Tuning Punto 75 Block with 1108 MPI head and cam shaft

[Seatpanda]

Hi all,

A part of my 1980 FWD Panda with 1.2 16v swap , I just bought a 2002 Fiat Panda 4x4 with a 1108 MPI engine (same as seicento)

On this car I don´t want to go to the limit because of the 4x4 gearbox (too weak)
So got lucky and found a 1994 Punto 75 with only 95k on the clock for a very good price.

Initially was going to swap the engine and wiring completely, but someone who did it before recommend me to change only the block for the following reasons:

-Torque, this panda 4x4 is mean to be used for Panda Raid and country side. Prefer to have 100Nm around 2500rpms with 65hp than 110Nm at 4000rpms with 73hp
-The 2002 ECU and 1108 mpi intake is much more advanced with extra sensors and will make the engine more smoth.
-The 1108 camshaft is less agresive looking for torque at low rpms.

What do you think about this modification?
I trust a lot this person as he has very good reputation, but I am worried about the result
First thing comes to my mind is compression ratio (head gasket)
According the numbers I made, with a 1,65mm head gasket I will be around 10,6:1 which is just OK for 95 octane petrol
I would prefer to use a metalic head gasket, but the metalics are only 0,5mm and will increase the compresion ratio to 12,2:1 which I think is dangerous for low octane petrol (morocco)


I make this question on cinquecento and seicento section because my panda 1.1MPI is exactly same as seicento and people here are experts with different engine modifications and combinations.

Thank you!

 

[bugsymike]

Hi all,

A part of my 1980 FWD Panda with 1.2 16v swap , I just bought a 2002 Fiat Panda 4x4 with a 1108 MPI engine (same as seicento)

On this car I don´t want to go to the limit because of the 4x4 gearbox (too weak)
So got lucky and found a 1994 Punto 75 with only 95k on the clock for a very good price.

Initially was going to swap the engine and wiring completely, but someone who did it before recommend me to change only the block for the following reasons:

-Torque, this panda 4x4 is mean to be used for Panda Raid and country side. Prefer to have 100Nm around 2500rpms with 65hp than 110Nm at 4000rpms with 73hp
-The 2002 ECU and 1108 mpi intake is much more advanced with extra sensors and will make the engine more smoth.
-The 1108 camshaft is less agresive looking for torque at low rpms.

What do you think about this modification?
I trust a lot this person as he has very good reputation, but I am worried about the result
First thing comes to my mind is compression ratio (head gasket)
According the numbers I made, with a 1,65mm head gasket I will be around 10,6:1 which is just OK for 95 octane petrol
I would prefer to use a metalic head gasket, but the metalics are only 0,5mm and will increase the compresion ratio to 12,2:1 which I think is dangerous for low octane petrol (morocco)


I make this question on cinquecento and seicento section because my panda 1.1MPI is exactly same as seicento and people here are experts with different engine modifications and combinations.

Thank you!

I think you are right in going for torque.
High compression can be a problem especially with the poorer grades of fuel these days.
Many years ago I rebuilt an engine on a rare Tickford Ford Capri 2.8, before he bought it the engine had been worked on by several "mechanics" due to it burning holes in the pistons as it was originally designed to run on 5 star (high octane fuel), it was missing when I first looked at it and on doing a compression test the readings on the good cylinders were 180psi which was much to high for a turbo engine of it's day.
I was able to obtain a set of Mahle quality pistons, but designed to give a lower compression more suitable for a powerful turbo set up.
On testing the compressions I had a good reading on all six cylinders of 150psi. The engine ran well and the customer was happy as once run in he was able to get max. power from the turbo where as before the engine was "pinking" which had been the cause of the holes burnt in to the pistons.
Modern engines can run high compressions due to better head design giving more even burning of the fuel, but also with the ECU controlling things better and the use of knock sensors etc.
In the mid 70s I became foreman of a Mazda Dealership and was surprised to find the Mazda's ran happily on low grade 2 Star fuel and yet had 180psi compressions (most English cars ran much lower compression) I put this down to the better cylinder head design giving more even and efficient burning of the fuel as it was well before Ecu's etc.

