A High-Performance Light Alloy Head for M.G.s

EXTRACTS From AUTOSPORT December 26,1952
and “ROAD and TRACK” December, 1953


The Laystall Engineering Co. Ltd. have made available a special head, designed ab inito in high-compression form. It incorporates the larger valves and stronger springs normally supplied for ” Stage II ” tune, and these are included in the price of £48. It is cast in RR 50 aluminium alloy, which not only eases all the heat-flow problems, but saves 16 lbs. of weight. The main feature, however, is the scientific proportioning of the ports and head shape, which greatly increases the air flow. The technical side of the project is the work of John Lucas, who has put the speed into many of our fastest engines.

On the bench a b.h.p. increase of some 20 per cent is recorded, by simply changing cylinder heads, and making no other alterations to the engine. Bench tests are all very well, but it is road behaviour that really counts. Accordingly, I took over a TD type M.G. recently, to see if the theoretical advantages were obtained in practice.

It will be observed that, in the data panel, performance figures are given for the car in standard form and with the Laystall-Lucas head fitted. These results were secured at the M.I.R.A. proving ground, and were electrically timed. It will be realized that the length of run available did not allow the ultimate maximum speed to be developed, but the figures are strictly comparable.

The actual changing of the heads was done inside an hour and a half, or one and threequarters hours if one includes warming up and checking valve clearances. In order to accommodate the specially shaped ports, the Laystall-Lucas head is somewhat wider than the standard article. The regular manifolds and gaskets go straight on, however, and any normally competent owner could do the work himself. The M.G. engine is very accessible, so the job is quite straightforward.

I also used the M.G. as my normal hack for a few days, and the improvement in performance was most marked. Although the maximum speed is considerably augmented, it is the better acceleration in the middle ranges that one notices most in everyday driving. I used 80 octane fuel, on which the unit was remarkably flexible.

During my test, freezing temperatures were experienced most of the time, and I did not even cover the bonnet with a rug at night. Nevertheless, starting was rapid and certain every morning. The fuel consumption worked out at 28 m.p.g., but as this included the flat-out timed runs, I would say that a full 30 m.p.g. could be relied upon for ordinary journeys.

This head is applicable to the TB, TC, TD and 1 1/4-litre saloon model M.G.s, also the new Wolseley 4/44. It represents a remarkably cheap way of augmenting the performance, for it is ” ready tuned “, so to speak, and no work is entailed apart from fitting.

Pause, then, you sports car owners, before you cross swords with an innocent-looking M.G. It may have a Laystall-Lucas cylinder head under its bonnet, and you will be in for a rude awakening!



Component Tested: Laystall-Lucas Cylinder Head, tested on TD type M.G. car. Price in U.K. £48, or £50

including fitting.

Material: RR 50 aluminium alloy, with valve inserts.

Valves: 36 mm. inlet, and 34 mm. exhaust valves, with 150 lb. springs.

Rocker Gear: Standard rockers and all other fitments.

Compression Ratio: 9.3 to 1.

Performance: 20 per cent. power increase.

Test Results: Standing figures are for last 100 ft. of 1/4 mile. Flying figures are for last 100ft. of 1,400yds.

Standard Iron Head, 1 1/4-in. S.U. carburetters, standing, 58.14 m.p.h.; flying, 70.79 m.p.h.

Laystall-Lucas Head, 1 1/4-in. S.U. carburetters, standing, 63.17 m.p.h.; flying, 75.45 m.p.h.

Laystall-Lucas Head, 11/2-in. S.U. carburetters, standing, 63.76 m.p.h.; flying, 76.52 m.p.h. Electrical timing, all figures are mean of runs in both directions.

Conditions: Snow, mud and ice.

