The biggest weak point on all Rover/LR V8s until GEMS moved them to computer controlled distributorless ignition. (1968-2000 Plus 8s)

Rover tried one distributor design and amplifier combo after another. Some getting a little better and some getting a little worse. They were the Opus, the 35D8, the 35DE8, the 35DM8, the 35DML8. They all had a few vital characteristics in common,

1. the design degrades the spark from coil to plug

2. they are vulnerable to the elements and complex to maintain.

3. they are 2 to 3 times the price of other proper options.

To address their issues, many solutions have been tried. Ignition modules like MSD, Lumenition, Micro Dynamics, or many others. For the
distributor itself, many aftermarket pop-in technologies has been suggested. However, with all these solutions, the core problem is unaddressed.
Ignition modules do not cure bad distributors and pop-in technology does not cure bad mechanical designs.

Mallory began in the early in the 20th century. They supplied Ford for many years until Ford moved to a cheaper supplier. They produce fine simple-to-deal-with product based on photo optics called the Unilite. The also make other distributors based on other technology. When the UK racers and tuners became frustrated a couple of decades ago, this is where they turned to for a solution. Carson City, Nevada. They are available in the UK from Real Steel, Rpi, Rimmer Brothers, and John Wolfe Racing. (Check the prices as they vary a lot!)

The greatest distributor on the planet will not give you more power. One cannot make a bigger explosion by using a bigger match. However, a substandard spark can be a @#%$! nightmare. One installs a Mallory because you are tired of fighting an unreliable component and you are searching for an instant start-up, a good idle and no hassles at any rev range.

I have a great Mallory story involving Kevin Vernon, the owner of Tudor Motors up in Shropshire. Though Tudor is a century old, Kevin has the same insatiable curiosity as our David Poole. At the time. he had the same set-up system on his Plus 8 as I have on mine. He had just installed a Mallory I sent over and was wondering what all the fuss was about. He pulled out his trusty oscilloscope and tested the spark produced by his stock distributor side by side with  the spark produced by my Mallory. He was amazed. He had set his oscilloscope to the spark range of his dizzy. The Mallory spark went right off the same chart!

I can recommend a Mallory Unilite for a Plus 8 with NO reservations. I have walked scores through the swap and all are happy. They are inexpensive, well made and there is a ton of backup within the Morgan community and elsewhere.
 

MALLORY DUAL POINT N.B. I do NOT recommend the Mallory Dual Point model for Plus 8s or Rover V8s. For some reason, they soon develop hassles, despite the fact they seem to work very well with other engines.

 

MALLORY M.B.I. MAGNETIC BREAKERLESS OR ELECTRONIC N.B. The external and internal wiring of their magnetic distributors (often called MBI for "Magnetic Breakerless" or "Electronic" is the same as the Unilite. They are inherently less sensitive than the Unilite..but they are also inherently less precise. They lose up to a degree in timing for every 1000 rpm. Considering that and our lack of familiarity with them, they are not a good option.

WHICH MALLORY DISTRIBUTOR?

There are some things you must know to order yours.

1. Distributored Rover V8s are divided into two generations..by timing covers. The first decade of Rover production (1967-1977) used a close copy of the Buick 215 timing cover. This cover had an oil pump with a female drive gear driven by a male distributor shaft. The second generation, (1977-GEMS cars), had a better oil pump with a male drive gear driven by a female fitting on the distributor shaft.) You must choose your Mallory to match your generation.

2. Mallory, like most top-flight earlier (and later) distributors must be ballast-resisted. (The earlier Rover already have one.) This can be done by buying a distributor ballast resistor from Mallory or your local car part store or buying a Mallory internally ballast resisted coil, a red top,  (which normally gets VERY hot!). This option simplifies the wiring but the coils don't last as long. I have had my Mallory internally ballast resisted coil crack with the heat. (Happily I carry another in the car). Go for a external ballast resistor. It works with any coil.
 
 
 

BALLAST RESISTORS N.B. If the ballast resistor terminals touch (be careful of your bonnet stays!) or is poorly grounded, the wring will deliver a full 12 volts to the coil and then the distributor. That will overheat the coil and/or destroy the photo optic heart of the Mallory.