 

[Seatpanda]

I think you are right in going for torque.
High compression can be a problem especially with the poorer grades of fuel these days.
Many years ago I rebuilt an engine on a rare Tickford Ford Capri 2.8, before he bought it the engine had been worked on by several "mechanics" due to it burning holes in the pistons as it was originally designed to run on 5 star (high octane fuel), it was missing when I first looked at it and on doing a compression test the readings on the good cylinders were 180psi which was much to high for a turbo engine of it's day.
I was able to obtain a set of Mahle quality pistons, but designed to give a lower compression more suitable for a powerful turbo set up.
On testing the compressions I had a good reading on all six cylinders of 150psi. The engine ran well and the customer was happy as once run in he was able to get max. power from the turbo where as before the engine was "pinking" which had been the cause of the holes burnt in to the pistons.
Modern engines can run high compressions due to better head design giving more even burning of the fuel, but also with the ECU controlling things better and the use of knock sensors etc.
In the mid 70s I became foreman of a Mazda Dealership and was surprised to find the Mazda's ran happily on low grade 2 Star fuel and yet had 180psi compressions (most English cars ran much lower compression) I put this down to the better cylinder head design giving more even and efficient burning of the fuel as it was well before Ecu's etc.

Thanks for the reply bugsymike!
It is a good comparation, the Capri is a Turbo engine and the Panda not, but this information is good to take it in account.

Could this means that the cylinder head design on the 1.1 MPI would allow me to increase the compression ratio?
Everywere I read the limit is 10.5:1 for 95 octane fuel. But for example, the Grande Punto 1.4 8v has 11:1 and uses 95 octane fuel.

Should I concentrate more on the "dynamic compression ratio" then?

 

[bugsymike]

Thanks for the reply bugsymike!
It is a good comparation, the Capri is a Turbo engine and the Panda not, but this information is good to take it in account.

Could this means that the cylinder head design on the 1.1 MPI would allow me to increase the compression ratio?
Everywere I read the limit is 10.5:1 for 95 octane fuel. But for example, the Grande Punto 1.4 8v has 11:1 and uses 95 octane fuel.

Should I concentrate more on the "dynamic compression ratio" then?

I have no specific knowledge on your engine, my technical data manual agrees with you on the 95 octane for the Punto75 and I see the 1.3 turbo uno listed at 98 octane , these are minimum fuel octane ratings.
Another point is some of the early engines were not suited to unleaded fuel as it wore the valves/seats quickly.
Is 95 octane all that is available to you?
Am I correct you are putting 1242cc into a 1100cc head in effect?
So 140cc divided by 4 so 35cc extra into each combustion chamber?
Would it be possible to remove metal in the chamber like engine tuners used to do to improve flow around the valves etc.
It would need to be done very carefully and the capacities equal across all four chambers and well away from gasket sealing areas.
It may be advisable to speak to a specialist in this area.
We used to do things like this in the old days with cast iron cylinder heads.
Re high compressions, around 1970 as an apprentice I had a Ford Anglia 105E 997cc, there was an old Ford Classic 1340cc bottom end in the garage, I was able to swap the crank shaft and con rods to the 997cc block which as I had nothing else I put the 997cc head on. It still looked like a 997cc on the outside and pulled well but pinked like hell on 5 star petrol, so it didn't last very long. Later I put a 1500cc engine in complete which was much better as it also was a five main bearing crank shaft.
Head design is important regarding compression rations and pinking etc. I believe the old double overhead cam engines in early Jaguars etc. had a "semi hemispherical" head design which allowed higher compressions on the poor fuel of the day.
Can you measure the exact capacity of a cylinder by filling it with measured oil at bottom dead centre and then do the same with your cylinder head with an old spark plug in to see what the actual figures are, apart from the head gasket.