Welcome to the RM Riley Technical Tips Web Site

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 Series Rileys

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.

Tips For New Owners So you have now bought your RM Riley but are a little unsure about 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.

Riley RM Maintenance Notes
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.
1½ litre modifications
2½ litre modifications

Riley also published Illustrated Parts Lists which give the Riley Part Numbers along with illustrations of the part.  Below are the Illustrated Parts Lists for both the RMA and RMB as published in 1951.  The RMB list also covers the RMC and RMD.
RMA Illustrated Parts List
RMB Illustrated Parts List

Standard 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.

SU Carburetor 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 Quick Repair.
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 Level.
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.

Checking Compression 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.

Compression Ratios
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 removed.

Piston Data
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 be.

Fuel Gauge Problems
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 Pressure
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.

Big 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 pump
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 description.

Charging Faults.
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

Body Woes - Weekend Repairs

A-Post Repair
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.

RM Brakes
1. Riley Sales and Service Bulletin Jan 1947
2. Riley Sales and Service Bulletin July 1948
3. Riley Sales and Service Bulletin Jan 1949
4. Girling Technical Bulletin April 1949
5. The Compensation Link
6. Girling Part Numbers and Sizes
7. Diagrams of Brake Assemblies and Master Cylinders
8. Basic Information on Brake Servicing
9. Description of Tension Master cylinder
10. Description of Compression Barrel Master Cylinder
11. Back Plate Steady Post Adjustment

Overcoming Problems with Hydro-Mechanical Brakes:
- When properly set up RM brakes are very good. Sometimes however no matter how often they are checked they do not perform as well as they should. The Workshop Manual covers most things but problems can arise which are not covered. Before making any changes to the braking system ensure that they are properly adjusted and that the shoes and drums are clean. The braking system is one of the most important system on the car and it must be both reliable and efficient. Decribed here are changes that have been made to some cars and in all cases these have worked well but are presented here for information only. Do not make any changes to your car unless you really understand what you are doing and accept any resulting consequences.

The first change relates to 2½ litre cars with hydro-mechanical brakes where it was found necessary to adjust the rear brakes very often to maintain good braking. The problem and the solution which was found to be effective are described here

The second change relates to brakes where one end of the brake shoes pivot around a fixed point. With the shoes achored to this fixed point they are unable to centre themselves properly inside the brake drum and achieve full face contact between the lining and the drum. The problem and the solution which was found to be effective are described here

Ball Race Part Numbers and Dimensions
The ball races used in RMs are all of good quality and will run for a very long time if they are properly lubricated but eventually everything will wear out so these too may need replacement. They are all easily found with an Internet search so here we give the part numbers and dimension.

Seal Part Numbers and Dimensions
Here are the seals as listed in the Payen Catalogue

Torque Settings
Here is a list of the torque settings from the Workshop Manual togther with suggested settings for the nuts not listed.  These are based on a Grade T steel and should treated with caution but since they are lower than the corresponding values in the Workshop Manual they should be safe.

Setting 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 done by careful measurements down to the ground. A much easier way without using any special tools is described here.

Front Suspension Wishbone Bearings
Taken from Riley Sales & Service Bulletin Vol.2 No.1, these photographs show exploded diagrams of the front suspension kingpins and struts.

Rear Road Springs
Basic specifications and rejuvination tips.

Connecting the Ignition Leads and Timing the Ignition
Setting up the ignition the easy way

Spark Plugs
List of spark plugs

Electronic Ignition
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.

Elusive Missfire
Unusual Cause of a Missfire

Keeping the Engine Warm in Winter

Fitting Snow Chains
Taken from Rileys Sales & Service Bulletin Vol.4 No.9 of February 1951, this is how to fit snow chains - hmmm.

Riley Patent Air Conditioning System
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 System.

Clutch Plate Alignment
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.

Complete Clutch Overhaul
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 easier.

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 Differences
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 and Alternatives.
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.

Slipping 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 palatives solutions.

RMB 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.

RMF Rebuild Project
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.

Shell Bearings Renewal
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 Notes CD.

Job done!

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