FOR EARLIER PLUS 8S (1968-1976): (aka Pre-Sd1)

The part number you need is 4764301. This Mallory Unilites comes with 24 degrees of vacuum advance (all Mallorys have an adjustable vacuum advance feature). Be careful, there are versions ending with a "2" rather than a "1" that come with 18 degrees of vacuum advance. You need 24 degrees. (though can alter either to what you want a 24 degree will make the Rover V8 happier from the box.)

This is the same application as the early 1960s Buick 215. Installation is straightforward. Click INSTALLATION. Click COIL for coil choices and WIRING.

FOR LATER DISTRIBUTORED PLUS 8S (aka post-Sd1) = Plus 8s 1977-1996 (in the US) and 1977-2000 (everywhere else)

The part number you need is Mallory Unilite 4768901. with vacuum advance. This Mallory Unilites comes with 24 degrees of vacuum advance (all Mallorys have an adjustable vacuum advance feature). There are versions ending with a "2" rather than a "1" that come with 18 degrees of vacuum advance). The model comes without the male ending you don't want but you will be required to swap the distributor gear and its female connection from your existing unit to the Mallory. This is not difficult and if you are uncertain, have a local machine shop or garage do it for you.
 

WATCHPOINT: Do NOT follow Mallory's instruction for the gear/female connector swap CLEARANCE. It is too large and can create a bit of oil seepage. Use a clearance of 5 to 8 thous

REMOVAL OF THE OLD DISTRIBUTOR
 

Many prefer to set the engine at TDC before doing this work. This is not strictly necessary but it will mitigate problems if you get anything wrong..

1. Remove the coil-to-distributor wire.

2. Remove the vacuum advance hose.

3. If you are unfamiliar with the order of the ignition leads (the big wires from the distributor to the spark plugs) order, mark the leads with something to identify them and take an image of the leads still installed on the cap and the engine so that you can have the right ignition wire on the right cap post going to the right cylinder. Actually, you only need to know where the lead to cylinder one should be (cylinder 1 is the front right if you are standing in front of the car.). The firing order, and therefore the order the cylinder leads are attached to the cap is (clockwise).

4. Remove the ignition wires and the connections.

5. If there is a separate ignition module (most Lucas versions). remove it as well, you will not be needing it.

6. Remove the cap and take an image of the rotor and the distributors relationship with the engine's .
 
 
 

7. Undo the clamp holding the distributor to the front cover.

8. Hold the rotor and lift upwards to slowly remove the distributor. The rotor will turn counter-clockwise about 15-10 degrees as the distributor lifts and it disengages the camshaft gear.  The relationship of the rotor angle and the distributor shaft end will become very important at re-installation.
 

9. Look down the distributor hole and take a picture or the orientation of the oil pump drive gear. The oil pump drive gear must be turned on re-installation of the new distributor to the angle that allows the rotor to arrive at the position you left it. You will likely have to turn the oil drive gear to permit this to happen. This can be done with a clean screwdriver.

10. Now you must swap over the distributor drive gear and female interface fitting (along with that little washer that goes on the shaft between the camshaft gear and the bottom of the distributor body. Mallory sent a new one with the distributor.
 

11. Tap out the pin the holds the gear and female interface to the old distributor's shaft. Slip the washer of the shaft of the Mallory and then slip on the gear and its attached female fitting.
12. You must now drill the shaft perfectly so that the clearance between the gear/washer and the distributor is .005-.008 inches (5 to 8 thous) measured by using a feeler gauge as shown at the left. To determine the correct bit, measure the removed pin. This is the part that scares most, with reason. If you are concerned, go to a machine shop. They can do the job perfectly in a few minutes.

13. Once the hole is drilled, use a pin, preferably a new one, to drive into the gear and shaft holes and firmly secure the gear to the shaft.

INSTALLATION OF THE NEW DISTRIBUTOR

14. (Also see "TIMING THE CAR" below.) There are two important things to understand for reinstallation of the distributor.

A. You want to start off with the rotor facing very close to the same way as it was when you took the old distributor out. This will only be possible if the oil pump gear the distributor shaft interfaces with is angled to permit this.  If you are too far out, the car will not start or back fire as your spark will be out of sync with the engine.

When you swapped over female interface gear, it is very unlikely its orientation in relationship with the rotor stayed the same as the same relationship with the old distributor. Ergo, the oil pump gear will often only cooperate to permit the correct final orientation of the rotor if you turn the oil pump gear to allow to arrive at the right place.

