Bits and Pieces

Lots more room for this item this month!

The Highs and Lows of Sourcing Parts

I’ll start with a ‘High’ but it then goes rapidly downhill!

I have been really pleased with the success of the polyurethane bushes for the TC and TD/TF. It’s good to receive feedback, favourable or otherwise and I have had plenty of the former. A recent satisfied customer e-mailed me as follows:

The poly bushes you supplied for the TC front springs have been very successful. They are the exact size, easy to fit and are an instant improvement to the car’s steering. Gone is the vicious oversteer when cornering hard and then hitting a pothole. Straight line steering is much improved and now it is nearly possible to drive in a straight line! We took the car to Castle Combe to a track test day and proved the benefits again.

Just a reminder, the 3⁄4” bushes (Part number 0074) fit the rear shackle pins on the TD/TF and YA/YB/YT) – eight (8) required per car. They also fit the front chassis tube on the TC – four (4) required per car. The 5/8” bushes (Part number 073) fit the rear ‘eyes’ of the front and rear leaf springs on the TC. Eight (8) of these are required for the TC.

The bush sets are supplied with sachets of special assembly lubricant and come well packed in a little box. As the bushes are light, postal charges are fairly moderate with typical costs being £2.30 (UK) £3.00 (EU) and £4.00 elsewhere.

As I own the moulds for these bushes and order in bulk, I get a substantial discount, which I pass on to TTT 2 readers. The cost per bush is £2.35 (which is exactly what they cost me, having amortised the cost of the two moulds over 600 bushes). In addition I ask for a contribution to TTT 2 funds of 50p per bush, which makes the effective asking price £2.85 per bush. Putting this price into context, the cost per bush from a major supplier is £8.35 and what is on offer is a “uni-fit” bush with the bushes for the front and rear leaf springs on the TC having to be trimmed to fit.

To order, please send an e-mail to John James at jj ‘at’ octagon.fsbusiness.co.uk (substitute @ for ‘at’) and I will send you a PayPal invoice. Alternatively, UK orders can be paid for by cheque and sent to 85, Bath Road, Keynsham, BRISTOL BS31 1SR.

Large Rear Shackle Bushes for the TC

Here’s the start of the downhill bit! No sooner had I read the e-mail from the satisfied customer quoted above when I opened the boxes of the large rear shackle bushes which I had collected a few days earlier. I was on the point of starting to send out the orders on hand when I thought “better make sure they are to specification first”. To my shock and horror they were not, being almost 1/8” short in the length. How this error could have occurred I know not, but I now have 100 scrap bushes.

By the time you read this I will have contacted the supplier and asked him to put matters right.

Rear Springs for the TC

On 22nd May I ordered eight (8) pairs of TC rear springs with a requested delivery date of the end of June. Towards the middle of June I received a phone call from the supplier saying that he was closing for two weeks’ annual holiday on 22nd June and whilst he had made all the main leafs, he was waiting for more steel to be delivered to finish the order. The indicative delivery date (the springs will be sent direct from the supplier’s premises) is now end of July.

Since I placed the order for the eight (8) pairs I have now received a request for three (3) more pairs and so as not to give the supplier any excuse for further delay with the initial order I have not ordered these yet but will do so when I know that the first batch has been made. Therefore a second batch is unlikely to be ready much before end of August/September.

Front Springs for the TC

I have had a request for six (6) pairs of TC front springs which I have not yet passed on to the supplier. These will be made with a 5/8” front ‘eye’ to enable a 1/16” bronze bush to be pressed in. The bronze bushes (SAE 660) are being made separately and I still have to resolve the issue of whether the spring supplier will fit the bushes or whether the bushes are sent out independently of the springs for them to be fitted locally. A delivery date of end of August/September is being aimed for.

Phosphor Bronze Trunnions for TA/TB

As mentioned earlier, I have organised a small batch of trunnions for the rear springs on the TA/TB (and for front if you have replacement springs with a 1⁄4” main leaf on the front). The price is £6.50 per trunnion, which is cost price but I would appreciate a donation of £1.00 per trunnion for the TTT 2 fund. They are still keenly priced compared with those elsewhere – one supplier is charging nearly £30 for a pair.

