is a lot less than that specified in
the books? We try to delve a little deeper into this so read on for
some interesting thoughts.
End Bearing Failure
Over the years many
owners have suffered that sinking feeling which follows the sound of
the dreaded big end knock. They know that they have
a lot of work
and possibly expense in front of them. We take a look at what
causes big ends to fail and outline the repair options available.
Water Pump Overhaul
Water pumps are generally very reliable but eventually they may leak or
the bearings wear out. Although this is quite well covered in the
Workshop Manual here is a fuller explanation of how to remove a pump,
strip it down and reassemble it.
Assembling the RMF water
The Workshop Manual details how to take the RMF water pump apart but
gives no information on how to reassemble it apart from pictures which
are difficult to see. Here we enlarge the pictures and add a
If you are having problems with the charging system our fault finding
check list will help you. It is taken from our RILEY RM MAINTENANCE
NOTES and if you need more information you will need these.
RM Body Structure
When carrying out a body repair or a full restoration it is important
to know how the body is constructed and how the various wooden bits fit
together. In these photographs we reveal all (well almost all).
Recovering a Saloon Roof
Woes - Weekend Repairs
How to make and fit a steel A-post to overcome wood rot problems and
ensure that the door lock striker plate never comes loose again.
1. Riley Sales and Service
Bulletin Jan 1947
2. Riley Sales and Service
Bulletin July 1948
3. Riley Sales and Service Bulletin
4. Girling Technical Bulletin
5. The Compensation Link
6. Girling Part
Numbers and Sizes
7. Diagrams of
Brake Assemblies and Master Cylinders
Information on Brake Servicing
of Tension Master cylinder
of Compression Barrel Master Cylinder
11. Back Plate Steady
Seal Part Numbers and Dimensions
Here are the seals as listed in the Payen Catalogue
Torsion Bar Ride Height the easy way
The Workshop Manual shows a large and cumbersome special gauge for
setting the torsion bar ride height or it can be come by careful
measurements down to the ground. A much easier way without using any
special tools is described here.
Taken from Riley Sales & Service Bulletin Vol.2 No.1, these
photographs show exploded diagrams of the front suspension kingpins and
Basic specifications and rejuvination tips.
the Ignition Leads and Timing the Ignition
Setting up the ignition the easy way
List of spark plugs
The most unreliable part of a Classic Car is often the ignition system
and particularly the contact breaker system. The constant arcing makes
the points burn and they push the distributor spindle sideways causing
the bushes to wear. They need regular maintenance involving either
being renewed or removed for the faces to be cleaned up on an oil
stone. Just to make life more difficult wear in the distributor makes
setting the correct gap almost impossible. Do you envy the modern
motorist with his trouble free ignition system? You can have an
ignition system like his too and it is easy so read on.
Setting Valve Clearances
With two sets of rockers to contend with setting the valve clearances
can get confusing but there is an easy way to avoid the confusion.
Unusual Cause of a Missfire
Keeping the Engine
Warm in Winter
Taken from Rileys Sales & Service Bulletin Vol.4 No.9 of
February 1951, this is how to fit snow chains - hmmm.
Riley Patent Air
Riley fitted some heaters in the factory using what was optimistically
termed the Patent Air Conditioning System. For cars not fitted with
factory heaters Riley suggested fitting recirculation heaters such as
those made by Smith, Clayton and Delaney Gallay. In March 1950 Riley
produced a Service Bulletin describing the Patent Air Conditioning
Refitting the clutch and gearbox with the engine still in the car can
be very hard work and nothing seems to line up first time. Here are a
couple of tips which will make life a bit easier.
Clutch Rod Repair
It is all too common to have the lower clutch rod break usually at a
very inconvenient moment! For those in a hurry there is a
simple way to repair the old rod which will minimize the risk of
further breakages even if the adjustment is not quite right.
The need for a clutch overhaul is usually indicated by the clutch
slipping under heavy load. This can be due to a number of causes
including poor adjustment, oil on the clutch facings and wear of the
clutch facings. Whatever the cause it should be attended to
immediately. Here we tell you how to do it and give tips for making it
2½ Litre Engine
Oil Leak and Seized Exhaust Camshaft
An oil leak from the head gasket behind the exhaust system is a common
sight - here's how to cure it. Seizure of the exhaust camshaft
bearing happens occasionally due to an oil way blockage as explained
here. Note also the paragraph below the
picture which explains why big ends fail.
The Hot Spot System
Many owners of 1½ litre cars have already removed the hot
spot system as it makes cylinder head removal much easier. The usual
procedure once everything is apart is to remove or simply cut off the
tubes from the exhaust manifold and plug the resulting holes. Nothing
needs to be done on the inlet side although the aluminum elbow can be
thrown away. However, a further advantage can be gained by complete
deletion of the hot spot system in both 1½ and 2½
cars. To see how read on......
Left Hand Drive
The differences between the LHD and the RHD variants is a question
which arises often particularly if the owner is considering change from
one to the other. In November 1948 Rileys issued a Bulletin covering
this. To view this read on...
Fan Belt Part Numbers
The original fan belts are no longer made and the way that fan belts
are specified has changed. Here is a list of the original fan belts and
their dimensions plus information on the nearest modern equivalents.
Small 2½ Fan Belt
A slipping belt which cannot be cured by normal adjustment is a common
problem with no simple cure but we present a few thoughts and possible
Fan Belt Removal
To a new owner fan belt removal may look a bit daunting and the
Workshop Manual and the Driver's Handbook only give an outline of the
procedure. Here we look in more detail at the way to do it.
Andre Kahr is undertaking a full rebuild of an RMF and is creating a
diary for the project which he is putting on the net for our benefit.
As well as a full description of the work being undertaken he is
providing a full set of excellent photographs showing all the gory
details. If you are considering a full rebuild or just want to see what
an RM looks like under the skin this is a "must see" site.
Many RM engines have been converted to take shell big end bearings and
this may have been done by a previous owner. The current owner may need
to renew these bearings and in some cases a crank shaft regrind will be
necessary. To assist in this the critical bearing data are given here
however if you want to convert to shell bearings from white metal ones
from scratch you will need the information contained in our Maintenance
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