16 replies to this topic

[Green-Chameleon]

1971 mini 1000

Just purchased 1971 mini near original condition, is there an easy way of telling if it has been converted to running on unleaded petrol.

Thanks in advance for any info.

Edited by Green-Chameleon, 10 March 2009 - 09:18 PM.

[Bungle]

not with out removing the head

[Green-Chameleon]

Thanks for the info

[Bungle]

*In response to a removed (incorrect advice) post*: the only thing that will do is block you fuel tank out let

get some castrol valve master lead replacement

Edited by Verns_Playmate, 10 March 2009 - 10:06 PM.
Post from this thread removed as requested

[mk1leg]

Hi..I see my last post was removed due to supposed wrong advice well It has not done My old cooper S any harm and that advice came from a physics teacher................SORRY if you think its wrong advice..............

[Jammy]

Adding a bar of lead will do nothing to your fuel. Nor will adding a bag of lead shot. Nor will adding those inline fuel lead 'filter' type canisters. Lead does not dissolve into petrol, therefore it does not add lead to unleaded petrol.

The ONLY way to run unleaded petrol through a head that hasn't been converted/designed to run on unleaded petrol is to use a liquid additive such like Castol Valvemaster (or Valvemaster + for an octane boost as well). This will actually mix with the petrol and allows the necessary additives to protect the valve seats in your cylinder head.

As for running unleaded petrol in a leaded cylinder head. If you have been using leaded petrol for a while it builds up a layer of coke on the valve seats. Once you start using unleaded petrol it begins to eat away at this layer of coke. This can take months, it can take years, but once this layer of coke has been consumed the unleaded petrol will begin to eat away at the valve seats. After a while this destruction will mean you start to lose compression on the engine, and when it gets really bad will cause problems with idling, fuel consumption and general tuning of the engine.

Please do not continue to give out advice that states you can just add solid lead to the fuel. You really can't. You make think that it is just our opinion that this advice is wrong, but it is an opinion that has very good and deep foundations. Rover, kings of cost-cutting, spent many thousands of pounds researching the affects of unleaded petrol on the A-series engine and in the end they decided to add the hardened valve seats. If they could have added a 'lead canister' to a fuel line which would have become a service part they could have made money from then they would have done.

[Dan]

Also bear in mind that ALL cars ever sold in Japan, Minis or anything else have always had valve seat inserts because they have never added lead to petrol in Japan. If there was a way around it which didn't involve hardened valve seats and valves or dosing the fuel then one manufacturer would have discovered it. The lead used in petrol is a compound called tetra-ethyl lead, lead by itself will do nothing even if it would disolve into petrol. Which it won't.

Edited by Dan, 11 March 2009 - 10:44 PM.

[mk1leg]

Adding a bar of lead will do nothing to your fuel. Nor will adding a bag of lead shot. Nor will adding those inline fuel lead 'filter' type canisters. Lead does not dissolve into petrol, therefore it does not add lead to unleaded petrol.

The ONLY way to run unleaded petrol through a head that hasn't been converted/designed to run on unleaded petrol is to use a liquid additive such like Castol Valvemaster (or Valvemaster + for an octane boost as well). This will actually mix with the petrol and allows the necessary additives to protect the valve seats in your cylinder head.

As for running unleaded petrol in a leaded cylinder head. If you have been using leaded petrol for a while it builds up a layer of coke on the valve seats. Once you start using unleaded petrol it begins to eat away at this layer of coke. This can take months, it can take years, but once this layer of coke has been consumed the unleaded petrol will begin to eat away at the valve seats. After a while this destruction will mean you start to lose compression on the engine, and when it gets really bad will cause problems with idling, fuel consumption and general tuning of the engine.

Please do not continue to give out advice that states you can just add solid lead to the fuel. You really can't. You make think that it is just our opinion that this advice is wrong, but it is an opinion that has very good and deep foundations. Rover, kings of cost-cutting, spent many thousands of pounds researching the affects of unleaded petrol on the A-series engine and in the end they decided to add the hardened valve seats. If they could have added a 'lead canister' to a fuel line which would have become a service part they could have made money from then they would have done.

Well I stand corrected and I would Like to appoligise as this was told to me in good faith many years ago when the old 4 star was taken off the pumps by a top physics teacher ..........

