Fiat 128 Engine Swap

Red128

New Member
Just picked up a 73 fiat 128. Debating to swap engine or rebuild original. It has a 1.3L 4 speed but I believe once rebuilt it won’t be fast enough to flow with traffic here in LA. 80mph average. I just don’t know what front wheel drive engine to drop in. I’d like to make it rear wheel drive but that’s a **** ton of work that I’m just not willing to do. Also does anyone know what size wheels fit? I was told 4x98 or 4x100 would fit just fine.
 

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Kevin Channer

True Classic
Just picked up a 73 fiat 128. Debating to swap engine or rebuild original. It has a 1.3L 4 speed but I believe once rebuilt it won’t be fast enough to flow with traffic here in LA. 80mph average. I just don’t know what front wheel drive engine to drop in. I’d like to make it rear wheel drive but that’s a **** ton of work that I’m just not willing to do. Also does anyone know what size wheels fit? I was told 4x98 or 4x100 would fit just fine.
Congratulations on your 128, I have owned a few and have fond memories. Welcome to the Xweb forum! Your engine swap proposal is an interesting idea. The most common approach is the 1500 Fiat engine from a later X 19, It is a fairly straight forward install, and can be enhanced by bigger or dual carbs, hotter cam, and a tubular header. This might put you in the 100-110hp range instead of the 75hp stock. The car will definitely feel faster. Its a light car and even in its stock form it does fine on the freeway. Your options for Fiat alternative engines are very limited. The Fiat 500 Abarth engine would be a great choice but the management system needs to interface with all original components to work well. The Uno Turbo 1.3 is another choice but it is a scarce import and old tech. A non Fiat option I would recommend is the Turbo engine and trans from a Chevy Sonic. They are powerful, reliable, and tune able and available. A member here installed a variant of this engine in his X 19 and it seems to be fantastic.
 

carl

True Classic
The 1500 X motor is a bolt in and makes the car OK for driving in modern traffic. Wheels have always been a problem with the 4X98 bolt pattern. Any classic Fiat wheel will fit, Maserati Biturbo wheels look great and are 14" and most of our vendors sell new wheels most 15".
The 128 has a pretty skinny engine bay so maybe that's why you don't hear about Honda motor swaps.
 

rx1900

1981 X1/9
Congrats and welcome !!!

First off though.......I think something is not quite right here....

I'm sure Jeff S. will be along to correct me - or confirm - BUT...I think a 1973 Fiat 128 would have come with an 1116cc engine with a single barrel carb ( easy to check - remove the air cleaner lid and look down inside ). Only from 1974 on did they come with a 1290 cc engine ( with a 2 barrel carb ).

And....a 1973 128 would have come with slim chrome bumpers. In 1974 ( only I think ) with big black impact bumpers. And from 1975 on with bumpers like the one in your pic. And I think your grill also indicates it is not a 1973....

So...what does your ownership say ?? Not a big deal...but if it is a 1976 or later that could be a real hassle for you if you live in California. As i think only 1975 and earlier are exempt for emission testing.

Not sure I would bother to rebuild an 1116cc engine when 1290cc engines are easily available. And yes...a 1500cc engine from a '79 on X1/9 - or Strada - can be fitted with some mods..and would give you sufficient power for modern traffic.....
 

Kevin Channer

True Classic
Congrats and welcome !!!

First off though.......I think something is not quite right here....

I'm sure Jeff S. will be along to correct me - or confirm - BUT...I think a 1973 Fiat 128 would have come with an 1116cc engine with a single barrel carb ( easy to check - remove the air cleaner lid and look down inside ). Only from 1974 on did they come with a 1290 cc engine ( with a 2 barrel carb ).

And....a 1973 128 would have come with slim chrome bumpers. In 1974 ( only I think ) with big black impact bumpers. And from 1975 on with bumpers like the one in your pic. And I think your grill also indicates it is not a 1973....

So...what does your ownership say ?? Not a big deal...but if it is a 1976 or later that could be a real hassle for you if you live in California. As i think only 1975 and earlier are exempt for emission testing.

Not sure I would bother to rebuild an 1116cc engine when 1290cc engines are easily available. And yes...a 1500cc engine from a '79 on X1/9 - or Strada - can be fitted with some mods..and would give you sufficient power for modern traffic.....
Yes RX1900, You are correct I noticed that as well, I just presume it was a typo. It looks like a 1978 without seeing the interior.
 

