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XPAG Drip Trays

14 Jan

These were the brainchild of David Pelham, who sadly passed away in 2013. Bryan Purves took over the project after David’s passing and he continues to supply these worldwide. He tells me that he can’t get enough of them! The price is 53 GBP and can be ordered from Bryan via his website http://www.bryanpurves.co.uk/contact-bryan/4578606936 If phoning, he is available to answer on Tues/Wed/Thurs. Please note that these will not fit the 5-speed gearbox.

Fitting a Rear Wing on the MG TA

12 Jan

Single Handed Wing Fitting

Translations for our readers in the US –
Wing = Fender
Fuel tank = Gas Tank

The Fuel tank must be fitted in the correct location.

Prop up the running board and leave an overlap to support the front of the rear wing.

Bolt the wing to the Fuel tank and then swing up to the correct position and balance on the wooden support.

Line it up laterally by eye; there are no published dimensions on to how far it should stick out from the tub. I did check the wing front was near vertical with a long spirit level.

I have limited space and my daughter bought a bicycle. I was not pleased. It was raining last night so I could not put it outside.

This is considered a large garage by the builders who sold me the house!!

Using tech tips from Doug Pelton, mark the hole spacing on top of the wing!

https://fromtheframeup.com/uploads/TT_BP116_Rear_Wing_to_Tub_Fastener_Locations.pdf

The tub frame is between 1¼ and 1½ inches thick, so mark a point 5/8 inches in from the inner edge of the marker line and drill the holes to clear the screws. Deburr the holes. I bought a tool from Screwfix, but it wore down fairly quickly.

Put the wing back in position and bolt to Fuel tank, set in correct position on the lateral line and drill and screw into place with as few screws as possible in case you change your mind! When you are happy then fit the rest of the screws.

Loosen the screws and fit the piping (yet to be made!).

Took around an hour, some people talk of taking days!

Episode 2

I lied as to how easy the wing was to fit! Working in a small garage with access to one side of the car only seems madness, but that is what I am stuck with. Having got the first wing on, the second has to match. I could not find many instructions on this subject. This is not a definitive set of instructions but a shared experience!

All did not go well at the initial fit of the second wing as I found a few issues.

  1. The hole for the tank bolt was in a different position on the offside wing compared to the nearside. (Filed oblong until the wing lined up.)

  2. The tank was not level with the rear of the body.

  3. I had not checked that the wings were the same circumference front to back.

  4. I had not measured the wing fit on the nearside, before I turned the car around and put it back in the garage and jamming it up against the wall.

  5. I marked it up before I measured the other wing. Worth having a set of coloured felt tips as the second set of marks were done in Blue instead of Black. (99p from the 99p shop).

The tank was sitting on 4 layers of 1/8 rubber sheet and removing one of these from the offside brought it back level. This dropped it around 3mm on the right hand side. Picky yes, but it needs to match the back of the body tub. I need to add that the dimensions of my car as found had strayed from the original as the body had dropped by 1.5 inches at the back since 1938. My thanks to Mick Pay for supplying a better set of measurements from his car. There is a debate on how far forward the wheels come in the rear wheel arches and does the front of the wheel just foul the wing when you remove it. I looked at a multitude of pictures on line to get the right fit. Micks fouls on one side and not on the other! Advice from Doug Pelton was line the wings up by eye!

There are three dimensions that are critical:

  1. Back tip of wing to top of body. Around 30 Inches. You can rotate the wing in the wheel arch around three or four inches. I was an inch out on the first attempt.

  1. Edge of wing to Sidescreen slot. Around 8 Inches. This controls how far the wing protrudes.

  1. Front bottom edge of wing to body tub (left). Should the base of the wing line up with the body – No idea! Black was first attempt with the wing too far in, blue was second. Mark the inside as well as the outside.

Finally, this shot shows how the wheel appears within the wing, with an oversize gap to the running board.

Occasionally it gets outside to see the sunlight…..but there is still a lot to do!

Tim Parrott Stroud, Gloucestershire.

Ed’s note: Tim has sent me a few pics of his re-wiring project, which I hope to feature in the next issue.

Bits and Pieces

8 Jan

TC1013

Ron Engstrom recently e-mailed me from California to say how pleased he is with his newly restored TC. He added that he is grateful for the help he received along the way from Bob Alley and Kerry McDonough. One very happy man! – you couldn’t send some of that lovely weather this way could you Ron?

Restoration Award for TD0267

Further to the story and front cover in the previous issue I’ve heard from Robert Browne that he’s received the Restoration Award from his Club ‘The MG Restorers’ Association’.

A richly deserved award, may I say (Ed).

(From the website www.mgrestorers.com )

The MG RESTORERS’ ASSOCIATION is Sydney based and was formed in 1979 by a number of MG enthusiasts whose primary aim was to promote owner restoration, preservation and maintenance of their cars as opposed to “cheque book” restoration. This goal continues to this day, however the social side of the group has grown, so that there is now a balance between technical activities and social events, such as weekend and midweek runs, weekends away and extended tours.

Membership comprises a close knit group of 60 enthusiasts with MGs dating from the 1930s to modern. Within the group considerable areas of technical expertise are on tap and assisting in other members’ problem solving and restorations is heavily promoted.

The benefits of membership include access to the Historic Plates scheme and Regalia. As no expensive journal is published, subscriptions have been unnecessary beyond a nominal joining fee. The Association is funded by the sale of badges, club merchandise and raffles etc. Members are informed of forthcoming activities by either email or telephone and organisational duties are distributed throughout the membership.