[998dave]

Well I stand corrected and I would Like to appoligise as this was told to me in good faith many years ago when the old 4 star was taken off the pumps by a top physics teacher ..........

Just goes to prove you can never trust a teacher! Especially not a Physics teacher talking about Combustion Chemistry.

As above though, it'll do nothing to your petrol, just make a rattly noise in the fuel tank.

Lead is relatively inert, hence being used for window framing, and as a result will happily sit for decades without doing anything to your fuel, Copper on the other hand, does leach in, but actually makes things worse by catalysing the formation of soot deposits, causing all sorts of issues in fuel injectors.

Dave

[Green-Chameleon]

Thanks all.

Also answered a question i was about to ask (what problems would occur of using un-leaded in a leaded car)

Thanks alot.

[p.park]

..it's got nothing to do with "being able to trust a teacher"!
that was an unnecessary and irrelevant comment.
that poor physics teacher was probably mis-quoted out of context.
...it's a little unfair ...

[bigmotherwhale]

actualy he was right, you can add a bag of lead shot, its not pure lead but an alloy of tin, lead and some other metal catalyst, i. so your physics teacher was probably right. i can find a link to somewhere that sells them, howver they dont provide anywhere near enough protection as the lead and tin will only dissolve in concentration of 1 part in ten million which is way below the concentration of leaded petrol, it does dissolve just not very much, and the protection they provide is minimal.

tho personaly i wouldnt bother with additives or anything, valve seat wear from unleaded petrol is over exagurated by a long shot and even if it does cause wear its not likely to cause a problem if the valve rocker clearance are set on a regular basis, as it causes the clearance to be reduced. leaded petrol does not build up a layer of coke on the valve seats that is not correct, coke is carbon deposits which will definately not build up on the seats and valves, the lead builds up as salts and is actualy pounded into the metal, which is why you have "lead memory" that provides continuing protection after the use of leaded fuel

it largely depends on how many rpm, the engine is exposed to, do you drive fast or hard or long distances? if not then it wont be and issue.
i would run it as it is untill it causes a problem then buy an unleaded head off somebody on here for cheap and whack that on instead. it will probably be fine for several years. and less expensive than keep buying additives.

Edited by bigmotherwhale, 23 March 2009 - 01:29 PM.

[Jammy]

Oh for gods sake I don't know why we bother!

As I said, a number of car manufacturers spent a lot of money researching this, and if they could have got away with not adding hardened valve seats to the cylinder heads when the switch to unleaded occurred, they would have done!!

[bigmotherwhale]

yeh but a car that only lasts for several years untill the valve seats become worn would not be acceptable, as i said it has the be run on leaded fuel in its life and then it will only provide limited protection, if you bought a car and a few years later the cylinder head had to be replaced you wouldnt be happy. its different to run it untill you find an unleaded head becuse it wont cause a problem. it will cause a problem IF you rev the nuts off it.

oh there is another reason that you cant add tin or lead to the fuel is because of the introduction of catalitic converters - it ruins them

Edited by bigmotherwhale, 23 March 2009 - 01:37 PM.

[Dan]

When leaded fuel was put onto limited sale various bodies from the IAE to Classic Car clubs, Haynes and many others did lots of testing to see how long lead memory would last. I seem to remember that on an average classic car being used as an every day motor the tests showed that lead memory would last one to two years, maximum. Those being used as a weekend runaround would last about five. Unleaded fuel is highly corrosive and it's the fuel itself that strips the lead memory, not the hammering of the valves. The cost of a lead replacement is very low, it will take several years for it to break even with the cost of a replacement head. Valve seat recession is a big problem. You can't avoid it just by keeping the tappets adjusted. It very rapidly destroys the quality of the seal at the valve and the gas flow through it. I had an engine that went from being perfectly normal to un-usable in less than 10,000 miles due to valve seat recession. The micro-welding happens in a random pattern which breaks up the even and smooth surface of the valve and its seat, it doesn't happen all around at the same time keeping it neat and tidy.

The device that disolved lead/tin compounds into the fuel was one very specific product. It hasn't been available for about 10 years or so and it was a feed-through metering type unit that the fuel ran through I seem to remember. It sort of vaguely worked. A bag of lead shot and all of the so-called lead catalyst things for fuel tanks are simply lead. Lead doesn't contain any tin, it's lead. How is lead supposed to disolve into tin when exposed to petrol? That would be alchemy.