How to prolong the life of your petrol-engined car!

I was listening to a chatty radio show this evening and someone mentioned that he knew someone who put £10 of deisel in with the petrol on every fourth fill-up. He swore it prolonged the life of his engines - and sure enough, his car has so far lasted 30 years....

Just thought I'd pass it on... and listen out for your comments.

Rich

Reply to
Rich
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There are plenty of 30 year old cars around, some of them with very high mileages.

The diesel will act as a lubricant to the fuel system and the valves. Modern petrol (read anything post ~1970) is well lubricated - a measured amount of larger hydrocarbons (a lot like diesel) is added to the petrol to act as a lubricant.

Adding diesel to your petrol is totally unnecessary. In addition, adding that much diesel to a tank of petrol (£10 = 1/3-1/4 tank?) will make the engine run like crap.

Reply to
Grunff

If you want to prolong the life of your engine and g/box use "fully" synthetic oils, not diesel fuel

Reply to
IMM

Well, the guy in question was an old farmer IIRC. He was probably a bit behind the times! Thanks for setting the record straight.

But what about Redex? It was once the in-thing to ask for a a couple of squirts every time you filled up, but no-one seems to bother any more. Perhaps it too is redundant for the same reasons you mentioned?

Rich

Reply to
Rich

This explains a lot. I know many farmers...

That was a looong time ago. Like in the 60s.

Same thing - valve lubricant (and bores to some extent). Won't make any difference with modern petrol.

Reply to
Grunff

I'm not so sure about that, on a 30 year old engine that is, lead was the upper cylinder lubricant in those days and many a valves life depended on it, current engine technology is such that lead is not required.

A mid '70's engine might well last longer if Redex is used, even with LRP.

This discussion would be more at home in the classic car group !

Reply to
:::Jerry::::

Bollox ! Other than on engines that have been designed to use such oil as a requirement. IMM again seems to have taken marketing blurb as gospel....

Changing oil and filter every 6k and driving in a style that is kind to the engine will be just as good as spending a small fortune on fully synthetic oils.

Reply to
:::Jerry::::

People use BP Ultimate petrol now.

Reply to
IMM

There is very little difference between different brands of petrol sold in the UK. Very little indeed. Many people seem to be able to convince themselves that they can 'feel the difference', but it would never stand up to a double-blind test.

Reply to
Grunff

Not quite. You could get proper 5 star until at least 1979 which had roughly the same effect. Once this disappeared we used to spend ages concocting fuels suitable for running 12:1 compression ratios properly once the scrutineer had checked our washed out tanks only had grot 4 star in them.

Reply to
Mike

Well, the engine is probably the least of your worries on a 30 year old car. Most will have serious rot problems long before the engine gives up - and even a totally clapped engine can be made like new for a fraction of the cost of fixing rust.

And the trouble with these 'my engine has lasted X miles because of Y' is that there is no control data to substantiate it.

Everyone searches for the elixir of life - for themselves, or their cars. Some will be convinced that a spoon of honey or whatever results in them living to 100, while others might say it's a pint of cider. And neither can be proved - or really disproved.

Our US cousins seem to think changing the engine oil every 3000 miles results in long engine life, but seem very reluctant to pay for other fluids in the car to be changed regularly - even although this is a service requrement, and might actually save larger repair bills.

All adding diesel to petrol might achieve for the good is upper cylinder lubrication - and there are better products to do this. The down side is that it will lower the octane rating of the petrol and possibly cause higher localised combustion temperatures on a high efficiency engine - and cause piston or valve damage.

Reply to
Dave Plowman (News)

Yes, true, the BP marketing people do say that...

Reply to
:::Jerry::::

I think you're being a bit strong here. When Mobil 1 first appeared we were able to stop changing the oil three times a rally. In fact it would probably have lasted several rallies, such was it's lack of degradation under harsh conditions.

Also changing oil and filter every 6k would cost more than using a synthetic every 18k.

Reply to
Mike

The Ultimate types of petrol have added detergents. They keep your engine clean. Some do give a small ump in power.

Reply to
IMM

Reply to
IMM

Blends do seem to differ, my old '75 V8 Rover didn't like BP, Shell or Q8 leaded 4 star back in the '90's, it was more than happy on the Esso or Tesco's own brand, even though AIUI they all came from the same distribution depot - you tell me !...

And I do know how to judge an engines performance / well being etc., it's part of my trade.

Reply to
:::Jerry::::

Unless your engine is 30 years old, in which case synthetic oils will piss out past every oil seal and cork gasket they can find.

Reply to
Andy Dingley

Ok, I was 6 years old then...

Reply to
Grunff

There is a big difference berween the role played by lead and that played by hydrocarbon lubricants.

The purpose of the lead was twofold:

  1. It reduced knocking
  2. It formed a coating on the valves + seats, and prevented the valves from welding to the seats, thereby causing valve seat recession.

Hydrocarbon lubricants act to lubricate the valve stem/guide, and the piston/bore.

If it's an iron cylinder head, unless it has hard seat inserts it needs either leaded or LRP with an alternative additive, otherwise the head will only last a few thousand miles.

Reply to
Grunff

A far to simplistic explanation, and what the head is made out of is irrelevant.

Reply to
:::Jerry::::

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