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Do modern oils means less frequent changes?
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Rich5ltr



Joined: 28 Mar 2008
Posts: 637
Location: Hampshire, UK

PostPosted: Sun Dec 06, 2009 6:07 pm    Post subject: Do modern oils means less frequent changes? Reply with quote

I've asked this on the AMOC forum but would be interested in the wider views of other classic owners on here. The service schedule in the original handbook form my 1958 Aston DB MKIII states that the oil should be changed every 2,500 miles. Given that oil technology has improved a lot in the last 50+ years do owners still change the oil this frequently? I use Castrol Classic XL 20w/50 - it's not that I'm bothered about the cost of the oil but likewise I don't see the point in dumping the lot if it's will last the 5,000 miles to when I change the oil filter. I'd be interested in your thoughts.
Rich...
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Rick
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PostPosted: Sun Dec 06, 2009 6:44 pm    Post subject: Reply with quote

I suspect a lot depends on how often you drive the car, and over what distances. I tend to change mine every 1500 miles or so, mainly because I tend to do shortish runs and the oil probably never gets up to full temperature.

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Rich5ltr



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PostPosted: Sun Dec 06, 2009 6:57 pm    Post subject: Reply with quote

When I drive it it tends to be for long journeys.
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Nic Jarman



Joined: 05 Oct 2008
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PostPosted: Sun Dec 06, 2009 8:40 pm    Post subject: Reply with quote

Materials and tolerances are different in modern engines. I use a higher spec oil than 20/50, 10/40 semi synthetic is fine for most cars even the 1928 Talbot. The oil pressure is a little lower but the oil is slightly thinner. I buy it in 25 ltrs so changing it every 2500 miles does not hit the budget too much. I would rather change the oil than the engine. Very Happy
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Jim.Walker



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PostPosted: Mon Dec 07, 2009 12:08 am    Post subject: Reply with quote

I would suggest that oil change periods should be dictated by the following, which is the result of fleet management over many years.

Short trips encourage sulpher acids to build up in the oil (H2SO3 and H2SO4) as the result of combustion in an engine rarely reaching full operating temperatures for long enough periods. Perhaps less serious if the sulphur content of fuel has been reduced as much as oil companies claim.

Older cars, unless modified, tend to have no or less efficient oil filtering. Straight oils which tend to drop particles and sludge into the bottom of the sump are best for these with frequent changes when hot (I believe this is a Millers Oil recommendation). Even the "straight" oils are much better spec. than 40 years ago.

Cooling systems on older cars tend to be less efficient meaning the working clearances are often greater, wear being a factor too. Which means it is not usually a good idea to use an oil of lower viscosity than recommended.

There are other factors and it is true that modern oils are superior in many ways, as proved by the fact that (taking the BMC A Series engine as an example because of its production longevity) engines were generally ready for re-ringing after about 35,000 miles in the early fifties, but later A series engines were commonly still running with over 100.000 miles on the clock at the turn of the century. I don't think any technology other than oil technology is responsible for that.

On high annual mileage vehicles oil change periods can be judiciously increased. In the end you make your choice, but if you value that engine which it might be difficult to find parts for I would say respect the manufacturers recommendations to be on the safe side and halve it if your engine is used infrequently and locally.
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buzzy bee



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PostPosted: Mon Dec 07, 2009 12:36 am    Post subject: Reply with quote

Hi

My personal oppinion, is to use oils from the same age as the vehicle. Well, not 50 year old oil, but the same grade etc, you know what I mean!

Then stick to the maintenance schedule at the very least.

Cheers

Dave
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lowdrag



Joined: 10 Apr 2009
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Location: Le Mans

PostPosted: Mon Dec 07, 2009 9:38 am    Post subject: Reply with quote

Somewhat shamefacedly I have to admit to being someone who looks at the dipstick and if it looks OK then I don't change the oil. After 3 years I've finally got around to doing this on the E-type and the engine doesn't seem to have suffered. Indeed, having had pretty rough treatment over a number of years, be it a lack of oil change or track days or hill climbs, the consumption is still around a pint every 3,000 miles, and that with 90,000 on the clock since the last rebuild. Another thing that comes to mind is consumption, since one of my cars uses a litre every 1,000 miles so in effect the oil doesn't get much time to even get dirty. One thing sure and certain though - I continue to use 20/50 mineral oils for the car, Duckhams being the main brand, since I reckon that is the oil the engine was built to use. Yet there are others who swear by synthetic or semi-synthetic oils just as there are some who swear one whisky is better than another or one watch brand is the best. I guess you pays your money and takes your choice.
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Jim.Walker



