On Land Rover Engine Conversions.
Nissan 5-spd gearbox (blue) and Mark's adaptors to Holden engine
and Land Rover transfer case.
Holden (General Motors) engine adaptors: there are several sources making them, some companies and some private individuals. It started with a company in Geelong making adaptors for Vanguard 2+L 4cyl motors in the 50s - more power than F-head (same block as Fergy) and freely available then apparently. A Sydney mob subsequently started making some for Holdens, in the 60s I think. The main difference in types is cast iron or even alloy models, vs welded steel plate models. I far prefer the latter, much stronger and neater, and threads don't rip so easily. I have 5 in stock at present for various models: any offers welcome [4WD will forward email] (they are in QLD).
I have met a few people making their own designs, in limited numbers (probably somewhat copied from commercial models).
With any conversion you need to consider:
- most kits use the Rover clutch on the Holden flywheel, some use the Holden clutch, a few use the Rover flywheel. Invariably there are some machining or drilling changes that are best done by experts, messy to recover from any mistakes here.
- spigot bush size difference in the Holden flywheel means a new bush is needed, don't know if this is freely available from bush suppliers.
- how is the adaptor attached to the engine? Usually by bolts to the back of the block in the same positions as the proper flywheel cover, but it may need longer bolts or flatter heads.
- how is the gearbox attached to the adaptor? It may need studs or bolts of different length or thread from vehicle originals.
- beware of different bell-housing hole patterns: Series I differs from later, and Series II has thicker layshaft after 1961? so you can't fit a Series I bell-housing onto a later Series II box or vice versa to match up bolt holes. This means that a 1959-61 bell-housing is worth its weight in halfshafts to Series I owners.
- need to get proper engine mounting brackets for a Holden block, that reposition appropriately for Land Rover chassis mounts. Welded are best, and need easy access to the mount studs for those many engine mounts you are going to have to replace due to added torque and oil-spray effects.
- make sure the engine is appropriate in power and condition as it will rev its guts out even with overdrive or diff surgery. The cogniscenti swear by 186 or 179, claiming the 202 gets holed pistons more easily. If you can get a `186S' with hardened crank, that's a bonus. Smaller models are not so desirable, but I have heard of 121? in a vehicle.
- make sure the carbie is appropriately jetted and set up. Problems here can be a cause of premature engine death and massive fuel consumption.
- decide whether to continue to use the generator (on an older Landy) or change to alternator, the mounting brackets are different of course.
- I don't know about distributor characteristics for Holdens but suspect that there may be differences between models.
A major warning is that the adaptor must be centred properly since the gearbox and clutch esp' will wear dramatically if the input shaft does not run true. You can check this using flywheel run-out dial gauge measurements at different positions around adaptor.
In the USA there is a different family of adaptors, for USA engines. In South Africa we used to put Chev V6 2.5 up to 4.1 L in, went very well, small motor and lots of space to get in. The main disadvantage with a Holden of course is the radiator issue: need a large unit for good cooling at high revs, but the engine is far forward so you need to move the radiator about 2-3 inches. This involves a chassis cut if the radiator is deep. I have seen some shallow crossflow radiators used, e.g. Rover V8, but it always needs surgery somewhere, if lucky only on the radiator valence not chassis. The ideal situation is to get a Series III 6cyl firewall and gearbox mounts, shorten/lengthen propshafts and just move whole powertrain backwards. My Series III has intact chassis and firewall as it was originally a 6cyl. Some adaptors also interfere with the standard 4cyl firewall so need surgery or skillful lowering of gearbox mounts, often by only 1/2 inch or so.
- Anthony Maeder © 1995.Further Reading:
4WD Vehicles A-Z
4WD Toys & Models
History of 4WDs