Lowtechprime

Daily Driver
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..
 

Red128

New Member
Congrats and welcome !!!

First off though.......I think something is not quite right here....

I'm sure Jeff S. will be along to correct me - or confirm - BUT...I think a 1973 Fiat 128 would have come with an 1116cc engine with a single barrel carb ( easy to check - remove the air cleaner lid and look down inside ). Only from 1974 on did they come with a 1290 cc engine ( with a 2 barrel carb ).

And....a 1973 128 would have come with slim chrome bumpers. In 1974 ( only I think ) with big black impact bumpers. And from 1975 on with bumpers like the one in your pic. And I think your grill also indicates it is not a 1973....

So...what does your ownership say ?? Not a big deal...but if it is a 1976 or later that could be a real hassle for you if you live in California. As i think only 1975 and earlier are exempt for emission testing.

Not sure I would bother to rebuild an 1116cc engine when 1290cc engines are easily available. And yes...a 1500cc engine from a '79 on X1/9 - or Strada - can be fitted with some mods..and would give you sufficient power for modern traffic.....
the title matches the vin and license plate as a 1973 fiat 128.
 

Red128

New Member
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..
yes it’s a 1973. Do you have step by step on how to swap the engine or maybe a video? I didn’t know it was direct bolt on swap with no mods
 

kmead

Old enough to know better
As you have a car which can be made pretty much what you want you have some options.

Some more pics of what you actually have would help.

First is pulling the engine and transaxle out the top, reinstall the new engine with a new clutch onto the transaxle and drop it back in. Then acquire a nice set of dual DCNFs, a hot cam, header and free flow exhaust and you will be in business. If possible rebuild the 1500 with high compression pistons before you stuff it back into the car.

As engine pulls go this is about the easiest one you will ever run across as there are so few connections beyond the ignition/starter wiring, heater, radiator, fuel lines and of course the drive shafts.

As the title and the reality of the car may not match, you may need to excise some of the emission controls to reduce the amount of plumbing in the engine bay. Keeping the evaporative charcoal filter and its associated lines are about all you need to keep.

4x100Mm bolt circle wheels can work with wobble bolts or nuts if you go to studs.
 

Lowtechprime

Daily Driver
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😁
 

carl

True Classic
The 1500 will need the oil pan, oil pump and dipstick from the 1300. You will also need the 1300 starter, flywheel and clutch assembly. These are simple bolt ons and just use the parts from the 1300 motor that's already in the car. Otherwise, as noted, it drops right in. Use the exhaust and intake from the 1300 as an X motor sits at a different angle from the 128.
 

Jeff Stich

True Classic
First off though.......I think something is not quite right here....

I'm sure Jeff S. will be along to correct me - or confirm - BUT...I think a 1973 Fiat 128 would have come with an 1116cc engine with a single barrel carb ( easy to check - remove the air cleaner lid and look down inside ). Only from 1974 on did they come with a 1290 cc engine ( with a 2 barrel carb ).

And....a 1973 128 would have come with slim chrome bumpers. In 1974 ( only I think ) with big black impact bumpers. And from 1975 on with bumpers like the one in your pic. And I think your grill also indicates it is not a 1973....

So...what does your ownership say ?? Not a big deal...but if it is a 1976 or later that could be a real hassle for you if you live in California. As i think only 1975 and earlier are exempt for emission testing.

Not sure I would bother to rebuild an 1116cc engine when 1290cc engines are easily available. And yes...a 1500cc engine from a '79 on X1/9 - or Strada - can be fitted with some mods..and would give you sufficient power for modern traffic.....
Correct on all of those. 🤓
 

Anthony4G63

Low Mileage
Congrats on getting the 128.
I personally drive a 88 Yugo GVL in the metro side of Puerto Rico, it has a 1.3 from a GVX and I drive it all day in between 70mph and way over 80mphs. Not only that but my family live on the south side of the island so I am always going back and forth, all over the island. Still has the OEM 4 speed and she handles pretty good, I’m currently building a 1.5 with ported and milled head, dual Weber carbs and a few extra goodies for more power. What everyone has said is right on the money about swapping in the 1.5.
Again congrats on the purchase and have lots of fun with it!
 
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