Heat Shields for TB/TC/TD and TF

It doesn’t seem entirely appropriate to be talking about heat shields, given the British summer we’ve had (or not had) so far, but I have a few in stock which have been supplied to me by Barrie Jones, Technical Specialist for the ‘T’ Register of the MG Car Club. They are made from stainless steel and are priced at £15, plus postage. The TF heat shield has larger holes for the H4 carburetters and must be fitted along with the original TF spacers. The TB/TC/TD version has smaller holes for the H2 carburetters. To fit this shield to the TB/TC/TD you will also need the aluminium spacers shown in the photo (at £5 per spacer). This in turn will require longer exhaust manifold studs (not supplied), ideally 60mm long, with 20 mm of thread at each end. The threads should be 10×1.5 modern metric.

Some questions have been asked about the use of aluminium for the spacers. Here is Barrie’s explanation of the theory behind his design:

“The main problem with modern fuel seems to be the Ethanol content. This apparently slows down the burn so that the partially-burnt fuel continues to burn after it has been ejected from the engine. This raises the temperature of the exhaust manifold, and the radiated heat could boil the fuel in the float chambers.

The TC/TD float chambers are very close to the exhaust manifold, so:

1) The polished stainless steel reflects the heat away from the float chambers.

2) The spacers move the float chambers further away from the exhaust manifold, reducing the effects of radiation even more.

There is a secondary problem. When Ethanol vapourizes as it exits the jets of the SU carbs, this has a refrigerant effect. On a cold, damp morning it could cause any water vapour in the air to freeze, blocking the jets with ice. This happens in aircraft. Pilots are taught that icing-up of a carburetter can happen with air temperatures as high as 20°C (68°F).

So, by making the spacers from alloy I am trying to get MORE heat to the carb body whilst I am trying to get LESS heat to the carb float chambers”.

Did Jimmy Cox Work on your TC?

Jimmy Cox started work at Abingdon on 15th October, 1945. The Factory had just resumed car production after the end of the war, but the model which was being produced, the TC, (the post-war successor to the tragically short lived pre-war TB) was not being completed in any great numbers, nor were there finished examples on a daily basis. Much of this was down to material shortages in the immediate post-war period.

The day after Jimmy started in the Factory, eight TCs (chassis numbers TC0273 to TC0280) were built. The previous batch was completed on 28th September and it was not until 30th October that a further batch rolled off the production line.

Jim started out in life as a Messenger (he was hoping for an apprenticeship, but his father was told that no apprentices were being taken on). The young lad was itching to get a job on the production line and after a few months he progressed to ‘Tea Boy’ and standing in (for any absent colleague) on the line. Here the story ends, but it will be told in far greater detail one day.

However, the purpose of this brief introduction is to advise those of you who have relatively early TCs (probably those manufactured in 1946) that you can tell if Jimmy helped to assemble your car by looking at the buffer pad which is located above each front spring and examining the punch marks at each corner. The 1⁄2” by 5/8” countersunk machine screws which attach the buffer pad to the buffer bolts (a buffer bolt and the screws are shown in the photo) were tightened and secured by peening the plate to stop the screw from turning. You can tell if Jimmy assembled this part of your car because he would put two punch marks on one corner of the pad on the advice of his dad, who told him that it would identify his work. The arrows in the picture show Jim’s handy work – the punch marks are clearer in the pad on the left hand side of the photograph.

The pads are from my car (TC0750) and Jim, who is still around, has seen the photo, albeit a different one taken by Tom Wilson.

So the next time you have your front end apart, take a look to see if Jimmy Cox worked on your car!

