45 replies to this topic

[minispark]

i run comma 20/50 mineral in mine and change every 2000 miles.

[Cooperman]

I always run a good 20w50 mineral oil and for the Cooper 'S' I use Valvoline Racing 20w50.

[Old Bob]

Nobody using Castrol R and putting a smile on the faces of everyone you pass?

Bob

[ANON]

slight hijack...if anyone wants any i've got some valvoline 20/50 racing i can do at a good price.

[jaydee]

• Does using synthetic oil damage engine seals?
  No. Synthetic motor oils are perfectly safe for all rubber seals.

Not correct. Not all the seals are the same rubber grade neither the oils. We're talking about 60 years old technology.
I have tryed both 0w60 and 20w50 fully synth (one is a racing oil from shell the other its millers) on a fresh engine they're great, if youre engine has done a bunch of miles, then steer clear from them.
Also, on a classic, where you've been using mineral for ages, the switch to a synth oil is not reccomendable.

Switching to a Synthetic on new and used cars

DO NOT USE a fully synthetic until the engine has covered a little more mileage (approx 10k) because the engine is still bedding in for some time up to this point. Then switch to a good synthetic.
What are the benefits? Less wear, less power loss in the engine, better fuel consumption.
Generally, the reference to synthetic oil for an engine can mean a Group 3 Mineral oil. But if it means a lubricant is formulated with a polyalphaolefin (PAO) base oil, then it is pure and is compatible with mineral base oils.
However, because the PAO base oil does not dissolve additives as well as a basic mineral oils, it is usually formulated with an ester co-base (usually di-ester and/or polyol ester). The additives are soluble with the ester and the ester is soluble with the PAO.
The PAO tends to cause seal shrinkage and the ester causes seal swelling, so the effects are offset when both base oils are present.
When switching to a fully synthetic on an older engine, or one with a higher mileage, it is the ester that can cause problems when one changes from mineral to synthetic. Ester base oil used alongside PAO base oil in lubricant formulation has excellent natural detergency. In other words, it will clean up deposits on component surfaces as a result of thermal and oxidative degradation of the lubricant. When one switches from typical mineral-based engine oils to a typical synthetic-based oil, the varnish layer will be removed by the ester in the synthetic oil and become suspended.
This suspended material can rapidly clog filters and can potentially block oil flow passageways and lead to component starvation. The same is true for gearboxes and other industrial machines. So think twice about switching to synthetic oils in applications where the engine or other machine has been operating for some time with mineral oils. It can be done but be aware of the potential for creating more harm than good.
This is also where oil seal leakage can be an issue as the beneficial layer of deposits on the seal are holding the oil in, but once cleaned off, the seal can initially shrink before settling again, so a short spell of oil leakage may result.

[jaydee]

Nobody using Castrol R and putting a smile on the faces of everyone you pass?

Bob

I though it was discontinued..

[firstforward]

• Does using synthetic oil damage engine seals?
  No. Synthetic motor oils are perfectly safe for all rubber seals.

Not correct. Not all the seals are the same rubber grade neither the oils. We're talking about 60 years old technology.
I have tryed both 0w60 and 20w50 fully synth (one is a racing oil from shell the other its millers) on a fresh engine they're great, if youre engine has done a bunch of miles, then steer clear from them.
Also, on a classic, where you've been using mineral for ages, the switch to a synth oil is not reccomendable.

