to homepage of viva-lancia.com
Fulvia Questions & Answers Click here to support us financially.
Engine - Fuel
Omicron Lancia Spares and Restorations
pre-Beta Lancia spares
and restorations
CASA FULVIA
Repair, service, restoration
Fulvia Flavia Flaminia

 

March 2005

I have been running my Fulvia's on 95 octane unleaded without additive now for some years. No problem. My Fulvia's are: S3 Fulvia coupe (818.303 engine), 2 S1 Fulvia coupe's 1.3 (919.302 engines) and a Fulvia S2 berlina (818.302 engine). Some years ago (see entry below, dated January 2002) I used 95 octane unleaded with Millers VSP Plus additive. After burning the valves of both the S1 coupe's, I concluded that while the additive may or may not have been the cause, it did certainly not prevent it. Thus better keep the money in the pocket and save it for a complete head overhaul when necessary (and not before for theoretical reasons). Works very well indeed.

Normal good practice is to change the exhaust seats to stellite, which I do if I do an engine for someone else and also used to do for my own engines. However, I have now so much confidence in the quality of the original Lancia seats that I don't change seats on my own heads if the original seats are still good. Seats, intake as well as outlet have to be replaced of course when they are bad. The replacement seats will automatically be stellite because the machine shops don't stock any other seats.

My experience is that if one overhauls a head, the guides have to be replaced always when they are still the original guides. If they don't have seals, they are likely to be original. In all cases where I left the original guides because they measured OK, I regretted it afterwards. In some cases they went bad within a 1000km.

Apparently the original Lancia valves were not too bad either. If they have to be replaced, it is nevertheless a good idea to use modern valves of austenitic steel (X53CrMnNiN219 also known as 21/4N) as one cannot be sure of the quality of replacement valves.

Although my Fulvia's run perfectly well on 95 octane unleaded, you have to carefully listen if it knocks or not. If it does, change to 98 octane. If it still knocks, you have a problem. I am talking about (reasonably) standard engines. Not highly tuned, high compression engines.

Huib, huib@viva-lancia.com

January 2002

I have now some more experience with today's fuels. Note, that my experience is practical and not supported by scientific tests as I simply do not have the time, money and quantity of Fulvia's to do a fully scientific job. My total mileage with Fulvia's is about 40.000km per year. Each car is different. Atmospheric circumstances differ. The quality of the fuel at the pump differs. Your experiences may be different.

Since leaded fuel became unavailable in Holland in 1995 I have used the LRP (Lead Replacement Petrol) offered by the oil companies for a number of years. The LRP comes from the 'red" pump, the same one where the leaded 98 octane super used to come from. Instead of the lead, the oil companies had added a lead replacement. The function of the lead was to increase octane rating as well as lubricate the valve seats to minimize valve seat recession.

With the new fuels there are thus two concerns:

  1. knocking - too low octane causes knocking which will burn holes in pistons. Usually knocking occurs between 1000 and 2000 rpm and can easily be heard. More rare is high speed knock which occurs at high rpm's. This cannot be heard because of the noise of the engine, but it can be measured at a rolling road tester.
    The higher the compression ratio of the engine, the higher the required minimum octane rating is.
    Knocking was not observed on any of my Fulvia's (I have no HF's, which require the highest octane rating).

  2. valve seat recession (VSR) - Every time a valves closes, it "welds" itself to the seat. When it opens again particles are torn off from the seat. The seat thus wears. The amount of wear depends on the quality of the seat and the temperature. The lead reduced this wear considerably as it formed a "buffer" between seat and valve. In low quality engines (non Lancia) the valve seats may wear so quickly, that the engine is destroyed in a few hundred km's. Fortunately the Fulvia engines are pretty good, but not necessarily perfect in this respect.

    When valve seats wear, the valve clearance (gap between the stem of the valve and the rocker) is reduced. On non-HF engines the valve clearance is 0,15mm for the intake valves and 0,25mm for the exhaust valves. When using the LRP I checked the valve clearance every 10.000km which is good practice anyway. On the 1971 S2 berlina (87 HP 1.3 engine) there was hardly any correction necessary. On the S3 1.3S coupe, valve clearance was was always reduced and had to be re-adjusted. An interval of 20.000km between checking valve clearance would have been too long and might have caused damage to the engine. Remember that this is with LRP, not with the green unleaded fuel. With the green unleaded the situation might have been the same but more likely it would have been worse.

    Because I was not happy with the obvious wear of the valve seats on the 1.3S, even with the LRP, I started inquiring which resulted in the belief that the lead replacement used by the oil companies was not as good as the old lead. This also leads to the conclusion, that many of the additives which are being sold in bottles, are not good. In the meantime Millers Oils had introduced a manganese based additive called VSP Plus. Millers claimed that it increased octane by 2 or 3 points and fully protected against valve seat wear. I changed to the green 95 octane and added the prescribed dose of VSP Plus. This was some years ago. It worked as advertised. When checking valve clearance every 10.000km I noted that even on the 1.3S engine the valve clearance was still good and hardly needed adjustment.

    On one engine (1967 coupe rallye 1.3) I have changed the seats of the exhaust valves to stellite, which is hard enough to prevent wear even without additives. This car runs on green 95 octane. On 98 octane it even runs well with a fixed ignition advance of 18 degrees.

Just out of curiosity I tested the 1976 1.3S for knocking when running on green 95 octane without additives for one tank. It run well without knocking. A good sign. The engine was not new though. Compression may thus not have been the book value of 12,5 bar. So, be carefull if you want to try your 1.3S on 95 octane without additives.

In short: if you were happy with the perfomance and maintenance schedule of your Fulvia on the old 98 octane leaded fuel and don't want to experiment, fill up with green 95 octane and add Millers VSP Plus.

Huib, huib@viva-lancia.com

Q: In Holland leaded fuel (called "Super") can not be bought anymore. The leaded fuel is now replaced by a fuel (also called "Super") which contains lead replacement additives.
Could you inform me if Fulvia's and in particular my 2nd series can run without modification on this 'lead replacement' fuel. This fuel is marketed by all larger oil companies like Shell, Esso, Texaco, etc. All claim that modifications may be necessary for (all?) older cars i.e. from before 1990.

A: In a few European countries leaded fuel is (unfortunately) not sold anymore. Lead in fuel is necessary to Fulvia engines for two reasons:
1) to avoid knocking (pinging) of the engine;
2) to lubricate valve seats.
The first issue can be dealt with slight (1-2 degree) retardation of ignition timing; the second is an unknown entity which can only be solved by replacing the valve seats with new ones of a different material. Lancia owners in Austria and Germany tell me that they have no problems in using "super" fuel. I would try to avoid long high speed runs when lead is not available in petrol. Nobody knows the long term effects yet.
- Andrea -

Omicron Lancia Spares and Restorations
pre-Beta Lancia spares
and restorations
CASA FULVIA
Repair, service, restoration
Fulvia Flavia Flaminia