SUPPLEMENT No.2

CONTENTS

Sec's Ramblings 1 BMC's Answer to Piston Failures 2-3 M.G. or Ferrari and YD1.662 Plans -B. Ditchman. 3 The Making of a Car Badge 3 Kiwi Improvisation - D. Hector. 4 Based on Fact, but Definitely not Recommended - P. Wood. 4 A MGA Twin Cam Production Analysis 5 Now for the Timing 6 Hi out There -D. Kiffer. 6 Reincarnation - J. Tofts. 7 Photo-Feature. Past Racers 8

SEC'S RAMBLINGS.

Due to the popularity of this communication medium with the club registers and centres I missed the booking of space on the date intended and the best we could achieve at the time of making enquiries for the second supplement was four pages this month and a further four in the December issue of Safety Fast. Be prepared for the latter half because to save space we may not have the customary lead section as above, unless we decide upon two four page suplements.

May I commend those members providing letters suitable for these columns, some follow. Keep them coming in.

The main features of this supplement deal with Piston Failure and the manner in which B.M.C. overcame the shortfall and the Twin Cam Production analysis of chassis specification against colour scheme.

Do not forget 1983 brings the 25th Anniversary of the Twin Cam production start, for which we plan a main attraction of a parade and enclosure at the race day Silverstone in May for twin cams and de-luxe cars. Please advise as early as possible of your participation. Ideas supporting this are developing: Twin Cam celebrities invited; EX 181 display; a souvenier booklet, any reason we should not call it '25 Years On'; followed by an evening get-together, buffet or dinner.

The number of cars recorded on the Register moves towards the one third production figure of 704. To mark this milestone the person raising the register to this level will receive a Radiator Badge. This should help see us towards the 750 and 800 mark. Both should be obtainable in a year or so.

About half our members have purchased the Radiator Badge which really does look superb on the front of the cars and at £1 it is good value. It would be nice to see one on all the cars. Do you have one ordered?

To give all some insight into the manufacturing process of our badge Tony Willis of Gladman & Norman has written the article 'The Making of a Car Badge'

Kevin Carroll 'S YD1. 1452, before restoration began with TD behind.

TWIN CAM GROUP Supplement No.2 Page 1 SAFETY FAST, September 1982 15

B.M.C.s Answer to Piston Failures

The following is compiled from the B.M.C. Service Memorandas MGl282, MGl296, MGl325 and MGl344 which were issued to their appointed garages.

Part of MGl282, issued 16th October 1959

Remedies for Possible Complaints, Piston Holing.

This is usually the result of over-advance of the ignition, use of incorrect sparking plugs, incorrect grade of fuel or a combina- tion of the three.

The engine is a high compresssion, high output unit and any additional ignition advance from the required setting will give excessive sparking plug and combustion temperatures, with consequent possibilities of damage to the pistons.

As already stated, the static ignition setting is top dead centre and this must never be exceeded.

In order to ensure correct ignition timing throughout the speed range of the engine, it is essential that the distributor advance mechanism should be checked by using a stroboscope timing light to observe the amount of distributor advance (with the vacuum disconnected) for various engine speeds.

The observed amount of advance should be within the limits specified in the following table:-

Crankshaft R P.M[ 600 1 1300 1 1800 1 3000 ] 4000 Dearees Advance1 l to 5 I 12-16 I 20-24 I 22-26 I 30 max

If any variation from the obove is observed, the distributor should be replaced.

In order to prevent any excessive ignition advance, the vacuum advance pipe should be permanently disconnected and the union on the distributor blanked off.

Champion N.3. sparking plugs (part no. 97H611) MUST be used for all normal work. A lower grade (hotter running) plug MUST NOT be used, as incipient detonation, due to a rise in plug and combustion temperatures, might occur and result in serious damage to the engine.

For competition purposes, where a high output is sustained Champion N.58.R sparking plugs (part no. 97H2275) should be used. These will ensure that combustion tempera- tures are not excessive and allow an increased margin of safety.

