1973 Fiat 128 Engine Swap

It's all nuts and bolts to install a 1500 into a 1300 128. Intake, exhaust, flywheel, clutch, oil pan, oil pump from the 1300 goes on the 1500 and off you go. Assuming you are keeping the 1300 gearbox. It's actually pretty simple.
Yes I think I’d prefer keeping the 4 speed gearbox instead of the 5 speed since I heard there really isn’t much of a difference
 
I would start with a carb and put all the fuel injection stuff in a box for now. I'm not sure if the injection parts will fit in the engine bay. I'm sure folks have done this. All the injection parts are bolt on and off. No problem bolting on the 128 intake manifold and carb. An injected X comes with a very nice electronic ignition so I would probably use that.
 
I would install the engine with the fuel injection and put all the carb stuff in a box forever.

The fuel injection system is effectively stand alone, the wiring is completely separate from the wiring harness in the rest of the car. It requires power, a fuse and a power connection from the ignition switch.

You will have to reroute some wiring due to the front drive engine with the primary injection electrical parts now behind the engine versus in front as it is on the X. There should be enough wire to accommodate the change in placement for the most part but expect to have to do some wiring extension of some of the wiring.

Get the engine running properly before you pull it and then shift everything over starting with the wiring and then the engine.
 
1300 to 1500 really require nearly no mods, the 5 speed does require a few changes though... If you keep the 4 speed though, the 1500 goes in just like the 1300 comes out😁
I want to keep the 5 speed. Can I just pull out the engine and trane from the x and drop it into the 128?
 
The 128 and the 5 speed from an X are very different. The X transmission is shifted from the front, the 128 from the rear. Additionally the driveshafts are tripoids on the 128 versus CVs on the X transmission.

There are two approaches to getting a 5 speed in a 128: getting a Yugo 5 speed transmission which uses the same axle approach or getting a Strada 5 speed and making custom axles which goes from 128 outer CV’s to the inner CVs used on a Strada transmission. Both of these transmission shift from the rear.

There is a third option which is rare and hard to find, a 5 speed kit which added the fifth gear onto the 4 speed transmission. It will be hard to find such a kit.

The easiest thing to do will be to just switch the engines and then find the parts to do the five speed conversion later.

Take if from me, get the car going and driving and then take on the various changes to the car. A car in pieces tends to stay in pieces.
 
I would start with a carb and put all the fuel injection stuff in a box for now. I'm not sure if the injection parts will fit in the engine bay. I'm sure folks have done this. All the injection parts are bolt on and off. No problem bolting on the 128 intake manifold and carb. An injected X comes with a very nice electronic ignition so I would probably use that.

To be honest and clear, the advice @carl is offering will be easier and faster to execute. Carl has tons of experience around converting a car to carbs, if this is something you choose to do, you would be wise to follow his advice and garner his input.

The negative about just bolting on what you have is that you will end up with the same emission strangled intake and carb the 1300 had. Both of these issues can be dealt with if you want to go to a single DCNF, dual DCNFs or even IDFs which have manifolds available to mate to either the 1300 or 1500. There are other carbs and manifolds for other twin throated carbs as well which are a bit less complex to install and cheaper.
 
In this situation I go for the carb as it's what I call a two box system, a fuel pump and a carb...and if your current carb is working then you know this will get the 1500 up and running. Then, as you drive around and enjoy the extra torque of the bigger motor you can plan your conversion to fuel injection. Going straight to the fuel injection means a large plenum an lots of plumbing. Then you need to add the injection electrical harness and don't forget all the sensors needed. You could end up with the car sitting on your driveway for months while you sort it all out. Oh yea, don't forget to install and wire up the special injection fuel pump.

We tend to fall into two camps here, guys who prefer carbs (me) an those who prefer fuel injection and we like to trash talk each other.
 
