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Back Cover Photos

8 Mar

Above: TD0778 belonging to Chris Sassella, which won the TD class at the MGCC Victoria concours at Mornington on 22nd February. The TD next along is TD12309 and is owned by Bill Collett.

Below: BJM 803 (Chassis no. HDC16/5512). A nice unmolested TF which still has its original engine (XPAG/TF/35070) having covered 195,000 plus miles. It’s been in the same family since 1960.

Tools for sale

8 Mar

Dennis Barker, a former Chairman of the T Register, has the following measuring instruments for sale: (All items plus postage at cost)

Moore and Wright Internal Micrometer set

Moore & Wright internal Mic. set, to measure bores from 2″ – 12″, comprises 10 rods, 1/2″ distance piece and 8″ extension handle very little use very good condition as new. Buck & Hickman new price c.130 GBP. Asking price 60 GBP or sensible offer.

Lufkin (USA) 3” – 4” Micrometer with Tunsten Anvils

Lufkin (USA) 3″ – 4″ mic with Tungsten Anvils used but in v. good condition – B&H new price c. 70 GBP Asking price 35 GBP or sensible offer.

Moore & Wright Depth Micrometer 0″ – 3″

Moore & Wright Depth Mic. 0″ – 3″ new condition, little used. B&H new price c 102 GBP; Asking price 50 GBP or sensible offer.

Moore & Wright small internal micrometer

Moore & Wright small Internal Mic. 1″- 2″ with 0.25″ & 0.625″ distance pieces together with 3″ handle. Very good condition little used. B&H new price c 85 GBP; Asking price – 40 GBP o.n.o.

Etalon – Proch Rolle Swiss Vernier, 0″ – 10″ scale 0-25 1/1000. inch or 0-250 mm.

Good condition little used in wooden case. The 0-1″ micrometer was never in the set. This precision instrument is a delight to handle and I preferred it to the digitalised instruments when absolute accuracy is required; Asking price 25 GBP o.n.o.

Dennis is downsizing his spares and tools and would like these items to go to a good home where they will be cherished as he has done since they were bought for him as a present by his late father when he completed his apprenticeship in the 1950s. E-mail dnb1932(at)btinternet.com {please substitute @ for (at)}.

MG TD / TF Remote brake reservoir kit

7 Mar

There have been a couple of articles previously published in TTT 2 showing very nicely how this can be done so it is not really new ground. The author is not trying to re-invent the wheel but thought that some owners would welcome something like this in a high quality kit form.

The workshop manual (WSM) stipulates that the brake fluid level should be checked and replenished every 1000miles/1600km. Access to the filler cap on the M/C is not user friendly due to the M/C mounting arrangement which entails crawling into the body tub. Not everybody has the ideal figure to want to do this on a regular basis. A remote brake fluid reservoir is a sensible worthwhile modification which allows daily inspection of the car’s brake fluid level simply by raising the side of the bonnet (hood).

The brake reservoir kit does not connect into the actual hydraulic lines; it connects into the integrated master cylinder (M/C) reservoir through the blanking plug at the rear. This reservoir then feeds the hydraulic lines.

The remote reservoir is essentially an extension of the volume of fluid available for the hydraulics and has nothing to do with the actual braking system as such. This will obviously work only on master cylinders which are factory fitted with a 1” blanking plug at the rear of the cylinder (as are all replacement Lockheed style cylinders on the market e.g. MOSS Part#180-730). The filler cap 1 1/4” has to be replaced with the non-vented type and non-vented caps are available or the vent in the existing cap can be blocked off. *The master cylinder in Fig 1 is not part of the kit but for illustration purposes only. Check to see if your M/C has a rear blanking plug before ordering this kit.

Fig 1- Basic Kit contents*

An 8mm rubber cushioned P-clip is included in the kit to fix the flexible dash 4 braided stainless braided Teflon hose to the bolt on the pedal box side cover. The mount for the battery clamp hook J-bolt is also included. It may be require to add a bracket to the clamp hook if the threads are not long enough to fit the reservoir mount supplied.


Fig 2 – Connection to master cylinder.


Fig 3 – Reservoir mounted on battery bar clamp hook (J bolt).

The kit may be installed without removing the master cylinder completely. It will be necessary to drain off some brake fluid to below the level of the blanking plug. The better option is to remove the M/C and replace the fluid as it is hydroscopic and should be changed at two yearly intervals as a matter of course.

There is not much clearance between the blanking plug banjo bolt and the cross member and it is advisable to remove the two M/C securing bolt and tilt the M/C to fit the banjo.

The blanking plug provided is a re-furbished second hand part which is tapped in the lathe to suit the banjo bolt and is supplied with a new 26x31x2mm copper sealing washer. If you want to retain your original blanking plug and tap it yourself feel free to do so but it must be done accurately to prevent sealing problems. This is not a job for hand drilling. I can offer an exchange service if required.