THE MICHAEL SEDGWICK AWARD

The Society of Automotive Historians in Britain present their Michael Sedgwick Award annually to a book, which deals specifically with aspects of motoring in Britain and which demonstrates “excellence in its research, presentation, readability and novelty, and will materially further our understanding of the subject”.

Instigated in 2011, the award is in memory of the much respected motoring author, the late Michael Sedgwick.

Last year, (in Issue 33 of TTT 2) we were pleased to report that the award was presented to Stewart Penfound for his book entitled “Harry Lester, his cars and The Monkey Stable”.

This year, we are delighted to report that the award has been presented to TTT 2 member and TC owner, Mike Harvey for his book Skinner’s Union – A history of the Skinner family and the S.U. Company. The book emerged as a clear winner from a final shortlist of three very strong entries.

http://sucarb.co.uk/skinner-s-union-book.html (£20).

Push Button Indicator Switch

Brad Purvis recently sent me pictures of what looks like a push button indicator switch on his TF. It’s actually installed upside down! Brad is at pains to point out that he didn’t install it…..

XPAG REAR CRANK SEAL

Anton Piller has issued a correction to the number of the oil seal mentioned in his recent article (TTT 2 Issue 39).

Instead of Oil Seal 95-120-12, order number CR 99369

It should read BAVI 95-120-12.

This article generated some interest in the form of comments posted on the ‘read directly on the website’ facility.

Ian Thornhill reported that he had sourced a 10mm Viton seal (rather than the 12mm, mentioned by Anton) and added “The seal has ‘SOG’ on it 95-120-10 it has a dust seal as well as the main spring filled oil seal. I purchased some of them from ‘Eriks’ https://sealshop.eriks.co.uk

They also sell a front crank seal in Viton, but with a dust seal rather than the single lip more commonly available. The lead time was about 5-8 days, but they were very helpful.

If they will not ship abroad, I am happy to purchase and send out using PayPal if it helps.”

Here are the pics of the rear seal:

MG TA Triple Valve Spring Caps and Bases

The following was received too late for publication in Issue 39, but was reproduced in the covering e-mail which announced that Issue 39 was available on the website.

The MPJG engine in early life had Double Valve Springs and matching Caps and Bases. At present, you can get new Triple Springs but there is no source beyond used for the caps and bases. On the other hand, if you still have an early engine with double springs there is no source of double spring replacements.

I am having 51 caps and 60 bases made for Triple Springs but I am happy to increase the order if I get further requests. I will have a spare set of 8 of each unreserved. Prices yet to be finalised but items will be supplied with a VAT invoice. tp@tpss.co.uk

The next issue is the collets. The Morris 10 ones were 6.3 mm long whereas the MPJG ones were 8.7. The MG ones are not available, however, the taper and internal diameter on the Morris 10, MPJG and the XPAG collet are the same/similar so any could reasonably be used. The recommendation is to use only the original size collets, however my engine came fitted with the shorter Morris 10 ones and there are no signs of any ‘ill effects’.

Since this notice appeared, all the caps and bases have been sold, but there is just one unreserved set of 8 of each available.

It is understood that NTG Motor Services may have limited stock available.

Whilst on this subject I noticed the following advice about Triple Valve Springs, which is worthy of publication:

(From The Light Car 1949)

“With all high-efficiency engines, the question of preventing valve bounce is important, and, in the case of the Midget, three springs are used for each valve. These are of the usual helical type and fit concentrically around the spring. The outer and inner springs have their coils wound in one direction, and the middle is wound the reverse way so that there is no risk of the coils of one spring becoming trapped between the coils of its neighbour, as would happen if the springs were wound in the same direction.”

MORRIS 10 or MG TA Pistons

The above sent by Tim Parrott. TA on the left and Morris 10 on the right. Rings and gudgeon pins will fit but pistons won’t due to different gudgeon pin height.

Fitting a Rear Wing on the TA

Single Handed Wing Fitting

Translations for our readers in the US –

Wing = Fender

Fuel tank = Gas Tank

The Fuel tank must be fitted in the correct location.

Prop up the running board and leave an overlap to support the front of the rear wing.

Bolt the wing to the Fuel tank and then swing up to the correct position and balance on the wooden support.

Line it up laterally by eye; there are no published dimensions on to how far it should stick out from the tub. I did check the wing front was near vertical with a long spirit level.

I have limited space and my daughter bought a bicycle. I was not pleased. It was raining last night so I could not put it outside.

This is considered a large garage by the builders who sold me the house!!

Using tech tips from Doug Pelton, mark the hole spacing on top of the wing!

https://fromtheframeup.com/uploads/TT_BP116_Rear_Wing_to_Tub_Fastener_Locations.pdf

The tub frame is between 1¼ and 1½ inches thick, so mark a point 5/8 inches in from the inner edge of the marker line and drill the holes to clear the screws. Deburr the holes. I bought a tool from Screwfix, but it wore down fairly quickly.

Put the wing back in position and bolt to Fuel tank, set in correct position on the lateral line and drill and screw into place with as few screws as possible in case you change your mind! When you are happy then fit the rest of the screws.

Loosen the screws and fit the piping (yet to be made!).

Took around an hour, some people talk of taking days!