The Fiat SOHC 1300 will cruise all day at 80 mph, it's high revving and was fine on the L.A. freeways.. That being said, some can never have too much power. I just installed a 1500 from an X19 +5 speed from a Regata, and I'm building a 2 litre for over the top laughs..
I would definitely NOT attempt a rear wheel drive conversion. The car has a flat pan bottom, there is no trans/driveshaft tunnel, the rear end needs to stay Independent suspended as there is no room for a solid rear axle, so the diff/axel selection becomes difficult. Plus, there's nothing wrong with the 128 front wheel drive, 4 wheel MacPherson strut suspended, it will scream though the California canyons quite nicely, so unless you're planning on drag racing I would leave it.... I would be a lot more concerned about the year of manufacture for registration in CA, you're going to have to SMOG that car..... 🤪 1975 and earlier is generally how you want to go..
I just bought a rusted up 85 X19. Planning on pulling the engine this weekend. I read somewhere tho that the 5 speed transmission does not fit into the 128. How did you get yours to fit?
 
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the title matches the vin and license plate as a 1973 fiat 128.

As I & others have said earlier, the physical attributes of the car itself say it is a 1975-on model, regardless of what your title says (titles can be in error). The aluminum-type bumpers on your car were introduced on the 1975 models, & the bumper shock technology used to mount them was introduced on the 1974 models (along with the methods of mounting the shock-tubes to the chassis, & the cut-outs in the front panel for the shocks to pass through). The slat-style radiator grille you have was also fitted to 1974-on models. The interior upholstered panels on your car feature a 1975-on embossing pattern. See a pattern here yet? Unless someone was reviving a '73 car using parts from a '75 donor, the chances of your car actually being a '73 appear pretty slim (but still possible).

The VIN itself will show the year of manufacture compared to known 128 VIN production charts. The sequencing of the letters/numbers of the license plate only indicate when the car was first sold/registered, but can be compared to other CA-based Xweb 128 owner cars for general referencing (year-wise). Most telling of all will be the white VIN tag that is mounted on the lower B-post of the driver-side door opening, which has the month/year listed on it in a box in the upper right corner. (I'm guessing that if someone modified the year on the Title, they most likely would remove this tag from the car as well, so it might be missing).

Also of note for your engine swap consideration: if this is a '76-on model, you'll need to retain all of the smog/emissions equipment on the engine/car in order to pass the CA-required smog inspection.
 
Your photo in your related "128 Seats Swap" post shows that your car is definitely not a '73 model:

128.jpeg


The raised section of the floor visible under the passenger-side seat was done by the factory to provide clearance for a catalytic converter to be mounted under the car. 1973 models did not have a catalytic converter (1975 was the first year a c/c was mandated).
 
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Your photo in your related "128 Seats Swap" post shows that your car is definitely not a '73 model:

View attachment 35578

The raised section of the floor visible under the passenger-side seat was done by the factory to provide clearance for a catalytic converter to be mounted under the car. 1973 models did not have a catalytic converter.
Noooooo so the small vin plate on the front windshield and California license plate matching the pink slip is all a lie! 😢
 
I once registered a titleless 124 coupe with a "title kit" that included a metal vin plate and the title that went with it. I drove the car for a few years but had absolutely no intention to sell the car this way. Turns out I returned the body to the guy who gave it to me and the title kit back to the guy who gave me that. I'm sure others may not have the same scruples as me. Don't all Fiats have the vin number stamped into the sheet metal, I know on the 124s it's on the top of the firewall and fairly easy to miss.
 
Don't all Fiats have the vin number stamped into the sheet metal, I know on the 124s it's on the top of the firewall and fairly easy to miss.

Yes, on 128's it's stamped into the passenger-side front inner fender/strut tower, right next to the large alloy VIN tag (similar to an X1/9).
 
Noooooo so the small vin plate on the front windshield and California license plate matching the pink slip is all a lie! 😢

Do these also match the VIN stamped into the body & alloy VIN tag in the engine bay? (passenger side) And on the white plastic VIN tag on the driver-side B-post/door frame?
 
Honestly, I wouldn't worry to much about the VIN, etc. You have an awesome project and with the help of this forum, we can make sure you end up with an awesome car. Just wait until you drive it, you will have a stupid grin on your face for a long dang time.
 
D
Do these also match the VIN stamped into the body & alloy VIN tag in the engine bay? (passenger side) And on the white plastic VIN tag on the driver-side B-post/door frame?
No, the title doesn’t match the vin on the passenger side strut tower.
 

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