TC braking

When TC0750 was on the road I always found the braking to be adequate. Recently, I took careful note of a posting on the tabc Bulletin Board by Carl Fritz of Gainesville, Florida. I think this is an excellent summary and is well worth repeating here for those who have not seen it:

I would contend that the real limiting factors on TC braking power are the following:

1) The size of the tire-to-road contact patches (Small, compared to more modern cars) 2) The tire compounds and tread designs available in tires of 4.50 x19 size, compared with more modern tires 3) The poorer friction characteristics of steel drum, compared with cast iron drums 4) The elasticity of steel drums, again as compared with cast iron drums 5) Linings used 6) Accuracy of the fitting of linings to drums

The TC’s standard brakes, IF properly set up, are perfectly capable of locking up all four wheels at almost any speed. Some “improvements” will reduce the amount of force the driver must exert, but will not change the ultimate retardation. Alfins will improve the efficiency of braking because items 3,4, & 5 above come into play, and will also delay the development of brake fade from repeated heavy braking.

NO MATTER HOW GOOD THE OTHER ITEMS MAY GET, ITEMS 1 and 2 WILL ALWAYS BE THE FINAL LIMITING FACTORS in determining how fast you can go slower.

An Honourable Trader

The following was received from Mike James:

Last year, at the Silverstone Classic I bought a number of books – from various stands. One of them, a copy of the Original MGT Series The Restorers Guide was marked as ‘limited edition’ on the inside front cover, with a pencilled price on the first page. The problem was that, only when I was actually reading it one winter’s evening did I discover that there had been a problem with the compilation. Apart from repeating everything about the Tickford and omitting the juicy bits on the TC, the repeated text was in French.

As I’d bought books from different stands I wasn’t altogether certain from which vendor I’d actually bought this one, so I e-mailed a couple of likely ‘suspects.’ Both responded and I was able to ascertain during a telephone conversation that it was in all probability purchased from JOHNS CARBOOKS. John Parsons told me that he operated from the Tonbridge area and that the pencilled mark inside sounded like his so he would collect and exchange the book the following weekend.

True to his word, he arrived at my home, examined the faulty book and exchanged it there and then.

Apparently this sort of thing is rare – but it happens and although this ‘limited edition’ is probably a collector’s item, the one I now have is far more useful so I was confidently able to spend loads more cash at the MG show in Stoneleigh, buying all the bits I didn’t realise I needed for my TC until I saw them.

So, if anyone is interested, I’d have no hesitation in recommending John Parsons of JOHNS CARBOOKS as an honourable trader.

Priming the XPAG Oil Pump

Following some correspondence with Mike James on this subject I asked Barrie Jones for some advice. He provided the following useful summary of changes to the XPAG oil pump:

There were several changes to the XPAG oil pump.

The TD2 engine (with 8” clutch) was introduced at XPAG/TD2/9408, the pump with the horizontal filter was introduced at XPAG/TD2/14224, and a priming plug was introduced at XPAG/TD2/20972.

In December 1953, during the production of the TF, the body of the pump at long last received an internal drilling at XPAG/TF/31263 rendering the pump self-priming. This modification could be made to earlier (horizontal filter) pumps by a competent engineer.

Note that the TB, TC and early TD pumps did not even have a priming plug. The only reliable way I know to prime them is by filling the oil gallery of the engine with oil through one of the external holes AND packing the gears with Vaseline petroleum jelly.

By the way, the Rover V8 engine has the same problem, and the V8 workshop manual recommends packing the pump with Vaseline.

Mike was having problems with lack of oil pressure on his rebuilt XPAG when he recalled to memory something he had read in TTT 2 about MG building cars without self-priming oil pumps. This put him on the right track and he eventually had success as follows:

Having ‘primed’ the oil pump on my rebuilt, early engine by removing the oil delivery pipe, putting a funnel full of oil into the hole and rotating it in top gear whilst pushing the car backwards (as the pump hadn’t been coated with Vaseline), when I eventually started it up it the gauge immediately showed 70+ pounds per square inch of pressure.

On its first run this weekend – to the MOT station, it continued to show between 50 – 70 lb’s – so thanks again for the timely article on how to avoid blowing a rebuilt XPAG engine.

That’s all for now folks – more in the October issue due out around about 15th September. The Editor

---