The reservoir should be mounted on the same side of the car as the M/C which differs from LHD to RHD. After installation, re-check for leaks at regular intervals.

In case of any problems please contact me at the address below.

Declan Burns
Liedberger Weg 6A
40547 Düsseldorf
Tel +49 211 371529 after 5pm.
Email : declan_burns@web.de
Note: declan underscore burns at web dot de

Ed’s note: Declan has drawn up a draft catalogue of his modifications which readers may have via email if they wish to contact him. He updates this every now and again when he has better photos or comes up with new ideas. Details of most of the items have already appeared in TTT 2, but there are a couple still to appear and they will be included in the June issue.

Harry Lester, His Cars & The Monkey Stable

6 Mar

Reproduced below is the front and back cover of a new book which is currently being printed and will be available in late April/early May priced at 25 GBP. The paragraphs on the back cover are reproduced here as they encapsulate the essence of the book.

“Garage owner and expert tuner of MG cars, Harry Lester was one of the more successful sports car competitors in the late 1940s and early 1950s. In 1949 he designed and built his own car, with a rigid tubular chassis, lightweight aluminium body and utilising the favoured engine of many club racers of the time, the XPAG unit from the MG TC.

So successful was the car in his hands that a trio of wealthy young amateur racers decided to form a team and commissioned him to build them a car each, plus a spare. They called themselves “The Monkey Stable” and enjoyed much success in their first year, 1952, a highlight being winning the team prize at the first 9 hours race at Goodwood.

In subsequent years their fortunes changed, as did their cars, going to Kieft MGs in 1953, then back to Lesters in 1955. In the interim, the Monkey Stable drivers twice drove for the Bristol team at Le Mans and one of their number, Pat Griffith, briefly became a works driver for Aston Martin, partnering Peter Collins in a number of long-distance events.

It all ended in tragedy, however, when team founder Jim Mayers was killed at Dundrod in the 1955 TT race, only weeks after another team member, Mike Keen, had crashed fatally at Goodwood.

Never before published in its entirety, this is the story of Harry Lester and his cars, together with the exploits of the Monkey Stable during their brief but significant racing career.

The story is told by Stewart Penfound, MG enthusiast and owner of one of the last Lester MGs made. Containing much previously unseen material from both Harry Lester’s and The Monkey Stable’s archives it is a story as much about the characters as the cars and is a significant addition to the record of motor racing immediately after the end of the Second World war.”

I suggested to Stewart that TTT 2 readers might like to learn how he came to write his book a sort of “a story of the story” if you like!

Over to Stewart…

“It has often been said that everyone has a book in them, and this is the tale of how mine came to be written. When I bought my Lester MG back in 1993 I didn’t really know what it was, or even who had made it, so, like most people who acquire a slightly unusual car, I tried to find out a bit more about it, and whether there were any more examples around. Well I did, and there were, and twenty two years later, and after a certain amount of prodding and cajoling from other Lester owners, I’m about to publish the result.

Firstly, though, I must go back to the mid 1970s, to when I dismantled my TA with the intention of restoring it as a T racer. With a couple of friends, I did a fair bit of flag marshalling, mainly at MGCC and historic race meetings. To us, the highlights of the MG meetings were always the T races, and as I had a car, why not have a go myself? That didn’t happen, and a number of years went by without any progress on the car. I kept up the marshalling, however, and got to know some of the drivers well, with the result that, when Malcolm Hogg retired as T Register Competition Secretary, I took over his role, as much to become more involved as to get off my backside and do something about that dormant dream to become a racing driver.

This was in the late 1980s, and it was around this time that Andrea Green joined the T Register committee and set up the Specials Register. Such cars were virtually unknown to the world at large back then, and this was when I first heard of a car called a Lester MG. A little while later one came up for sale by Ron Gammons. Here was an opportunity, I told myself, to acquire a car ready to compete in and with the bonus that the TA could be restored to use on the road. The Lester turned out to be the car that I had helped push over the line at Wiscombe when it had stuttered to a halt by our marshall’s post a year or two previously. I hadn’t taken much notice of it then, not knowing what it was.


Stewart Penfound driving his Lester MG at Prescott (photo by Derek Hibbert).

It didn’t turn out to be as ready to go as first thought, and I spent the next five years restoring it, treating it to a new aluminium body in the process, and converting it to wire wheels and all the while finding out more and more about Lester MGs and the man who made them, Harry Lester.

Specials in general were beginning to get more recognition, and just before the car was finished I displayed it in the MGCC tent at the 1997 Coy’s historic meeting at Silverstone along with two others, Chris Pamplin’s Dargue MG and Keith Hodder’s Parson MG. It was here that I got to know Mike Cross, who was restoring one of the two surviving Monkey Stable cars and as a result he, Chris and I shared what information we had on Lester cars and have done ever since.


One of the two surviving Monkey Stable cars – owner, Mike Cross.


