Hi guys!

There doesn't seem to be much information regarding this kind of swap. Most of what I've seen is either people fitting 16V engines, or P75 engines to SPI cars.

I reckon that, from what I've seen in my car and the donor parts I have, it should be pretty straight forward. However, I've got a few questions about a few bits and bobs, that were raised when I looked up some of the swaps here in the forum, as well as that great guide for the 1.4 swap

So, first of all, here's what I have. The car is a Seicento S, but it's an MPI version, so a 1.1. It has the older (uno-style, I believe) gearbox with the long driveshafts and inner cups. No power steering, AC, electric windows or any other "extra" stuff in this car.

The donor parts are a huge mix of things I collected in my garage throughout the years. For the engine block, I have a PMK2 60 engine block to go in, it still has the original head in it, albeit cracked, would still work for a cento. I also have a spare P75 head laying around with no anciliaries, and in much better condition, so this will be used. A donor gearbox off a Seicento Sporting, and driveshafts off an SPI Seicento Sporting as well.

The main idea here is, for now, to swap the engine with OE anciliaries, and replace the gearbox with the better one from the Sporting. Then build it up from there, with the engine already running and in the car. But a few questions arise, mostly due to the fact that my Sei is not a Sporting to start with.


1. Do the Sporting driveshafts fit the hubs on a standard Sei?

2. Does the standard Sei gearbox lower mount also fit the Sporting gearbox, or should I be looking out to buy a new one?

3. Will the Punto MK2 exhaust manifold fit between the engine and radiator? The catalytic converter is MASSIVE! I reckon this will be needed due to the fact that the Sei manifold is shorter in height (10mm) and should not clear near the sump. It's also a bit more restrictive. A plus is that I want to use aftermarket punto exhaust manifold at a later point in time, so I can have the exhaust system made to order meanwhile.

4. Will the Punto clutch/flywheel fit OK? I reckon it's the same size as the cento, however the part number is different. Maybe the flywheel changes as well?

5. Will the alternator from the Sei fit the 1.2 as a straight swap? I know this is an issue with the 1.4 swap on SPI centos, from the guide, but since the 1.2 8V engine is different... I remember it was even an issue when I swapped my Punto, the 8V alternator had to be spaced out to fit by a couple milimeters.

6. Last but not least, will the harmonic damper from the Punto work? Or if I fit the Sei harmonic damper, will it be a straight swap (i.e. align with the camshaft VR sensor properly)? Not looking forward for oil pump swaps...

7. Bonus question: Is the Grande Punto 1.4 8V MLS headgasket a good swap for the 1.2? From what I've seen, it should fit, measurements look to be about the same, but I don't see anyone talking about it, so maybe it doesn't?

If you guys know the answer to any of these questions, I'd be greatly appreciated. Considering making a guide for this kind of swap afterwards, so people will not have to ask the same questions I did

3) The Punto Mani-Cat won't fit.
4) The flywheel has to match the type of gearbox used.
5) The Seicento Alternator won't fit with the Punto pulley system without spacing.
6) You may have clearance issues with the Alternator belt. The Seicento auxiliary pulley cannot be used with the Punto oil pump without some kind of bodge.
7) MLS head gasket will fit but the compression ratio may be too high for the standard ignition map.

Thanks a lot for your input cc1!

Say, shouldn't the gearbox on the sportings be similar to the Puntos? Then it should be good for the Punto flywheel. This was exactly my concern, since my Sei gearbox is of the older design and it likely won't fit?

Also, can the radiator not be moved forward to clear the Punto cat? It seemed to me like it would fit, albeit a very very tight fit

The Punto and Seicento sporting gearbox's (C514) are the same except for maybe the ratios. You will need new drive shafts for these gearboxes. The gearbox you have is a C526. If you want to keep the manicat then extend/replace the downpipe after the cat on the 1.1 version. The Punto manicat is huge so don't even try to shift the radiator.
If it were me, I would change the oil pump and use the Seicento cam pulley system. Not shure if the cambelt covers will clear the chassis but I think so on the older engines with the slimmer cambelt.

As mentioned, I have a C514 off a Sporting set aside for the swap, along with driveshafts and all. So that one should clear the Punto clutch and flywheel I believe

As for the manifold, I'll look up a solution. If all else fails, extending the original will do!

