Midget 1500 - run on unleaded?

[unrepentant]

Hi

My influence has paid off and we're looking to buy a Midget 1500 for my daughter as a first classic. She has several to look at and has asked about unleaded petrol. One owner has replied that he has always run the car on unleaded with no problems but it has not had any conversion. Does that sound correct?

Thanks

Paul

[DeanoX]

For a complete answer try
http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgb...

I have a 1275 Midget - so knowledge of the 1500 engine isn't 1st hand. Its the triumph engine rather than the A Series so you could also try triumph sites where any info on 1500 Spitfires should be relevant.

I dont personally believe any of the Midget engines were designed for unleaded. There is allegedly "a memory effect" on many older engines where if the engine has done a huge amount of miles on leaded - the valve seats will cope with unleaded for many miles before showing adverse signs.

I've had mine for many years and since the demise of leaded have used an additive. I only really do about 2K miles a year in it so the additional cost isnt really an issue(£10/Bottle = 250Litres Fuel treated). I have however replaced the engine this year and as the head was in the Machine shop had it converted to unleaded. On an otherwise good head that was £110+VAT.
Dean

[Ginetta G15 Girl]

I've just rebuilt a 1500 for a customer. The engine in question had been a replacement or re-con at some time owing to the fact that the engine number indicated it to have come from a Triumph 1500 FWD. From the state of the bearings (mains and big ends) the wear present showed it to have been either a relatively recent replacement, or not driven much.

However, inspection of the cylinder head showed a great deal of exhaust valve seat regression from running on unleaded fuel. This required seat replacement with modern hardened seats which then required cutting.

Along with replacement valve guides the total for the job was in the region of £150.

Given that the casting of the head is relatively soft I would suggest for these motors to run with long term reliability on unleaded fuel that the exhaust valve seats are replaced as a matter of course at a one off cost. Alternatively you could use a fuel additive such as Millers CVL but this will be far more expensive over time.

[unrepentant]

Thanks for the replies guys.

[wadgebeast]

General advice has been to run them on unleaded and then replace the valves and seals when required. They will eventually burn out, but certainly not immediately. Fuel additives are considered to be a waste of money. 1275 is a better car than the 1500 too.