Engine Oil

Can anybody advise me which is the best engine oil to use for a commando 750cc 20.50 SAE40-50 10W 40 confused . com :?: :?: :?:

Depending on what part of the world you live in you'll get advise on what on brand of oil is available. I personally use Castrol GP 50 in my 73 750 and it seems to do the job.

Thanks for the reply all my riding is done in the uk all weathers.

Since the late 1960s I have always used Duckham’s 20/50. It goes in green and comes out black. That is the oil Detergent working- the crankcase interior stays pretty clean too, when you strip the engine down, which I don’t see happening with any other oil.

In a series article that Alan Goldwater published in the Norton Notice and with the INOA late 1990s he found under hard conditions the head temp got over 400F which caused very rapid molecular breakdown in most oils. The conclusion of the article was synthetics using a pentl polyester base had the best resistance to temperature breakdown. Of the the oils he tested, Redline 20w50 used this base and under the hard condition was recommended to a safe service interval of 2000 miles. The runner up was Mobil One 15w50 with recommended service at 1000 miles. Again this is under high temp/performance conditions. The article is available under articles section at www.nortonclub.com

As a newbie to the subject I also find the oil threads quite confusing; because there is so much contradictory opinion sincerely held it's hard to pick out what actually applies to my circumstances .....a Mk3 Commando that will be ridden in UK (cool and probably wet) conditions....and is available this side of the pond.

It would be great to hear the opinion of a UK owner who has covered some real mileage without detriment to the camshaft (which seems to be among the first things to suffer in most oil related problems) ....hopefully using a readily available UK branded oil.

Can anyone help with that?

Mick......kettle738

I have been using Tesco fully synthetic for years since the cam was replaced and not stripped it since. I have no idea what the cam or any other engine parts now look like, but I have noticed it runs better from cold, runs cooler (check the with hand on the oil tanks before and after changing to synthetic - it is very noticeable) Because I work away for weeks/months at a time, it eventually wet sumps, so I have also noticed the magnetic drain bolt collects a lot less debris than when I ran it on non-synthetic oil. The logic is that like many cars I run an engine that contains plain and roller bearings (just like car engines - no surprise there) surprisingly, Tesco spec was at the latest standard compared to Mobil 1 when I first starting using it, though I believe it may be bottled in the same part of the UK. Also, why buy a straight oil or multigrade with lower spec for more money? Had it been available in the 70's I'm sure it would have been recommended then. Ensure that you use a filter designed for synthetic oil, MANN or equivalent top make, and you will be surprised that the oil also takes longer to change to black.

This is the sort of topic that will run & run :roll: and you will get recommendations ranging from the cheapest Halfords Classic oil (20W/50, API grade probably about SC) thru to the most expensive synthetic. You pays your money & takes your choice. I've used Halfords in the past, but now I buy modern 20W/50 API grade SG (because its recommended for my aircooled BMW boxer engine and I now buy enough to do both bikes at the same time). Currently using Castrol GP Act Evo 4T because thats what is available, but have previously used Putoline FORMULA V-TWIN 20W50 which is same grade. The one thing I would say is that whatever oil you use, change it and the filter regularly and if you ever get the engine really, really hot (like I did once stuck in a huge bike meet thru nearby Cassington village) then change the oil asap regardless of how old it is.

Cheers, Alan.

After sitting up long enough to wet sump, its a good thing so first kick over wets cam lobes before head drain down can. Avoid periods of dead slow idle as cam can't surf at low speed and blow by moisture is highest then too at cool oil state of operation. Our lifters like up to 1500 ppm of ZDDP but more looses some the initial nil oil start ups. Synt. oil last longer than non synt oil but if both have sufficient ZDDP and other additives and changed out reasonably either will serve long term. Save your money on switching filters with oil changes, regular oil filters can only filter out the size stuff that can clog a passage, stuff that can get into bearing and rub spaces, but passes filter element easily and casues wear and the nano metallic dust that makes up the balk of sludge settlements. It take a very long time or a blow up to dirty fliters in out small engine. Search this up yourself for logical or emotional filter practice. But can't have fresh enough oil or clean enough filters.

Thicker oils leak out less easy is one advantage and wear protection too, if not so thick when cold it won't start flowing quickly. Always good practice to look in tank on final shut down to get idea how much to top off before unknown amount settle in cases.

Thank you for those replies.....that is interesting stuff, and all the more so because it's not what I was expecting to hear. The advice on changing the oil any time the bike gets too hot irrespective of the age of the oil is very sound......IMHO.

I recently looked at a couple of cans of straight oil from a regular vendor at a large autojumble, I think one was Castrol GP50 and the other was a Morris oils straight 40.....I didn't buy either simply because there was no additive information on the container (which came as a big surprise as there is usually too much) and I was looking for the zinc content.

The hunt continues with a couple more options......I know everyone dreads oil threads on most classic forums, but it's one of those things you just want to get right first time and stick with it.

Mick.......kettle738

I've never joined an oil thread that I can remember, but hey, it's a new year...

Seeing as the OP is in the UK, would you not see oils rated using the ACEA system?

If yes, then I would look for an oil that had an A3/B3 rating.

Why? Well, I'm not a Norton guru, but it seems sensible to pick an oil that has the following traits: low viscosity on start up (synthetics in general win here), assist in keeping the insides sludge free (synthetics win again), and most importantly, an ability to maintain "in-grade" stability under use (heat and sheer actions tends to degrade, i.e., a 20W-50 down to straight 20 weight).

