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MG TD TF 1500 - Unleaded fuel

I don't how things are on the other side of the big pond, but overhere in Europe only unleaded fuel is available.
For use in old cars additives can be added, also
modification of the cylinderhead is an option, be it a rather expensive one.

Has anyone any idea about the pro and cons?

I've read somewhere, that old engines do have so much
lead burnt into the metal of the cylinderhead, that if you don't use your car extensively, there are no risks for the first 20-30.000 kilometres.

And if not, what is accualle the problem that occurs, if you keep on using unleaded?

It also seems, that unleaded fuel makes the engine hotter with a greater chance on vapour lock.

Any experiences?

Thanx Erik van Hardeveld
Erik vanHardeveld

This subject has been well and truly thrashed to death. Try archive search. Unleaded Fuel. and select all of these words to narrow the search.
J James

Hi Erik. The US has been unleaded for a long time now. And the concensus seems to be if you have lots of extra cash, you take the head off and have your machine shop fit hardened valve seats to minimise seat recession. If your wallet isn't bulging, you just drive as if nothing happened. I've been doing the latter with no ill effects. Additives aren't generally well received, a pain in the ass actually.

Erik, Tom is right. Just keep on going as useall. I have been using the cheapest unleaded 95 fuel since its introduction and it never did any harm to my unmodified MG's.

Point of attention is to check your valve clearences every now and then.

If they decrease dramatically again and again you know there may be a seat going but that's early enough to take action and spend your money.

Apart from that there seems to be no recession whatsoever below 3000 rpm.

When I purchased the TF it had a can of "lead additive" in the glove I kept using it. Rebuilt engine this year and did away with the need for it! If I ever get around to it check ebay...I still have almost a full case of the stuff I keep meaning to put on there. If you decide to "play it safe" it by the case it's much cheaper that way!
David 55 TF1500 #7427
David Sheward

Hi Erik,

Having seen the disatrous effects of not a) putting in stainless valve seat inserts, b) continually adding additive or c) ever again driving the car for fear of droppig a valve like I saw a few years ago; I can heartily suggest you take the steps to prevent your valve seats from crystalizing (from lack of lead and from running at somewaht higher temperatures) and avoid destroying the cylinder head.

There is no doubt that over a given period of time, it will be less expensive to continyally add additive, but frankly, it becomes a pain in the ass. I did it for 5 years and finally gave in to valve seat inserts and I've put it out of my mind ever since - no muss, no fuss, no bother!

Gord Clark
Rockburn, Qué.
Gordon A. Clark

I have put 35,000 miles on my TF 1500 since rebuild. Standard valves, NO SEATS, and a normal regrind. Pulled the head yesterday (another story!) NO seat recession, valves and seats look great!

I have been using 93 Octane unleaded the entire 35,000 miles with just a few addatives in the first 3000.

Don't get too advanced, you will burn valves. Keep your timing right and you don't need to worry about all the stories about unleaded>
Don Harmer

this has all been hashed out in the archives, but since people are posting to this question.... lead was added to fuel raise the octane number. it was not added to lubricate anything. there is a technical journal of car restoration called "skinned knuckles". they accept no advertising dollars. years ago they did extensive testing and their results mirror what a couple of the writers here have stated. drive your car and don't worry about it. whatever you do DO NOT waste your money lead additive. save your cash and the environment. tom
tm peterson

Actually the lead added to fuel contributed to burnt valves as it would build up in uneven deposits and cause valve seating issues, which caused hot spots and consequent burning. It was never intended to "protect" valve seats, only raise the octane number. One of the premium fuels of the period was Amoco Unleaded, also called "white gas". Many people(that could afford it) used this for years with excellent results.
Dallas Congleton

Is it uncool to answer someone without a "check the archives first" comment? It discourages people from helping and novices from asking, as well as taking up almost as much bandwidth as not answering at all. And I think it's really rude, like saying to somone: "Oh, you didn't know that?" Like saying it's a stupid question. Why have a bulletin board and discourage people from using it? If someone links to where they know there's an answer, I think that's wonderful. My dos centavos.

Maybe my opinion has already been thrashed to death too, but I don't have a link to it.

Hehe, must have swallowed a bitter pill! Cheers.

Tom, the times I suggest someone check the archives is that some of these things have been discussed in very great detail repeatedly over the years. Some of the original posters may no longer be active on the board. Things posted in the past that were fresh on someone's mind may be forgoten by now. Certainly no slight toward anyone! Now if the archives search worked as well as Google....George
George Butz


Thank you all for your reactions.

I did some investigation in previous threads but couldn't find a satisfying answer, and when I read
some of the reactions below, it does not seem to me that everybody is of the same opinion on this topic.

Nevertheless, thank you all again for your trouble and I'll just take my chance and wait untill I've to
do the cylinderhead anyway and combine things.

Happy motoring


Erik vanHardeveld

Answering someone's honest question with a "It's been in the archives a hundred times", It's been in the TSO a dozen times since 1975", "This subject has been well and truly thrashed to death", "Try archive search", or the "It's on the CD" comment is an arrogant attitude that is a disservice to the entire MG community. We all would like to have been there when you bought your first MG ... but of course, you never asked any questions, did you?

Surely, you must still be suffering from the trauma of the one time you actually did ask a question ... I'm sure you were encouraged by some other arrogant sphincter - suggesting that you read every book written on MG's and if you couldn’t find the answer, well, you just were not MG Worthy.

Possibly you, Sir, should drive a Hillman Minx.
R.P. Ewing

That is why I suggested you did an archive search. There are so many different opininions about the effects of unleaded petrol on "old" valve seats that a new thread would barely cover the subject. Choosing whether or not to add additives seems to be a case of what side you bed you get out of on the day. Biut from what I have read, several respected experts say run the car on unleaded without additives it will not harm your engine unless you drive like a maniac.

Mr Ewing - I wouldn't mind a nice little Hillman Minx to keep the TF company
J James

This thread was discussed between 19/10/2005 and 08/11/2005

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.