4G32 DOHC Engine Specifications

The engine being fitted to my Lancer is from a 1971-72 Galant GTO-MR. It was the first production twin cam engine from Mitsubishi and only 850 were built, all destined for the Japanese domestic market. Due to the rairty of the engine and the fact that it was only available from Japan, tracking down information and verifying it to be correct can be very difficult.

I have managed to obtain a copy of the factory workshop manual for Galant GTO, which includes the GTO-MR, so I have the basic details of the engine.

The factory specifications are below (some of the specs have been changed in my engine):

Engine Transmission Model 4G32-1-90A
Number and arrangements of Cylinders 4 in-line longitudinal
Method of cooling Water
Operation cycles 4
Combustion chamber type semi-spherical
Valve Arrangement Double overhead valve type
Bore and Stroke 76.9 x 86
Total Displacement 1597
Compression ratio 9.5:1
Compression pressure 125psi @ 250rpm
Maximum output 125ps @ 6800rpm
Overall dimensions 616 x 615 x 666 mm (L x H x W)
Engine weight with accessories 142 kg
Piston type solid
No. of piston rings 2 (compression) 1 (oil rings)
Valve timing Intake opens – B.T.D.C. 32º
Valve timing Intake closes – A.B.D.C. 52º
Valve timing Exhaust opens – B.B.D.C. 52º
Valve timing Exhaust closes – A.T.D.C. 32º
Valve Clearance Intake – 0.30
Valve Clearance Exhaust – 0.30
No-load speed rpm 800 to 850
Starting method Starting motor type
Blow-by gas removing system Closed
Ignition method Battery ignition
Ignition timing 18º B.T.D.C. @ 800 rpm
Firing order 1-3-4-2
Ignition coil type TB63
Distributor type TVG- 4CR
Performance of spark advancer Centrifugal type – 0º/500rpm, 16º/2000rpm
Performance of spark advancer Vacuum type – 0º/40mmHg, 20º/160mmHg
Spark plugs Type – BP6ES (NGK)
Spark plugs Thread – 14mm
Spark plugs Plug Gap – 0.7 to 0.8mm
Carburettor Type – Solex type with idle limiter
Carburettor Model – 40PHH
Carburettor Gas valve diameter – 40mm
Carburettor Venturi diameter – 32mm
Carburettor Choke type – Manual choke type
Fuel pump Electromagnetic type
Oil pump type Geared pump type
Oil capacity 5.0 litre

Here are some photos of the engine


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