| Author |
 Topic  |
|
bahnisch
Australia
674 Posts |
 Posted - 22/03/2008 : 10:06:05
|
| What is the current trend in regard to oil changes? None of my cars ever cover the recommended mileage to warrant changes so I go on time. I used to change the oil every two years or so but have extended this to three. I use "premium" mineral oil (because I believe that they combat contaminants more effectively) but if I used synthetic would this obviate the need for changes at all? I realise that the engines will easily "see me out" but have always maintained my cars as well as possible. |
|
|
David Allison
United Kingdom
665 Posts |
Posted - 25/03/2008 : 11:47:18
|
Pre-war engines on plain bearings were not designed for modern oils.
I always use Castor oil in the engine (which I change each spring) and SAE 40 in the pre-selector gearbox. In the rear axle I use SAE 140 and I use the same oil to lubricate the chassis.
I have used multigrade in the pre-selector gearbox - but straight SAE 40 does not leak out so readily when hot.
Modern synthetic oils are too thin in viscocity in my opinion and they are so detergent that they tend to cause lots of damage.
Oil leaks seem much worse with cars run on modern oils too - again due to the thinness when hot.
Oil is cheaper than engine re-builds!
On a car used lightly I would recommend changing the oil every 12 months or 3000 miles.
The fresher the oil the longer the components last!
The standard filter should be replaced every year anyway and I think the modern cannisters have the same advice.
Hope this helps
Regards David
|
 |
|
|
Bob Stringfield
United Kingdom
854 Posts |
Posted - 25/03/2008 : 21:30:43
|
Presumably it would make the environmental lobby happier if we all changed to Castor oil since it is a 'bio-oil' rather than a fossil product?
Go Green with MMM. |
|
|
|
Rodney Collins
United Kingdom
424 Posts |
Posted - 26/03/2008 : 09:33:00
|
David I seem to remember a thread on the subject of oil some time ago, I run a search but nothing came up, however I do recall reading somewhere that some members who like myself have had modern engine rebuilds and are using new type canister oil filters were using modern oils i.e. Castrol GTX etc. I personally use Castrol classic XL 20/50 in my PB blown enging, but I have oftern wondered if there is any benifit in using castrol R which as you know is caster oil. I would be interested in your view on the modern oils in newly built engines?
Rodney.
PS i do have oil leaks!! |
|
|
|
David Allison
United Kingdom
665 Posts |
Posted - 26/03/2008 : 10:39:15
|
Rodney
I only relate back to my own rather sketchy knowlege gained over the years - my experience with MMM cars has been curtailed for a few years while I concentrated on earning a living.
I did my apprenticeship with my Dad in the 80's and during that time raced an MG Midget.
I was sponsored by Newton Oils for 1989-1991 and they advised that I run my A series engine on Castor Oil.
When they introduced a synthetic oil in 1989 we specifically asked for guidance on its suitability to the MMM engines ad their advice was that it was better to stick to the type of oils the engines were run on originally.
White metal bearings run much tighter tolerances than the thinwall shells and the MMM car oil pressure is also very high, but delivery and direction of the oil supply is questionable.
They understood that if you got everything wet - then it must be lubricated and used oils which ensured this.
Modern synthetic oils are designed to suit the shell bearings and high flow low pressure supply all directed to the most relevant places.
Oil misting can cause internal explosions inside the crankcase and modern engines use oils which are designed to lubricate where directed and then return to the sump.
The oils are very detergent, very thin and designed to work best at optimum working temperature in the engine.
Castor oil does none of this!
It needs to be warmed up slowly and circulated at high pressure.
At low temperatures it is similar to treacle in viscosity.
But - it does not break down as easily as the synthetic or multigrade oils. Indeed castor is recommended for stunt aircraft because of this - when the engine is inverted the oil can easily drain away from important components and castor still maintains a wet residue long after supply failure.
Although this can not be relied upon of course - it does give a safety net.
Newton were taken over by Morris' and I still use their products in the NA - mostly because Dad still has an account with them it has to be said.
I have no problem using 20W-50 multigrade oil in MMM cars - however a lot of the multigrades now available are much thinner 10-30 is not uncommon.
The oil seals and gaskets around our 70-80 year old castings struggle to contain thinner oils - particularly when hot.
My preference is for straight 40 in the engine because in my experience anything thinner tends to run out too easily.