Episode 2

I lied as to how easy the wing was to fit! Working in a small garage with access to one side of the car only seems madness, but that is what I am stuck with. Having got the first wing on, the second has to match. I could not find many instructions on this subject. This is not a definitive set of instructions but a shared experience!

All did not go well at the initial fit of the second wing as I found a few issues.

  1. The hole for the tank bolt was in a different position on the offside wing compared to the nearside. (Filed oblong until the wing lined up.)

  2. The tank was not level with the rear of the body.

  3. I had not checked that the wings were the same circumference front to back.

  4. I had not measured the wing fit on the nearside, before I turned the car around and put it back in the garage and jamming it up against the wall.

  5. I marked it up before I measured the other wing. Worth having a set of coloured felt tips as the second set of marks were done in Blue instead of Black. (99p from the 99p shop).

The tank was sitting on 4 layers of 1/8 rubber sheet and removing one of these from the offside brought it back level. This dropped it around 3mm on the right hand side. Picky yes, but it needs to match the back of the body tub. I need to add that the dimensions of my car as found had strayed from the original as the body had dropped by 1.5 inches at the back since 1938. My thanks to Mick Pay for supplying a better set of measurements from his car. There is a debate on how far forward the wheels come in the rear wheel arches and does the front of the wheel just foul the wing when you remove it. I looked at a multitude of pictures on line to get the right fit. Micks fouls on one side and not on the other! Advice from Doug Pelton was line the wings up by eye!

There are three dimensions that are critical:

  1. Back tip of wing to top of body. Around 30 Inches. You can rotate the wing in the wheel arch around three or four inches. I was an inch out on the first attempt.

  1. Edge of wing to Sidescreen slot. Around 8 Inches. This controls how far the wing protrudes.

  1. Front bottom edge of wing to body tub. Should the base of the wing line up with the body – No idea! Black was first attempt with the wing too far in, blue was second. Mark the inside as well as the outside.

Finally, this shot shows how the wheel appears within the wing, with an oversize gap to the running board.

Occasionally it gets outside to see the sunlight…..but there is still a lot to do!

Tim Parrott Stroud, Gloucestershire.

Ed’s note: Tim has sent me a few pics of his re-wiring project, which I hope to feature in the next issue.

XPAG DRIP TRAYS

These were the brainchild of David Pelham, who sadly passed away in 2013. Bryan Purves took over the project after David’s passing and he continues to supply these worldwide. He tells me that he can’t get enough of them! The price is 53 GBP and can be ordered from Bryan via his website http://www.bryanpurves.co.uk/contact-bryan/4578606936 If phoning, he is available to answer on Tues/Wed/Thurs. Please note that these will not fit the 5-speed gearbox.

Lost and Found

6 Jan

Peter Wilgoss is hoping that someone out there might have some information which would lead to him being reunited with his TC (pictured above). The photo of Peter and his TC was taken around 1965 when he lived in Perivale, West London. Un- fortunately, the chassis number cannot be recalled to memory. If you can help, Peter would like to hear from you peterwilgoss.mg(at)gmail.com please substitute @ for (at).

Peter Warne has managed to research much useful history of his TB (TB0493), registration mark EWK 447, but has so far drawn a blank from the time it was exported new to Denmark with a KPH speedometer until it was registered again in the UK on 15th December 1988 and was given the age-related registration mark EWK 447 (a Coventry number, first issued in July 1939).

It is possible that the car came back to the UK well before the date it was registered here; a possible clue being that it was allocated ‘T’ Register number 117 dating back to 1961, but any further details have been lost in the mists of time.

From the date of its re-registration in late 1988 there are various MoT Certificates from garages in Milton Keynes/Burton on Trent/Uttoxeter, the last one in Milton Common in April 1999.

Owned briefly by the late Peter Gregory, it was sold by him to Howard Harman in July 1999, who fully restored the car to a high standard, including a new body.

Purchased by John Garden through Barry Walker in January 2011, it was flown to Calgary, Alberta, where it only covered 15 road miles in four years and was flown back from Calgary to Heathrow in January 2016, having been bought by Peter Warne the month before.

It has since been fitted with a supercharger by Steve Baker and set up on a rolling road, it has recorded 80 BHP at the flywheel.

Peter is keen to fill in the gaps of his car’s history, so if you think you can help, please e-mail him at jpswarne(at)hotmail.com please substitute @ for (at).

TC2045 (was in Texas – now in Belgium)

Dirk Meersschaert from Belgium contacted me a few weeks ago to enlist my help in contacting the previous owner of his TC. As with some technical queries I receive, which I cannot answer myself, I generally know “a man who can”. So it was with Dirk’s request. He had experienced some difficulty in contacting William E Mott III in Dallas, Texas (the previous owner), so who better to ask than a fellow Texan! By a stroke of luck, Bob Lines had just e-mailed an advert for the sale of his TD so I asked him to facilitate contact between current owner and previous owner. Bob Duly obliged and contact has now been made.

Dirk sent me a couple of photos of his car and it is so nice that I’m going to show another one. Both photos were taken whilst on a historic rally accompanied by his wife in west Flanders near Ypres.

TC1988 (GDF 939)

Towards the end of summer 2016 (seems a long time ago now!) Charlie Makin contacted me about a TC owned by his father, Michael. At the time, Michael had just died and Charlie was going through some old photos for his father’s memorial service. He came across a 1950s photo of Charlie’s TC with the registration mark GDF 939 and wondered if I had any information about the car. As I recognised the registration mark straight away, being the car belonging to TTT 2 printed copy subscriber Chris Tordoff, I was able to bring both parties together.