Should also mention that my MK2 Punto didn't have AC, so the timing teeth are on the outside of the harmonic damper. It actually looks very similar to the Sei one, and not like the ones I've seen on MK1/MK2 Puntos with AC or PAS belt. I'll have to take a better look at it. I really didn't want to replace the oil pump, since this is the major reason for doing the swap anyway... The current one is on it's way out.

thunderfox5 said:

1. Do the Sporting driveshafts fit the hubs on a standard Sei?

Click to expand...

Yes, but I don't think that's what you mean! Sporting driveshafts will fit your hubs, but not you gearbox.

thunderfox5 said:

2. Does the standard Sei gearbox lower mount also fit the Sporting gearbox, or should I be looking out to buy a new one?

Click to expand...

It'll fit

thunderfox5 said:

3. Will the Punto MK2 exhaust manifold fit between the engine and radiator? The catalytic converter is MASSIVE! I reckon this will be needed due to the fact that the Sei manifold is shorter in height (10mm) and should not clear near the sump. It's also a bit more restrictive. A plus is that I want to use aftermarket punto exhaust manifold at a later point in time, so I can have the exhaust system made to order meanwhile.

Click to expand...

No idea. Try it! You may be able to extend the Sei manicat.

thunderfox5 said:

4. Will the Punto clutch/flywheel fit OK? I reckon it's the same size as the cento, however the part number is different. Maybe the flywheel changes as well?

Click to expand...

Flywheel of P60 is probably the same. Certainly the S and SX 1108 flywheel will fit the Sporting, which I believe is the same as the P55/60 one.

thunderfox5 said:

5. Will the alternator from the Sei fit the 1.2 as a straight swap? I know this is an issue with the 1.4 swap on SPI centos, from the guide, but since the 1.2 8V engine is different... I remember it was even an issue when I swapped my Punto, the 8V alternator had to be spaced out to fit by a couple milimeters.

Click to expand...

Historically, folk have used the Cento alternators.

thunderfox5 said:

6. Last but not least, will the harmonic damper from the Punto work? Or if I fit the Sei harmonic damper, will it be a straight swap (i.e. align with the camshaft VR sensor properly)? Not looking forward for oil pump swaps...

Click to expand...

There are two issues, the pulley and the harmonic damper in the pulley. Use the Punto harmonic damper pulley -- the Sei has no damper in there!

thunderfox5 said:

7. Bonus question: Is the Grande Punto 1.4 8V MLS headgasket a good swap for the 1.2? From what I've seen, it should fit, measurements look to be about the same, but I don't see anyone talking about it, so maybe it doesn't?

Click to expand...

The bore is wrong. There's an MLS gasket for later 1.2s, too.

Lots of worms there!

I'd forget the P75 head. Just use the cam. If the P60 block has the lugs for the knock sensor, I'd just use that bottom end and your Sei head. Make sure that the cam and water pump pulleys have the same profile.

Thanks for your input as well fingers99!

So you reckon a 1.2 8V gasket from, let's say, a brand new Panda would be the perfect choice? I can live with the ignition mapping issues, if anything I'll turn to Megasquirt and call it a day.

Sporting driveshafts should fit both the standard hubs and a sporting gearbox then?


I also had a thorough look at the cento this afternoon, and I don't see a visible difference between the 8V alternator on the Punto and Sei. Even the mounts and mounting places are the same. Could obviously be wrong though, but it all seems like a straight swap, I'll have to take some measurements tomorrow and figure it out!

Also, why use the P60 head? The 75 has better porting and I've got the pulleys out anyways, so it's an easy conversion while I'm at it. Also the P60 it's on its skimming limits

Yes, any of the later cars will have a MLS gasket -- talk to Fluffy at eurocarcare,net. In theory you should get the block fine surfaced, but folk have got away without it.

Yes -- hubs are the same on all Cinqs and Seis (apart from the ABS stuff fitted to MS).

P75 is arguably better, but little, if any, better than MPI Sei and has no cam sensor. Inlet mani is very different, takes longer, different impedence injectors. Easier to use the Sei MPI ECU. If it's a non-micro one it'll even be reliable, if a little fussy.

