Lagondaforum

Subject: Suitable Engine Oil

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I have been using Morris Oil Magnol 20/50 in my 2 Litre engine for a number of years however it now seems difficult to find. I have used a multigrade since it has been rebuilt and it also has an external modern oil filter. I know that there is a school of thought that "any cheap oil will do" as long as its changed frequently but in relation to the cost of an engine rebuild I've always felt more comfortable using a more expensive oil (or am I wrong !). If I am unable to locate any more Magnol... does anyone have a view as to what would be a good oil to switch to ?

Subject: Re: Suitable Engine Oil

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Here in North America the removal of zinc from most oils is a cause for concern as that is what protects cam lobes and lifters from excessive wear. Fortunately, for now over here we have available Shell Rotella 15W 40 oil formulated with highly stressed diesels in mind and possessing the needed additives for our elderly designs. This subject has been widely discussed on many other forums and not being a petroleum engineer can not comment further . I do believe the philosophy of using any cheap oil is incorrect.

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Subject: Re: Suitable Engine Oil

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I'm not a lubrication expert but the following may just be worth mentioning. I understand that modern oils contain detergent additives which help keep the internals clean. I've just stripped my LG6 engine which has not had much work done on it for many years. I've removed the plugs from the crankshaft webs and scraped out a heaped teaspoonfull of crap from each oilway and also found thick deposits in the crankcase oilways. I've run the engine on SAE30 grade oil and not had problems.
I wonder if I had changed to modern oil with detergent additived, if the oil would have loosened the deposits whose next journey would have been through the big end and main journals doing whatever damage it may have done or which might have caused a total blockage causing big end or main bearing failure.
If you're running a fully reconditioned engine I'm sure that most modern oils will do fine but if its not been touched for a while a more basic oil may be best. There may be a difference between 'cheap oils' and basic grade oils which may be good quality but without the additives which modern 100bhp plus per litre engines so desperately need.

Subject: Re: Suitable Engine Oil

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I have to agree with what has been said here.
For the price of oil compared to an engine build, it is best to use as good a grade as possible. we use Duckhams/BP 20/50 or Motul 300V 20/60 on "performance" engines. But only if recently rebuilt!

Old engines as has quite rightly been said, contain a lot of sludge and "crap" and it is not always a good idea to loosen this into the engine and oil system, so a good Non Detergent oil should be used, Millers for example.
I tend to stray away from straight grades as they generally give too high pressure when cold and don't help poor old engines with corroded and frail fittings and pipework etc! Not to mention the strain on the oil pump drive!

If you have a newly rebuilt engine, this should have been meticulously cleaned and scrubbed and so should not have any sludge to "shift" what so ever, your engine does not "know" it's an old engine, it's just an engine, nothing else! so give it the best oil possible, including a detergent to stop any future sludge etc from accumulating. With today's oils there is a good range of very high tec oils available to help our engines run for many more years!

Regards,
Julian

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