In the period photo shown above, Michael is in the driving seat and Charlie’s grandmother is standing by the bonnet.

According to Charlie, Michael owned the car from the early/mid 50s ’till early ’60s and loved it. He drove to Italy in the TC with his wife for their honeymoon in 1957 (flying from Lydd and driving through the Alps.) He ‘blamed’ Charlie’s birth in 1960 as the reason he had to sell it! He later owned an MGBGT, as did Charlie and his brother, so the marque is clearly in the Makin family DNA.

The intention was always to try to find the car (or another T-series) for Michael’s 90th birthday, which would have been this January, but it didn’t materialise; yet unbeknown to the family, Michael’s old TC was located just a few miles from where he lived!

Chris Tordoff has owned TC1988 for over 47 years, having acquired it in 1969. Chris has done much research on past ownership, but through the contact with Charlie Makin he has been able to fill part of a large gap in its early history. Before the contact with Charlie, Chris was able to ascertain that his Gloucestershire County Council registered TC was first owned by a Mr & Mrs Brill from Tilehurst, Reading (why they should have bought a new car from a garage in Gloucestershire remains something of a mystery). The car then passd into the ownership of one Alan Grant Narracott of Stevenage in October 1965 and Chris has details of two subsequent owners, up to the time when he acquired the car.

Now, rebuilt from the chassis up by Chris soon after its purchase, it ought to be good for another 47 years!

Modern Petrol and Classic Cars – the Manchester XPAG Tests

4 Jan

Introduction

Even if your classic car runs well on modern fuel, the chances are you know somebody who has problems. The most common issues people suffer from is called the “Hot Restart Problem”. Drive your car any further than 10 miles or so, stop for 10 minutes – for example to fill up with petrol – and when you get back in your car it will not start. A related problem occurs if you are driving in slow traffic, especially on a warm day; the engine coughs and splutters to a stop as though it has run out of fuel.

These are the most obvious problems with modern fuel. There are others which people have reported, including burned exhaust valves, cracked cylinder heads, not to mention the worries of ethanol blended fuels.

I have owned my MG TC since 1967 and, for those who can remember back that far, I used to run it on 2* leaded fuel. It ran like a dream. My problems started after the demise of leaded petrol and have resulted in a great deal of time spent in the garage trying to sort them out.

Around 15 years ago, I realised my problems were caused by differences in the composition of modern petrol and started testing different concoctions and types of petrol in my TC and writing articles about my findings. These tests culminated in a student engineering project at the School of Mechanical, Aerospace and Civil Engineering (MACE), who installed an XPAG engine similar to the one fitted in my TC in an engine test cell, aimed at investigating these problems.

Unfortunately, the students ran out of time before completing the tests. The good news is that with additional support from the MG Car Club and help from MACE, these tests have been completed, providing a fuller understanding of the problems caused by modern fuel, things that can be done to mitigate them and, on the way, debunked a few myths.

Thanks must go to Andrew Owst who loaned the engine, David Houghton who came out of retirement to manage the test cell and those who gave up their time to help with running the tests.

Thanks must also go to the MG Car Club, Burlen Fuel Systems, Totally T-Type 2, Octagon Car Club, Federation of British Historic Vehicle Clubs (FHBVC), MG T Register, MG Y Register, Anglo American Oil Company, NTG, Distributor Doctor, 123ignition, who have sponsored this project either financially or by supplying parts or fuels.

Why an XPAG?

Almost the first thing people say is “Why test an XPAG, they are an old engine, designed in the late 1930s and only fitted to MG T-Types”. While it would have been ideal to test a range of engines, the high cost of installing the engine in the test cell prevented this. In practice, the XPAG or ‘X’ series engines were used in virtually all Morris and Wolseley cars until 1956, including the many thousands of the Morris 10/4 Utility cars & vans made during WW2.

The XPAG is a good compromise. Its long stroke bottom end shares a great deal with earlier engines, while the cylinder head design is virtually identical to the A and B series engines fitted to later cars. It also demonstrates the problems of running with modern fuels very well.

What is wrong with a rolling road?

Other people have asked why not use a rolling road? The dynamometer at MACE provides the ultimate test cell for an engine. The engine is fully accessible allowing a range of thermostats, vacuum gauges and exhaust gas monitors, etc., to be fitted. In addition, it is easy to change the fuel that is being used. The throttle setting can be fixed and the revs controlled by the dynamometer, enabling part throttle as well as full throttle conditions to be investigated. This set-up allowed a very large amount of data to be collected for many different scenarios.

The picture above shows the water braked dynamometer with its large RPM gauge. This was managed from the control room where the gas analyser and various other readouts were located. As the pictures show, there is a lot more you can do with an engine installed in a proper test cell than you can with a rolling road.

What is the cause of our problems?

Modern fuel is different from classic petrol in two main ways. Firstly, it most probably contains ethanol and secondly, it is made from of a much wider range of hydrocarbons.

The picture below shows the engine ‘hiding’ behind a set of meters with the air fuel ratio meter on the left-hand side and an array of 8 yellow temperature meters connected to thermocouples on the fuel pump and carburettors. At the top right are the temperature readings for the water and exhaust gasses. The rectangular blocks on top of the carburettors are to allow the height of the piston to be measured and you can just see one of the vacuum gauges connected to the inlet manifold to the left of the rear carburettor.