The Monkey Stable cars lined up before the start of the Goodwood 1952 9 hours race, Jim Mayers’ car in front. Harry Lester is in the trilby hat, standing at the nearside of car number 33 but partially hidden from view.

The Monkey Stable’s team of three Lester MGs had won the team prize at the first Goodwood 9 hours race back in 1952, so, when Lord March announced that his inaugural Goodwood Revival Meeting (in 1998) would be having a race for cars that would have been eligible for the 9 hours race I cheekily contacted the organiser and said I had a car that was of the same type as the Monkey Stable cars and what’s more, had a couple of mates who had similar cars and would also like to join in.

To my surprise and delight, he said he had seen the cars on display, and were just what he was looking for. The Parson couldn’t make it, so we got George Cooper’s Cooper MG to come instead. So, in my first year of racing I found myself at Goodwood, out on the track with C type Jaguars, Aston Martins, Frazer Nashes etc. Scary stuff, but an experience I’ll never forget!

It was at this meeting, in September 1998, that I met two people whose knowledge and enthusiasm for all things Lester culminated in me writing it all down. They were Roy Jacobson and Dick Duncan, both Americans, both Lester owners and who both came over especially to see a Lester racing again at Goodwood.

Roy had owned one of the Monkey Stable cars for years and had done an immense amount of research into their competition history, as well as tracking down surviving Lester cars. Dick owned the only Coventry-Climax engined Lester and had done his own research, to the extent of tracking down and interviewing surviving members of The Monkey Stable. Roy subsequently sold his car and has disappeared from the scene, but five years ago Dick and his wife, Carolyn, came over for a visit, bringing his interview tapes and other material with him.

Over the course of a very convivial few days, I found myself agreeing to write it all up, naively thinking it would only take about 12 months. It soon became apparent that there were two stories to be told; one about Harry Lester and his cars, and one about The Monkey Stable, who went from Lesters to Kiefts and back to Lesters, whilst also driving for Bristols at Le Mans. It all ended in tragedy for them when in 1955 team founder Jim Mayers was killed racing a Cooper at the Dundrod TT, just after fellow Monkey Stable driver Mike Keen had lost his life at Goodwood, also whilst driving a Cooper.

More and more facts about Harry Lester, Jim Mayers and The Monkey Stable came my way over the ensuing five years. I was put in touch with and interviewed Peter Musitano, who knew Harry Lester well in his later years. I was also privileged to be given access to Harry Lester’s surviving personal archive, which revealed much new material.

Mike Cross had acquired Roy Jacobson’s car and with it came correspondence between Jim Mayers and the car’s first American owner, Bill Lloyd. Dick Duncan had also given me a personal account by Monkey Stable driver Trevor Line, who witnessed the disaster at Le Mans in 1955 when Pierre Levegh’s Mercedes was launched into the crowd, killing 80 spectators. Trevor was in the pits, getting ready to take over his Bristol from Mike Keen and saw it all…

Quite a few articles have appeared over the years about Harry Lester and The Monkey Stable, but to my knowledge the complete story has never before been told in its entirety. It is a story not only about the people and the cars, but about a period and aspect of motor racing when a struggling garage proprietor could produce a car that caused heads to turn and enthusiastic young amateurs could compete at the highest level. It has been a fascinating exercise, made ever more enjoyable by the people you meet on the way.”

Stewart Penfound


The Lester MG badge and the Monkey Stable logo.


Harry Lester competing in TA KJH 114 at a VSCC sprint at Silverstone, in April 1949. This later became Jim Mayers’ car, fitted with the lightweight Lester body from George Philips’ TC.


Jim Mayers competing at Boreham, 21st June 1952.

Ed’s note: Thank you Stewart for a most interesting article. The book will be available from the T-Shop as soon as it is published and I understand that Stewart will be taking several copies to MGCC Silverstone in June.

The book certainly deserves support.

Bits and Pieces

5 Mar

Broken Fan Belt Pulley

Derry Dickson has e-mailed with details of a recent ‘happening’ as he was motoring along a dual carriageway at 65 mph in his TC. A fairly loud sharp clank was heard and Derry thought that he had run over something, but as all seemed to be working, he kept on motoring – as one does! It was only after he had embarked on his winter servicing schedule that he noticed that the fan belt was slack – the reason was as per the photos below. A classic example of metal fatigue.

Derry cautions against over-stretching the fan belt, suggesting tensioning the belt to allow for a 1/2 inch “give” between the water pump pulley and the dynamo.

Rebuilding a Windscreen Wiper Motor – a note of caution

Russell Dade has recently rebuilt a windscreen wiper motor and used Jonathan Goddard’s article as guide, which he found most useful and excellent.

As he had two decrepit motors he made up one good one with the addition of an armature from Paul Beck. However one detail cropped up that Russell thinks would be useful for any wiper motor repairer and that is that the brush holders are not necessarily interchangeable. It would appear that the legs on the brass type are ½” deep and on the steel type 5/8” deep, as the following photos demonstrate.