As I understand it, the A3 rating, vice A1, is garnered due to resistance against degradation due to High Temperatures and High Sheer (HTHS) conditions, either of which reduce an oil's ability to stay "in-grade". To get an A3 rating the oil has to have an HTHS value >3.5. In the data below (source: Lotus Enthusiasts Club) a couple of A3 oils are listed with their number -- Note, a bigger number is better:

Mobil 1 0W40 HTHS 3.6

Castrol RS 10w-60 HTHS 3.7

Castrol RS 0w-40 HTHS 3.7

Silkolene PRO S 5w-40 HTHS 4.07

Motul 300V 10w-40 HTHS 4.19

Motul 300V 5w-40 HTHS 4.51

Redline 5w40 HTHS 4.6

Redline 10W40 HTHS 4.7

Mobil 1 15w-50 HTHS 5.11

Silkolene PRO S 10w-50 HTHS 5.11

Silkolene PRO R 15w-50 HTHS 5.23

Motul 300V 15w-50 HTHS 5.33

Redline 15W50 HTHS 5.8

Millers and Rock oil have a very good reputations and easy to get hold of. Been using Millers 20w50 classic for a while with no problems. Others swear by Silkolene and Morris so it's really down to personal choice. As already mentioned the most important thing is to change it regularly.

http://www.millersoils.co.uk/pdf/automo ... ochure.pdf

http://www.rockoil.co.uk/cm/

I'll repeat what a friend who probably puts more miles on a Commando in one trip then most of us put on one in a couple of years suggested "Some oil is better than no oil; clean oil is better than dirty oil; worrying about the brand of oil is a waste of time and energy, if you need some, add whatever the service station has."

Though I am not quite as liberal, IMO, any motor oil you can buy over any counter in the world that is in the correct viscosity range is adequate for the engine. If there is an engine that is less demanding re motor oil, it's on your lawnmower.

I know most of you will turn your nose up at this, but mono grade delo suitable for older turbo charged diesel engines.
It still contains the additives older engines require, designed to run through a hot turbo,the oil companies aren't going to supply sub std oil to their biggest users,

As Splatt suggests, there are some very good monogrades out there, but these are usually run in constant speed engines, oil is pre-warmed, cleaned with centrifugal filters and changed when the oil analysis indicates the oil has had it. Ships DG's and engines come to mind, as it is uneconomical to change oil if the oil has good life left in it and the timescale involved looses money as the ship is not moving and thus not earning money.
Just because an oil is called classic,it may not contain some additives that were available when the original oil was made due to the dreaded H&S regulations removing it from use - usually the reason for a brand to move to the latest spec, lack of it on the market as the production of small volumes of it are unworthwhile. I stick to the best modern spec at the lowest cost and change it regularly.

The problem with determining the efficacy of motor oils is that most of us never know how poorly an oil is doing until we have a failure. The person who says I've run XXXX 30-50W for years and never had a problem doesn't know how well that oil is performing unless he does a tear down or at least some analysis of the used oil. For my money, a good quality synthetic is a good choice. If your liking is of dino oils, make sure it has lots of zinc. Needless to say, even the best of oils isn't worth a damn once its dirty and worn out.

The problem with determining the efficacy of motor oils is that most of us never know how poorly an oil is doing until we have a failure.

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I go by the magnet in the sump, using dino oil its gets furred up with iron filings at each oil change, using fully synthetic oil the magnet stays clean. Taking that as a proxy of engine wear the synthetic wins hands down.

I use a 10/60W fully synthetic oil by Millers based in UK, as recommended by the local madmen in their 70's based Ford rally Cars that went to that oil to stop the engine burning all the oil in one rally.

kommando said:

The problem with determining the efficacy of motor oils is that most of us never know how poorly an oil is doing until we have a failure.

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I go by the magnet in the sump, using dino oil its gets furred up with iron filings at each oil change, using fully synthetic oil the magnet stays clean. Taking that as a proxy of engine wear the synthetic wins hands down.

I use a 10/60W fully synthetic oil by Millers based in UK, as recommended by the local madmen in their 70's based Ford rally Cars that went to that oil to stop the engine burning all the oil in one rally.

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Proofs in the pudding - sounds like a real practical approach.

I'm a close looker at sump magnets and photo recording and very pleased surprised I could not really find any but mereish dust, not obvious until rubbed a bit cleaner, in Trixie run only on Rotella 15/40 dino diesel oil and more remarkably the lifters became better finished than Comstock's touch up did. Trixie had about 7000 miles on her when opened d/t inhaled grit in cracked carb boots opening up ring gap. Prior in Peel I ran only Mobil One but now read and see it ain't the same stuff. Peel showed ~1/8" layer of ferric fur between oil changes about 1000 miles intervals. I ain't saying Rotella is the way to go, as definitely not as good as hi end synthetics, so only thing I can assume was my bad habit to ignore wet sump and not let her idle to warm up, just blipped til taking good throttle then head out in low enough gear and low throttle to keep rpms above 2000 till all warm and toasty.

How to check your engine oil.



http://www.google.com/#hl=en&sugexp=les ... 00&bih=341

Rotella 15/40 dino diesel oil

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Question.... :?:
I was given 20 litres of Rimula Super 15W40 API CI-4 Plus and its been sitting around for months.....is this ok to run in a bike? ( or an aircooled VW)