Technical Fiat 128 Fuel

[AorN]

Hi,

Apologies if this has been asked before.......but is an 1100cc Fiat 128 okay to run on current UK unleaded fuel or will it damage anything?

Thanks.

 

[bugsymike]

Hi,

Apologies if this has been asked before.......but is an 1100cc Fiat 128 okay to run on current UK unleaded fuel or will it damage anything?

Thanks.

Others on Forum will be more specific, I used to have a reference disc for all the makes and models at the time, but can't find it.
In general terms there are two issues.
One. Damage/rapid wear to the valves and valve seats due to the lack of Tetraethyl Lead which lubricates the valve seats.
There is line of thought that engines with aluminium cylinder heads had hardened valve seats fitted from new anyway, so may be less of a problem.
Two. That same lead is an Octane Booster. So in the old days high performance vehicles used 5 star fuel and basic stuff tended to go for the cheaper 2 Star petrol.
It also depends on the amount of mileage you are going to do, more miles = more wear.
Many years ago I had an old Fiat Uno, totally used and abused, when fitting a diesel engine to my boat, on changing to a plastic fuel tank as original was galvanised and very rusty so was unsuitable, I had a large quantity of 5 Star petrol dating from before 1982 as boat had been standing and the original 150Hp Volvo Penta V6 only ran on that.
After filtering all the rust and water out of that fuel, I used it up in the old Fiat Uno, I can honestly say it ran much better than it had been running on the then current Unleaded at the pumps with no adjustments, which showed to me the rubbish fuel we have to put up with for environmental reasons and that, if we didn't have ECUs and fuel injection making them run as good as possible modern cars would be in a bad state!
I recall in the early 90s many cars had problems at the change over from carbs. to injection and catalysts etc. along with the lack of higher octane fuels at the same time.
To sum up if only doing low mileage, valves should be less of an issue, but "pinking /pre ignition" may be, as that will damage engines quicker than the wear rate to valves and seats.
There are Octane Boosters and Lead Replacement substitutes available, but I have no particular knowledge about how good they are.

 

[AorN]

Others on Forum will be more specific, I used to have a reference disc for all the makes and models at the time, but can't find it.
In general terms there are two issues.
One. Damage/rapid wear to the valves and valve seats due to the lack of Tetraethyl Lead which lubricates the valve seats.
There is line of thought that engines with aluminium cylinder heads had hardened valve seats fitted from new anyway, so may be less of a problem.
Two. That same lead is an Octane Booster. So in the old days high performance vehicles used 5 star fuel and basic stuff tended to go for the cheaper 2 Star petrol.
It also depends on the amount of mileage you are going to do, more miles = more wear.
Many years ago I had an old Fiat Uno, totally used and abused, when fitting a diesel engine to my boat, on changing to a plastic fuel tank as original was galvanised and very rusty so was unsuitable, I had a large quantity of 5 Star petrol dating from before 1982 as boat had been standing and the original 150Hp Volvo Penta V6 only ran on that.
After filtering all the rust and water out of that fuel, I used it up in the old Fiat Uno, I can honestly say it ran much better than it had been running on the then current Unleaded at the pumps with no adjustments, which showed to me the rubbish fuel we have to put up with for environmental reasons and that, if we didn't have ECUs and fuel injection making them run as good as possible modern cars would be in a bad state!
I recall in the early 90s many cars had problems at the change over from carbs. to injection and catalysts etc. along with the lack of higher octane fuels at the same time.
To sum up if only doing low mileage, valves should be less of an issue, but "pinking /pre ignition" may be, as that will damage engines quicker than the wear rate to valves and seats.
There are Octane Boosters and Lead Replacement substitutes available, but I have no particular knowledge about how good they are.

Thanks for this. I don't intend to do many miles, but would like to keep it in as good condition as possible. I had one of these in the late 70's (it rusted to bits by 1982 ). But I do remember that I had to do a full top end overhaul (I was a student so I did it myself) at 70,000 miles as the valve stem oil seals were failing and it was burning a lot of oil. But even then the valve seats were starting to suffer.

My concern is whether there is any other parts of the engine or ancillary items that could be damaged.

 

[portland_bill]

The lead in the fuel was only for octane boost, then later found to lubricate the valve seats as a bonus, allowing cheaper seats to be fitted. Mostly that was just iron cylinder heads, with the seat just cut into the iron.
Aluminium heads had to have separate seats fitted, so all were harder material.

I think the 128 was not particularly stressed, so ordinary 95 octane unleaded should work fine. If mine, I'd be happy to throw ordinary unleaded into it.

For me, the main thing would be any rubber fuel hoses. They need to be new, and specifically methanol resistant. Not expensive, but time consuming and potentially awkward, if there's one or two at the tank.

 

[bugsymike]

Thanks for this. I don't intend to do many miles, but would like to keep it in as good condition as possible. I had one of these in the late 70's (it rusted to bits by 1982 ). But I do remember that I had to do a full top end overhaul (I was a student so I did it myself) at 70,000 miles as the valve stem oil seals were failing and it was burning a lot of oil. But even then the valve seats were starting to suffer.

My concern is whether there is any other parts of the engine or ancillary items that could be damaged.

To the best of my knowledge it was just what I mentioned. Obviously as cars age other issues come along.

 

[AorN]

The lead in the fuel was only for octane boost, then later found to lubricate the valve seats as a bonus, allowing cheaper seats to be fitted. Mostly that was just iron cylinder heads, with the seat just cut into the iron.
Aluminium heads had to have separate seats fitted, so all were harder material.

I think the 128 was not particularly stressed, so ordinary 95 octane unleaded should work fine. If mine, I'd be happy to throw ordinary unleaded into it.

For me, the main thing would be any rubber fuel hoses. They need to be new, and specifically methanol resistant. Not expensive, but time consuming and potentially awkward, if there's one or two at the tank.

Many thanks, really useful........although changing the rubber hoses certainly sounds like a pain. Do you think it's worth simply using E5 Super unleaded to at least reduce the amount of ethanol going through?

 

[portland_bill]

Using a lower ethanol fuel will only slow the deterioration process, not prevent it. The hoses will be old anyway, so full replacement is a must at sometime, ideally before any leak.