“Road and Track”

Speaking of M.G. performance, we have been conducting some interesting tests on a stock TD. Space did not permit a full road test report this month, but as a brief preview, we found that the new Laystall-Lucas head (now available) added an honest 12 m.p.h. to the top speed and reduced acceleration time to 60 m.p.h. by over 5 seconds. It was quite an experience to watch the tachometer during the high-speed runs. We have to watch something to judge whether the car has reached terminal velocity. In this case, we kept going farther back each time, and the tach kept edging up during each timed run. Finally, it hit the peg (about 6,200 r.p.m.) and we watched the speedometer continue to climb from 90 to 95 before it stabilized. The best run was clocked at 89.10 m.p.h. with top and side curtains installed. Needless to say, we came away convinced that the Laystall head gives more than 20% added peak b.h.p. which they claim for it.

Sample Performance Figures

Stock M.G. TD                                                         Laystall-Equipped

0-60 24.2 secs.                                                        18.0 secs.

Best top speed 77.6 m.p.h.                                   89.1 m.p.h.

                              (Timed Runs—Windshield Up—Driver and Passenger)

Editor’s note: The picture of the Laystall head, the extracts from Autosport and Road and Track and the advert for Cromard liners and pistons came from a brochure for the Laystall-Lucas head and Cromard liners which was kindly e-mailed to me by Paul Gent. I have re-typed the extracts from Autosport and Road and Track because the type face/font in the brochure is very small and some of us would need a good pair of reading glasses to study them.

In his covering note to me, Paul reckons that the Road and Track Test is the more convincing in some ways, although he points out that the text states that the Laystall head reduced the 0 to 60 time by over five seconds when the figures show over six!

I must say that I put an index finger over each eardrum (waiting for the bang!) when I saw the figure of 6,200 r.p.m. from, presumably, a stock engine.

And…….89.1 mph with two people on board – were they going downhill and was there an escape run-off to aid stopping?

Note the price of 48 GBP, which included the larger valves and stronger valve springs! The current price for the head with guides and valves is 1795 GBP (excluding VAT), 2154 GBP inclusive of VAT.

The writer of the Autosport test review, John V Bolster enjoyed a career as a racing driver, commentator and motoring journalist. He was well known for his “Bloody Mary” special – a twin engined JAP powered sprint and hill climb car that he built with his brother in 1929. It finally ran on methanol based fuel and Bolster is reported to have remarked that the car seemed to enjoy her alcohol as much as the owner does his!

Bolster raced at Donington, and other circuits in the 1930s and 1940s, but his motor racing career ended when he suffered serious injuries in a crash whilst driving Peter Bell’s ERA at Stowe in the 1949 British Grand Prix.

His racing career over, he took up broadcasting and served as Technical Editor of Autosport from 1950 to 1984.

From reading accounts of his life on the Internet it seems that he was a larger than life character; one snippet from a forum, which I took a special note of, because it appealed to my sense of humour, concerned Bolster’s reported ‘clarification’ (my interpretation) of the reason for the retirement of a works Ferrari in a race. The “official” reason for the retirement was “Electrical”; however, when Bolster reported on the problem, he said that the Ferrari retired due to electrical problems brought about when a piston exited the block and smashed the distributor.

Bolster died in Tunbridge Wells in 1984.

His memory lives on through the John Bolster Award for technical achievement. The is one of a series of awards presented annually by Autosport magazine. Previous winners have included Eddie Jordan (for achievements in motor racing) and Toto Wolff (for achievements with Mercedes AMG).

Mercedes AMG GmbH, commonly known as AMG, is the high-performance subsidiary of Daimler AG under Mercedes-Benz division. It independently hires engineers and contracts with manufacturers to customise Mercedes-Benz AMG vehicles.

2 thoughts on “A High-Performance Light Alloy Head for M.G.s

  1. Rolf schweizer says:

    I am intrested in head for my 1952 td wich already has tf specs welves and 1 1/2 inch carbs.what would the improvment be since i live in johannesburg on 1800m altitued?

    • Tom Lange says:

      Rolf: the Laystall head has these specific advantages over an iron head: it is lighter by almost 16 pounds, and it has re-designed intake ports and combustion chambers that develop more power. It probably also has a higher compression ratio than your present head. Because the head is slightly wider than an iron head, though, the L-L head can be a bit harder to fit under the bonnet.

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