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MG Midget and Sprite Technical - Type 9 oil (II / update)

Blame Richard (Wale) for this! I do. :)

The recent thread on (limited-slip) diff oil got me thinking about possibly getting even better oil for my Type 9 gearbox (and rear axle).

Currently I use Castrol Syntrans Multivehicle 75W-90 (fully synthetic, GL4 spec) which seems very good, and seems to feel even better in cold weather gear changes, so I want to see if I can get an oil that seems even better throughout the range of weather temperatures.

The previous thread discussed the need for a GL4 spec oil in the Type 9 gearbox as it was uncertain which GL5 spec oils might be suitable as some additives in some GL5 spec oils could attack the yellow metal (copper, brass, bronze) components of the gearbox.

Recently I asked Opie Oil about recommended ester based silicone oils that would be suitable and from the list I choose to follow up the Millers one, CRX 75w90 NT, as I already use Millers for engine oil and I like to use a British company if their products are good.

I emailed Millers Oil and their Technical Advisor replied –
“The additives that we use in our oils today are no aggressive to yellow metals, where as in the older years the additives did attack yellow metals so please do not worry about that.”

When the subject was discussed on the forum a couple of years ago the following was quoted from a paper from America, titled The Difference between GL-4 and GL-5 gear oils (and I note the paper (now?) has Revision 1-2016) –
… when they say their Sulfur/Phosphorous additive will not corrode the yellow metals, they are also correct, but if there are enough to meet GL-5 protection, they will slowly peel away your brass synchronizers.

The reply to this was –
“As previously stated I can confirm that no additives within any of our products including the CRX 75w90 NT will not damage/ have any effect on yellow metals.”

(yes the typing and grammar is at email standards)

So when the weather improves and I feel like it, around spring or summer, I’ll syphon out as much of the existing Castrol Syntrans Multivehicle 75W-90 as possible and refill with Millers CRX 75w90NT and report back on what I find.

I’ll also put the Millers in the rear axle to see if it helps there too, and it would also be handy to have one oil for both.



http://www.opieoils.co.uk/p-60230-millers-oils-crx-75w-90-nt-competition-full-synthetic-transmission-oil.aspx

http://www.millersoils.co.uk/automotive/tds-automotive.asp?prodsegmentID=183§or=Motorsport

http://www.widman.biz/uploads/Transaxle_oil.pdf

Nigel Atkins


Nigel,

I trawled the ford turbo forums as I have just added a Quaife ATB LSD to my rear axle and wanted an oil for it,interestly this was the same oil as the Ford boys recommend for the type 9. I have some bottles on the shelf ready to add as soon as I get my new half shafts in. The oil was a Comma SX75W 90
semi synthetic

Jon
Jon White

Jon,
as a generalisation I find car people to be very conservative (with a small 'c'), not so open to innovation, so recommendations and advice don't always get updated or accepted.

The Comma oil isn't a bad oil but it can be bettered.

The Comma oil was recommended for the T9 box but I found by my personal (road use) of the Comma oil in the T9 box that Castrol Syntrans Multivehicle 75W-90 Fully Synthetic MTF oil was better, especially for cold weather gear shifts.

And Mobilube 1 SHC 75W-90 was very good in my standard midget diff (much confusion as to whether it can be used in GL4 recommend g/boxes like the T9).

As I've put in this thread I think I can get even better oil and I think you might too.

For more info see the (reactivated) thread here called 'dif oil' and the later half of the recent thread (that is now in 2016 archive list on here) called 'Limited slip diff advice'.

If you use the Comma oil you already have (might be a false economy?) and if you've had the oil on your shelf for lots of years then give the bottle a good shake as I've read in engine oils at least the additives can separate out a bit over a long period of time.

If you might want to research a bit more to decide what type of oils you want to use, you could look at this site –

http://www.kewengineering.co.uk/Auto_oils/index.htm
Nigel Atkins

The Castrol Multivehicle has the lowest viscoity at 0C of any oil I can find figures on.

I have used it on many vehicles gearbox's with low temperature shift issues with good results but not always a complete cure.

For low tempretures gearchange ease you are wasting money buying anything else.

I cannot understand some of your comments here, when an oil manufacturer and they mostly do it now, advises you that modern GL5 additives do not cause problems with internal components and that has been the case for over 10 years why you will not believe them.

It is no longer an issue as the modern oil additives do not shed their contents during use.

