The 'J' type Overdrive was introduced in the early 1970's, and was adapted to fit Volvo, Triumph, Vauxhall Opel, American Motors and Chrysler motorcars and Ford Transit vans. In 1959, the Laycock Engineering Company introduced the 'D' type Overdrive, and this was fitted to a variety of motor cars including Volvo 1's, Sunbeam Alpines and Rapiers, Spitfires and also to early 3-synchro MGBs.įrom 1967 the 'LH' type Overdrive was introduced, and this featured in a variety of models, including 4-synchro MGBs, the Ford Zephyr, early Scimitars, TVRs and Gilberns. Later the A type Overdrive was to be fitted to the entire range of TR cars. Famous marques including Jaguar, Aston Martin, Ferrari, Austin Healey, Jensen, Bristol, AC and Armstrong Siddeley were amongst the manufacturers to incorporate the overdrive unit into their engine systems.

The first unit to be created was the 'A' type Overdrive, this was fitted to many sports cars during the 1950's. The Overdrive Unit was a result of a chance meeting the year before, between Ken Walker, Production Engineer at Laycock Engineering Limited, and Captain Edgar de Normanville, an American Transmission Designer. The Laycock de Normanville Overdrive Unit was first introduced to the Motor Industry in October 1948, when it was fitted to a Standard Vanguard. I think it's highly unlikely that parts for those early units are still available so what you have John could have a value well beyond what the parts you need for your later LH would cost so I'd definitely speak to Quantum There were 4 different models of OD and in fact I've learnt something from this thread which is that they were not introduced alphabetically but went A, D, LH, then J ! We've all been asked for serial numbers when ordering spare parts and even on the MGB itself the first part of the VIN is generic despite the differences over the years. Jul 24 Do-nut Donut Spare Wheel And T.Īssuming the labels are the originals the first part of the serial numbers (22/61972) identifies them as the same model but with the Birfield one being a very early example and it's perfectly possible that they made internal modifications in those early years under a common model number recording changes by production serial number.Sep 30 MDMGs On The Rocks British Car.Sep 23 NCBCCWNC Autumn In The Mountains.Sep 21 NCSoutheastern Austin-Healey Cl.Sep 16 DEBCCD Annual Fall Car & Motorc.Sep 09 ORWest Coast Sprite Midget Chal.

Sep 03 NYAutumn Sports Classic Super C.Aug 27 NYMGCC Sports Car & Auto Festival.

Laycock lh or j type overdrive