If the incorrect brush holder is fitted then the brushes will not align with the commutator of the armature and could damage the windings, a costly mistake if one has just purchased an armature from Paul Beck.

On the question of brushes for the CW1/CWX wiper motors, Russell has recently purchased some from www.solenttools.co.uk They are slightly oversize but easy to correct.

Their stock No: 2297-214 correct carbon content for 12volt dc motors.

Another company mentioned by Jonathan Welch is Anglo Carbon
http://www.anglocarbon.com/acatalog/automotive.htm

Anglo Carbon stock the correct bushes but according to Jonathan they weren’t much longer than his worn ones. However the company said that they could make them longer if required.

Recommended Suppliers

Nick Abbott has come up with a couple of suppliers who have given him good service so I have added them to the suppliers’ list on the website. Details are as follows:

For chrome plating SH METAL FINISHING at No. 2, Albert Street Works, Albert Street, Droylsden, MANCHESTER M43 7BA. The proprietor is Mr Len Hughes Tel: 0161 371 1876 or mobile 07944 085203 or e-mail: leonardhughes123(at)btinternet.com {substitute @ for (at)}.

Nick speaks highly of his work, particularly for radiator surrounds, and he is quicker than most.

For powder coating ASHTON POWDER COATING LTD at First Floor Oxford Mill, Oxford Street East, ASHTON-UNDER-LYNE OL7 0NE www.ashtonpowdercoating.co.uk

Nick says that this company is particularly good at wire wheels and very good on price. Tel: 0161 344 5186 or mobile 07786 980 904. E-mail addresses are given on their website.

XPAG Engine for sale

Ron Ward is building the following specification XPAG engine for outright sale. 1380 cc (i.e. +140). New three ring solid skirt pistons, Allen caphead pinch bolts, crank no. 168557 (see TCs Forever page 129) at .020/020 (crack tested), new shells, lightened flywheel, 8” clutch, all balanced. Lip seals front and rear (using Speedi Sleeve) new billet steel fast road camshaft, vernier timing sprocket set at 109 degrees, new bearings, oil grooved cam followers, combined horizontal oil pump/filter. Cylinder head stage II, unleaded, large vaklve, Metro stem seals, bronze guides ported by (Edney/XPAG Eng.) Engine can be supplied with either TC or TD/F/Y type front engine mounting plate. Contact Ron at 01422 823649 (or for e-mail address, please contact the Editor via the TTT 2 contact form).

Woolies (Trim, Upholstery and Fittings for Vintage and Classic Cars)

Woolies, founded by Ian and Caroline Woolstenholmes 39 years ago, stock a useful range of items, as you will see from their website. www.woolies-trim.co.uk I recently ordered some upholstery screws from them and probably due to my own fault (wife says I mumble) I only received one packet of one of the items, when I thought I had ordered two. Phoned them straight away and was amazed by their ‘no quibble’ response and they wouldn’t even think of taking up my offer to pay the excess postage. That’s what I call service!

Repair of Clocks

The services of David Ward were mentioned in Issue 24 (June 2014). David’s offer was as follows: “If any of your members are interested I would be willing to see if I can repair their clocks. A very small fee would cover my expenses”. David can be contacted by e-mail at:
warddavidc(at)virginmedia.com Please substitute @ for (at).

David has contacted me recently to say that he can do nothing with some of the clocks he receives for repair due to unavailability of spare parts. He suggests that in these cases (with the owner’s permission) he removes the innards, as some parts may still be useful, and returns the clock minus the innards. This would enable him to build up a stock of parts, which should result in more clocks being capable of being repaired. A sort of “borrowing from Peter to pay Paul” if you like!

The following has been received from Dick Knudson of The New England T Register:

The Cecil Kimber Society

The Board of Directors of The New England MG T Register approved the formation of The Cecil Kimber Society at its January 25th meeting in Hartford, Connecticut. The Society’s purpose is to foster networking amongst those enthusiasts genuinely interested in M.G. history. Fellows in the Society will share their research interests in order to receive and exchange information freely.

Still in the planning stages, suggestions for further action ranged from forming an internet website, forum, and a regular page in The Sacred Octagon, the journal of The New England MG T Register. Further discussion and planning will be the focus of one of the sessions at the annual Kimber Festival organised by the Register. This year the Kimber Festival is being held at the Northeast Classic Car Museum in Norwich, New York from April 10-12.

The Sacred Octagon will publish completed research papers. These papers may also be approved for Kimber Festival presentations as well as for seminars at future Gatherings of the Faithful, the Register’s two regular annual meetings.

There are no dues. The requirements for becoming a Fellow of the Society are three-fold: an active interest in M.G. history, a willingness to share one’s knowledge, and to assist others in their research. A first step would be to email Dick Knudson at FC7900(at)gmail.com {substitute @ for (at)} with your name and your specific research interests.