Both Mazda and Subaru recomend both GL4 and GL5 oils in their gearboxes apart from a few boxes like the certain 6 Speed MX5 boxes that they recommend a GL4 to get over low tempereture shifting issues.




Eddie Cairns

Hi Eddie,
>>I cannot understand some of your comments here, when an oil manufacturer and they mostly do it now, advises you that modern GL5 additives do not cause problems with internal components and that has been the case for over 10 years why you will not believe them.<<
I do believe them - it's others that don't, plus on the previous thread there was a lot of discussion about GL5, and I found that Mobilube in the past was stated to be suitable and the manufacturer changed their minds at the time of the previous thread to now again possibly reverse again.

Where I can I like to put up more info (sometimes leading to a view contra to mine) so that others can make there own minds up and as you know I sometimes (often) make mistakes and get things wrong so I want to know if I have for the sake of others and myself.

I'm after a more overall improvement with gear changes throughout the range of weather temperatures plus the best and long lasting protection from the oil used so better as a whole rather than just cold weather changes. Where I live we don't usually get many very cold days in a year (but I admit enough at 0 and below).

I like the extra margin of protection that the better oils offer (especially in the engine where 'water' cooling problems can soon introduce extra headache).

My g/box has leaked from when it was first fitted (and "repaired") by the "specialist experts" so I also want the best protection in case the leak ever gets bad.

I've also found Castrol Multivehicle to be very good, especially with cold weather changes, and have regularly recommended it, I just want to see if I can better it.

I'm wary of comparing paper figures, I accept they're a good guide but they refer to the oils when new, often refer to two measured points only, different measuring units can be used*, different standards of measurement used*, and sometimes the info isn't made available by the manufacturer.

(* yes I know conversions can be made and standards looked up, not that I'd necessarily understand the technical details)

Take for example the Castrol Multivechile data sheet, the one on Opie Oil is out of date according to Castrol UK website but then I've found before that maufacturers' (not just of oil) have their own websites with out of date or errors in the information or products available.

http://www.opieoils.co.uk/pdfs/castrol/syntrans-multivehicle.pdf

http://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/3A2AC3E19A7AEE6D80257E83003062B0/$File/BPXE-9ZWFHN.pdf
Nigel Atkins

Change/partial refresh
This weekend, I was able to syphon out I guess about two-thirds or more of the existing gearbox oil and replaced it with Millers CRX 75w90 NT.

I chose now as the weather’s so hot (warm to those that like it) at around 28C making the oil as warm as possible on the warm up drive and keeping it warm on the siphoning out so that I can get as much of the existing oil and muck out as possible.


Change of colour
The oil that came out was a dark brown colour, when it went in two years before it was a light honey colour.

The oil that was put in two years ago was Castrol Syntrans Multivehicle 75W-90 and it was again about a two-thirds or more change/refresh which was a repeat of the change/refresh five years ago. Before that Comma SX SX75W-90 (GL-4) was used and in the box from its installation in Oct. ’09.


Different feel to changes
I realise this is purely subjective but to me with my gearbox the changes with the Millers oil feel as if the oil might be “thicker” than when the Castrol was in. As the weather is so warm it suggests to my very simple mind that IF I’m right in my feeling then the Millers might be better with heat than the Castrol, even allowing for the two years of use the Castrol had, which makes sense as the Millers is for competition use where the cars can get very hot. Of course it’s just how it feels to me and I could be imagining things and wrong and wrong with my supposition plus it’s early days yet.


More use required for a conclusion
As we don’t get too many days of the year at 28C and above and my car is road use only I need to find if the Millers is good for the rest of the year and particularly when it’s cold and very cold in the winter as my Midget gets used year round and sits outside 365 days a year. One of the reasons I bought it was because it’s described as “Exceptional cold flow properties for easier gear changes.” so it could be as good as the Castol in the cold and better than the Castrol when hot so better overall (that’s my hope anyway).
Nigel Atkins

My comma oil is still on the shed shelf awaiting a rear brake conversion DIY project which I have been doing, just waiting for a company to mill out the alloy calliper brackets before i can bolt it al up and get the oil in both the rear axle and the gearbox. (same in both to make it easy)
Good to hear you think it's made some improvement
Jon White

Jon don't forget to shake those bottles well if you do use them.

I might be fooling myself with the Millers, I don't think I am - but then that's how you get fooled. :)

When I put it the rear axle it sounded different (again it might be placebo effect, even ego), if it sounds different then its probably doing something different is my reasoning (might be making things just different or even worse of course).

