MG Midget and Austin-Healey Sprite Maintenance Guide

Written by Petro Olekhnovych, mobile mechanic in Aylesham, Kent

Good MG Midget maintenance is mostly about little and often. Change the oil regularly with a classic 20W-50, grease the front kingpins and trunnions frequently, and keep an eye on the lever-arm dampers and the sills. The same applies to the Austin-Healey Sprite, which is mechanically the same car.

Midget or Sprite: know which car you have

Owners call both cars “Spridgets”. The MG Midget arrived in 1961 as a badge-engineered, slightly more expensive version of the Mk II Sprite. The Sprite ran from 1958 to 1971, starting with the “Frogeye” Mk I. The Midget carried on until December 1979.

The engine matters most for maintenance:

• 948cc, 1098cc and 1275cc: BMC A-series engines, fitted to Sprites and to Midgets up to the mid-1970s.
• 1493cc: the Mk IV Midget used the Triumph Spitfire engine instead.

The rear suspension also changed. Early cars used quarter-elliptic leaf springs, later replaced by semi-elliptic springs. Check which engine is actually fitted before buying parts. A workshop manual for your exact model is worth having.

The A-series engine: oil and wear

MG Owners’ Club Spares says the Midget 1275 and other A-series engines suit 20W-50 oil. It explains that a thin modern oil may not hold a proper oil film across the bearings of an engine built to older, wider clearances.

Zinc (ZDDP) matters too. The A-series uses flat tappets, and ZDDP protects the cam lobes and followers, especially on cold starts. Many modern oils have much less of it. Choose an oil sold for classic flat tappet engines.

MGOC Spares suggests changing the oil around every 3,000 miles or once a year, whichever comes first. If the car does few miles, go by time rather than mileage.

Signs an A-series needs attention, according to buyer’s guides from Autocar and Classic & Sports Car:

• rattles, leaks and heavy breathing from the engine
• low oil pressure, oil smoke and fumes
• a leaking head gasket, worn valve stem seals or noisy tappets
• tappet clearances closing up with a loss of power, which can mean the head needs hardened valve seat inserts

On the 1500 engine, Classic & Sports Car warns about crankshaft thrust washer failure. Its tip is to watch the front pulley while someone presses the clutch. Autocar adds that the 1500 had weak crankshaft journals, so listen for rumbling from the bottom of the engine.

If the oil pressure gauge drops sharply or the oil light comes on, stop the engine and get it checked. For engines that are already badly worn, we do classic engine rebuilds in our Kent workshop.

Kingpins and trunnions: grease them often

The front suspension needs more attention than most modern cars. Classic & Sports Car says the front end “needs frequent lubrication”, and tells buyers to check the kingpins, trunnions, lower wishbones and wishbone pivots.

How often? An Enjoying MG article by Richard Ladds recommends greasing the front suspension at every 6,000-mile service, or at least every six months. If your car does few miles, the six-month rule is the one that counts.

The same article makes a few useful points:

• King pin or swivel pin wear is a common cause of MOT failure on MGs, most often due to lack of maintenance.
• Get a firm fit on the nipple and keep pumping. Old, dirty grease comes out first, then the flow runs clean.
• Avoid graphited grease on king pins, as it is not suitable for machined surfaces.
• If a nipple will not take grease, it may be blocked. Pressing the centre ball with a small nail can clear it.

Autocar lists worn or corroded kingpins among the common faults on Midgets. It also suggests looking for fresh grease on the lubrication points as a sign of a car that has been looked after. If the steering feels loose, heavy or knocks over bumps, have it checked before you drive far.

Lever-arm dampers

These cars were designed with Armstrong lever-arm dampers. On the front, the damper does more than control bounce. On the Frogeye Sprite, the lever-arm damper acts as the top link of the front suspension, so a worn one can affect how the wheel is held as well as the ride.

Autocar names leaking dampers as a common fault. A bouncy ride, or oil around the damper body, is a reason to have them looked at. Check your workshop manual for the correct fluid and filling method for your model.

Rust: where to look on a Spridget

Rust is the biggest threat to these cars. Autocar says the sills, A-posts, doors and wheel arches rust badly. It also flags:

• the floors, especially on cars used with the roof down in wet weather, which soaks the carpets
• the boot floor, particularly where it meets the rear upright panel
• the rear spring hangers, which corrode badly

Classic & Sports Car adds two checks. Use a magnet to look for filler where the front wing, sill and A-post meet. And look under the carpets at the box section above the back of the sill, over the rear wheel arch, which is often ignored.

Keeping drain holes clear, drying wet carpets and washing mud from the underside all help. Our MGB maintenance guide covers rust prevention on the bigger MG in more detail, and much of it applies here too.

How we can help

We are a mobile mechanic based in Aylesham, and classic car work is a big part of what we do. Our classic car servicing in Kent covers Canterbury, Dover, Deal, Sandwich, Folkestone and the villages in between.

We can service your Midget or Sprite on your driveway, including oil and filter changes and greasing, and carry out fault finding when it is not running right. We also offer recommissioning for cars that have been laid up. If you think there is a suspension or steering fault, we can come out, diagnose the cause and tell you what it needs.

Labour is £30-£50 per hour depending on the job, and parts are extra. We agree the price with you on WhatsApp before any work starts.

Frequently asked questions

Are the MG Midget and Austin-Healey Sprite the same car?
Mechanically, yes. The Midget began as a badge-engineered Mk II Sprite, and later cars differed mainly in badges and trim. The Mk IV Midget’s 1500 engine is the main exception.

How often should I grease the kingpins?
An Enjoying MG article recommends every 6,000 miles or at least every six months. Little-used cars should go by time.

What oil should a Midget A-series engine use?
MGOC Spares recommends a classic 20W-50 with a high level of zinc (ZDDP) for the flat tappet engine.

Does my Midget still need an MOT?
It depends on its age and how much it has been changed. Our guide to historic vehicle MOT exemption explains the rules.

Need help? Send a WhatsApp to 07563 350335 with your car’s make and model and we’ll come to you.

Sources

• MG Midget (Wikipedia)
• Austin-Healey Sprite (Wikipedia)
• Buyer’s guide: MG Midget & Austin-Healey Sprite (Classic & Sports Car, January 2025)
• Used car buying guide: MG Midget (Autocar)
• Classic engine oils (MG Owners’ Club Spares)
• Basic maintenance: greasing the front suspension, Richard Ladds, Enjoying MG (via MG Experience)