Lancia Motor Club

Model Technical and Interest => Fulvia => Topic started by: eyore on 31 May, 2007, 08:59:14 PM

Title: Petrol Additive.
Post by: eyore on 31 May, 2007, 08:59:14 PM
Does everybody use a lead additive to petrol?. A few people I have spoken to say they do such limited mileage that they don't bother. Personally I do, and think its worth the small extra cost.

Title: Re: Petrol Additive.
Post by: stanley sweet on 01 June, 2007, 08:38:44 AM
I've been using Castrol Valvemaster Plus (has an octane booster) since leaded disappeared. That must be a few years ago now. No idea what the effect has been exactly as I'm not one to strip the engine to find out. But the main thing is I haven't noticed any adverse effects since switching to unleaded with the additive. Engine runs as nice as ever, no loss of power etc. The cars use has changed now to runs out on nice days but previously I did 4 years of sprinting/hillclimbing covering fair distances and using high revs at the venues. I would say use it, it won't do any harm and seems to work. The main thing is to choose one brand and stick with it. They have different base make ups (can't remember the technicalities) and you shouldn't swap between the two. I think you can mix two of the same chemical make up but that's too much thinking for me. Just decide on one and stick with it.

Title: Re: Petrol Additive.
Post by: fay66 on 01 June, 2007, 10:02:27 AM
I run my Fulvia 2c Berlina on unleaded & Millers VSP, I've used this for the last 8 years (I think!) after my engine was rebuilt after a piston ring broke, the valve seats were fine as she had stood for 21 years without turning a wheel, so apart from being lapped in were left.
I agree with Stanley, pick one & stay with it, there was a report at the time, stringent controlled tests were done on the various additives and devices that were submitted, very few of which stood the up to the test; all the additives that did were in liquid form such as Millers Vsp & Valvemaster, two of the recommended ones, I believe only 3 or 4 altogether were approved.
As the 2c only has a 1091cc engine with a 4 speed gearbox, you have to use the gearbox & lots of revs to keep best part on a tonne of car moving at a respectable speed, a lot of my changes are at 4000 rpm or therabouts.
Since using Millers Vsp I've covered about 13,000 miles, many at 70-75 mph, in fact on our return from a trip to Portugal in 2004 in which we covered 3500 miles, travelling from Salamanca right across the "Plains of Spain" where contrary to the rhyme, the rains didn't; we were driving at a steady 75mph and 5000rpm in 30c, heat hour after hour with infrequent stops, for over 300 miles, (only problem at all, was if balked when climbing the mountains from Portugal into Spain or the Pyrenees, the coolant temperature gauge climbed pretty high, we then stopped & let "Fay" & us cool down, but on the flat it wasn't a problem)  then after that another 100 miles climbing the Pyrenees into France.
In the next 2 days we drove right across France, & home to Bedfordshire, throughout the trip we averaged 300-400 miles per day which were mostly at high speed.
Our return from Turin last year was a similar pattern of driving.
So for 5000 mile on two trips that amount to about 20 days actual driving my 2c has never missed a beat, shown no sign of distress or any ill effects from not using leaded petrol.

So I'm fairly convinced that the technology works, although I do fill the tank with BP super fuel or whatever it is they call it, every now & again when the fancy takes me.

Brian Hilton 8227 8)

Just hope I haven't blown it by speaking about it ::)

Title: Re: Petrol Additive.
Post by: eyore on 01 June, 2007, 09:17:06 PM
I am using Castrol valvemaster also and although it makes no obvious difference,I imagine it must be better for the engine than using normal modern unleaded,bearing in mind even late Fulvias are really an early 1960s engine.

Title: Re: Petrol Additive.
Post by: Nick Pope on 04 June, 2007, 02:08:24 PM
I use Valvemaster too.  My Fulvia is almost entirely used for competition work - historic road rallies plus the odd sprint, gymkhana, autotest of whatever - so lots of revs and throttle.  No idea whether the stuff makes any difference except that it does give me leace of mind!

Title: Re: Petrol Additive.
Post by: YKR 567J on 04 June, 2007, 04:35:04 PM
I remember reading in a Fulvia buyer's guide in Classic Cars (July 2005) that S1 cars are fine on unleaded because their valve seats are sufficiently hard. Some early S2s are OK, but later S2s and all S3s need either an additive or hardened seats thanks to Fiat cost-cutting. The information came from Martin Cliffe at Omicron who I'm inclined to trust. I also read somewhere else (can't remember where) that all 1600 engines have hard valve seats and don't need an additive. I use super unleaded in my 1971 1600HF, on the standard 8deg BTDC ignition timing, and all seems fine so far.

This link to the viva-lancia website might be useful:

Hope that helps.

John Simister

Title: Re: Petrol Additive.
Post by: julian on 05 June, 2007, 11:57:05 AM
I run my S2 Fulvia on Valvemaster ‘Plus’ with the added octane booster.

