Unleaded spitfire engine--how can you tell?

[Terryb]

I have been enquiring about a 1500 spitfire from a dealer and he had been told by the previous owner  to "just put unleaded in".

I am a bit uncomfortable about buying a car with no proof that the head has been done.

Is there any obvious signs the head has been made unleaded, I am assuming not as it's all going to be under the rocker cover.

[KevinR]

Without removing the cylinder head it is very difficult to tell if the head has been converted or not - without waiting a long time and measuring the valve clearances to see if they are closing up with time.

 

If you have an endoscope, you may be able to examine the exhaust valve seats via the sparkplug holes, or via the exhaust ports on the head.

[Terryb]

I have just found out that the car comes with all the paperwork/MOTs for the last 15 years so there may be a clue in there.

Would it do any harm to put the additive in the petrol anyway--as a precaution?

What does the additive usually cost and how long would a bottle last?

[KevinR]

The usual advice is to just run the car on unleaded fuel and monitor the valve clearances, and if they keep closing up then bite the bullet and get the head converted.

 

Try googling the subject - try "Lead Memory" for starters.

 

http://www.canleyclassics.com/?xhtml=xhtml/infodatabase/unleaded.html&xsl=infodatabase.xsl

[Pete Lewis]

I m convinced addatives are made just to scare the driver into buuying the stuff, it often causes more troubles than it allegedly has any  magic cure.

 

save the money buy fuel of the best octane you can get , these were built to run on 100 so any 97 or higher will get close to the factory performance with factory setting.

 

   95 ** was used in motor mowers and side valves when these cars were developed,

 

    having driven a  non converted 1964 vitees6 pretty hard for 12 year without any valve recession , proves there is sufficient lead memory absorded by the casting to last thousands of miles , ( also the seats we machine cut during its possession) 

 

    so like it or not,  use the money to buy  good fuel  and use car , for many happy miles .

 

just some thoughts   Pete

[Terryb]

OK thanks, I had been reading about the lead memory, I guess the previous owner was right to say run it on unleaded as the engine has done 96,000 so the valves should be pretty hard.