| || |
Slotting the Toyota 4AGE or Datsun 1200 into your Moggie
In New Zealand, the most common engines fitted to Minors are the Morris Marina 1300 and the Datsun 1200 engines, although, the much more modern and powerful Toyota 4A-GE Twin Cam 1600 engine is making an impression on the Modifying scene.
In the UK a very popular engine swap is the Fiat Twin Cam.
Another engine making an appearance on the transplant scene is the Rover K-Series twin cam engine. It's available in 1100, 1400 and 1800cc sizes and there's a kit being produced by the likes of JLH Minor restorations.
If you're looking for high-revving POWER in your Minor then this must be one of the best available options. The engines come from the rear-wheel-drive versions of the Toyota Corolla range, dating from about 1983 to about 1988. The engine fits surprisingly well into the Minor engine bay. It's almost exactly the same length as the Datsun 1200, maybe even a little shorter (the ancillaries like water pump and fan blades stick out less).
The 4A-GE puts out around 110bhp in standard form, so if you follow this path you should expect to have to change the rear axle, and obviously the brakes all 'round. The poor old Minor diff just wont take the power and the front drums are hopelessly inadequate for slowing a car rapidly down from a possible top speed of around 130mph/200kph !
The choice of differential is up to you, but the humble Vauxhall Viva does an excellent job of coping with the standard power output of a 4A-GE. If you are looking for more power, then think about buying an entire RWD donor Corolla. Buying a donor car will ensure that you get all the right bits, the diff will be designed for the engine, and with a bit of prudent shopping around, you may even get a disc braked rear end. For these try finding a Trueno or Sprinter (model names may differ outside of NZ).
If buying the engine & box by itself, make sure that you also get ALL of the plumbing. This includes all wiring from the engine back to the plug fittings, the electronic ignition, fuel injection unit and the 'Black Box'. The Box is VERY important, 'cause it's this that controls all the electronics, ignition timing, knock sensor etc etc. Buying a Box by itself later could prove expensive.
Fitting of the engine, gearbox and new diff should probably be performed by a professional. Fitting a new diff involves manufacturing new spring & axle mounts, and the WOF/MOT men will look closely at the work done.
My advise when it comes to welding important bits - Let Someone Else Do It!
Even MORE Power!
The Toyota MR2. Toyota's mass produced 'Sports' car. 1600cc Twin Cam. 130bhp in standard form. Plenty you say? Want more? Of course you do, so, SUPERCHARGE IT!
The 4A-GE is also available in Supercharged form, as in the 4A-GZE, as fitted to the MR2. Fit one of these babies into a Minor and you'll have one awesome piece of machinery! I have yet to see one in-the-steel, but I'm sure one can't be far away. The 4A-GZE puts out around 150-160bhp. These engines also perform well if converted to use 'Old-Style' carburetors. An Off-Roading friend of mine removed ALL of the electronics and fuel injection, made up a casting to accept a Holley 350 carburetor, fitted a smaller supercharger pulley and locked it in place so that it operates at all engine revs giving about 15 pounds boost at all times! Driving through a VW gearbox (the engine sits in the back of the Off-Roader) it dynoed at 160bhp AT THE WHEELS!
Fit a 'GZE to a standard-looking Minor and you have an awesome Sleeper!
The Datsun A-series Engine
Believe it or not, the Datsun 1200 is actually very closely related to the Austin/Morris A-series engine. The Datsun A10 engine was rated at around 1000cc and apart from superior manufacturing and machining processes, was in fact a clone of the good old 850 and 948cc engines of the late 1950's.
The Japanese, with their know-how of taking a good idea and making it great, transformed the ageing BMC lump into a fairly good performing, high(ish)-revving engine of 1170cc. This powered a range of Datsuns from the early 1200 series of cars through to the 120Y and Sunny family-cars.
When transplanted into the Minor, the slightly lighter body and the lower ratio differential results in a liveliness from the Datsun 1200/120Y engine that hadn't previously been seen in it's mid-size vehicle incarnation.
