Engine technical information


Ian Linton’s Arnott supercharged TA

MPJG, XPAG and XPEG casting numbers and codes
There is lots of information on chassis and engine numbers identification as a sub section on our Register of T Types page. This includes Roger Wilson’s article on MPJG, XPAG and XPEG head and block castings and referenced to their casting numbers.
And we also have the first real piece of evidence of how to decode the XPAG/XPEG casting date code found near the dipstick and this includes a discussion of the original Austin-Morris standards document.

Autocar technical articles on the XPJM engine from November 1939
In 1939 the Autocar magazine published two technical articles on the subject of the Morris XPJM engine. This engine of course was the source of the MG XPAG engine and it’s introduction intrigued Autocar enough to send Montague Tombs to investigate its advances in design.
The two articles were published in the 17th and 24th of November 1939 editions and are here published by kind permission of The Autocar magazine. We hope they prove of interest to those wondering about some of the finer points of the design of the XPJM and XPAG engine.
You can visit Autocar’s website at http://www.autocar.co.uk.

Modifications to the XPAG Water Pump
Eric Worpe’s talk given at the T Register’s Rebuild event held at the British Motor Museum, Gaydon in April 2023, describing modifications that can be made to the XPAG water puimp.
The transcript takes the form of Eric’s original slides with additional text.
Note that Eric used hand drawn flip chart diagrams.


Lucas manual on testing the charging circuit – original Lucas manual on a step-by-step approach to testing the circuit.

SU carburettor tune up – original SU manual for tuning and servicing of Type H SU carburettors.

Engines for MGs – Neil Cairns’ excellent history which includes lots of information about the XPAG/XPEG engine.

Complete engine tune up Pt1 – Chicagoland MG Club

Complete engine tune up Pt2 (includes tuning the carburettors) – Chicagoland MG Club

Cooling the XPAG/XPEG engine – Chicagoland MG Club

How to stop oil leaks without resorting to a modern lip seal – Chicagoland MG Club