Murphy’s Law

The few paragraphs on ‘Murphy’s Law’ in the previous issue raised a few chuckles. Comment was also received from Jeffrey Jennings who suggested that Murphy was an optimist and he prefers to use ‘Paddy’s Law’!

Lost and Found

4 Mar

A bumper crop for this issue!

First off the blocks is TC2277, Registration mark SX 5836. An early 1947 TC, registered in West Lothian on 3rd March, 1947. The current owner, David Whiteley david(at)whiteley0.plus.com {substitute @ for (at)} bought the car in 2012 from a Mr Maguire in Chepstow. She had one owner (according to DVLA) until 2006 when she was bought by Mr Maguire for restoration but, as occasionally happens he never got around to it and needed the space for other projects.

The previous owner was a Mr M.O. Bass who subsequently resided in Clock House Lane, Bramley, nr. GUILDFORD and sold the car on 1st May 2006. The original colour is thought to have been green.

The car is unusual in that it has a neatly installed strengthening hoop aft of the firewall, not unlike that found on a TD.

David would be pleased to hear from anybody who might have known of the car, or of Mr Bass.

The next car is TC3591 (HTF 933), an ex-Lancashire police car, now in the US. It was brought to the US in 1969 or 1970. It was always registered in the Lancashire area after it was released from police duty in 1955. When the car was in England it would have been white.  The odd thing is, it arrived in the USA with a trailer hitch.

If anybody has any information on the past history of HTF 933 Floyd Lancaster would love to know coyote_70(at)hotmail.com {substitute @ for (at)} and please note that it is coyote (underscore) 70 @ …

Malcolm Llewellyn is enquiring about his old 1947 TC HTD 303 (TC2765). Yet another ex-Lancashire police car, there is currently no trace of it. Hopefully it has not suffered the same fate as HTD 302 (TC2764) which is recorded as scrapped.

Malcolm recalls the following:

I used to weekend at Mayfield in Sussex and passed xxx motors on my 1937 350 cc Triumph every time. So saw this black MG. One day my uncle drove me over in his Mini and we called in and bought the MG in the window for £235 with two new tyres. This would have been in 1961.
               
I sold it to Hollands garage in Winchester in 1963 I guess and moved on to Ford saloons. Sadly I am not mechanically minded so was unable to maintain it like my brother can and does.

Malcolm can be contacted at marl(at)numada.com {substitute @ for (at)}

Colin Newby is enquiring about JOK 783, a late TC which he owned in the 60s. He says that the DVLA website shows it as licensed so would love to chat with the current owner and fill in some gaps in its history. The enquiry came via our Facebook page and I don’t have Colin’s contact details to hand but I’m sure we can get in touch. In the meantime perhaps any ‘leads’ could be passed to the Editor via the TTT 2 contact form.

Back in 1970 Harold Jacobs bought TC3506 from Anglo American Automobiles located at the Cedar Lodge, The White House, in Woodford Green, Essex. The registration mark was JC 8748. He is currently engaged in a frame up restoration and would like to trace the car’s history and where it was first registered. He can be contacted at geokir2(at)whidbey.com {substitute @ for (at)}

Ed’s note: JC was issued by Caernarvonshire and I have passed this information on to Harold along with the details of who to contact for any old Caernarvonshire records which might exist (it seems that quite a few do).

Another one from our Facebook page as follows: “Many years ago I owned a TA 1939, registration mark DTF 654 fitted with TC engine and gearbox. 50 years later I would wish to locate the TA, which I last saw in the 1970s in Redditch, Worcestershire UK. Any information please contact: https://www.facebook.com/martin.endsor “

Ed’s note: DTF 654 is/was TA3076 an ex-Lancashire police car. Hopefully it has survived.

Now for some information regarding TC4440 (HON 530). Here’s a scan of the original sales receipt.

It’s wonderful to have this and if the car has survived (it has not to my knowledge surfaced anywhere, but might have left the UK) I would be pleased to pass this on.

Also within a month of taking delivery of the TC it went back to the garage that supplied it to have a radio fitted. I also have the receipt for this but have not scanned it in to save space. However, the details were as follows:

For those who would like to check the addition, remember that there were 12 pence (d) to the shilling (s) and 20 shillings to the pound (£). I must admit that I struggled – but then, decimalisation was introduced in the UK 44 years ago!

Alas, after just over 16 months from taking delivery of the new TC it was sold on 29th August 1949 to the Solihull Motor Company, High Street, SOLIHULL (West Midlands) for £561 pounds and 10 shillings. £560 was paid by cheque and £1.10s.0d was paid in cash. I have the sales receipt.

Just a further bit of information on TC4440 (registration mark HON 530), the original body colour was red (Regency Red). This was indicated on the sales receipt from the Solihull Motor Company.

Sounds Sweet!

3 Mar

Introduction

Go to any ‘natter’ and you are likely to find a group of enthusiasts standing around a car listening to the engine and making comments such as “that engine sounds really sweet”, or “sounds as though it’s running a bit rough”. Considering the cacophony of noises made by an engine, especially earlier ones such as the XPAG, it is quite amazing people are able to distinguish these subtle differences in sounds to make comments such as this.

