What do you think? I have an old (1985) petrol landy, I was wondering if I should add a weak mix of 2 stroke oil say around 5-10%? to the petrol in order to give better lubrication to the valves and piston rings. Not something I’d do to a modern car, the cat or lambda sensor in one would be knackered in no time. But old landy has no such scary expensive technology and probably would not look too out of place trailing a big cloud of blue smoke either

It may need a decoke a bit more often but that’s no hardship as it's a doddle on these engines and I like to poke about inside now and again, certainly a lot less hassle than the cylinder bores wearing. No worries about the performance suffering either as I already don’t have any...

Do you think doing this would extend the life of the engine? I think so. Would the engine run cooler from less friction? Not sure but probably.

But how much oil should I add, I don’t want too much smoke really, just enough to help

I have used redex for several years in the Bluebird but tbh apart from the carb venturi looking very clean have noticed zero improvements to anything else and despite it's claims is really to thin too have any lubrication effects on the rings or valves

Tbh measuring the quantity of oil my be a case of dumping some oil down the filler before the petrol, though if I do it when filling right up from almost empty to the top I should be able to ge an approximately correct mixture strength.

Anyone tried or does this to their old cars? Any 2 stroke oil you'd recommend? though may just try some scooter oil at first

It will make it smell nice but other than that, I doubt it will help the engine at all. Most of the oil will be burnt before it gets a chance to do anything. In a 2 stroke, the oil does its oiling whilst in the crankcase and under the piston, not once its climbed up on top of it.
It could oil the valve stems but the original engine design will be taking care of that.

Would probably just end up clogging the fuel filter long term.

It's supposed to make a difference with diesel cars, now they have yanked the sulpher out of the fuel the pumps etc are wearing out.

It will accelerate plug fouling and carbon build up on valves and combustion chamber and will weaken the mixture and make it visibly smoke. Completely daft thing to consider IMO.

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Originally posted by MikeRJ
It will accelerate plug fouling and carbon build up on valves and combustion chamber and will weaken the mixture and make it visibly smoke. Completely daft thing to consider IMO.

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If you do decide to add a lubricant to the fuel it does not need to be that much. Competition 2 strokes run at 2% as their only source of lubrification...

Gotta be REDEX for an alternative fruitier flavour

It's not going to achieve anything putting oil in the petrol as above, you'll just be spending money on oil that is doing nothing. You need a lead replacement like Millers VSP which is also an octane booster.

I thought in a standard engine you have oil coming up from below anyway, which will lube the cylinder walls where the piston rings rub? And the same happens at the top of the engine, the part of the valve that is actually rubbing against something is oiled from above?

So the only thing that's not getting any oil is the very top of the cylinder and the valve seats, which are also the areas that burn hotter than hell for a certain proportion of the time. And if the oil gets hot enough to burn, you no longer have nice slippy oil you have nice sticky sludge and soot.

Personally I've given up on all fuel additives. Most modern fuels already have the equivalent of Redex in diluted form, it seems pointless to then pay more and dilute it further. The only thing that worries me is the percentage of ethanol, but since I don't yet own a car that is affected by it I'll do a bit more digging on that when it's appropriate.

Edit: Of course, the lead replacements are justifiable additions if your car ran better on 4 star.

[Edited on 19/3/12 by Slimy38]

Modern 2 strokes run at 50:1. If your engine is 35 years old then you probably have nearly that much oil breaching your oil control rings anyway.

I used to put my unused 2T race petrol in my Mk11 Escort, as we always used fresh for race weekend. Killed off 2 engines pretty quick, clogged everything up. Bad idea.

ok good points there, won't bother

cheers