On the run to Turin last year, I tried a couple of tanks of both normal and ‘full fat’ super unleaded, and found that the car ‘seemed’ to run more smoothly on the super unleaded. As the Fulvia has quite a highly strung little engine it does seem to benefit form the additional octane. The only problem you may find is the engine runs hotter.

However, I do believe that a great deal depends on getting the set up of the carbs, ignition etc, spot on.

Regarding the valve regression, I cannot comment as I have never had my head off.

Just my thoughts


Title: Re: Petrol Additive.
Post by: Scarpia on 05 June, 2007, 04:06:16 PM
 A test in germany some years ago involved running 5 classics for 40 thousand km on unleaded without additives . Heads were pre and post inspected and no measurable valve seat recession was noted! I think this is only true for low stress/ low compression engines but if so would suggest that the cost of these additives is not justified compared with checking the head when you would anyway.

That said, I have used an additive until now. By my understanding, sticking to one "make" is a generalisation; sticking to one generic type is the key to the matter. There are several basic types on the market.Some use pottasium , some manganese  and others sodium (I've read sodium is a source of problems and best avoided).

I had understood that lead was introduced in the 20's to delay ignition of the early fuels (as octane does) and the valve protection it gives was an unexpected benefit discovered later? Can anyone confirm this as not an urban myth?
If so, then it is to be expected that unleaded 95 may cause knocking in a higher compression engine such as fulvias, where 98 octane may avoid this but should make little difference in for example an aprilia which has a compression ration of 5.75 to 1, (compared with a fulvia that is 10.5 or higher even.).In this case,the hotter running that accompanies running on 98 oct  makes the additives advisable I think. Unfortunately I cannot begin to do the calculations necessary to make some objective decision about with which compression ratio and other factors an additive will help.My gut feeling is, I don't need it in the aprilia but do in the fulvia. Truth is, I don't dare stop using it in the aprilia... Anyone know the real technical situation?

Title: Re: Petrol Additive.
Post by: inthedark on 05 June, 2007, 04:32:14 PM
I have run my Gamma Coupe on pure unleaded since the 4* dried up, 9000 miles with
no problems including Turin, North Yorkshire etc, and as most people will tell you I fall
into the 'Hooligan' class (left Turin 11:30 am arrived Calais 21:30 (ish)
I was told by and engineer when I requested 'hardened' valve seats, that this was a waste
of time/money "after all" he said "we'll only drive out the old steel seats and replace them with
new steel seats". In his opinion the only problem with running unleaded was having to retime
the ignition correctly.  Unleaded fuels burn a lot easier than leaded fuels

Geoff 'the colonel'
of course I was very very drunk

Title: Re: Petrol Additive.
Post by: RhysHF on 05 June, 2007, 06:40:45 PM
I use Valavemaster in my 1600HF and usually try to use BP Ultimate or Shell V-Power as they have a higher octane level. I can't say I have noticed much difference but my philosophy is that 4* was a higher octane and whilst I had read that the valve seats are very hard, the engine was ultimately not designed for unleaded.


Title: Re: Petrol Additive.
Post by: Richard Fridd on 06 June, 2007, 06:44:11 PM
interesting to hear that S1 fulvias have suitable seats.i actually run my S1 only on leaded fuel from thrust which is available from 50 outlets in total according to their website

Title: Re: Petrol Additive.
Post by: YKR 567J on 07 June, 2007, 09:12:32 AM
Using leaded petrol from Thrust does seem unnecessary in a Series One. There are two separate issues here, which got confused in the public's mind when 97-octane four-star was supplanted by 95-octane unleaded: octane rating and valve-seat protection, both of which are increased when petrol contains tetra-ethyl lead.

Lead additives, manufactured in the UK mainly by Associated Octel and originally developed by the Ethyl Corporation in the US, were first put in petrol in the 1930s to improve the octane rating or knock resistance, thus allowing higher compression ratios and more efficient engines. A happy side-effect, but not the original reason for the additives' inclusion, was the lubricating effect of the lead-containing, post-combustion ash on the valve seats which prevented the valve-seat recession that otherwise occurred at high revs and temperatures with soft iron valve seats, the sort that are cut directly in an iron head.

When lead started to be taken out of petrol, the public was fed fuzzy information about the need to have some engines 'converted'. Depending on the engine, this meant either or both the fitment of hard valve seats and/or simple retarding of ignition timing to suit the lower-octane, faster-burning unleaded fuel, which by European agreement had (and has) an octane rating of 95. Retarding the ignition reduces power and fuel efficiency, however, and some engines take to this badly. The answer, if the engine has hard valve seats like many Fulvias, is to use super unleaded which has an octane rating of 97 (in some cases higher) in the UK, and 98 in mainland Europe for reasons of differing base fuel stocks. With hard seats there's no need for an additive even though the engines' design pre-dates unleaded fuel.

Later Fulvias have softer valve seats, even though they are inserts in an aluminium head and are still harder than the seats of a cast iron head, so these either need to be changed or an additive used. If using an additive, it makes sense to use one with an octane booster and buy the cheaper 95-octane unleaded fuel, the combination ending up with an octane number around 97.

