Lead Additive.

[Phil H 4]

To add or not / what are the groups thoughts regarding fuel additives.

My 72 hasn't been converted to unleaded so I am adding a lead replacement additive.( Red X)

I have been reading various articles regarding exhaust smells in the cabin and that this is possibly exacerbated by using a fuel additive.

I have quite a strong exhaust smell when the roofs down and have checked the obvious, boot and light seals, exhaust pipe lengths and have fitted a wind break that has helped but am now considering dispensing with the lead additive .I assume in the short term this will not be a problem, or should I just stop using altogether.

Thanks

Phil

 

 

[Crawfie]

I used to use an additive when I didn't know any different .  Used the Millers stuff

Stuart put me straight . Not used it for years.

No smells .

[Phil H 4]

Sound like a pure fill up next time then.

[Andy Moltu]

The lead is there to reduce vale seat recession (and to increase the octane) - the valve seats are cut into the cast iron head. Without lead or an alternative additive the exhaust valve seats will erode more quickly than with.

How long before the recession is significant  is variable - depending on how hard the car is run and how far. It's probably not worth using the additives unless you really don't want to have the head off to have hardened valve seat inserts fitted.
Similarly it's probably not worth taking the head off just to do the valve seat inserts, wait until it's required or you have the engine stripped down for other reasons in which case you are not making work or expense for yourself.