With my history of car component and system failures I value any extra protection margin I can get to limit the outcome.
Nigel Atkins

Nigel. I've always considered you to be very knowledgeable where oils are concerned, so at your suggestion a few years ago, I changed my type 9 oil to Syntrans. The cold shifting improvement was noticeable immediately, and it seemed very good across a whole range of conditions. However, I came back from Spridget Treffen in Germany yesterday and the drive through Holland and Germany on the way back, and particularly on the way there, was very hot and I found that my 'box was getting a bit baulky in the lower gears. When it cooled down it was OK.
So, when I do my major service this winter I think I might change to the Miller's. I'll use it in my diff as well, which is the original item and must have done about 150,000 miles with only the thrust washers having been replaced last year.
Many thanks for the update.
Bernie.
b higginson

Hi Bernie, problem is I'm not that knowledgeable and rely on the info I can get and understand and my own experiences, hence mistakes.

Another problem you've now highlighted is that I don't usually drive my car when the weather is hot (warm to some) as I can't take the heat so I have previously wondered that if the Castrol is so good in the cold whether it'd be so good in the heat (Eddie who's much more knowledgeable posted something similar on another thread too) hence me trying out the Millers.

As my g/box takes (I think) 1.9l and the axle about 1l I thought I'd get 4 litres to allow for a little flushing of the axle and top ups on the g/box but as buying 4 x 1l bottles was pence more or less of a 5l can I bought that instead.

They've now change the label and bottle/can colour from grey to black (known as 2016 and 2017 in some places) but I think the stuff inside is the same but I've NOT checked.
Nigel Atkins

Slightly off topic but any recommendations for semi/fully synthetic oil in a standard (A series engined) 4 speed transmission?
Jeremy MkIII

Not really from me other than don't get too hooked up or confused about the, often marketing, descriptions of semi or fully synthetic, a good oil is a good oil be it fully mineral, marketing semi or fully synthetic or fully and/or properly fully synthetic.

I'd try contacting some company like Millers and others that supply oil to classic cars rather than the general companies that supply to modern cars to see what they'd recommend.

If you put a good oil in your engine you could stick with that for the gearbox too (*see also below) or another idea I've seen is to put in different colour engine oils in the engine and g/box to help see where the leaks are from.

*I think the bit often missed about oil in the gearbox, especially if it's engine oil, is to change it regularly, to thoroughly drain it and replace it with some sort of frequency. The MGB Workshop manual has it at 2 years or 24k-miles whichever is the sooner.

I think the thoroughness of the draining is very important, get the oil as warm as possible and leave it to drain out for as long as possible to get as much existing oil and muck out of the gearbox as possible. I'd even let a small quantity of fresh oil drain straight out as a sort of flush the get any muck out I could.
Nigel Atkins

Thanks Nigel,

can always rely on you.
The oil in the gearbox has been in for 7 years so I'd better change it.
Jeremy MkIII

Cheers Jeremy.

I think you'd find a change after 7 years interesting and beneficial but don't expect miracles, it won't quieten the tappets. :)

I'd certainly put some some fresh oil through the box with the drain plug out so it acts as a bit of a flush. I'd do this as the box empties to the dips and dregs to try to literally flush out the last of the old oil and muck.

I'd also have the fresh oil warmed a bit simply by having it standing on concrete* in the sun this time of year or the can standing in a bucket of warm/hot water when colder weather.* This would be to help with that final flush and perhaps to help equalize the temperature of the oil a bit to the possibly hot/very warm box - but you don't have to go over the top with this, no need for extra large Thermos flasks.

*For the pedantics - you could shake the warm can of oil up to distribute the warmest part of the oil. ;)

If you've got the gearbox and oil in the gearbox very warm/hot you may be surprise how quickly (the majority) of the oil empties out leaving the gearbox very warm/hot.

As purely an example of air/grass/concrete temperatures at the current time of typing Pitsford weather station shows -
. air - 22.4C (windchill - 22.4C)

. *Apparent temperature* - 24.4C

. grass - 31.7C

. concrete 36.7

*Apparent temperature* = I had to look this up, my way of putting it is how it feels to someone, look it up yourself for a better and fuller explanation, to me personally it feels more like 30+C.
Nigel Atkins

Jeremy,
for recommendations for semi/fully synthetic oil in a standard 1275 engine, 4 speed transmission from Millers see the new thread (I'll start after tea).

Nigel Atkins

This thread was discussed between 21/12/2016 and 21/06/2017

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.