The now-defunct lead replacement petrol was effectively super unleaded with a potassium-based additive to reduce valve seat recession. That it was cheaper than super unleaded was a bit of a scandal, super unleaded being very overpriced in the UK compared with the price differential between regular and super unleaded in Europe. The additives currently available usually contain either a manganese compound called MMT (highly toxic), such as Miller's VSP, or a phosphorus compound (such as Valvemaster, made for the UK by, ironically, Associated Octel). It's true that different chemical types of additive shouldn't be mixed if they are to be effective.

I once wrote a supplement for a Classic Cars magazine on this whole subject, focusing (and paid for) by Valvemaster. It didn't appear because around the same time Car magazine, owned by the same publisher, ran a column from a US contributor on the scandal of the big lead-additive corporations and how they knew about the poisonous effects of lead yet carried on making money from it. So Octel pulled the supplement leaving, I thought, a smoking hole in its foot.

By the way, I hope no-one here is using the so-called fuel catalysts which either are plumbed into the fuel line or take the form of metal pellets in the fuel tank. They are a complete waste of time and have no scientific basis for working. I tested one such system for What Car?, called PowerPlus, in an Austin Metro, and discovered exactly what valve-seat recession really looks like. PowerPlus paid for a new cylinder head after the test. The engine was nice and quiet before the compression disappeared, though, thanks to the closing-up iof the tappet clearances.

John Simister

Title: Re: Petrol Additive.
Post by: fay66 on 08 June, 2007, 11:18:21 PM
[ but should make little difference in for example an aprilia which has a compression ration of 5.75 to 1, (compared with a fulvia that is 10.5 or higher even.).
apologies to Scarpia for not including the full quote, but this is the relevant bit I would like to comment on.

Having just checked my manual, I note that the nearest Fulvia to the Appia was the Normale Berlina( the first of the Fulvia's) which had a 58 hp 1091cc engine and a compression Ratio of 7.8 to 1.
The 2c which followed (as my Fulvia) was also 1091cc but the twin Solexes & other mods, upped this to 70 hp. with a 9 to 1 compression Ratio.
all other series 1 Berlina 1216cc/1231cc/1298cc, had a
9 to 1 Compression Ratio.

All series 1 Coupe  had the following.
1.2/1.2HF/1.3 =  9 to 1
1.3 HF           = 10.5 to 1
1.3S              =  9.5 to 1
1.2/1.3           = 9 to 1
1.3S               = 9.5 to 1

Series 2

1.3 Berlina (Saloon) = 9 to 1
1.3 Coupe & Sport  =  9.5 to 1
1.6 Coupe & Sport  = 10.5 to 1

Brian Hilton

Title: Re: Petrol Additive.
Post by: Scarpia on 09 June, 2007, 08:40:34 AM
I was generalising somewhat but the point remains that whether 9.0 ,9.5 or 10.5 the compression ratio of a fulvia is significantly higher than the aprilia and these are factors that may influence the choice of 95 or 98 and the use or not of lead replacement additives.
As you say, early saloons were as low as 7.8:1.Some 1.3 HF's (1216cc) were 9.8 increasing to 10.5 later.

Title: Re: Petrol Additive.
Post by: inthedark on 20 June, 2007, 06:23:24 PM
Just to let you know,
I checked the valves on the Gamma  at the weekend and guess what  NO CHANGE  at all
inlet .30 mm exhaust .35 mm  and that's after 14,000 mls running on normal unleaded fuel
and as you know I do belong to the Hooligan element
Geoff 'the colonel'

Title: Re: Petrol Additive.
Post by: ColinMarr on 20 June, 2007, 08:46:42 PM
I have been away and slow to pick up on this thread. I have played with all the additives for my 1600 HF engine, which has the added complication of having the head planed and so has a somewhat higher CR than it should.

My favoured option is ‘Castrol Valvemaster Plus’, which is highly concentrated and easy to administer. My favoured unleaded petrol is Tesco’s “Unleaded 99” with a 99 Octane rating that is higher than the others I have tried and somewhat cheaper too. 

Happy knock-free motoring,


Title: Re: Petrol Additive.
Post by: YKR 567J on 27 June, 2007, 05:19:43 AM
I also read somewhere else (can't remember where) that all 1600 engines have hard valve seats and don't need an additive.

Found it. Go to and find 'restoring' then 'mechanics'. Second paragraph, second sentence.

John Simister

Title: Re: Petrol Additive.
Post by: rogerelias on 17 August, 2007, 07:47:52 PM
Hello All. I drive my 1600 hf fairly hard, and when going to the Great Northern weekends, it will always include long trips up the motorways, i don't tend to use any additive all the time, and tend to sit at 80-90 on the motorways and have never had to adjust tappets, and have not noticed any drop of power, if i do occasionally decide to use one,  i use valvemaster plus, but I too remember something about the 1600hf's having harder seats. Hope that throws a bit more light on the subject.( no pun intended at Italian electrics)  :D  p.s. I used to do night events around here in a 1300s ,and never used an additive, and still beat the local RS 200s.