The Control Room

Crude oil consists of many different hydrocarbon molecules. When heated, these molecules boil off at different temperatures, lighter ones evaporating first and the heavier ones at higher temperatures. Crude oil is cracked, by heating and condensing out the components or distillates over the different temperature ranges; for example, light gasses such as propane and butane are condensed at lower temperatures, petrol at higher temperatures, diesel at higher temperatures still and tars at the highest temperatures.

With a wide range of distillates, modern petrol starts to evaporate or boil at lower temperatures than classic petrol and the high boiling point components require higher temperatures to evaporate.

Before petrol can burn in the cylinder of a car, it must be a vapour. While the low temperature distillates make starting a cold engine easier, they are the sole cause of the “Hot restart problem”. Some of these evaporate well below the operating temperatures of engines and under some circumstances will boil in the fuel system and carburettors, stopping the engine running properly.

This will be covered in more detail in a future article.

Ethanol

In the UK, up to 5% ethanol alcohol is blended with petrol, in France this can be up to 10% with even higher levels in other countries.

Adding ethanol to petrol is not new. Cleveland Discol was introduced in 1928 and sold until 1968 claiming to “contribute to a brilliant performance and better mileage because it keeps the engines cooler and cleaner”, “the perfect cold-weather fuel”. However, it is not known what percentage ethanol Cleveland Discol contained, making it difficult to compare with modern fuels.

Were Cleveland’s claims true? An E10 blend of fuel obtained in France was tested in Manchester and the report of how the XPAG ran on this fuel will appear in the Engine performance article.

There is a large amount of published information about ethanol blended fuels and their potential damaging effects to fuel hoses, seals, etc., however, probably the most worrying problem is their ability to corrode metals such as steel and aluminium.

Hoses are relative cheap and easy to replace, carburettors, fuel pumps and the like, far more expensive and for older cars, parts may no longer be available.

Is corrosion of metal components really a problem?

You can see the corrosion at the bottom of one of the float chambers in my TC. Especially worrying as I have been using premium blend fuels that I thought were ethanol free fuels for the past 6 years.

There are two different types of corrosion; one where the metal is attacked, usually by an acid: the second requires two different, electrically connected metals in a conducting medium, called an electrolyte. This arrangement forms a battery and as the current flows, the anode corrodes. This is called galvanic corrosion.

Ethanol blended fuel causes both these types of corrosion. The corrosion in my float chamber (above pic) was around the steel bolt connected to the aluminium body, suggesting it is galvanic corrosion. There is little information on the protection offered by the additives against galvanic corrosion and is something I will investigate further this winter.

Do classic cars run as well on modern fuel?

The way petrol burns in the cylinder is very complex. An overview of this process helps in understanding why classic cars can run hotter and why modern fuel apparently burns more slowly.

The following graph, from a research paper, shows the burning velocity (flame front speed) of different hydrocarbons plotted against the fuel air equivalence ratio. Air equivalence ratio is defined as 1 when there are the exact number of oxygen molecules in the mixture to allow each of the hydrogen and carbon atoms in the fuel to oxidise or burn. Optimum power is produced at an air/fuel ratio of around 0.95 (or 1.05 on the graph as this shows fuel/air ratio).

While the flame front speed in different hydrocarbons is small, it is very sensitive to the differences in air/fuel ratio. What is also interesting to note is the fastest flame front speed in Gasoline (Petrol) is a very sedentary 35cm/sec.

The bore of an XPAG engine is 6.67cm. At a speed of 35cm/s, it would take 0.2 seconds for the flame front to cross from the spark plug to the other side of the cylinder. If this were the only factor in burning the fuel, it would limit the engine to a maximum of 50rpm! The only reason spark ignition engines can run at high revs is because turbulence in the gasses mixes the flame front in the cylinder, allowing the burning to spread out more quickly. The turbulence of the air/fuel mixture in the engine is a function of design of the head and inlet manifold and not the type of fuel being used.

There are three phases during the combustion cycle. Firstly, when the spark plug fires, a fireball of burning mixture about the size of a pin head is created. This fireball grows as the flame front moves outward at approximately 35cm/sec, depending on the pressure in the cylinder and air/fuel mixture around the spark plug. This initial phase of the combustion is slow and a significant factor in the time taken to burn the fuel. Once the fireball has grown to approximately the size of a pea, the second phase begins when turbulence starts to take over and spreads these ignition points throughout the volume of the cylinder, rapidly igniting the remaining mixture and raising the pressure in the cylinder. Finally, any fuel which did not initially evaporate or was trapped around the valves or piston, burns in the extremely high temperatures created during the second phase.

It takes a relatively long time from the spark that creates the initial fireball to all the mixture being burned. As revs increase it is necessary to advance when the spark plug fires to provide sufficient time for the fuel to fully burn before the optimum timing when the piston is approximately 17 degrees after top dead centre. On very early cars this was achieved manually, on later cars and the majority of MGs this is done by bob weights in the distributor, which fly out as engine revs increase, causing the ignition timing to advance.

There is also a second effect. The growth of the initial fireball is dependent on the pressure of the mixture in the cylinder which, in turn, depends on throttle setting. At light throttle settings, cylinder pressure is low and the growth of the flame front slower. This requires the timing of the spark to be further advanced for light throttle settings. On later cars, this is achieved using the vacuum advance pod on the distributor which is connected to the inlet manifold. A light throttle setting reduces the pressure in the inlet manifold causing the pod to advance the ignition timing. Earlier cars do not have a vacuum advance.

