All i want is a straight YES or NO !!!

[Jon]

Can i run my 1968 122s (?) 133 - maybe with a b18b engine on unleaded petrol. I've read pages and pages of drivel and come to the conclusion i have to drive around searching for Shell low lead 4 star !! I haven't even see a Shell garage anywhere near where i live and even if i did, what should i do when i'm up the other end of the country.

Someone please.... YES or NO. ( i currently use LRP !)

[Andrew (UK)]

I am afraid that there is no such thing as a straight answer. It depends upon your driving style to a large extent. There are two main problems with unleaded, the lower octane causing pinking and valve seat erosion.
The pinking can be avoided by altering the timing and mixture, there should be no need for thicker head gaskets, they simply rob power.
Your engine does not have hardened valve seats. High speed driving will erode the valve seats a lot faster than low speed town driving. If you intend to do a lot of motorway driving you have three realistic choices (in no particular order):
1)Buy real leaded petrol from a garage listed in http://www.bayford.co.uk/ at about 1.00 GBP per litre.
2)Buy the lead to mix with unleaded from http://www.tetraboost.com
3)Have hardened valve seats fitted and adjust to prevent pinking.

However if you only do a limited amount of driving, or it is mostly low speed then you have another choice, you can simply use unleaded petrol (having adjusted as above to prevent pinking), but you will need to regularly check the valve clearances. When it gets to the point you can no longer adjust them within spec then you will need to get hardened valve seats fitted, but this day may be a long way off or indeed may never come at all.

I have not heard anything good about LRP and I will not use it unless as a last resort.

[jamie taylor]

In addition to the above thorough answer you could if your option is to run on unleaded until your seats need replacing use a product called Flashlube.
It drip feeds in through the vacuum of your inlet manifold and lubricates your upper engine.
The Aussies have used it for years especially when running their cars on LPG as I am also running my car on LPG and no new hardened seats. I belt up and down the motorway once a week for the last six months and the 30 year old engine has only improved so far.

[Jon]

Thank you very much, at last some 'real' ideas rather than speculation, i'll look into the flash lube thing although my manifold isn't tapped for Vacuum advance i'm sure i can weld a tube in !!

My driving is normally belt up the motorway to show ground and then belt home again as quickly as possible, occasionally i'll go for a cruise around town and down on the seafront to let the boy racers know whats up ! ;-)

[jamie taylor]

you do not have to weld it just drill out and the connectors are supplied
Ring martin at Powertec Brooks Automoyive developments ltd 01508 538000/538889 Nr Norwich
or go on the internet for a supplier in Holland or their own site from Aussie

[Briwyn (Guest)]

Can't be definite, but I know a guy who sells 120 series who swears he has run on unleaded for years with no particular ill effects

[Thomas Bellew (Guest)]

The answer is yes, you can change to unleaded as I have.