Harvs.com.au – Tom Harvey

Taking the engine out of our 1970 1275cc MG Midget

Posted in Cars, MG Midget by Tom Harvey on January 2, 2009

It was becoming embarrassing to drive the car, when taking off from traffic lights the car/s behind would disappear in a cloud of blue smoke. After much procrastinating it was time for a quick engine rebuild.

Firstly off with the head to measure the capacity using a burette. Bearing in mind that the head was only cleaned up 18 months ago, there was a huge amount of carbon build up, an indication of how much smoke the car was burning.

MG Midget 1275cc Head With Carbon Deposits

MG Midget 1275cc Engine With Head Removed

MG Midget 1275cc Engine Head Removed Carbon Deposits on Pistons

Using a burette purchased off ebay for $25 AUD, some kerosene and a perspex disc we measured the head capacity – a consistent 21cc (standard). It appears the head is unmolested and hasn’t been skimmed. The nifty little magnetic stand was a worthwhile purchase (bought at a machine shop called Hare & Forbes ) it kept the burette perfectly steady and could be easily and quickly adjusted.

MG Midget 1275cc Measuring Cylinder Head Capacity

Using the same method we measured the capacity of the bore – 10cc. This is slightly less than standard, and explained by the AE 21253 pistons that were fitted.

 MG Midget 1275cc Measuring Block Capacity

The a-series is a pretty small engine, and could probably be lifted out by two people – but a borrowed engine winch made life very easy.

MG Midget 1275cc Engine Crane

MG Midget 1275cc Engine Removed

Just as a matter of interest and to try out our new dial gauge and stand – a quick check with a timing disc show the camshaft to be within 1 degree of the recommendations in the workshop manual.

MG Midget 1275cc Measuring Cam Timing

MG Midget 1275cc Engine Removing Con Rods From Crank

Pistons came out without any dramas. Appear to be in very good condition. Revealed extremely glazed bores and piston rings with an excessively large gap of 0.0026′.

MG Midget 1275cc Engine Removing Pistons From Block


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