I also find that SAE 140 is much better for cooling the overheated rear brake shoes on the NA - what do you mean there is supposed to be an oil seal at each rear hub?
An oil technologist from Newton told me that the best reason for using castor oil was science - when I asked him to explain he said.
"The oil film of castor oil is much more resiliant to break down during periods of high stress and temperature - making the specific viscocity higher than otherwise stated!" - when I asked him fo rthat in english he said - "it sticks to metal like S*%T to a blanket!" - it convinced me.
Regards David
|
|
|
|
sam christie
United Kingdom
3107 Posts |
Posted - 26/03/2008 : 11:20:22
|
The oil topic was touched on under the heading 'Oil for the coming season'.
Presumably castor oil is great for highly stressed and frequently rebuilt engines. - But if normal use is much less demanding and the car sits unused for the winter or weeks on end and the cost of a rebuild is dreaded, is castor oil still the better option?
Should the use of a modern oil filter have any influence on the choice of engine oil?
Sam |
Edited by - sam christie on 26/03/2008 12:47:25 |
|
|
|
DSW
Germany
95 Posts |
Posted - 26/03/2008 : 12:47:04
|
Surely castor oil is a little too exotic for everyday use, although certainly a good lubricant for racing. I've used 20W/50 in my standard PA for years without suffering either from puddles of oil under the car or engine issues. The oil drops come from the total loss chassis lube system! Engine oil gets changed yearly although it looks cleaner than that out of my everyday car, simply because I feel with irregular use the condensation products are likely to be detrimental and the cost is not large. This year I changed gearbox and back axle for the first time in 10 years, and use straight 140 gear oil.
I have a modern filter conversion, but if using the old felt element I would only avoid a modern high detergent oil since then the dirt will surely just keep in circulation.
David |
|
|
|
David Allison
United Kingdom
665 Posts |
Posted - 26/03/2008 : 14:52:55
|
Sorry maybe I did not make myself clear.
I prefer to use single grade straight 40 (SAE 40) as engine oil in everyday MMM engines - what you guys do is up to you.
I avoid multigrade oils on the basis of what I was told by an oil company representative some years ago - maybe things have changed?
I am notoriously lazy about cleaning my car, anything which means more car cleaning is a bad thing as far as I am concerned.
I also think the oil ought to be changed annually - this is a personal choice based on the mileage I do and the way I drive the car (which is quite hard I admit).
My considered opinion is that castor oil makes it smell nicer than mineral oil too! Even though the side effects associated with biting your finger nails are severe (even cured me of doing that - so theres another plus point).
Castor oil is only my particular choice - 20W-50 multigrade is more than suitable for most cars - it was the thinner modern multigrades and synthetics I personally think should be avoided.
You should certainly (in my opinion) avoid the 5-30 - 15-30 grades which are very thin.
Hope this clears up your queries?
Regards David
|
|
|
|
Gordon
United Kingdom
692 Posts |
Posted - 26/03/2008 : 16:31:18
|
Some questions about castrol R. Is there a downside to using it in a car that is not used daily? Can an engine be converted to Castrol R without tearing it down and meticulously cleaning - I thought it was considered disastrous to risk even small degrees of contamination with conventional oils or is there a flushing oil/proceedure? Is there a minimum oil temperature which should be reached before driving?
Anyone any experience of using Valvoline 20/50?
Gordon |
|
|
|
David Allison
United Kingdom
665 Posts |
Posted - 26/03/2008 : 17:09:49
|
Gordon
You can convert to Castor oil quite easily - although it is probably best left to next strip down.
You can empty the mineral oil and fill the sump with flushing oil - this works well on engines that are not too established (first oil change).
Once flushed the sump should be drained and the filer changed - before refilling with new oil - as I said earlier though the hassel involved is too much in my opinion!
Modern castor oils are not as fussy as the original pure castor oil - they are much more freindly to occasional use and as long as the oil is changed regularly there are no real problems.
If you run on methanol it is advisable (racing only here guys) to run on pure castor oil - this is more suitable for use with methanol because it has a high resistance to film breakdown when fuel gets into the sump.
This stuff is very fussy and has to be kept very fresh - it actually goes off with a mould forming on the oil film if left for long periods.
Valvoline 20W-50 is a very good oil - I used it in my wifes everyday car (a Peugeot 309) until the car was replaced by something more modern a couple of years ago.
