Does fuel treatment really go off or degrade?

[M.J.S]

Five or six years ago before I took the car off the road I bought a dozen bottle of Millers VSP, as a lead substitue and octane boost.

I have just noticed it has a 'use within 2 years' of date, which means the whole lot is useless.

Can this stuff really go off when left in a sealed bottle in a cupboard, or is a ploy to sell you more? It's not cheap.

Cheers.

[nigelrbfurness]

IMHO give the bottles a good shake and I reckon they'll be fine. I can't see how the chemicals in the additives can degrade over time. However it won't do any harm to use them. TC valve seats are hard enough to use without lead additives anyway, though the octane boost might help pickup from idle if you are using the standard timing settings and maybe a few bhp in the power band.

Nigel F.

[M.J.S]

Thanks Nigel.

[HJF]

Sorry, but they do degrade with age.

By coincidence I called Millers? Technical Helpline to discuss their VSPe additive a few days ago. Their engineer explained that oxidation does indeed degrade the octane boost factor once opened and it has diminished to a low level by the end of the two year period. As always, go to the source if you can rather than relying on forum opinions. Look at Millers? website for their technical helpline phone number. They are really helpful and happy to chat.

[HJF]

On another point, according to Wilkins? book on the Twin-cam engine, the valve seats originally were cast iron and damage will occur on lead free as you need sintered seats fitting. See chapter 9, page 176, 3rd paragraph down.