does a 1962 triumph herald need a petrol additive ?

[tom-bund1]

I run a 13/60 Herald on 95 octane petrol, it's recently started to sound a bit rough... do I need an additive ? does it just go in the tank or also in the cylinder bores ?...thanks, Tom

[tonyav]

Yes it needs a lead replacement additive, I'm 99% sure it goes in the tank.

[Tilly2]

Oh Tom! my first car was a Triumph Herald convertible. It was a lovely, shiney red. Couldn't see through the back window when the roof was up because the window was all cracked and opaque. Used to drive around with the top down even in freezing weather but I was young and didn't care.

[tonyav]

Just a thought tom, have you been running it without lead additive ?. If so you may have already damaged the valve seats.

[MantaRay]

Yes, you should be putting additive in the petrol every time you fill up. It's called lead substitute or something like that though it's name will vary according to the manufacturer of the product. You say the engine is running a bit rough, so, if you haven't been using a lead substitute in your fuel it's possible you may have burned out a valve or valve seat. A compression test would be advisable, if that reveals one cylinder substantially lower than the other three [and valve clearances are correct] then it will probably mean the cylinder head must come off for overhaul.

[Martinthefirst]

Has it been converted to run on unleaded?

[mjwman]

As a Spitfire owner I can say that eventually you will need to have the valve seats changed but if you are only doing low mileages it will take ages before any resession shows as there will be a lot of lead memory.
You will need to check and adjust your valves now anyway and if any significant cahanges take place then get the head sorted.