This came to me very forcibly when I took my TC to a rolling road to test the effect of using a petrol / kerosene mixture. I went prepared with a separate supply tank to bolt onto the fuel pump so we could change the mixture very quickly and pre-mixed bottles of petrol and kerosene. The first test was using “pure” petrol. The car was run up to 3,000 rpm and the mixture and timing checked. We then swapped to 5 parts petrol to 1 part kerosene, ran the engine up to 3,000 rpm again and that is when the three people present looked at each other in amazement. The engine sounded very much smoother.

Situations like this do not occur very often, specifically, where everything about the engine is the same, yet in the space of the few minutes it took to change the fuel, it sounded as though it was a different engine. Mixture and timing were rechecked and found to be the same as the previous run. The only measureable difference was the reduction in unburned hydrocarbons and NOX confirming that the engine really was running better.

What I still find amazing is that three people were clearly able to hear this improvement. The only possible explanation I can offer is that our ears were able to separate the sound made by the combustion of the fuel from the rest of the rattles, knocks, clicks and bangs.

This made me wonder if it were possible to actually measure this effect.

The human ear is a remarkable organ; it is not only able to hear very subtle differences in sounds but also to pick out those sounds from a very noisy background – something that presents a serious challenge to any measuring equipment. However, modern signal processing techniques may provide the means.

This article describes my investigations which give an indication of the possible value of this technique. Unfortunately, I have very little experience of signal processing and now we have the funding for more tests at Manchester University kindly offered by the MG Car Club, NTG and Totally T Type 2, I would like to include these measurements in the planned tests. I therefore request that anyone who might be able to help me with this contacts me.

Fourier analysis

Before presenting my findings, I apologise that I need to introduce some physics.

Display a picture on your computer and look at it under a powerful magnifying glass. You will see that a pink face is actually made up of thousands of small red, blue and green dots. It is only when you look at it from a distance that these primary colours combine to give the colour pink.

Sounds are very similar. All sounds are made up of a combination of sine waves of different frequencies. Close your lips and make a “hummmm” sound. This will be close to a pure sine wave. Press your tongue against our teeth and make a “zzzzzzzzzzzzz” sound of the same pitch. This will consists of the sine wave like the “hummmmm” sound along with many high frequency components (called harmonics). This is why it sounds harsher.

In practice, like the dots on a photograph, any sound can be broken down into a fundamental (normally referred to as the first harmonic) and a number of higher frequencies. The second harmonic is twice the frequency of the first, the third, three times the frequency, and so on. When added together with different amplitudes and phases, the harmonics change the shape of the sound envelope. For example:

You can see from the graph how the second harmonic changes the shape of the pure sine wave to be more what we would expect the combustion in the engine to look like. A rapid rise as the fuel burns followed by a slow fall as the piston goes through its power stroke. Adding the third harmonic smears the sine wave, something that could indicate an engine’s timing wandering or the fuel not burning consistently.

It is possible to analyse a sound recording to determine the amplitude of the different frequency components that make up that sound. This is called Fourier analysis which can produce a plot showing the amplitude of each of the harmonics that make up that sound. For example:

The graph on the left is probably a close approximation to the combustion pressure profile in the cylinder and has been produced by summing the first five harmonics. The chart on the right shows the relative amplitude of each of the harmonics that were summed to make the graph on the left. If you analyse a sound with the profile on the left into a Fourier analysis system, you will get the chart on the right.

Tests

In theory, it should be possible to reconstruct the pressure profile in a running engine just by recording the sound it makes. While this may sound impossible, the rolling road experience showed the human ear was capable of doing this, so I thought it worth a try. While the preliminary results show such an analysis is possible, more care needs to be taken both with the recording and analysis to produce anything meaningful. Hopefully, this can be achieved during the Manchester tests.

The first problem with making any such recording is the frequency of the first harmonic. For an engine running at 3000rpm this is 50Hz which is a very low frequency for sound and secondly is the same frequency as the mains which means any measurement could be affected by mains hum. In the tests I ran the engine at around 2750 rpm to avoid this problem.

The second problem with the XPAG is that it is a very noisy engine and with mine still using the mechanical distributor, it has poor timing consistency. However, one advantage is that, like the rolling road, I was looking for differences between fuels rather than any absolute measurement so anything that does not change should cancel out.

Armed with a low frequency microphone positioned in the engine bay to the rear of the engine, I started with my modern 2 litre Audi. The main problem here was I could not change fuels without running the tank dry and it was very difficult to maintain a consistent engine revs for the recordings, despite a block of wood under the accelerator.

