Fitting an Isuzu Bellett with a different engine (transplants)

So, the old engine is tired and you would like to update it to something a little better, and faster. There are several choices available to the Bellett enthusiasts’ wish for more power and later technology. 

The standard Bellett 1500cc engine, used in the sedans.

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Craig Robinsons' Bellett sedan fitted with hot Gemini SOHC engine.

This is a fairly simple conversion, only requiring new engine mounts off the front of the engine and slight modifications to the transmission tunnel and gearbox mount. The Gemini gearbox must be used, as the Gemini starter motor is on the other side.

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My previous 1966 Bellett sedan fitted with Isuzu 1800cc DOHC engine  and twin SU carburetors.

Again this is pretty simple, with similar engine mount requirements but the Bellett gearbox can be used. This car has a genuine DOHC 4 speed with remote shifter. The handbrake lever had to be relocated rearwards.

Glenn's DOHC Bellett

2000cc Isuzu DOHC, fuel injected, in my previous 1967 Bellett GT  I fitted a hydraulic clutch to the 5 speed gearbox.

 dohc-efi.jpg (17205 bytes)

Bellett Engine Swaps

So, the old engine is tired and you would like to update it to something a little better, and faster. There are several choices available to the Bellett enthusiasts’ wish for more power and later technology. The choices can be summarized as follows in order of power available (unmodified).

A) Gemini SOHC 1600 engine and gearbox (also 1800/2000 Rodeo)

Fitting is fairly simple requiring fabricated engine mounts to front mount the Gemini engine. Clearance around the oil filter on the right hand side should be born in mind. The standard sump fits in a Bellett. The clutch mechanism can be either converted to cable type using a Gemini cable and a modified clutch pedal to provide an extension with a hook on the top for the cable. Or, the Bellett mechanism can be used if the Gemini box is converted to a pull type action. Fairly easy by fitting a Bellett throw out fork and moving the internal pivot point. The rear gearbox mounting holes need to be moved back by 80mm. The lever comes out the original hole. The tail shaft will fit, depending upon the gearbox spline. Some extra clearance for the starter motor requires the firewall to be modified slightly also. Speedo cable fits and gauges will work too.

This conversion is probably the favourite as these engines are still available and can be cheaply rebuilt, although head corrosion is a big problem, so pick an engine with care.

B) Isuzu DOHC 1800/2000 (twin cam)

Probably an easier conversion than the Gemini motor as the front mounts can be adapted from Bellett mounts and the starter is on the left. Gearbox may be either Bellett or genuine twin cam 5 speed or even a Rodeo 5 speed. Rear mounts are 80mm further back. Some engines have the correct sump, others may require the fitting of a Gemini SOHC sump with the front 100mm (approx.) removed and the original sumps front grafted to it. The oil filter on the engine should be of the type that points upwards, not forward at an angle. (from an early model 1800 SOHC engine as fitted to late model Bellett GT's)

These engines are getting hard to find now and spare parts are a big problem with them, especially gaskets, which will make a rebuild expensive.

C) Piazza 2000 Turbo

This conversion is not for the faint hearted, either in the fitting or possibly the driving. (power to weight approaches that of a 5.7litre V8 HSV Commodore) This engine is a very tight fit in a Bellett engine bay and much more difficult to fit than either of the above. New front mounted engine mounts need to be fabricated and the alternator must be moved over to the right hand side of the engine where another problem awaits you. The oil filter block. I should also mention that the engine needs to be fitted about 13mm further forward to clear the rear mounted pipes. A small recess in the firewall is required to clear the rear mounted distributor just to complicate things. The distributor, by the way, is solid state and needs a special electronic box to drive the coil. Back to the oil filter block. This thing, which is essential, sits smack in the middle of the engine mount on the cross member so it has to go, somewhere. How to do this is a problem since it carries all the oil passage ways to the engine for the filter, oil cooler lines etc. One way, is to machine up an alloy adapter which allows the thing to be rotated, moved up and back. Possibly expensive if you need to get someone to do it for you. Once that is solved, you can use either a Piazza gearbox or possibly a Gemini box, 4 or 5 speed. Clutch mods as per the Gemini swap info.

This engine, is of course, fuel injected and either the original computer and loom etc are required or an aftermarket type, along with efi fuel pumps, return fuel line to tank, etc. The engine is originally fitted with an intercooler and remote oil cooler which should also be fitted, if possible. Fitting these into a Bellett is also a challenge!

A disk brake conversion (preferably all wheels) and power assistance is essential for this conversion along with an engineers inspection/certificate. (about $450)

One advantage of this conversion is that parts are available from Holden dealers, but are expensive. The engines themselves are available occasionally, from the usual Japanese engine importers. Prices vary a lot, so shop around. (about $1500 in Feb 2000) Don’t expect to find many parts from wreckers as very few will touch them and those that do think they are made of gold, so be warned.  I guess they are, since apparently only about 200 cars were imported.

This is just a brief rundown of the methods I have used to tackle these conversions. If you have any questions, feel free to contact me.

1800 SOHC engine in a 1971 Bellett GT

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The DOHC in 1600, 1800, or 2000cc variants. This is a 1800 efi type (ex Gemini ZZ) Note the oil filter housing should be changed for the type that places the filter in an upright position (from a SOHC engine) About 95 -100hp

These engines are extremely rare.

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Sump is from a 1600cc SOHC gemini engine which needs to be shortened at the front (see overhang near pulley in picture above) or cut and shut with the original sump off the DOHC engine. About 120hp.


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The Piazza 4ZCT 2000cc turbo engine. Very tight fit, note the oil filter/cooler casting on front right (left in picture) of the engine. This has to be removed and turned 90 degrees to the left of picture. Alternator needs to be moved to this side also. A fair bit of fabrication required. Intercooler required and very hard to fit since little room behind grille. If the radiator is moved back about 50mm, then a small intercooler will fit. Holes need to be made in the radiator support panel for the pipes.  This engine is about 180hp.

Late Gemini 4XE1 Turbo engine, to a Bellett

This is not a project I have done myself but I have some pictures of a conversion, using the FWD Gemini 4XE1 turbo engine fitted, (using a home-made adapter plate) with a Nissan (!) FJ20 5 speed gearbox and then turned to drive the rear wheels in the Bellett.

An excellent job done here. Findin gone of these engines, though, will be difficult.



 No guarantees are given or implied as to the suitability of this material for any purpose whatsoever. You should contact your local authorities before modifying your vehicle.

Last updated December 26, 2006