SEO Description: MGA Starter Motor Parts, Lucas M35G-1 Pattern Inertia Starter (New and Reconditioned Exchange), Starter-to-Gearbox Mounting Bolts (Original and 3-Synchro Gearbox), 3/8 UNF Hex Head Bolts, Spring Washers and Later MGB Pre-Engaged Starter for Conversions | MGOC Spares Body copy: The original MGA starter motor is the Lucas M35G-1 inertia-drive starter (Lucas part number 25022), fitted across every variant, pushrod 1500, 1600 and 1600 Mk II, Twin Cam and De Luxe, with only minor production-change updates across the model's lifespan. The M35G-1 is an inertia-drive unit, meaning the starter pinion is thrown into mesh with the flywheel ring gear by a helical spring when the starter spins up (the Bendix drive), then retracts when the engine fires and the pinion's speed exceeds the starter shaft. This is the classic pre-war and post-war Lucas starter configuration, used on virtually every British car until the introduction of pre-engaged starters in the later 1960s.
Production changes across MGA variants
Although the same M35G-1 starter was fitted throughout MGA production, several production-change points affect identification and ordering. Chassis 61504 (January 1959), the introduction of the 15GD engine on late 1500 cars raised the physical position of the starter motor on the engine block. The starter motor itself was not changed, but a rubber cover was fitted between the gearbox tunnel and the right-hand toeboard to protect the exposed Bendix spring. This cover is also found on Twin Cam and all 1600 models.
February 1961, the commutator end bracket and the brush tension springs were modified, a service-level change affecting brush replacement rather than a complete starter redesign. Engine 16GC/6435 (1600 Mk II), the starter motor internals were redesigned on Mk II cars, and the revised unit was listed as the Lucas M35 type (part number 25079). The M35 is interchangeable with the earlier M35G-1, so either starter can be fitted to any MGA. All factory starters were mostly painted engine red to match the engine colour, though some were black.
New and reconditioned exchange starters
MGOC Spares stocks MGA starters in two options. The new or reconditioned starter is supplied outright without requiring a core return, the correct choice when the original starter has been lost, completely failed, or where no usable core is available to exchange. The reconditioned exchange starter is supplied on a core exchange basis with a surcharge on the initial order, refunded when the customer's original starter is returned as a core; the more economical option for routine starter replacement where the original unit is still available as a core. Both specifications cover the Lucas-pattern M35G-1 starter, the item is described as "A+MID" because the same starter specification is shared between the MGA and the MG Midget, both of which use the same inertia-drive Lucas pattern.
MGB pre-engaged starter, for conversion use
A later inertia pre-engaged starter for post-1967 MGB cars is also listed under this node. This is not the factory MGA starter, the post-1967 MGB uses a different, geared pre-engaged starter architecture, but is stocked here for MGA owners who have converted their car to MGB gearbox and bellhousing specification and require the matching pre-engaged starter. This is relevant only to MGAs modified for MGB running gear; for any factory-original or near-original MGA, the M35G-1 inertia starter is the correct item.
Starter-to-gearbox mounting
The starter motor mounts to the bellhousing of the gearbox via two bolts passing through the starter's mounting flange into threaded bosses on the bellhousing. Two bolt specifications are stocked.
The original-pattern 3/8 UNF hex-head bolt, 1 5/8 inches long, is the correct bolt for the factory MGA gearbox and for other non-synchro-on-first BMC gearboxes. The 3-synchro-type starter-to-gearbox bolt is stocked for MGA owners who have upgraded to the later MGB 3-synchro gearbox, which has a different boss specification at the starter mounting point. The MGA's factory gearbox is non-synchromesh on first gear; many owners replace this with the later MGB gearbox during restoration for the better usability, and the 3-synchro bolt is the correct fixing for this common conversion. Spring washers in 3/8 size secure the bolt against vibration loosening.
Ordering considerations
Starter selection starts with whether the car retains its factory-specification gearbox (use the Lucas M35G-1 inertia starter, new/reconditioned or exchange) or has been converted to MGB specification (the post-1967 MGB pre-engaged starter may be appropriate).