Due to the high compression ratio of the engine, premium fuels of not less than 95-octane rating should be used; lower grades of fuel will result in excessive combustion temperatures.

For maintenance of peak efficiency, it is preferable to use the Super grade fuels of 100-octane rating.

MGl296 issued 28th January 1960

Piston Failure.

To prevent the possibility of piston failure, a new distributor, part no. AEJ41, was introduced at engine no.2222. All engines subsequent to that no. will be fitted with the new distributor at the factory. The following engines also were fitted with the new distributor:- 2028, 2029, 2038, 2040, 2041, 2188, 2200, to2206, 2209 to 2219 inclusive.

In the event of piston failure occurring with an engine prior to the above numbers, the new distributor should be fitted when the pistons are changed. As the new distributor does not have a vacuum advance mechanism, the vacuum pipe (carburetter to distributor) should be discarded and the tapping in the carburetter blanked off with a plug (part no. AUC1289)

Before fitting the new distributor, it is important to ensure that there is no excessive backlash in the distributor drive gears. This check should be carried out as follows:-

1. Remove header tank hose to gain accesss to distributor

2. Remove distributor cap and rotor arm

3. Lock up automatic advance mechanism of the distributor by removing screw 'A' (fig 1) from centre spindle and refitting it with a washer 'B' . This washer should be made from a length of wire 0.030in. (0.76mm) diameter and l Vsin. (28.57mm) long, bent to form a circle.

4. Make up a pointer (as shown in Fig 2) and attach it to a rotor arm by drilling through centre of rotor and fitting nut and bolt (as Fig 3).

5. Fit rotor and pointer to distributor, ensuring that the rotor is really tight on the spindle (by wedging with a piece of paper, if necessary).

6. The pointer should now be turned so that it is over flange of camshaft cover (see Fig 4) and then tighten on the rotor arm. The backlash in distributor drive gears is now indicated by the maximum movement of pointer. Turn pointer anti-clockwise and mark position of end of pointer on flange then turn pointer clockwise and mark again (see 'A' Fig 4). If distance between the two marks exceeds Viein. (8mm) distributor drive gears must be renewed before new distributor is fitted.

Careful attention must be paid to ignition timing (see MGl288).

MGl325 issued 16th. August 1960

Piston Failure. (See MGl344)

In the event of piston failure attributable to the use of fuel below 95-octane. a replacement set of piston assemblies providing a ratio of 8.3:l should be fitted.

Such pistons are now available in standard and oversizes, to part No. AEH690, to operate with a static ignition setting of 8O BTDC and N3 sparking plugs.

Accuracy in obtaining the ignition setting is again stres- sed (see Service Memoranda MG/248, 296 and 301).

9.9:l compression ratio pistons part no. AEH681, will still be available but their use should be confined to competition work with 100-octane.

MGl344 issued 19th January 1961

Piston Failure. Cancelling MGl325.

In the event of piston failure attributable to the use of fuel below 95-octane, replacement set of piston assemblies providing a ratio of 8.3: 1 should be fitted,

Such pistons are now available in standard and oversizes, to part no.AEH690. They are designed to operate with a static ignition setting of 8 O BTDC and N3 sparking plugs.

Accuracy in obtaining the ignition setting is again stres- sed (see Service Memoranda MGl248, 296 and 301)

9.9:l compression ratio pistons, part no.AEH681 will still be available but their use should be confined to competition work with 100-octane fuel.

In future, the undermentioned will be supplied by BMC Service Ltd. fitted with 8.3: 1 compression ratio pistons, part no. AEH690:-

Stripped Engine part no.AEH37 Half Engine part no.AEH36 Block &Pistons part no.AEH35.

i

16 SAFETY FAST, September 1982 Page 2 TWIN CAM GROUP Supplement No.2

M.G. or Ferrari, and plans for YD1.662.

Life goes on at a hectic rate these days and unfortunately I win miss Silvestone this year.

I trust you are all well and can assure you that I read all your bumph and mean to write more often. Please confirm badge price as I of course will want one.