A Datsun-powered Morrie is a Morrie transformed; capable of cruising happily at 115kph/70mph all day, and even 170kph/105mph with little modification.
is Best - 1200 or 120Y?
It doesn't really matter which version of the engine you get, although you should probably go for as late a model as possible, simply because it's far less likely to have done HUGE numbers of miles. That said though, it's still fairly easy and cheap to fit new rings and bearings to all of the Datsun engines, and you'll probably want to do that as a matter of course once everything is set up for your Minor.
Fitting the Engine and Gearbox
There is a subtle difference between the blocks of the 1200 and 120Y, and this is in the area of engine mountings. Depending on which block you have, when using Ford Escort or Cortina engine mounts, the engine will sit either WAY down in the engine bay, or will be lopsided. Both cases will mean when fitting the engine mounts to your Minor you will have to weld the mounts on top of an 'n'-shaped piece of thick steel (preferably at least 3mm thick).
When fitting the engine and gearbox, you may also find (depending on how high the engine is placed in the engine bay) that the top of the gearbox fouls on the Minor steering rack. This is easily fixed by shaving some of the excess aluminium from the ridge that runs down the top of the box'. In extreme cases you may have to actually cut a hole in the top of the 'box. Don't worry, the 'box is not load-bearing and wont collapse (not unless it's a really HUGE hole, in which case there's something wrong with your setup elsewhere!!). If you do end up opening a hole in the box, you may like to think about cutting out a piece of sheet aluminium and riveting or glueing it over the hole to keep dirt and grime away from the clutch mechanism.
When positioning the engine in the engine bay, it will be necessary to push the engine as far back in the engine bay as possible in order for the fan blades to clear the radiator. DO NOT DRILL HOLES OR WELD THE ENGINE MOUNTS IN PLACE YET !!
Mark out where you think the engine mounts should be positioned, but this may have to be shifted slightly when fitting the gearbox cross member and the drive shaft.
Gearbox Cross Member and Drive Shaft
Depending on the type of engine/box you have, you may be able to use the original Minor gearbox Cross member. The later model Datsun 120Y engines had the Cross member mounting positions located further back on the gearbox than the earlier 1200-series engines. These later gearbox mountings are in almost exactly the right spot for bolting to the existing Minor Cross member. Just a couple of extra long bolts and a rubber bush is required to secure the gearbox in place. At this stage I recommend you offer up the Datsun drive shaft to the Minor diff'. It should bolt up directly to the Minor diff', although you may require slightly longer bolts.
Fit the nose of the drive shaft into the back of the gearbox and adjust the position of the engine & 'box so that there is 15 - 20mm of slide movement on the drive shaft splines. This will then give you the required position of the engine mounts. Of course this may have positioned the engine too far forward and the fan blades will foul the radiator. In this case you will either have to fit an electric fan (I suggest in front of the radiator, behind the grill slats), or find yourself a thinner core radiator from a late model vehicle (the standard Minor radiator does an excellent job of cooling the water, and a thinner one shouldn't provide any significant cooling problems. If you're worried, you may like to fit an extra-wide radiator).
You can leave the clutch linkage as-is on the Datsun 'box, but this will result in the lever exiting the 'box high up on the driver's side against the floor pan. If you cut a slot diagonally opposite the current lever slot in the bell housing and rotate the clutch release fork and lever 180 degrees the lever will exit the bell housing at the lower left (passenger side). You will have to build up a pivot point in the bell housing for the clutch fork/lever and also drill and tap two holes in the outside of the bell housing to accept the clutch cable bracket. There is a convenient flat casting in exactly the right spot for this. You will also have to make up a bracket to hold the clutch cable in place. This only needs to be a simple 'L' shape, but you should make it out of 2mm thick steel, at least.
Well, that's the basics of it. I know there's a few murky bits in the text, but because of the infinite number of combinations of engine, gearbox, drive shaft, engine mounts and Minor models, it's impossible to know exactly what you require.
In general, you can expect to have to fit and remove the engine and 'box at least half a dozen times before you get everything in the right place.
Maybe it's easier to get someone else to fit it ... ?