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Celica (A20/A40)

1970-1981 / Coupe / Liftback / Japan

All Celica (A20/A40) problems All workshop issues
Common Engine -- 18R-G Twin-Cam

Twin Carburettor Synchronisation

Symptoms

Uneven idle, poor throttle response, one side running rich while the other runs lean.

Cause

The twin side-draft carburettors (Mikuni-Solex or Aisin) must be synchronised -- both carburettors must deliver equal fuel and air at every throttle position. Synchronisation drifts with vibration and thermal cycling. Throttle linkage wear also affects balance.

Fix

  1. 1 Synchronise the carburettors using a flow meter or Unisyn tool. This is a regular maintenance item -
  2. 2 check synchronisation every 10,000 km or whenever the car idles unevenly. Rebuild kits for the side-draft carburettors: $50--100 each. Synchronisation tools: $30--60
Cost mentioned in fix
$50$30

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Other known issues

Minor Engine -- 18R-G Twin-Cam

Twin-Cam Head Component Scarcity

When the twin-cam head needs work -- cracked head, worn cam journals, broken valve springs -- replacement parts are difficult to source.
Minor Engine -- 18R-G Twin-Cam

Cam Journal Wear

Ticking noise from the valve train, loss of power, rough running.
Critical Body and Structure

Floor Pan Corrosion

Soft or thinning floors, particularly in the driver's and passenger's footwells. Wet carpet after rain. Road noise increases.
Critical Body and Structure

Lower Quarter Panel Corrosion

Rust and perforation in the lower rear quarter panels, behind and above the rear wheels.
Minor Body and Structure

Inner Guard Corrosion

Rust in the engine bay around the inner fenders and strut tower bases.
Minor Body and Structure

Sill Corrosion

The rocker panels soften, crumble, and lose structural integrity.
View all 18 Celica (A20/A40) problems