I have just returned from a month's leave, but during my last period of seven months away from U.K. I developed a hankering for a Ferrari so much so that I looked into the matter when on leave. This

+ resulted in starting to negotiate for the one I

fancy, a 365GT4 2 2. My intentions were to sell the P-type and keep the Twin Cam of course, but possibly sell the V8. Well the outc ome is I have deferred the Ferrari as the real reason for considering it is that I do not have enough time for the M.G.'s.,however the upkeep of a Ferrari will need the same if not more time so I gain nothing except the glamour, also with l/. the money I would have spent on a Ferrari I am going to get the P-Type finished and the Twin Cam rebuilt and put back to original Glacier Blue

Now I spoke to Roger Elvy when home and he confirmed that he would be pleased to do the work. Please will you send me his address so that I can write and confirm it to him and put things in hand.

So all in all it is good news and I am quite pleased with my decision, however I shall get a Ferrari one day - quite unbelievable mechanics and looks in my opinion, but Ferrari people in the main are on a plain above ours (must be when a service costs about £40 for labour but of course I would intend to avoid paying somebody else and that is where the time factor comes in).

By the way Peter Wood has built me a spare engine from all my spares so I have achieved that one.

I hope to be home again about mid August and all being well may call up to see you or at least give you a ring.

Enjoy Silverstone. Why don't you buy a V8 before they are all snapped up!

BARRY DITCHMAN, enthusiast at present i n Nigeria

The Making of a Car Badge

The process of agfeeing a design with a car club must often be one of compromise, since many clubs design badges which are impracticable or even impossible to enamel. This problem over, however, the agreed pattern is then cut into a steel die made of Swedish grane steel which withstands high pressures under the drop stamp.

The stamped impression in gilding metal (85% copper, 15% zinc) is then clipped to the required shape in a press. Next comes the soldering of any fittings (rear lugs etc) and the plate is then dipped in Aqua-fortis to clean and brighten the metal ready for enamelling.

The enamelling of the colours is done entirely by hand; the enamel being a mixture of finely ground glass and pigments, which give a range of some 50 colours and shades. The various colours are laid onto the metal plate using a pen-nib, and when fired in a kiln under high temperature the glass particles become molten, and flow into the various patterns of the plate.

After cooling, the enamel becomes solid but with an uneven surface, which is 'linished' smooth on an automatic abrasive belt, and then fired once more to give the final shiny glass effect.

Finally, the last process is to polish out any fine scratches in the metal and then the badge is chrome plated and polished.

Some of the interesting car badges that we have made recently, apart from your own Twin Cam badge, include those M.G. Car Club of Sweden, Morgan Car Club of Washington, Lagonda Owners Club, Bentley Drivers Club andPeking to Pans Rally.

TONY WILLIS of Gladman & Norman.

Gladman & Norman Ltd. (Established 1910)

Manufacturers of SPORTS TROPHIES, MEDALS, ENAMELLED BADGES, NAMEPLATES

CAR PLATES, STAMPINGS & PRESSINGS

51-53 TENBY STREET NORTH, BIRMINGHAM B1 3EG Telephone: 021-236-5752

TWIN CAM GROUP Supplement No.2 Page 3 SAFETY FAST, September 1982 17

Kiwi Improvisation.

I'm afraid I'm about the world's worst correspondent, the last time I wrote must have been about three years ago or more. Since then Bill Baxter from Ohakea has told you that my Twin Cam Roadster is back on the road. The answer, I finally came up with the answer to my camshaft problem, by getting it reground to Jaguar 2.813.4 profile. The timing is within 2' but the ramps are different which calls for valve clearance of 6 to 8 thou. So far the car has been running with mixed success for 2% years but I cannot blame the new cam profiles for any of my problems.

