Classic cars forum & vehicle restoration.

[Richard H]

This is interesting. The first A35 I had I religiously ran it with Castrol Valvemaster, and I had no problems. When I bought my 2nd blue A35 the owner told me he'd fitted a 'catalyst' in the tank that cost £80! so it would be alright for unleaded petrol. I drove it for 3000 miles with no problems at all. I've done about 7000 miles in the last year in my current black A35 with no additives, nothing. Again no problems. I did a decoke and reground the valves and seats about 1000 miles ago, there was absolutely no sign of any recession.

About 20 years ago Practical Classics did a test of running a Morris 1800 on unleaded petrol for 3000 miles, which included lots of hard motorway driving. After the test severe valve seat recession was discovered. I wonder if some engines are more prone to it than others?

So I'm a bit worried as I have one unconverted B series car already and am thinking about buying another one. Mind you, Castrol Valvemaster is £8 a bottle, so it doesn't take much additive to match the cost of having hardened valve seats fitted.

[Kelsham]

Well there is no doubt that valve seat recession is real. It can be masked by the lead already deposited on the components.

Less likely as time passes.

The problem is worst when the engine is extended. If you only do local journeys at slow speeds the valves and seats may survive without assistance.

I use valvemaster in my 1932 BSA three wheeler aircooled Trike. Obviously this runs hot.

I personally prefer the insurance the valve master promises.

My Morris 1800 finally recessed the seats when I developed an air leak which weakened the mixture. I couldnt really blame the additive as I had exceede 30,000 miles on it.

Regards Kels.

[Jim.Walker]

[Rich5ltr]

Without fuelling the debate I would say Tetraboost, which has already been mentioned is the real deal - tetraethyl lead. But you may have difficulty importing it to Malta. Regards the use of leaded fuel in older cars, one cannot make mass generalisations, some cars had softer valve seats so are more liable to valve seats receding into the head. If the head on your car is readily available then fine but on my car the heads are like hens teeth, while reproduction replacements are about £3,000. Also there is not a lot of metal between the valve seats and the waterways and ports so it's advisable to not to run it and hope for the best. Better to use lead replacement or get hardened seats.

[Salopian]

I think I mentioned Tetraboost earlier - it is absolutely the real deal. Going slightly off the additive topic the point made by Rich (5 litres by 'eck I'm jealous) about the valve seats is interesting. I've always felt the castings on say an A series are not so hard as many pre war cars but this is entirely subjective.
I've wondered how long the so called "memory" lasts and whether with our limited (generally) mileages it is really a worry. After all we have no vested interest in selling anything if you see what I mean.
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Jonathan Butler
Alvis SD 12/50 1928 MG TD 1950

[Richard H]

Always used unleaded in the Austin Sevens, the engine was designed before lead was introduced to petrol and it actually says in the original handbook "unleaded petrol can be used without detriment to the engine"

[Nic Jarman]

The Talbot and Morris 8 were built before lead was put in petrol but they do run better with an additive (valve master).
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush

[Salopian]

But I suspect reading the Handbook further may reveal decokes every 8000 miles or less -- and valve reseating. Who is up for greasing every few hundred miles?
We are rather spoilt nowadays - who last did a decoke and valve grind on a newer car.
The modern car - electronics aside - is an excellent product compared to that of the pre and post war era so far as durabilty and maintenance is concerned. In spite of that I love my old stuff.
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Jonathan Butler
Alvis SD 12/50 1928 MG TD 1950

[Nic Jarman]

OK Jonathan, put new engines into old cars - sorted!
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush

[Salopian]

I fear in the case of many vintage cars that has already happened - you can buy a surprising variety of new reproduction engines!!!!
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Jonathan Butler
Alvis SD 12/50 1928 MG TD 1950

[baconsdozen]

I think this argument will go on and on.
The way I look at it is that the additives are pretty cheap,maybe the valve seats on my old buses will start to recede without them and maybe not but for the sake of a few bob I might be able to stop it from starting it if it was the case that it needs stopping,if not ,I've spent a few quid on stopping something that wasn't going to start anyway but if it did start would make the engine stop and never start,eventually.
I think I've clarified that rather well.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[P3steve]

[Jim.Walker]

Please accept my resignation fom this topic!
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Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[Phil - Nottingham]

Mine too
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Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2