Would it be hard to fit a SPI 1108cc Fire engine into the Uno? And have it running the SPI system?
Quite a lot of work for a small gain, I think. The biggest problem to think about is the fuel supply. The 999cc FIRE has a mechanical pump that sucks petrol from the plastic fuel tank. The 1108cc SPI from the Punto will rely on an electric pump in the (steel?) tank, which I don't think will fit the Uno tank (I could be wrong). Therefore I think you will need the steel fuel tank out of a later (Mk2) Uno that has SPI, e.g. a newer Uno 45 than you have.
Then you have the rest of the ECU and wiring to think about - quite a lot of bits, my biggest concern here is that you end up destroying a serviceable Punto. I think you'd be better off to think about getting a 1242cc 8V engine from a wreckers and use that in the Uno instead (along with a later Uno fuel tank as mentioned) - could be a fun little project. But check with your insurance company too.
I can agree with your reasoning for the decision - I've driven Mk1 Uno 45 carburetted FIREs, and while they're quite nice and smooth most of the time, the manual choke is very old hat now (I wonder if I'm the only person who's forgotten to push the choke in on a long trip
) and there can be bad stuttering/flat spots especially when cold - has to be driven quite hard to get anywhere. In the words of my father (referring to earlier cars, but just as valid here) an Uno 45 FIRE "wouldn't pull the skin off a rice pudding when cold" - needs lots of revs just to move the car and dies way too easily, often needs restarting several times
I agree that your mother will appreciate the smoothness of an SPI engine and it will probably be just as economical, if not more so.
But I wouldn't bother with taking a Punto off the road to do it. That's just my thoughts, don't let me stop you doing whatever you decide to do
As an interim measure (before undertaking the engine swap), you might like to check over a few things on the Uno 45 at the moment if you haven't already (just a few of my favourites, reads a bit like an old 70's-style Haynes manual, I apologise if you already thought of these):
- Check the vacuum advance capsule (should not be possible to draw air through it, otherwise it's an air leak that affects idling, plus the timing is wrong)
- Check that the cam timing is correct (especially if cambelt recently changed). Remove cambelt cover (three bolts). With the flywheel notch at 0 degrees (TDC) in the clutch bellhousing window, the fine line on the cam pulley should align with a V-shaped notch in the cam cover at about '12 minutes to the hour' - i.e. just above the joint between cylinder head and cam cover. Common mistake is to have the fine line horizontal (in line with the joint), which is one tooth retarded - knocks the edge off the performance even though engine runs smoothly. Check belt condition (look for cracks/perishing) and replace as necessary, though if the belt does fail in service, the engine is not damaged
- Reset the ignition timing to 5 degrees BTDC with vacuum advance disconnected, timing light on cylinder 1, engine running slowly
- Check/change the spark plugs, inspect leads and cap with engine running in the dark to look for flashes of light (high voltage tracking), particularly on the distributor cap itself between the closely-spaced leads (all four are in line)
- Check/change air filter. Make sure the hot air pipe to the air filter is in place
- Remove carburettor jets (with air filter housing off) and check for blockage/debris. If debris found, remove carburettor top and blow out with compressed air, then replace (or fit) fuel filter between pump and carburettor
- Check the choke linkage is set correctly (with its fast idle screw set to increase engine speed to 2000RPM before choke flap starts to close)
- Check the thermostat isn't stuck open (preventing engine warm-up), a very common fault
- Grease the clutch cable fitting on the pedal, and also the semicircular block at the clutch arm on the gearbox
- And finally, repair slack by inserting washers at the pivot on the gear lever itself, if applicable. On a similar note, check handbrake lever for loose (cracked) mountings, and lower control arm balljoints for slackness causing wandering/lurches while driving, though I expect these will be picked up in the MOT check
That's just a quick checklist of many possible items that could have caused it to be "abit ****ty to run recently"
As you'll know by now, the 'annual service' for an old Uno usually involves a bit more fettling than just changing the oil as we might for a newer car. I usually find that a few hours' work reaps big rewards!
Just resetting the ignition timing can immediately liberate an extra 10mph of top speed...
-Alex