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Gordon
United Kingdom
692 Posts |
 Posted - 01/04/2008 : 12:12:48
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David
Thanks for your input on proceedure for changing to Castrol R. I don't see that using a flushing oil helps because it is a mineral oil itself. Modern Castrol R does indeed have a very small amount of mineral oil in it. I believe that to change to R you have to remove 97/98% of oil from the engine. Hence the advice that the best way is to strip the engine down which is logical. Could you achieve an acceptable result by draining the oil when hot and removing the sump to allow the remaining oill to drip out and clean the sump? Also whilst the sump is off would there be any benefit in filling the tecalamit housing with R and motoring the engine over, without plugs, to pump some round the engine and let it drain out? It would also seem sensible after doing this to fill with R and run at tickover to get warm (30C) and then drain and throw that first fill away?
Regards
Gordon
Gordon |
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rbm
United Kingdom
141 Posts |
Posted - 01/04/2008 : 13:20:36
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gumming up of parts by castor oil based oils has always been a known problem no matter what oil sysem it is used in, modern R is better than it used to be, but it will still gum up parts if left standing, more so on a closed system, than total loss - however filtering does help though.
Richard |
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David Allison
United Kingdom
665 Posts |
Posted - 01/04/2008 : 13:42:43
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Gordon
No I dont - I still think waiting till next strip down is the best idea.
I never like even changing oil brands without doing this - let alone changing mineral oil for castor.
As I said my advice is to not do it - ask your engine builder what oil they recommend and stick to it!
Regards David |
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Gordon
United Kingdom
692 Posts |
Posted - 01/04/2008 : 19:21:23
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David
Thanks for the clear advice.
Gordon
Gordon |
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Bob Hudson
United Kingdom
67 Posts |
Posted - 01/04/2008 : 21:12:50
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I have run my C(s) on Castrol R40 since its rebuild in 1997.I change the oil and filter every year, draining it after my last run late in the year and refilling just before the 1st run next year.
The car does about 3000miles a year. When car was rebuilt in 97 I was reccomended to use R because the car was blown (Marshal 87 giving 12psi max boost). I had a shell bigend failure in 1998 which left the crank and rod blued, I suspect with mineral oil I would have had a complete seizure and major damage. The only time I have had rings gummed in the pistons was on the MMM US visit in October 2006 when the car was driven on and of a trailer and on and of the car ferry without warming up and was running on fuel with 10% ethanol
added (standard US unleaded pump fuel)We also had some very cold mornings and I did not always have time to warm the engine fully. The problem was probably exacerbated by the modern very narrow piston rings.
The engine is fitted with a modern filter and oil pressure on first
starting takes about 20- 30 seconds to register a reading on the gauge and up to a minute to reach full pressure of 80psi. I am very
aware that the R's stickablilty is protecting the engine while this
happen. |
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John Reid
United Kingdom
704 Posts |
Posted - 01/04/2008 : 21:15:12
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Gordon and David,
To toss a small stone into a smooth pond, this is what I found on a Castrol website:
"Vehicles should not be stored indefinitely with R30 or R40 remaining in the crankcase. It is better to 'lay up' the vehicle, using either synthetic or mineral engine oil or Castrol Storage Oil, following the change-over procedure outlined below:
Recommended draining and flushng procedure when changing from mineral oil to Castrol R - or vice versa:
1. Drain the Mineral oil or Castrol R when warm
2.We recommend the following:
Flush the engine. After draining the Castrol R, refill with Castrol Flushing Oil to a level approx 25-20mm above the normal fill level. Restart the engine and run at fast idle for 5 - 10 minutes. During that time the engine should be given a few bursts to moderate revs.
NOTE: The vehicle should not be driven or the engine put under heavy load during this period. Stop the engine and thoroughly drain all flushing oil and replace or drain any filters in the system.
3. Refill with the desired Castrol R (or Castrol engine oil) grade.
Personally I am not a fan of flushing oil and if you want to change oils then I would do it after a major strip down - as you have suggested.
John R
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Edited by - John Reid on 01/04/2008 21:23:07 |
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Bruce Sutherland
United Kingdom
1568 Posts |
Posted - 02/04/2008 : 00:34:48
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Gentlemen,
I am no expert in tribology matters, but engineering experience helps me to recognise well-reasoned information.
May I suggest that you take a look at "Lubricants for Vintage and Veteran Engines" as published in the Morris Lubricants website - http://www.morrislubricants.co.uk/.
On re-reading my posting above, I have recognised that my tone could be taken as dismissive of some of the earlier contributions on this topic - this was not my intention.
The practical experiences of the many well-versed Triple-M'ers makes good reading; rather my intent was to alert others to an informative explanation specifically aimed at classic and pre-war engines. (Admittedly from a source who could have their own commercial interests to serve).
My apologies to any I may have unintentionally upset.
Bruce. |
Edited by - Bruce Sutherland on 02/04/2008 19:34:04 |
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Bruce Sutherland
United Kingdom
1568 Posts |
Posted - 06/04/2008 : 10:17:12
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Paul, your observations about rebuilt engines are well made. I have contacted Morris's direct for their thoughts and received the following, which is agrees with you.
"For a pre war MG we would recommend the following: -
Engine = Supreme 30
Gear Oil = AG 140
Axle = AG 140
Engines which have been completely rebuilt with retro fitted, modern full flow oil filters can use Multivis 15W-50.
We trust this answers your questions; however, should you have any further queries, please do not hesitate to ask.
Regards,
Mr Simon Matthews BSc(Hons), MRSC, CCHEM, CSci, MEI, AIQA
Technical Advisor
Morris Lubricants."
Further, regarding the recommendations for axle and gearbox lubricants, for those of us who have rebuilt these replacing the old bearings and bushes which contained components made with 'yellow metal' (i.e. brass or bronze), then I believe the 'EP' variant of 140 gear oil would be better...........'EP' extreme pressure additives being deleterious to copper, brass, & bronze.
Bruce. |
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David Allison
United Kingdom
665 Posts |
Posted - 07/04/2008 : 15:15:39
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EP oil is designed to suit the higher loads inside hypoid differentials and gearboxes - the EP stands for extreme pressure.
The oils have I believe a high content of moly-disulphide from memory.
These oils are not really suitable for non hypoid gear trains such as in MMM cars.
That said they dont really do any real damage and are a usefull get you home in the event you cant get hold of the right gear oil.
EP 90 is quite a bit thinner than SAE 90 - the oil has a viscocity similar to 20-50.
The MGB gearbox always used 20-50 but the MGC and the V8 both used EP90 - not really relevant but Quite Interesting!
To be honest as long as the oil is clean and changed regularly it is up to the owner - my knowlege is some 15 years out of date.
Regards David |
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