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PostPosted: Mon Dec 07, 2009 11:39 am    Post subject: Reply with quote

Lowdrag mentions Duckhams oil.
Back in the early 80's I had a Morris Oxford which used a pint of oil every 300 miles. I came across a Duckham's offer in a local car parts shop which tempted me to change my brand. I was amazed to find the car immediately started doing over 1000 miles to a pint. Since that day I have never used any other in my cars or motorbikes (except for a modern Kawasaki which specifies semi-synthetic), though it seems more difficult to find these days.
The car in my avatar has now done around 110,000 miles on Duckham's since I started running it at about 39,000 miles. It still never needs topping up between 6,000 miles oil changes.
The quality and performance of an oil is down to the multitude of additives used, pure mineral oil being a lousy lubricant. Duckham's seem to have got the balance right.
I think it is wonderful oil and as long as I can get it I will use no other. I must add that I have no connections with Duckhams.
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Nic Jarman



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PostPosted: Mon Dec 07, 2009 3:48 pm    Post subject: Reply with quote

I worked at Silverhook who blend and bottle motor oils and other products. A huge amount of rubish is spouted about oils and the only factors to be aware of is the viscosity and the API spec. Some producers put other additives in their oils and they may suit some engines better than others. Even older engines with no filters are better off with a modern oil BUT they must be changed regularly. Straight oils are little better than base oil with a thickening agent and these oils tend to contain detergent. My 1500 Midget runs much better with 10/40 semi, it sounds better and does not overheat like the ones running 20/50. It does burn a bit of oil but I can live with that. Pace Product run their 1930s Talbots on fully synthetic.
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Rich5ltr



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PostPosted: Mon Dec 07, 2009 4:18 pm    Post subject: Reply with quote

Thanks for all the comments chaps, I think I'll simply drain the oil and refresh it but to me it seems counter intuitive to do that and not change the filter, which is what the handbook suggests - oil change every 2,500/filter every 5,000.

And like Tony, I used to use Duckhams but switched to Castrol in protest when it stopped being green Wink
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47p2



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PostPosted: Mon Dec 07, 2009 5:40 pm    Post subject: Reply with quote

I was a confirmed Duckhams fan until I had problems with a newly rebuilt engine. I spoke with the engineering shop that did the work and the boss told me that Castrol was a better oil. I've now been using Castrol of various guises for over 30 years and never had to strip an engine down since.

I recently sold a Merc that I bought new and it had 190k on the clock. It doesn't use any oil between its 15k services and never let me down once in the 10.5 years I owned it. Always serviced on or before the service intervals using Castrol Magnatec
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Nic Jarman



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PostPosted: Mon Dec 07, 2009 8:02 pm    Post subject: Reply with quote

If it is any help, Halfords classic 20/50 is green.
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SV8Predator



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PostPosted: Mon Dec 07, 2009 11:06 pm    Post subject: Reply with quote

Nic Jarman wrote:
A huge amount of rubish is spouted about oils and the only factors to be aware of is the viscosity and the API spec.


Is no one else here a member of a car club that is affiliated to the Federation of British Historic Vehicle Clubs?

They gave out a very clear warning about using modern oils in classic cars a while back. (I'm sure it has been covered in great detail on this site, but I couldn't find it).

Have a look at:

http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9014112&contentId=7027140
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Jim.Walker



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PostPosted: Tue Dec 08, 2009 12:03 am    Post subject: Reply with quote

Nice one SV8Predator.
That link seems to answer most of the questions. I tried to condense a working lifetime in the motor trade in my previous post. For years being in charge of the maintenance of a large taxi and limousine fleet. The front line taxis, kept for 3 or 4 years averaged upwards of 60,000 miles per year. I soon found what deviations from recommended service intervals was acceptable and what was not. After having used oil samples for different mileages analysed by Stephens Oil (who lubricated George Stephenson's Rocket) I found that the high mileage cars could be confidently left for 10,000 rather than the 5,000 (then) recommended. I also discovered that a hearse with the same engine which did short runs at low speeds and rarely got properly hot because it stood for long periods outside houses and Churches etc. needed an oil change every 2,500 miles to protect the engine.
As the link shows, there are a lot of additives in engine oil and a lot are not even mentioned. Examples are Viscosity Index Improvers (long-chain polymers), anti-foaming agents etc. etc.. These additives are constantly being improved even for the "classic" oils.
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Nic Jarman



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PostPosted: Tue Dec 08, 2009 12:07 am    Post subject: Reply with quote

I prefer my advise to be independant. Does anyone remember the millenium bug? Nice marketing.
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