Fortunately, by performing the Fourier analysis on only 10 seconds of the recording where the revs were consistent, I obtained the following Fourier spectra for two different fuels, A and B. In practice the car ran considerably better and smoother on fuel B:

Encouraged by the results with the Audi, I ran similar tests on the TC:

Some things were a little simpler. Firstly, I blocked up the back wheels and ran the engine in top gear to provide a load; secondly, I was able to fix the revs with the slow running control and finally, I used the small container fixed to fuel pump so I could change fuels more easily. This allowed me to complete the recordings within ½ hour rather over a couple of weeks as with the Audi.

Results

The results for the Audi clearly show differences between the two fuels but also demonstrate the difficulties of making these measurements.

The recording on fuel B was taken at 2800 rpm and that of fuel A at 2600 rpm hence the difference in the frequencies of the harmonics between the two fuels. What is also interesting is that the 3rd harmonics from one cylinder at around 70 Hz indicates a problem. With a four cylinder engine running at 2600 rpm, there are around 44 “bangs / second”. However, each cylinder is only “banging” 22 times per second. With the microphone placed at the rear of the engine (to avoid the noise of the timing belt and alternator), it clearly “heard” one cylinder louder than the others which shows as its 3rd harmonic at ~70 Hz.

Despite these difficulties, differences can clearly be seen between the two fuels. Fuel A has broader peaks showing the timing between each “bang” is changing more than fuel B. While driving the car on fuel A, this appears as rougher running than with fuel B. In addition, the ratio of the 1st and 2nd harmonic peaks is different between the two fuels suggesting the combustion profile is different.

The results for the XPAG are equally interesting.

For each fuel the throttle setting was the same, controlled by the slow running control as is the load resulting from the transmission losses. The fact that the engine was running slower on fuel A, relative to fuel B suggest that perhaps it is producing less power. Certainly the car appears to drive a lot better on fuel B.

Compared to the Audi, the peaks are wider, something that would be expected considering the mechanical timing of the TC vs the electronic timing of the Audi. What is most obvious, however, is the dramatic differences in the relative amplitude of the harmonics between the two fuels which must imply a different combustion profile.
Where do we go from here?

For me, these results appear to offer a tantalising suggestion that it may be possible to electronically measure how “sweet” an engine sounds and this could provide a quantitative measure of what fuel should be used. The next stage is to improve on these results during the repeat engine tests at Manchester.

Perhaps, at last, the possibility of a little box that will tell you how well your engine is running is around the corner. However, I do not think it would ever replace the enthusiast’s comments such as “that sounds really sweet”, or “sounds as though it’s running a bit rough”.

© Paul Ireland
January 2015

MG TC Stub Axles

2 Mar

Well documented problems with the TC front axles include cracking at the root radius with the upright. In addition to visible signs of cracking, the axles on my TC, undergoing a total restoration, were very badly worn.

I have read several articles about fitting new axles to existing stub axles and acquired a pair of new axles via John James (which came across ‘the pond’ from Bob Grunau – Ed).

I entrusted a local machinist, recommended by a work colleague, to remove the old axles (the ‘pins’ – Ed) and produce a suitable bore plus spotface on the rear of the remaining stub uprights.

For assembly of the interference fit components I planned to heat the stub uprights prior to fitting the new axles.

The new bores in the stub uprights were machined and honed so that on assembly with the axles a resultant diametric interference towards the upper end of an H7 / s6 interference fit of + .0019in would be produced.

This was chosen because using a domestic oven and heating the steel stub uprights to 200°C would, according to my calculations, produce an increase in diameter of .002in.

The left hand axle outer diameter was 1.1274 in and the right hand axle diameter was 1.1272 in so the corresponding bore diameters in the stub uprights were honed to fall into the range of diameter 1.1255 / 1.1263in with a proviso to achieve diameters as close to 1.1255in as possible, to ensure the tightest possible fit on assembly (+ .0019in maximum).

A small lead in chamfer, to aid installation, was also machined onto the axle diameter that would assemble into the stub upright.

In the articles I’d read, some very beautiful jigs have been produced to enable the axle to be held squarely to the stub upright during the assembly process. However, with no means of replicating / machining any such jig in my modest restoration emporium I looked for alternative solutions.

I had already acquired an old Jones and Shipman ‘Made in England’ Arbor Press for £30 via an e-Bay auction, which would assist in assembling the axles to stub uprights. All I needed was the jig to hold everything square.

As a design engineer by profession I am familiar with the statement ‘think of the problem in reverse’.

Having stripped the old worn bearings from the original front hubs these were found to be a nice close running fit onto my new axles due to spinning that had been taking place during TC0894’s past life.

‘Thinking of the problem in reverse’ produced an assembly of old wheel bearings, groups of washers (held together by masking tape), axle nut and the stub upright which, when the nut was lightly tightened up, ensured that everything was pulled square as shown in the photograph.

The two wheel bearings have identical outer diameters and the TC front hub has a deep lead-in inner diameter for assembly of the outer wheel bearing before the close tolerance diameter where that bearing fits is reached. As this diameter is slightly larger than the bearing outer diameters it thereby provides a running fit, which would act as the guide for keeping everything square. Additionally the overall diameter of the outer threaded hub section is just right for supporting the stub upright as shown in the photograph.