Switching to a Synthetic on new and used cars

DO NOT USE a fully synthetic until the engine has covered a little more mileage (approx 10k) because the engine is still bedding in for some time up to this point. Then switch to a good synthetic.
What are the benefits? Less wear, less power loss in the engine, better fuel consumption.
Generally, the reference to synthetic oil for an engine can mean a Group 3 Mineral oil. But if it means a lubricant is formulated with a polyalphaolefin (PAO) base oil, then it is pure and is compatible with mineral base oils.
However, because the PAO base oil does not dissolve additives as well as a basic mineral oils, it is usually formulated with an ester co-base (usually di-ester and/or polyol ester). The additives are soluble with the ester and the ester is soluble with the PAO.
The PAO tends to cause seal shrinkage and the ester causes seal swelling, so the effects are offset when both base oils are present.
When switching to a fully synthetic on an older engine, or one with a higher mileage, it is the ester that can cause problems when one changes from mineral to synthetic. Ester base oil used alongside PAO base oil in lubricant formulation has excellent natural detergency. In other words, it will clean up deposits on component surfaces as a result of thermal and oxidative degradation of the lubricant. When one switches from typical mineral-based engine oils to a typical synthetic-based oil, the varnish layer will be removed by the ester in the synthetic oil and become suspended.
This suspended material can rapidly clog filters and can potentially block oil flow passageways and lead to component starvation. The same is true for gearboxes and other industrial machines. So think twice about switching to synthetic oils in applications where the engine or other machine has been operating for some time with mineral oils. It can be done but be aware of the potential for creating more harm than good.
This is also where oil seal leakage can be an issue as the beneficial layer of deposits on the seal are holding the oil in, but once cleaned off, the seal can initially shrink before settling again, so a short spell of oil leakage may result.

What site are you quoting that from?

[momini]

Halfords 20w50 Green stuff. Good quality 18 pounds 5 litres

[Orange-Phantom]

Mmmmmmmm........ Castrol R........

Great in a 2 stroke, smells fantastic! Can clearly remember the smell as a kid, the 2 stroke TT bikes used to use it.

Can't imagine it would really smell from Mini unless it was burning oil, that and the gumming up of your Engine when cold!

[Old Bob]

Nobody using Castrol R and putting a smile on the faces of everyone you pass?

Bob

I though it was discontinued..

That's the trouble with progress - things get better but no longer seem as good!

Bob

[Old Bob]

Mmmmmmmm........ Castrol R........

Great in a 2 stroke, smells fantastic! Can clearly remember the smell as a kid, the 2 stroke TT bikes used to use it.

Can't imagine it would really smell from Mini unless it was burning oil, that and the gumming up of your Engine when cold!

I used it on a 600cc Scott Special trials outfit. Total loss lube system but such a glorious smell - the smell of five pound notes burning.........

Bob

[iMurray]

I use 10 40 mineral oil... Bad?

20W/50 would be better, particularly for the gearbox.

Take note people.... This is how you answer a question.

[Tamworthbay]

Halfords 20w50 Green stuff. Good quality 18 pounds 5 litres

I get trade at halfords so it works out quite cheap for me. BUT I have done back to back comparisons with Comma sonic and when using the halfords oil the oil pressure 'peak' startup and hot pressures drop off by as much as 10psi within 1500 miles, whereas the comma is still going strong at 2000 (I change the oil at 2000 whatever). I have tried a few oils over the three years and 30000 miles I have been running MGBs as daily drives and the comma is the best performance, but to be fair I don't try the expensive stuff like valvoline as none of the places I trade with stock or supply it. I work on the grounds that a reasonable oil changed frequently is better than a good oil changed once in a blue moon.

[govig]

Oils have improved out of all reasonable comparison since 1959 as have engines. It's very easy to be bamboozled by all the specs but just remember this : thin synthetics and semi synthetics have been designed for engines which in the main are OHC with very narrow oil galleries and for cars with catalytic converters and only have to lubricate the engine rather than an engine and gearbox. Whilst they are hugely better lubricants, they are not for the A series. Just use a good quality mineral 15w-50 or 20w-50 SF spec (15w-50 are usually SG) and change it often. Personally, I change the oil and filter every 2500 miles, it's only about £25!

The only problem I see with this simplification are minis with cats. The older high ZDDP oils (which damage cats) are best for the A series. Mine hasn't got a cat so it's not a big snag for me. In reality how much of a problem is it? You often see minis with 100k on the clock where the owner has put any old rubbish in and they still mostly survive maybe with a bit of a crunch 3rd - 2nd. Best not get too raveled up with this unless you have a high output A series. If you can afford it, use Valvolene or Morris' (others probably just as good), if not there's always Wilko. The main things is to change it much more often than we are now used to with modern cars. Do that and stop worrying.

PS Has anyone used ZDDP additive?

Edited by govig, 01 November 2012 - 09:54 AM.

[Mini_Magic]

Good point on the cat, think this is why some recommend 10W/40 for later injection cars. I've fitted a de cat pipe so I can use good 20W/50 without worrying about damaging the cat