Oil temparetures - I try to get the oil temp up to 30 degrees or so before driving with any vigour - the oil pressure is rather excessive at temps below this figure.
if the temp starts to drop as you drive (cold days) it is best to slow down and let the temp climb.
The oil pressure on the NA runs pretty constantly at 80 psi and i try to keep the pressure below 100 if I can - thin hot oil gets around the engine much more easily and smoothly than cold and thick oil.
The car pretty well tells you if it is happy though - the NA is very sluggish when cold.
With a pre-selector you need to make sure that the gearbox oil is warmed gently too - not too much sitting in neural though with the engine running.
Hope this answers your queries.
Regards David |
|
|
|
bahnisch
Australia
674 Posts |
Posted - 30/03/2008 : 11:26:51
|
| Many thanks for the responses which are pretty much in line with the information I received from the oil company "help line" which I contacted after my MMM query. It may be of further interest that I was advised that the use of synthetic oil would make no difference to changing intervals, condensation (being mildly acidic) is the bugbear and the additives in more expensive oils are better at combatting its effects. |
|
|
|
sam christie
United Kingdom
3107 Posts |
Posted - 30/03/2008 : 11:57:32
|
Printed on a quart tin of oil which came with a new M-type in 1929 -
For "Safety Fast" Confidence
Duckham's
New Process
N.P5
Oil
Officially Recommended
By
The MG Car
Company Limited
What was Duckham's N.P5 ?
Sam |
Edited by - sam christie on 30/03/2008 11:58:24 |
|
|
|
David Allison
United Kingdom
665 Posts |
Posted - 31/03/2008 : 08:32:30
|
My searching turned up Duckhams NP 5 as a summer weight oil - SAE 50.
During the winter the same company had a NP 3 which was an SAE 30.
Hope this helps.
Regards David |
|
|
|
Rodney Collins
United Kingdom
424 Posts |
Posted - 31/03/2008 : 10:24:52
|
David, a lot of information but to my simple mind some unanswered questions, what is a modern castor oil? who makes such oils? Is Castrol R a modern castor oil? And if you must not sit with your engine running in nutural how do you warm up your castor oil and your pre-selector gear box oil? Do you run the engine with flushing oil, or just let it run through the engine? Having spent a fortune on my engine rebuild and bearing in ming that the engine is blown and producing 88bhp at the wheels, and I do perhaps drive a bit to spirited at times! Oil is important to me, as you say oil is cheaper than Tom Dark!
Rodney. |
|
|
|
rbm
United Kingdom
141 Posts |
Posted - 31/03/2008 : 10:44:03
|
castor based oil will not mix with mineral oils, so it you are thinking about going to a castor oil then, it is best as David said to wait 'till you next pull the engine down.
down sides to castor based oils (my own view) you must run the the item with the castor oil, up to working temprature frequently as the oil residue becomes sticky (gums in piston rings etc). It has to be said this may not occur with engines/gearboxes that are just poodled arround, but it has been a problem in the race engines from our Cooper - we now strip the engines in October remove all traces of used oil and recoat with fresh.
Castrol R is a modern castor oil based oil.
for us the other downside is cost of R as we run total as a total loss system, oil goes in at the top and round the engine and out into the drip tray.
Richard |
Edited by - rbm on 31/03/2008 10:45:19 |
|
|
|
David Allison
United Kingdom
665 Posts |
Posted - 31/03/2008 : 11:09:32
|
Rodney
Modern castor based oils - Castrol R - Morris 40R have inhibitors to fungus and bacteria - thus make the oil more long lived than the pure castor oil.
I agree that with a total loss oil system such as a motor cycle engine you can get gummed rings - MMM engines are a bit more sophisticated and have a pressure fed system with a very good in line oil filter as standard (although this is only true of the later cars admittedly).
Warming the car with a pre-selector has to be done in gear - driving the car gently until the oil temperature rises to around 30 degrees minimum.
I normally start the engine and run it at just above idle (say 1000 rpm) for a few mins just to get the oil circulated and then drive gently for about 10 miles.
Race cars are warmed up on the quicklift jack in gear with the wheels suspended - normally about 10-20 mins for the first phase and then another 10-15 mins just to get the car properly warmed through.
The car is then pretty well ready although they do cool down very quickly.
Flushing oil - yes you do run the engine (it sounds like death though) I prefer not to use it.
If I were you I would use the oil recommended by your engine builder!
Regards David
|
|
|
|
Topic |
|
Forum Locked
Topic Locked
