Triumph Dolomite Unleaded Fuel Info

Intro

Leaded Four Star petrol was withdrawn from sale in the UK on 1st January 2000. However a small number of garages are now licenced to sell Leaded Four Star,use the link below to view a list of suppliers.Yes,leaded four star is more expensive than LRP but personally I believe that leaded four star is the best solution.As most Dollies cover fairly low mileages annually I think it's worth paying the extra for the peace of mind.

Leaded Four Star Suppliers in the UK

All Triumphs were originally designed to run on leaded petrol so the withdrawal of leaded petrol may be a great worry to many owners.There is so much conflicting information available out there and many people are understandably very confused by it all.The purpose of this page is to try and reassure Dolly owners and *hopefully* persuade them not to scrap their cars needlessly. Please note that all advice is offered in good faith and represents the personal opinions of the author,who cannot be held responsible for any adverse reactions!

Overhead Cam Engines (Sprint and 1850)

Valve seat recession *shouldn't* be a problem with these engines - the valve seats in these alloy cylinder heads should already be hard enough to cope with unleaded fuel.This still leaves the problem of pinking or pre ignition, which can cause serious damage to pistons.This is caused by the Octane rating of ordinary (Premium) unleaded petrol being too low for the engine (95 RON)- leaded Four Star has a rating of 98 RON.This can be reduced by retarding the ignition... but that affects the performance and can lead to overheating.Another solution is to use an octane booster such as Millers VSP or use LRP (which has an octane rating of *about* 97RON)AND an octane booser.The best advice regarding LRP is that it shouldn't be mixed with Leaded Four Star.Also,if using additives (such as Millers VSP) ,choose one brand and STICK TO IT - don't mix brands.

An alternative is to use 97 RON Super Unleaded petrol,which in my opinion is probably a better bet than using LRP -at least the Octane rating is consistent,unlike LRP which can vary.

Overhead Valve Engines (1300(TC), 1500,1500TC,Toledo,Dolly 1300/1500)

Things get more complicated here,but there's no need to panic.The relatively soft valve seats can be liable to valve seat recession when using unleaded petrol.The *best* solution to this is to fit hardened valve seats.This shouldn't cost hundreds of pounds (don't allow *some* less reputable companies to rip you off!).However,there is a school of thought that says that this is unnecessary,at least for engines that have done more than about 50,000 miles.The logic here is that engines that have done that mileage will have a coating of lead on the valve seats which should offer protection for several thousand miles. As most Dolly owners only cover a couple of thousand miles a year,it would be years before any problems surfaced.Better to wait until then before shelling out any sum of money - if it ain't broke don't fix it! For engines that haven't done such high mileages or get regularly "thrashed" ,another solution is to use an additive such as Millers VSP and Premium unleaded or LRP and an additive (I don't believe that LRP on its own provides enough protection against valve seat recession).The problems with pinking apply for the overhead valve engines as much as the overhead cam engines (so read the section above).

Conclusion

There's no need to worry about the demise of leaded Four Star - if in any doubt go along to your local Triumph Dolomite Club meeting and talk to other owners.I've heard stories from several club members who have used unleaded petrol for years without any problems.Approved additives such as Millers VSP can be obtained from local stockists.

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