The tests at Manchester have shown how important correct ignition advance is in allowing the engine to run cooler.

Cyclic Variability

A weak or rich mixture around the spark plug slows the growth of the initial fireball. This can have a significant effect on the timing of combustion cycle. Even if the carburettor is set to deliver the perfect fuel/air mixture, there is no guarantee that, after the compression stroke, the mixture around the spark plug is correct. It is quite possible that it will be either too weak or too rich depending on how well the fuel is atomised in the carburettor, mixed with the incoming air, and vaporised during the compression stroke. A slow growth of the initial fireball leads to retarded combustion of that cycle. The graph that follows depicts the results of cylinder pressure measurements in a running engine and show a difference of some 10 degrees difference between the timing of the peak pressure.

Cycle by cycle variations in the mixture of the small volume of gasses of around the plug when it fires and subsequent changes to the speed at which the initial fireball grows, leads to a phenomenon called Cyclic Variability. The timing of each combustion cycle varies every time that the cylinder fires. Even with a perfectly tuned engine with the correct centrifugal and vacuum advance, cyclic variability causes a percentage of the combustion cycles to burn too slowly as though the engine is running retarded, increasing the temperature of the hot gasses leaving the exhaust.

The other effects of cyclic variability are that it causes an engine to run roughly and slightly reduces power output, normally something most people will not notice. However, large cyclic variability will noticeably increase the temperature of the exhaust gasses and under bonnet temperatures. It is worth trying different fuel suppliers and blends and noting how smoothly your car runs. Should you find one on which your car runs more smoothly, use that as a preference.

Where do we go from here?

Accepting that the corrosion caused by ethanol blended fuels is well documented, the problems caused by the low boiling point of modern fuels and cyclic variability are related. Cyclic variability leads to more heat being generated in the cylinder head and exhaust which raises under bonnet temperatures which in turn make the problem of vaporisation of the low boiling point components of modern fuel worse.

Slight differences in tuning, use of different brands of fuel, etc. can reduce cyclic variability, under bonnet temperatures and the impact of the low boiling point components in the fuel. This is probably why the symptoms of the problems, such as the Hot Restart problem, can vary between seemingly identical cars.

Initial tests with my TC using the findings of the Manchester tests are encouraging. Further articles will be published covering the Manchester tests in more detail, reporting on the findings and suggesting ways to make classic cars run better on modern petrol. Watch this magazine!

Paul Ireland

Ed’s note: Quite fascinating to know what is going on under the bonnet (hood) of your XPAG!

A personal profile of Paul, who has made those wonderful videos of the three most recent TTT 2 Tours, follows.

Paul Ireland – Personal Profile

Paul was born in the early 1950s and bought his first car, a 1949 MG TC for £60 in 1967. With the help of his father, the body was removed and suspension, wheels, steering and brakes refurbished and he rewired it with a home-made loom. New wood in the sills and a brush coat of paint made the car roadworthy. With no money to rebuild the engine, Paul rattled and burned oil around Manchester University in his TC.

In the early 1970s student cars were a rarity and owning a classic MG, no matter what condition, was a real status symbol.

With a PhD in experimental Nuclear Physics, Paul is the ‘black sheep’ of the family, both grandfathers, his father and two sons are proper engineers. However, this experience has allowed him to take a more academic approach to the problems he has faced running his TC on modern fuel and enabled him to gain a better understanding of the problems for the benefit of all.

After his chassis up restoration in 2003, Paul has shown his TC and used it for tours and longer trips, and for testing different fuel mixes.

Before and after ‘shots’ of Paul’s TC. The ‘shot’ below was taken at the Passo del Bernina, a high mountain pass in the Bernina range of The Alps in Italy.

Above: Note the load carrying capacity of Paul’s luggage racks. He still has a couple available at 315 GBP plus P&P. Paul(at)Ireland-family.orgplease substitute @ for (at).

XPAG Overheat – an unexpected but common cause

3 Jan

Engine overheat is a common problem within our T-series cars. It has been discussed on many forums and there is a logical decision tree to go through to help trouble shoot. However, it is not uncommon for the problem to remain after exhausting the list of common sense things to check. First, let us review the obvious and then reveal the not so obvious solution.

Radiator – Flush your radiator and block periodically. If you have your radiator off, you can check if your radiator is plugged by filling with a garden hose and see if the flow in from the top is equal to the flow out at the bottom. If blocked, have it rodded out by a professional. Proper cooling fluid is mandatory and the additive “Water Wetter” may also help.

Water Pump – Understand that the water pump pulls cooler water from the bottom of the radiator and forces it into the block to circulate and cool the block and head. Then the hotter water exits the head through the front water outlet, up through the thermostat, and on into the top of the radiator to recycle and cool down through the radiator to repeat the flow. If pump is bad there will be no flow, but this is not the common problem.