Firstly, take a look at the images you took to see where you want;

i.  the distributor aligned (using the cap clips or the vacuum unit as references with points in the engine).
ii. the rotor aligned, from the image you took with the cap off but 15-20 degrees more counterclockwise. Click here for why.
iii. At your workbench, hold your lightly distributor in your table and align the rotor and distributor to approximate the same relationship in the image.
iv. Now look under the distributor to see how the slot is angled in the female interface fitting. Compare that with how the oil pump gear is angled..either by looking down the distributor hole on the engine or the image you took.
v. NOW using a long screwdriver, turn the oil pump gear in the engine to match the angle of the female interface on the distributor
vi. Reinstall holding the rotor and turning it the same amount clockwise seen in #ii. as it engages the oil pump to seat ENTIRELY.
 

WATCHPOINT: You are now close to starting OR 180 degrees out. If it doesn't start (with a friend turning it over and you fiddling at the dizzy. Remove and turn the rotor 180 and reinstall. see below.

15. Reinstall the wires as indicated below.

16. Put the vacuum advance hose back on.

TIMING THE CAR

There is some understanding necessary to timing a 4 stroke engine. The crankshaft pushes the piston up twice for every one spark. That has consequences.
Here are the strokes and what is happening during each.

1. COMPRESSION stroke where the fresh air/fuel air mixture is compressed (all valves shut)
2. POWER stroke, starting with the spark and resultant combustion that pushes the piston down.
3. EXHAUST stroke, where the piston comes back up but with the exhaust valve open to allow the spent gases to escape.
4. INTAKE stroke when the piston goes down sucking in a fresh air/fuel mixture with the intake valve open.

In other words the piston is at the top, pointing to the same scribe, in two of the four strokes, COMPRESSION and EXHAUST. Set the rotor to the COMPRESSION stroke and you're fine. Set the rotor to the EXHAUST stroke and you are exactly 180 degrees off. Without other measures, you have a 50-50 chance you got it right.

Frankly, for most people, that is the best way of discovering WHETHER they got it right. Try to start the car. If they are Piston 1 COMPRESSION stroke's top, the car will at least attempt to start (sometimes with a bit of adjustment. If they have it on the EXHAUST stroke, the car will not start or may even backfire. If that happens, I simply tell them to lift the distributor enough to disengage it and turn the rotor 180 and re-engage it.

Of course, there are WAYS of determining the real TDC. But for most people I help, it is a bit beyond their skill level and too invasive. One way is to use your thumb to block the number 1 spark plug hole while someone hand cranks the engine. When it is on the COMPRESSION stroke, you will feel compression against your thumb. (When it is on the EXHAUST stroke, there is no compression as the exhaust valve in that cylinder will be open.) When you know you are on the right stroke, you simply have your friend turn the crank until scribe marks say it is TDC.

The other way, surer, is to remove the valve cover, have a friend turn the crank until it is approaching the TDC scribe make with both piston 1 valves closed. (BTW, never trust Rover or LR scribe marks. They are inaccurate 50% of the time.)

I have found it useful to use a bit of white paint to mark timing points I need after I have found them. For example, one for TDC and another for where my car likes to run on the fuel I normally use. This is especially important for high compression variants of the engine. With these engines, I have one mark for TDC, another mark for normal running and a last mark for running when I am traveling and the quality of the petrol drops.
 

WATCHPOINT:  Outside of great quality workmanship on the mechanicals and its billet rather than cast body, Mallory Unilite magic is based solely on its optical trigger unit which is common to ALL Unilites for all cars and easily found. This device can be tested in situ in seconds roadside and replaced in minutes. If I can do it, anyone can do it. Outside of the USA (where the modules are available at every auto store on every corner, carry an extra module with you. REMEMBER not jump start your car with the ignition hooked up as this can kill the Unilite's ignition module. Disconnect battery and charge IT! or disconnect the distributor.

WIRING A MALLORY UNILITE FOR A LR/ROVER V8
by Lorne Goldman

If Using an Internally Ballast Resisted Coil

OR

If Using a Ballast Resistor and Standard Coil (recommended)

If using a ballast resister and standard coil.