The distance from outer hub face to internal, outer bearing flange feature, is also sufficient to allow for the required movement of the axle during assembly into the stub upright.

I used one of my new front hubs for the jig.

As the assembly was to be effected by heating the stub uprights, everything had to be ready for a very quick assembly after removal from the oven to avoid any significant heat loss that would probably result in incorrect partial axle assembly.

Therefore, to avoid wasting any assembly time I bolted a thick aluminium base plate to the base of the press onto which two wooden guides were screwed. This ensured that the axle / hub assembly could be positioned quickly / correctly / directly under the press arbor as shown in the photograph.

Each axle was initially held in a vice so that once the stub upright was removed from the oven, quick assembly of the bearings and washers could be effected whilst also allowing easy gentle tightening of the axle nut to square everything up prior to sliding the resulting assembly into the front hub.

A length of scaffold tube was also at hand in case the arbor press lever required extending to increase the available assembly force.

Both axles assembled perfectly and the scaffold tube extension was required to increase the available assembly force during each axle’s assembly. The left hand axle having the larger outer diameter resulted in all my weight hanging off the scaffold extension to achieve correct assembly into the left hand stub upright.

A finished stub axle assembly is shown in the photographs below.

S. Cameron
TC0894 (under total restoration)

Ed’s note: I’ve confirmed with Bob Grunau that he still has the axle ‘pins’ in stock, but freight charges from Canada to the UK are a consideration (the ‘pins’ are surprisingly heavy) as is the potential liability for Customs charges. Bob can be contacted at grunau.garage(at)sympatico.ca {please substitute @ for (at)}.

Tim Patchett can supply newly manufactured stub axles at £650 per pair. He may well have a pair left from the last batch he had manufactured. Tim can be contacted at happypeople222(at)gmail.com {Please substitute @ for (at)}.

The Editor

1 Mar

Welcome to the April 2015 issue of TTT 2!

I’m sure I’ve said this before but I always feel that Spring has sprung here in the UK with the start of the Cheltenham National Hunt Festival (horse racing over hurdles and fences for four days – a magnificent spectacle). Unfortunately, it doesn’t feel much like Spring due to the cold weather and most, but not all, T-Types won’t be venturing out just yet.

The first day of March was the date for the Stoneleigh MG Spares event. This was the second year that the event has been a combined MG and Triumph affair. Regrettably, the lessons which should have been learnt from the access problems last year were not. Reports of traffic gridlock waiting to get into the site were frequently heard and it appears that it was even worse than last year.

There were a number of formal complaints to the Show organisers (as there were last year) but these were responded to by means of a standard reply. Brian Rainbow, who shared the stand with me as ‘TA Brian’ put together a detailed appraisal of what went wrong, only to receive the standard reply, which failed to address his carefully crafted points. As an added ‘bonus’ the letter wasn’t even signed!

Notwithstanding all this, it was good to meet so many owners, especially those from overseas; sorry about the difficulties, but the message to the Show organisers is that the learning points which should have been addressed from problems at last year’s Show, were clearly not, and as a result, some visitors have said they will not come again.

MG Day Stoneleigh
Setting up at Stoneleigh; Brian Rainbow is on the left of the TTT 2 banner, Steve James to the right and the editor at the back of the stand.

THE 2015 TTT 2 TOUR – LANCASHIRE LANES AND YORKSHIRE DALES

The Tour organisers are Grant and Barbara Humphreys.

Much activity is going on behind the scenes and Tour participants should by now have received a request for the Tour entrance fee (£30 per car).

An updating report will be given in the June issue of TTT 2.

THE 2016 TTT 2 TOUR – THE FOREST OF DEAN AND THE WYE VALLEY

Bells Hotel

Bells Hotel (www.bells-hotel.co.uk) Coleford, Forest of Dean, Gloucestershire, has been booked for the 2016 Tour. The dates are Friday 26th August to Monday 29th August 2016.

The rate negotiated for the Dinner bed and breakfast package is £57 per person per night and the reservation number for bookings is BK07359 – guests to make their own bookings accompanied by a deposit of £25 per person.

There is a supplement of £10 per night for single occupancy of a twin bedded/double room.

The Raglan Suite has been booked for a gala dinner on Saturday night.

Tour organisers are Brian Rainbow and John James.

MG Airbag
Modern technology from Frans Sitton.

JOHN JAMES


DISCLAIMER BY THE EDITOR

Totally T-Type 2 is produced totally on a voluntary basis and is available on the website www.ttypes.org on a totally FREE basis. Its primary purpose is to help T-Type owners through articles of a technical nature and point them in the direction of recommended service and spares suppliers.

Articles are published in good faith but I cannot accept responsibility or legal liability and in respect of contents, liability is expressly disclaimed.