Thermostat – The thermostat is closed at start so the engine can warm up to operating temp. While it is closed, no water goes to the radiator top tank. Instead the water coming out of the head returns to the engine block via the bypass hose and into branch pipe to the water pump and then block. This cycle continues until the engine is warm and then thermostat opens allowing hot water to go to the radiator top tank to cool. There are 2 scenarios involving the thermostat to be the problem. First, it could be plugged or frozen. If so, water will never get to the radiator and over heat will occur. Second, overheat could be caused by the bypass port being full open and thus the water is bypassing the radiator. The outlet on the side of the thermostat housing should be partially blocked, which will deny full flow of water to bypass cooling and return to the block even with the thermostat open. Original thermostat housings automatically blocked this port when thermostat opened. Modern replacements have this port partially blocked for same purpose.

Fan blades – Fan blades can be installed incorrectly. Install originals with the rear blade having the offset holes and the reinforcements facing forward. A common change for more cooling is to install the 7-blade fan from the MGB. This will give more air flow and may help. However, if you have an overheat problem you should find the source of the problem and not mask the problem.

Block – Engines that have been stored for a long period tend to be full of corrosion. You may be able to chemical flush the block while in the car but the best way is to clean during engine rebuild.

Carbs – If the carbs are adjusted too lean this will cause the engine to run hotter. Making them a little richer will help your engine to run cooler. However, check your plugs first. If they are dark with carbon, your carbs are already on the rich side and the carbs are not the cause of overheat.

So, the above are all the commons things to check. While these topics are all common sense there is often a root cause that is not on the list – the distributor.

Distributor – Engine timing can greatly affect the operating temp of the engine and a worn distributor can have a serious impact. The engine is normally timed at idle at 0 degrees TDC. However, with modern fuels you should set the timing on the advanced side.

But what happens with a worn distributor at high rpm? If the shaft and bushing have end play the dizzy gear will ride to a higher contact point on the cam gear. This retards your timing at high speed and can cause over heat. Your advance weights and springs can also be the culprit and add to the problem. There is a simple check you can do for your dizzy. Remove the cap and rotor and pull on the rotor shaft to see if you have any end play (up & down movement). If you do, have your dizzy rebuilt or replaced. Although this is the last item in this article, consider this one of the first things to check. The dizzy’s are 60+ years old and are tired and need attention.

FTFU will be glad to assist trouble shooting your over heat issue. We also offer every one of the above discussed items to include rebuilt distributors. Don’t run it hot, stay cool.

Doug Pelton

480-588-8185 www.FromTheFrameUp.com


TC7045 – An 18-year Restoration

2 Jan

Readers of TTT 2 who were ‘subscribers’ back in the early days of the magazine will recall a series of amusing articles from Chris Oswald, describing the trials and tribulations of the restoration of his TC ‘Busker’. Chris has now completed the restoration and has sent me a ‘comic strip’ article which catalogues the task from start to finish. Whether or not you are embarking on a restoration it makes for interesting reading…..

This was taken in USA with Frank L. Barrett before being re-imported in 1990.

Back in ‘Blighty’ on the day of arrival in 1991.

Having fun in 1992, but the body was already showing signs of instability!

Then in 1993 lots of gremlins struck at once…. and the full horror story began to be revealed.

Woodwork above the rear axle – missing parts or eaten away by termites.

More rot……….

Bodged repairs……..

More rot……get the message?

Body panels surface rusty, but sound thanks to the California weather.

I suppose it’s one way to repair a wooden body frame……

..but, by now, I was on a mission

And things are beginning to look a bit sparse.

……but it’s too late to stop now!

Off to get the chassis straightened and some welding done……

at last I can think about putting it back together; body panels wait on top of the frame to save space and….

…….have to wait for the ash frame – I made as much as I could myself and bought in the complex compound curved parts.

Diff frame with all four new wood pieces now – (compare with ‘shot’ taken on dismantling). Rear axle rebuilt to stop leakage into the rear brakes.


Body panels back from chemical strip and first fit – beginning to look like a car.

Daylight for the first time in many years.

How I discovered the original colour – patient rubbing down with wet-or-dry.

So back to red it goes…to my secret delight


Must contain excitement – lovely ‘paintman’ Tom in background who allowed me the use of his paintshop at weekends so I had space for the careful reassembly of the panels

Nearly ready to come home…………

Lookin’ good but still a long way to go – so back into the gloom of the garage……

Now, this needs fixing!

On left – original panel all chrome as done by Hollywood sports, Studio City, California – on right, after some work.

Above: Winter job – dash harness. Below: And refinishing the front – 16 coats of varnish endlessly rubbed down and repeated.

Meanwhile, down in the garage… bit better than how it started.

Quick, join them all up before the smoke leaks out!

Only kidding – they all worked, including the indicator light hidden in the sidelight fairing …but, oh, that radiator. New paint shows it up.

Aah, £600 lighter but that’s better – beautiful chrome and upholstery colour slats – also, note correct fog lamp now.


Now, while you were concentrating on the body, there was also the mechanics…., leaking diff, seized shock absorbers, wobbly fan, oil and grease everywhere………..

Poorly located front axle – no not quite as bad as seen here but, as evidence, the cage bolts.

Just….. mess and crud everywhere. Hours of stripping, cleaning, examination and either refurb or replacement….and a leaking block…..

Space management was a bit of a challenge at times. Dexion framing came in very useful – chassis below, body above, axles in front. Engine was parked to one side on its own frame awaiting restoration as I worked on the chassis.

Front axle now secure, with straight cage bolts.

Springs separated, cleaned and in place – new brake shoes to go on – new brake pipes in place – seized shock absorbers rebuilt.

Pedal assembly, Master cylinder and brake switch looking a lot cleaner now.

