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Fuel Change to unleaded

PostPosted: Thu Sep 15, 2005 5:35 pm
by admarti
Anybody with any views on changing the valve seats so my S1 can run on unleaded.
LRP is getting rare!

Re: Fuel Change to unleaded

PostPosted: Thu Sep 15, 2005 6:14 pm
by Hamish Coutts
OK LRP is getting rare, I agree. There are loads of additives for lead free petrol that will do the job perfectly well.

I use the red line stuff. Expensive and I think, voted the best additive by some classic car group. (If you want to know I will find out). However, I don't do a high milage in a year. I suppose the lead free conversion decision would hinge on that. :?
My low milage saves me the hassle (and expense) of doing the conversion to the head. I rebuilt the engine about 400 miles ago and apart from a bit of grinding in, left the valves and their seats well alone.

Hope this helps,


Running on unleaded

PostPosted: Thu Sep 15, 2005 6:51 pm
by hatman
Run on unleaded? Are you mad? Would you run your pride and joy on paraffin? (several desperate motorists actually did this during the second world war). Get yourself a supply of Tetraboost, mix it with Shell Optimax and continue to run the car on the 100 octane leaded juice that it was designed and built to use in the halcyon days when life was cheap and Health and Safety fascism amounted to nothing more than the occasional 'Beware of the dog' sign.

Re: Fuel Change to unleaded

PostPosted: Thu Sep 15, 2005 10:28 pm
by twincamman
i run both tcs on 80 octain regular non lead with no problems-----hi test is better but the regular works at 10 and 16 degrees advance ed

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 4:50 am
by 1964 S1
speaking of dogs, I don't intend to raise any hackles but.... here in the USA my S1 has been running fine on premium unleaded (octane 93) for the last seven years. (Except when I drag race it, then I use race fuel) So far..... so good......
should I expect disaster in the next decade or so?

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 7:39 am
by Dag-Henning
This discussion runs all over the car-world, and seems full of examples of "no problem running on lead-free." Funny enough, I can't recall any good stories of engine break-downs.....( !!) - despite all warnings.
From our friends across the border in Sweden, I recall the head of the Cortina Owners Club running his std. 1500 cast- iron- integral-valve-seat engine on lead free for years, and reporting no damage at all. His "test-results" were published in the "Quarter Bumper" magasine of the Lotus Cortina Owners Club. in the UK.
On the other hand.... :lol: to be sure :lol: , I guess it is adviseable to go for hardened seats if rebuilding the engine, - just to be sure......
Lead/ no lead is one thing, but the octane value of the fuel is another. My experience ( - bad....) is that you don't always get what you believe you do. Sometimes pinking is a problem, - sometimes not-, using "the same quality ". Guess we should all run racing-fuels to be 100% sure what you get, but of course that is very expensive and unpracticle......
Rgds Dag ( Norway )

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 8:52 am
by wildoliver
Must be honest I have run Unleaded 95 in my classic cars for the last 7 years, that was in an mg midget 1275, a pair of mgb's, a porsche 924 and now a porsche 911, i will be running my elan on unleaded too.

The most notable example was my Mgb which i drove to work every day for a year doing a thousand miles a week, it clocked up 40,000 miles that year with no faults at all, no valve seat recession and it was used very very hard with autotesting on the weekend, Eventually I had to rebuild the engine at 120,000 miles due to a piston having disintegrated at high rev's, at that age and mileage and use it wasn't something i begrudged the car tbh.

Personally i think most of these products to "replace" lead are at best unnecessary and at worst "quack" cures.

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 3:01 pm
by Alasdair
I have used unleaded since inception (20 years?) in Ontario, Canada, without ANY changes to any of my engines, Elans, Climax Elite, 2CV, big Healey with no plans to change +8 Morgan or E-type projects. I only use Sunoco 94 unleaded and find it is excellent even when driving hard, I do not like nor will I use any additive.

I really hope Sunoco continues with the 94 product going forward. In emergency I have tried other fuels with big disapointment.

I have yet to hear about, or experience valve issues due to unleaded fuel and certainly will not spend the money changing seats, I see no reason to do so. Perhaps this is due to being a frugal Scot!


Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 3:28 pm
by hatman
You guys surprise me. Yes, the twin cam will run on unleaded, with or without valve seat changes; it will also run with cheap supermarket oil in the sump and third-world tyres on the wheels. But, having spent a fortune in time, money,anguish and sweat of the brow in attempting to get your Elan into the best possible condition, what on earth is the point in compromising matters by sticking the wrong fuel into the tank just because that's what Joe Public uses in his vehicle these days?

Surely your quest for the best-presented, best-performing Elan should extend to the vitally important stuff that makes the whole lot come to life, ie petrol (or, if you must, gasoline). By mixing your own leaded fuel you and you alone have the say on quality control and consistency. This way and only this way can you set up the tune for optimum spark advance, safe in the knowledge that you will not be risking pinking and premature engine failure by inadvertently filling up with lower octane juice in the lottery that is the run-of-the-mill unleaded retailing via the many different forecourts scattered across this fair land (and others too, I imagine). Bear in mind that the modern, 'computer-controlled' ignition and fueling systems used on current cars are entirely capable of making the instant adjustments needed to cope with these variations; the iron-age technology of the twinc cannot - that's your job.

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 3:44 pm
by wildoliver
I disagree, I lose no performance from using unleaded, I show no signs of engine damage even over long periods of time and mileage, bearing in mind my cars get used very very hard.

The analogy between fuel and oil is a nonsense, the difference between good quality and poor quality oil is immense, however a better analogy for those who believe terminal damage will occur if unleaded is used alone, would be synthetic to mineral oil, our classic cars were only designed to run on mineral oil without half the additives and detergents used in even the cheapest of oils today, most people would not dream of using anything other than a good quality mineral oil in most classic british engines due to it being a total waste of money.

The simple fact of the matter is if using additive makes you feel better then fine but in the same way we all laugh at reddex now realising it does nothing i think in a few years we will feel the same about fuel additives.

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 4:24 pm
by types26/36
I think there are two distinct but different issues here, one being the the question of lead and the other being the issue of octain rating and these are being confused.
Our engines were designed to run on high octain fuel and high octain unleaded is available so there should be no issues with using it to get maxium performance with regard to ign. advance.
The use of lead to preserve the valves and seats seems also to be a non issue judgeing by the the number of people who have had no problems with its use, I have been useing the LRP but now it has been withdrawn I will be useing unleaded with no additives.

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 6:41 pm
by wildoliver
Very well put, totally agre with everything said, crazy thing is however.............some engines seem to miss high octane fuels and others don't!

On the Mg's which were designed to run on 5 star 100 octane, no difference can be felt running super or ordinary, and the porsche's are all designed to run on low octane anyway.

But some engines do prefer super, although the elan I've just bought apparently doesnt mind!!! Which is good as I won't be buying optimax at those prices!!

Re: Fuel Change to unleaded

PostPosted: Fri Sep 16, 2005 7:10 pm
by twincamman
about the only difference I can see is the hi test race fuel turns the skin on my hand white when I check the fuel pick up in the fuel cell and regular non lead doesn't--and I wont use the pixy dust additives -ed

Re: Fuel Change to unleaded

PostPosted: Sat Sep 17, 2005 2:30 am
by 1964 S1
I don't consider unleaded the "wrong fuel" when the cars start and drive without problems. Kerosene = wrong fuel perhaps. Also, I've not spent any time, money, anquish, (maybe a little sweat) "attempting" to get my Elans into the best possible condition. I bought two for what I consider very reasonable prices, especially considering their restored condition, and just jump in them and drive, fast. And as far as octane lotteries, I've never heard any pinging in years and years of driving, even in the hot heat of summer in heavy traffic, ever, so I assume I've always gotten premium.

Lead memory

PostPosted: Sat Sep 17, 2005 1:07 pm
by purplepete
In the aircooled vw scene,there was a lot of similar discussion about the use of unleaded,and the conclusion was that theres no need to change the seats due to the accumulation of deposited lead,and that the dissy had to be changed to one with a suitable advance curve for unleaded.
As long as the engine is in reasonable condition,this seems to work for me-have built about 12 engines since 4star was banished,all running fine.
You also have to think about the compression ratio.lead memory unaffected by decoking and grinding the valves in.
Whos the engine guru in the lotus world?try asking them.
can probably sort out the info as far as vws are concerned if it helps.