I think it was in the AROC UK magazine I read that most pre unleaded Alfa's had hard metal in the valve seats. I think the Alfa Sud didn't fall under that criteria so you should get the valve seats redone. Should be about 100 squids per cylinder if I remember right.

 

I thought all Alfas could run unleaded as they have alloy heads and therefore hardened valve seats already fitted.... Is this different for the Boxers?

wrinx

 

My Boxer has ALWAYS used unleaded.

Is a 33 Series III though (1990) so might be a later design????

Bob

 

They should have hardened valves out of the box like Wrinx said as it is an alloy head.

You can run unleaded in a boxer. http://www.alfa-pages.co.uk/unleaded.htm

 

I thought all Alfas could run unleaded as they have alloy heads and therefore hardened valve seats already fitted.... Is this different for the Boxers?

wrinx

My Dads '69 Spider runs better on unleaded - just have to use some additive stuff - possibly octane booster

 

I thought all Alfas could run unleaded as they have alloy heads and therefore hardened valve seats already fitted.... Is this different for the Boxers?

wrinx

I know for a fact that this doesn't go for all Alfas. Mine NEEDS high octane with a lead replacement additive.

 

I know for a fact that this doesn't go for all Alfas. Mine NEEDS high octane with a lead replacement additive.

Where did you get this fact from?

 

Where did you get this fact from?

Uhmm, driving a 1972 Giulia every day!

 

Driving a car everyday does not give you that fact. Who told you? Where is this documented?

Simon

 

I thought all Alfas could run unleaded as they have alloy heads and therefore hardened valve seats already fitted.... Is this different for the Boxers?

wrinx

The Aluminium alloy engines used in the 116 series of Alfa Romeos had cast iron inserts. So theoretically, to use unleaded you need to use an additive or replace the inserts.

 

You have two completely separate issues here in running your car on unleaded fuel.
The tetraethyl lead has two functions, the first is to cushion and protect the valve and seat from burning and recession.
The original Alfasud valve seats and valves are of sufficiently good quality to run unleaded fuel. You will find that if the engine has been run on leaded fuel for at least 10,000km since the last valve grind the valves and seats will be work hardened and quite capable of running without lead or additive. If you are concerned about this simply check your valve clearances more regularly. If you find that the clearances are reducing, use an additive, if not continue to use straight unleaded.
The second issue is the 'anti knock' quality of the fuel. Tetraethyl lead protects the engine from pre ignition to assist even combustion in the cylinders.
You will need to run a high octane fuel to compensate for the lack of lead and may require octane booster if the compression has been increased from standard and maybe retuning of the carbs and ignition timng ito suit. If you have twin carbs find someone with a dyno and experience with carbs to tune it properly and you should be able to run the car reliably and smoothly witout resorting to expensive additives and boosters.

 

Driving a car everyday does not give you that fact. Who told you? Where is this documented?

Simon

Not being a tech wizzkidd, I listen to advice given to me by people who know. So, when my Alfa Specialist tells me not to run her on unleaded fuel, I do so.

So it's documented in his brain

 

lead replacement additive.

Thats the stuff i was on about

 

I know for a fact that this doesn't go for all Alfas. Mine NEEDS high octane with a lead replacement additive.

Strange, my 1953 Twincam runs fine on unleaded, timing is spot on too. Perhaps yours needs retarding a bit?

wrinx

 

I have a scan of an Alfa GB dealer briefing at home, so I'll post all the info when I get home on Monday!

From memory, some were fine - unleaded no adjustment, some needed only ignition resetting (included boxers), and a few were don't use it at all (unless you have the valve seats done!).

Hope you can wait, Treffynnon!

Buck

 

Strange, my 1953 Twincam runs fine on unleaded, timing is spot on too. Perhaps yours needs retarding a bit?

wrinx

Considering the quality of petrol available in 1953 , current petrol would be like liquid 'gold'

 

Mmm, good point

wrinx

 

Thats the stuff i was on about

I get the feeling that fuel over here is not produced in the same way as elsewhere. My Giulia runs on high octane fuel, with a lead replacement additive, since leaded fuel is prohibited over here.

Technically, I give her 98 super with lead replacement.

In Italy however I found that their description of what fuel you can buy is not as clear. At some stations (driving a 146 Ti at the time) I wasn't sure they even sold Low octane (95 normal petrol). The text on the boards gave me the impression that they were selling some sort of mixture

Anyone with experience?

 

Considering the cost of valve seat replacement is now madnesss relative to what it once was (before this unleaded fiasco started if you tookyour cylinder head to my local engine shop, they would replace all the valve seats in an 8v head for about £40. When the u/l hit, the price soon tripled!), you'd be far better off running the car and ,as was suggested earlier, keep tabs on the valve clearances. If they suffer get the seats done. If not, don't ,and spend the money elsewhere (pub etc)You've nothing to lose.
I tried the Arna on u/l with a lead replacement/octane booster, and packed that in when I checked it's compatibility, reset the timing, and got better starting, running and performance with u/l on it's own!

 

Considering the cost of valve seat replacement is now madnesss relative to what it once was (before this unleaded fiasco started if you tookyour cylinder head to my local engine shop, they would replace all the valve seats in an 8v head for about £40. When the u/l hit, the price soon tripled!), you'd be far better off running the car and ,as was suggested earlier, keep tabs on the valve clearances. If they suffer get the seats done. If not, don't ,and spend the money elsewhere (pub etc)You've nothing to lose.
I tried the Arna on u/l with a lead replacement/octane booster, and packed that in when I checked it's compatibility, reset the timing, and got better starting, running and performance with u/l on it's own!

Thanks! I'll check with my Alfa specialist. Valve clearance was set about 8 months ago, so that should not be a problem. Could, mine having a set of Dell Orto carbs and KN open air filters, have anything to do with this?

 

Hi,
I bought my 76 Alfasud 5m 3 years ago with 30.000 kilometers.
Since then I have driven another 10.000 kilometers on unleaded premium which has 92 octane.
So far absolutely no problems, like pinging or hesitating. For environment reasons I do NOT add any lead additives, nor do I add octane boosters.
Best regards from San Diego, CA
Hans

 

Thanks! I'll check with my Alfa specialist. Valve clearance was set about 8 months ago, so that should not be a problem. Could, mine having a set of Dell Orto carbs and KN open air filters, have anything to do with this?

As long as your not running lean I cannot see what affect they would have.

 

True, lean mixture on light throttle cruise will cause high exhaust valve temperatures and possible damage.. if the jetting is standard it should be fine though.

 

Thnx, but that still does not explain why my specialist advises me to go high octane leaded.


And for being right on fuel mixture being different over here: 92 octane gas is not sold over here...

 

And for being right on fuel mixture being different over here: 92 octane gas is not sold over here...

The USA quotes fuel octane ratings differently to the rest of the world.
Most places quote the "RON" rating, however in the USA they quote (RON+MON)/2 which results in a lower number.
So in the USA 92 octane isn't as low as you may think.