After six months including some competition in interclub gymkhanas, I thought I'd give the diff. a treat and change the oil, clunk in the bucket, after some grovelling I found the bits of a broken ball race seperator. On dismantling the main assembly, the preload came off the side bearings, it was obvious that I had a two part diff. carrier. Local dealers had the price of a replace- ment but no part, so from the wreckers I obtained a 41 :9 diff. for around £20 With new bearings and rebuild with 43: 10 CWP, all was well. Further rushing about, the odd sprint and error of errors -I took it on a night rally. This round the houses looking for check signs did not appeal to the car at all and by the time we finished the plugs were fouled. The drive home over Haywards Hill, a good solid climb of a mile which requires full throttle to maintain top all the way, was the last straw and by the top of the hill we were clearly on three. Very careful driving for theremain- ing six miles home, we just managed enough energy to make the rise on the drive into the garage. A quick compression test and probing with wire showed for the first time in 28,000 miles I'd holed a piston. With only three months to the Pre-56 rally, to which MGA and Zs were invited, urgent repairs were needed. As finding a set of pistons and rebore was unlikely in the time (you see we enjoy Christmas for a long time) the damaged piston was welded and the clown faced. With minimum of milage before the rally everything went right at the event to such an extent that I beat a blown J2 and Bill's de-luxe complet- ing the 1.88 mile Manfield circuit in l min 45 secs. Since then no problems, but for the clatter each time we start which is getting a bit much, oil consumption is climbing and the compressions are reducing again.

Considering the cars 65,000 miles and I knew the bores were on the limit at 37,000, time has definitly come for an engine rebuild.

As I've had 28,000 miles with only one problem on the original vacuum advance distributor and 9.9: 1 pistons, I would like to retain the present performance, and not go to 8.3:l pistons, so long as parts are available.

DAVID HECTOR

Goodwood in classic days. Just look at the variety of home bred racers.

Based on Fact, but Definitely not Recommended.

This article comes with the year 1982. I reckon it was about 1962 that I first became involved with Twinks, a twenty relationship.

In these days when more Twinks are cherished by their owners some of whom have had their cars for some years, very few are used each day, apologies where they are, and now there is a comprehensive back-up of specially produced parts so that virtually every part is available, I find it quite humourous to recall the stories of fact, and some hopefully fiction, that have been endured by our cars.

To put things into perspective, I think it was between the year 1964 to 1968 when Glass's Guide gave up quoting 'trade in' prices or omitting any reference all together, and I think the last quoted figure was £150

How about:- What is blue, oval and squarish and got teeth in it?

Answer, a twin cam tappet shim when things got hot and you were short of the correct size.

Did you hear of the hermetite engine red 'head and brown cam covers and something filling the void betwixt instructs you to pour milk on it and so afterwards goes snap, crackle, and pop.

What about bent camshafts? I was told of a fellow who inserted a chain round them and lifted his engine out, oops, iron toes and steel capped boots required for this exercise. Cylinder head gaskets were a tricky store item, I understand that Fry's Cocoa tins were one of the early suppliers.

Morris Minor distributors do work-honest-but they tend to leave pistons with crankcase compression, rectifiable-surely-all you do is take a lump of Vain. thick steel, shape it to the top of the piston, drill and tap and countersink the holes and just screw it on. I forgot to ask the chap if he used Loctite.

Then there was the 9,918.319.918.3 compression engine. Sounds a bit like a Jowett Bradford twin. Or the early-late con-rods Twin Cam Syndrome. Sounds nervous, so does the car with everything shaking in unison.

Did you know you could 'pack a pad' and 'run a disc'. You can, and I swear you can shave on the edge of the disc soon after.

Twin Cam front and rear brake caliper cylinders are inter- changable-and it really helps especially when approaching the Armco backwards. Much better brakes that way round.

Early handbrake maintainance - leave well alone, and when it gets really bad "You shall have music wherever you go" like an offbeat steel band.

PETER WOOD.

YD2.2208 had engine 1856 when Geoff Meaney took this a few years ago. Has she been seen in Australia more recently?

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18 SAFETY FAST, September 1982 Page 4 TWIN CAM GROUP Supplement No.2