I've taken a good look at the car and all the parts, and some answers popped up:

The alternator is exactly the same as the Punto, even the part number is the same. Since they both are shallow mounted to the block side, I'm taking a wild guess and saying that, even though the harmonic damper is different (and it is, I've checked), the belt spacing should be just fine with the Punto harmonic damper. The VR sensor on the other hand... I don't know if it will fit (i.e. if the size is the same). To be checked.

That's one problem solved for now.

One other question has arisen though: Will the starter that is fitted to the C526 gearbox fit the C514 (Sporting) as well?

The 899 might be a bit under powered? Ideally you need a 0.9Kw starter.

The VR sensor on the other hand...

Click to expand...

No idea what that is!

The 1108 S/SX starter motor will fit and can be used on the C514 box -- there is, though, a strange dowel pin that has to be removed. So do a full trial fit off the car. When I fitted a C514 (Sporting) gearbox to my S I ended up wasting the best part of a day fiddling around in the dark. It's still held on by two, rather than 3, bolts.

That's great to know! Thanks a lot!

I had a look at it earlier, and the motor seemed pretty close to the one fitted to Puntos (which is actually 0.8 kW on my MK2). I'll swap it onto the other engine before I get it inside the car then. Thanks!

By VR sensor I was referring to the crankshaft position sensor, which locates next to the camshaft pulley timing ring.

One more question. In theory, a flywheel/clutch that fits the C514 should also fit the C526, right?

I'm done trying to gather all the pieces for the C514... It's not going to happen in a realistic time scale. This must be finished by saturday at most, and the teardown is only starting today

Flywheel is the same, not 100% about the clutch (when I did the S to Sporting gearbox conversion I swapped the clutch since it was all apart).

Took the damaged driveshaft to a mechanic guy this afternoon who managed to disassemble the whole thing in like 2 minutes.

This may actually be happening with the C514 in after all!

Dismanteling has started... Too late to go back now

I've taken a second look at the C526 and C514 gearboxes. I'll need to swap the speed sensor, since my C514 came off a cable-driven cinq apparently.

Will the VSS sensor fitted to the C526 fit the C514 as well? How about the clutch cable? Seems too short for the C514...

Cable is different. Reverse switch needs the right connector for the (different) switch in the other box.

Not sure about the sensor -- try it?

Yeah, the reverse is different. Will have to adapt the cables.

I guess I'm not escaping a new clutch cable then... Oh well. From what I've seen, the whole clutch assembly is different for the C526 gearbox, so fitting the Punto clutch as intended is a no-go with that one.

That leaves me one of two choices:

- Either replace the flywheel with the cento one on the new engine, and fit the C526 gearbox again, with the damaged passenger side transmission shaft, and worn clutch and god-knows the state of that gearbox since it whines like a mother,

- or replace the gearbox with the C514 but everything will have to be made to fit. I can get a VSS sensor from one of my Punto gearboxes, so that's not a big issue per se. But I really REALLY didn't want to go buy any extra parts to make the C514 fit, and I'll always have to rebuild the damaged transmission shaft I got for this one, buy a new clutch cable. Also, the selector cable bracket is missing, which means a new one from FIAT must be ordered.

Choices choices... I'll know better when I have everything apart.


Any other things I should consider that may be incompatible?

Source a Punto VSS from my parts bin, as well as the cable couplings...

C514 going in, definitely.

Okay, I've got news

Swap is done... But the engine won't start

At first I was trying to use stock ECU w/ stock injectors. Figured it would be able to start even though it would be rough. Much mislead! It sounded like it wanted to start, but nothing.

Then I swapped the injectors with slightly larger injectors off a Punto 85 (these are pico as well, about 30% larger IIRC) to check if there was lack of fuel. Nothing, it was even worse, now the engine doesn't seem like it wants to start at all

I went to swap the fuel rail again and noticed this time there was some air in it as well as the fuel pressure not building up to the usual "squirt" when you press the purge valve. Also swapped the plugs since the ones on the engine were fouled with oil and not in very good shape (I forgot to change them with new ones).

I think I'm out of fuel at this point, so will have to get some fuel to further diagnose the situation. However, can I be missing something? The engine should still start (albeit roughly) with the P866 cam and the Punto MK2 60 block, right?

Any input is appreciated. I think I just came to a dead end here and I'm out of ideas