Technical Punto 75 mpi conversion

[Rosso83]

It's time I put a bit more poke into the Sei, after reading the following in the FAQ's ive more or less decided this will be the easiest, cheapest and best bang for buck conversion for me.

The MPI Sei and Punto 75 intake manifold stud patterns are the same, so fit the engine whole. Use the MPI Sei intake manifold.
The exhaust will just clear the driver's side driveshaft rubber boot without modification, but if you can get it altered a little more clearance will help. There's no joint on the front pipe like the SPI car, so you can't just fit a spacer - there isn't anywhere to put one!

The 1108 MPI Sei has a knock sensor - the Punto block doesn't have a hole to bolt it to in exactly the same place, but about an inch or two further down there is an unused threaded hole (probably from the Punto's alternator mounting bracket) which will do.

Cam drive. The 1108 MPI has a different pitch belt to the Punto 75, and also a knobbly bit on the inboard edge. This knobbly bit points at the cam position sensor, which is what the extra bit with the wire on next to the oil filler cap is. So you need to use the Sei crank pulley, water pump and cam pulley - and a belt from a newer mk2 MPI Punto 1242 8v. Oh, and the Sei cam cover complete with sensor.

You will also need to use the Sei's water rail on the front of the engine, the Punto one exits at a different angle.

Mounts, gearbox, starter and alternator from the Sei can be retained. The flywheel, clutch friction and pressure plates from the 75 and Sei are the same, but the Sei release bearing is different.

I have a few questions...

Has anyone on the forum done this conversion into an Mpi Seicento?

With regards to the wiring loom and ecu, what am i going to need? Is the loom the same? Can i use the standard ecu or will i need a 75 ecu, if so what probs will that cause with transponders etc...

Are these engines pretty easy to get hold of? and how much should i be looking to pay for one, and the other bits needed.


All information greatly appreciated!

 

[Asteris]

Here in Greece, there is a MKII Sei that runs on Punto75 engine. He uses both ECU's, Punto 75 ECU for engine management (front harness) and Sei ECU for the rest.

 

[rich_lufc]

Ive did the conversion on my car almost 2yrs ago. The wiring loom is exactly the same so you dont need to touch the ECU. The only minor difference is theres a knock sensor which doesnt have a fitting on the 1242 so you will have to hide it somewhere solid, no big deal.

These engines are everywhere. Go to your local scrappy or do a search on parts gateway, they will get you loads of quotes for the engines. You shouldnt be paying much over £120 for the full engine with around 30000 on the clock. Ebay is also thriving with the engines at bargin prices.

Any other questions just ask.

 

[randomizered]

Has anyone on the forum done this conversion into an Mpi Seicento?

That means you currently have an SPI? If so its not a straight swap. I'd just use the 75 code box and ecu. You will need to trace a lot of wires to join though.....or go aftermarket.

I'm not so sure that converting spi to mpi ECU wise is that easy. I have heard one or two do it, but no real details, and not sure how well it works.

Kristian

 

[rich_lufc]

I thought he meant sei mpi to punto 75

 

[Rosso83]

I do, i have a phase 2 MPI Seicento, and want to fit the punto 75 MPI lump.

So its a case of taking inlet and exhaust off, swapping everything over following the above guidelines, and retaining 1.1 ecu?

With regards to the release bearing being different, do i need to change that or will it work?

£120 for a 30,000 sounds like a bargain, looks like its going to be cheaper than i thought.

 

[fingers99]

If you're keeping the Sei gearbox, keep the Sei release bearing. The engine change would be a good time to pop on a new clutch.

 

[PuntoMK3]

im doing this conversion.

in the middle of re building my 75 engine back up now, completely stripped down just to make sure every things sound. so hopefully going to put it in my seicento schumacher middle of next month, also got gt front brakes to go on.

 

[Rosso83]

Take some pictures! I would greatly appreciate any tips or things to watch out for when you do yours, I've just begun the sourcing of mine.

What markings/numbers will be on the 75 lumps and where will i find them?

 

[Smiler121]

Ive did the conversion on my car almost 2yrs ago. The wiring loom is exactly the same so you dont need to touch the ECU. The only minor difference is theres a knock sensor which doesnt have a fitting on the 1242 so you will have to hide it somewhere solid, no big deal.

What did you mean by "hide it somewhere solid"?

 

[rich_lufc]

At first I taped it to the underside of the battery houseing but it does have a handy hole through which you can attach it to a spare stud within reach of the knock sensors wire. Ill see if I can get a pic of what Ive done with mine as I cant quite remember.

 

[fingers99]

Alternatives are the alternator bracket or, there's a boss below the place where it should go which can be tapped.

 

[randomizered]

Down point is the ecu will actively advance timing , based on knock, to ensure better combustion and emissions. If the knock is not working properly, it may advance and due to no knock feedback you will get knock.

Its not going to be drastic...it is a factory fit ecu....but its not that good for the engine.


bolting it anywhere on the block is better than where you put it

 

[fingers99]

Are you sure it does advance the timing? If it did, I'd expect more performance on 98 octane. My Sei runs no better/faster on it.

 

[Rosso83]

Mine neither, though in theory it should. Seems I'm spoilt for choice on 75 lumps, so I have the luxury of being very picky.

The original article suggests using the alternator bracket, seems like the best way to go.

 

[randomizered]

Are you sure it does advance the timing? If it did, I'd expect more performance on 98 octane. My Sei runs no better/faster on it.

Well, it either has a more advanced spark table compared to spi and just retards timing if it sees knock....or it advances timing until it sees knock.

Either way it must be doing something, else they wouldn't fit it lol


Kristian

 

[fingers99]

I think it's probably the former!

 

[Rosso83]

Whats the easiest/cheapest way around the exhaust issue? will i need it cut and a piece welded in to counteract the height difference on the blocks?

How have other people got around this?

 

[Oldschool]

Whats the easiest/cheapest way around the exhaust issue? will i need it cut and a piece welded in to counteract the height difference on the blocks?

How have other people got around this?

What about making a spacer?

 

[Rosso83]

I read a spacer wasn't suitable for the MPI due to the different setup?