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MG MGB Technical - LRP and Esso

Just been to the local Esso garage (Henley) they've stopped selling LRP,
and by the Esso flyers on the counter it looks like Esso are stopping it in a
number of garages.

Having only come back to classic cars recently, (and I apologise if I open
old arguments) what's the best thing to do?
a) use unleaded (or super unleaded) with an additive (if so which?)
b) get the head machined with valve inserts (if so can anyone suggest an
engineers in south Oxfordshire?)

If it's converted to run on unleaded, then what's the new timing for a 1972 engine?

Thanks guys
M S Akehurst

For the time being, use unleaded with an additive. Many people like Castrol Valvemaster (available in Halfords), which can be purchased with an octane booster. I think LRP is going to disappear everywhere shortly. You may have to retard your ignition timing a degree or two with unleaded even with an octane booster if you get significant pinking.

The ultimate answer is to buy an exchange unleaded head, freely available from many sources from about £150. They are of variable quality and in my opinion, if you are going to the bother of a head change, you might as well get the shape of the chambers improved and a proper 3-angle seat cut done. What timing you use will depend entirely on how the head performs. If you want to go down this route, which will cost around £400 for a modified head, I can't give you better advice than to contact Peter Burgess in Alfreton who will do the head work expertly and give you a rolling road session to get the settings just right. It worked for me. Alternatively, you have Oselli there in Oxfordshire who have a good reputation for engine work.

Mike
Mike Howlett

Yes, LRP is being phased out due to low demand, and leaded four-star from Bayford Thrust is likely to go the same way, I hear. But LRP only ever gave partial protection, inadequate for high-speed (i.e. motorway) heavy load running.

My experiences are that standard unleaded, with or without the octane booster, makes pinking (and running-on before I did the mod) much worse. Retarding the ignition to control it saps power significantly and increases running temps. I use Super Unleaded/Optimax and ordinary Valvemaster which seems as good as four-star leaded but cheaper. But in practical terms North America has not had leaded for years and I have never heard of anyone claiming to have had valve seat recession, and I have none so far. I won't bother having my head modded until it needs it.
Paul Hunt

I've just gone over to using Valvemaster plus Octane boost (6 for 5 from the club or Castrol - sod Halfords). This was caused by a panicky drive back down the M40 recently where I was looking at running out of fuel (no LRP). Seems to work just fine with ordinary unleaded and works out cheaper than LRP too(!) No sign of pinking at all and I'd swear the fuel consumption has improved. Must have snake oil in it :-)
T J C Cuthill

This thread was discussed between 22/07/2003 and 23/07/2003

MG MGB Technical index

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