mm fuel aditive

[joe clark]

hi all,just a quick one,should i be using an aditive in my ,51 mm sidevalve though i only drive it occasionally . thanks Joe

[lambrettalad]

I say yes ,some say no,takes your pick

[irmscher]

I wouldn't bother

[charlie_morris_minor]

With my A series engine, i do not bother with addatives, after all unleaded heads are readily available so if it does fail well i have saved the money on the addative and can buy an unleaded head and swap over..

My side valve MO gets the addative every time as a rebuild is very expensive

[bmcecosse]

The side valve engines were built to run on POOL petrol - which had no fancy lead additives.... So, no need for any today! Do however keep an eye on the valve gaps - not easy I know with a side valve, but they must not be allowed to close up.

[rayofleamington]

The side valve engines were built to run on POOL petrol - which had no fancy lead additives.... So, no need for any today!

They were also built to run on monograde oil - simply because that's what was common at the time, not what's best now.

If it's a pre-water pump engine then I'd definitely use an additive (the cooling will be very limited when you're stuck in traffic and also less effective when driving hard, and the valves will get hotter).
For a water pump engine you're slightly better off but if it was me I'd still use an approved additive.
Checking valve gap isn't very effective as it relies on even valve wear. VSR is not always even and the resulting hot spot from the gas leakage can burn a chunk out of the valve.

[joe clark]

well thanks for your advice folk. The engine was bored recently but we didn,t renew valve guides,guess I,ll go with the aditive as i only use the country lanes round our village thats assuming it doesn,t cost a bomb. Not a fast car are they, I get tractors flashing me road hogs ! Joe

[rayofleamington]

Driving style is a major influence to valve damage - if you drive very hard & for long periods this leads to valve seat wear (even faster without a good additive).
If you're driving is only pootling around country roads, you've got as lot less to worry about.