Master and slave cylinders lined with stainless steel to avoid corrosion. Silicone fluid inside. Extended securing nut improvement.

Original engine and gearbox overhauled, lead free head, MGB 7 bladed plastic fan fitted – less noise and vibration – waterless coolant.

No more rusty manifold, but deeply unpopular with wife over fumes from UHT paint in oven.

No, I don’t want the dog poo brown plastic upholstery it came with, or black wheels and the wing mirrors were useless so…rebuilt and painted silver wheels if you please – and a new set of rubber. The old luggage rack polished up nicely and the modern motor bike indicators fit in with the look.

The original upholstery was red – Dilemma – I don’t like it. Well, beige was a factory option with red body so that’s how I’ll go.

Once the covers were taken off…. more rot in the seat frames and 68 years’ worth of YUK.

Bits of old carpet to dampen the springs and frame held in place with hardened old leather strips.

New back board needed……… and seat bases.

New made, old used. New cushion and cover, new hessian in place.

New leather seat covers, frame refurbed.

New back and leather cover and the interior goes in to match.

Will the dog fit in that space, I wonder…? ….. I can’t wait to fit into this one – note original export steering wheel.

Oh, my goodness………. it’s actually going to be ready soon!

Still in the garage, like a butterfly inside the chrysalis…..until……

The Editor

1 Jan

Welcome to the first issue of 2017!

What a momentous (tumultuous/tempestuous?) year that has just passed – perhaps the less said the better – just keep tinkering with/fettling/driving our T-Types and enjoy them while we can.

January is the month when we get down to detailed planning for the 2017 TTT 2 Tour and I know that Peter and Vanessa Cole will be visiting the Chichester Park Hotel soon to firm up our booking arrangements.

They will then be thinking about mapping some routes through the lanes of West Sussex and Hampshire.

If you haven’t yet booked the dates are 18th to 21st August. The hotel website is http://www.chichesterparkhotel.com and the telephone number of the hotel is 01243 817434.

Booking reference is GA000367. The hotel will ask for your credit card details to confirm the booking, but nothing will be deducted until your arrival. An acknowledgement of booking will be e-mailed which includes the hotel’s cancellation policy.

The rate for the weekend is £370 per room based on 2 guests sharing, to include dinner, bed & breakfast. For those not staying on the Sunday night the equivalent rate is £270.

Single Occupancy rooms will incur a supplement of £25.00 per night.

When you have booked, Peter would appreciate an e-mail advice from you to let him know that you have done so. Peter’s e-mail address is as follows: pcoleuk(at)gmail.com {substitute @ for (at)}.

We have decided to set the entry fee this year at £45 per car with two occupants or £35 for entrants without a passenger. The entry fee covers the cost of road books for the Saturday and Sunday runs, the rally plate, entry to any of the attractions we will visit, wine reception on the Friday evening, and wine provided on the tables for the Saturday night gala dinner.

To lighten Peter’s workload, I’d be grateful if those of you who have already booked could e-mail him requesting an entry form; he can then ‘piggy back’ on your e-mail and send you the necessary.

For those yet to book, Peter will send you an entry form when he receives your advice of booking.

I have just booked for the 2018 TTT 2 Tour which is being held in the Cotswolds from 17th to 20th August and is based on the Wyck Hill House Hotel & Spa, Stow-on-the-Wold, Gloucestershire.

Don’t forget the Carole Nash International MG & Triumph Spares Day at Stoneleigh on Sunday 19th February. As usual we will be in Hall 1 on a shared stand with ‘TA Brian’. Peter Cole will be joining us on the stand.

Another date to note is the MG Octagon Car Club’s ‘Founder’s Weekend’ which is being held over the weekend of 19th to 22nd May and is based at the Petwood Hotel, Woodhall Spa, Lincolnshire. Organiser, Brian Rainbow tells me that his allocation of rooms is almost used up, but there are still a couple of vacancies. Full details were given in the last issue.

Dr Christian Bianco is organising another of his MGs in the Dolomites events https://mg-dolomites.jimdo.com/mg-meetings. The event takes place from 14th to 19th June and the application deadline is 8th February. A UK contact is Gary McCarroll Tel: 01604 404939.

I reported in the last issue that we have now got our incorporation through as THE MG ‘T’ SOCIETY LIMITED. Since then we have now come through unscathed from the tortuous rigmarole of setting up a Treasurer’s Account with TSB Bank, albeit, at the time of writing, we are still awaiting bank cards and paying in/cheque books.

Now that we are registered with Companies House under Company number 10411553 we have to observe rules governing companies under The Companies Act. Apart from filing accounts with both Companies House and Revenue and Customs, we also need to keep better records of members and their postal addresses. Our existing records are not acceptable so we have to start afresh. In particular we have to ask members to agree to act as guarantors and give an undertaking to contribute £1 (1 GBP) in the event of the winding up of the company.

This means that we must wipe the existing facility from the website, including the registration process to receive an e-mail whenever a new issue of TTT 2 is uploaded to the site. This will be done as soon as this issue is launched. In future, only members will receive this e-mail, but of course, you will still be able to access TTT 2 on the website if you have not joined as a member.

To join now as a member of THE MG ‘T’ SOCIETY LIMITED please go to http://ttypes.org/ttt2/join – there is no cost to be a member and it only takes a couple of minutes. On receipt we will process your application and confirm your membership.