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Hi all,
I know that the oil subject was discussed many times at the forum, but I searched the forum
and also did allot of reading regarding oils generality lately, (Molecules length, heat and whatever)
But I could not find what the answer to what curious me:
Why, basically we need to use only “non-synthetic” oil for the BSA engine?
Is it the metal composition?
Thanks,
Noam.
email (option): noam10@gmail.com
This should get interesting.
I am wary of modern gearbox oils because of the risk of the additives affecting the bushes, but for engine oil my reasoning is that it just isn't worth the extra cost. Most of us don't do vast mileage and the oil changes are quite frequent so mineral is good enough.
I have run synthetic in my Commando, showed lower oil pressure cold and higher hot vs the equivalent non synth, but it if you have a small leak with non synth you will have a much larger leak with synth oil.
Have also tried Synth gearbox oil in the Commando. Gearbox oil i change when the shift is no longer silky smooth, which tends to be more frequently that the manual says, and synth did last longer.
Also i believe synthetic is designed for modern bikes which are this new fangled unit construction so their engine oil sees more than just the engine, so i presume has stuff in it that we don't need and possibly don't want?
In both cases on my Commando i decided the extra cost wasn't worth it and went back to my old ways, which is where i am at with my 16H as well.
oilway drillings in modern engine are thinner because of the thinness off synthetic oils so with older engines with larger oilway drillings it might be harder to get up to a good oil pressure i have done a modern ford oil pump/pressure valve in because i put old 20/50 oil in it
I use Rockoil RTM in my Commando and Dommie which is rated as a 20/60w oil and synthetic. It's a race oil and good for high temperatures. It's expensive at £28-£30 for 4 litres but I think it's worth the extra cost as I have trashed engines with lesser oils and cheaper than an engine rebuild. For the number of miles I do on each bike which isn't much, it's getting max protection. It's very viscous and sticks like sh*t to a blanket. I've been using 50w Rockoil in the singles and I'm thinking of changing to TRM for the same reasons. I know people use it in gearboxes but I haven't tried that. That's my 2 penny worth
email (option): horror@blueyonder.co.uk
Synthetics have more detergent power than mineral oils. There may be (or there may not be) places in your engine which are not leaking because they are impacted with sludge. If you switch to synthetic the additional detergents may dissolve this sludge causing leaks. Remember, leaks are not always in places where you can see them - they may be internal.
Also, dissolving the sludge may place harmful metal bits into the oil stream, even though this second problem can be taken care of by a relatively early next oil change which would remove these bits permanently.
The greater detergent power is also why you won't want to use synthetics in the gear box, as it may mess up the bushes.
email (option): jonny.rudge@verizon.net
Hello to all and thank you for your answers.
OK, so if I understood correctly,
There is nothing that really prevents from using synthetic or half-synthetic oils,
rather than leaks and cost..
I also do not do high mileage (Kilimetrage, in my case..) -about 30Km (About 20 miles) a week max,
But most of it is on a highway, with a sidecar, and in about 57 Mp/h, as measured to me by a friend last Friday,
(This WM20 has a light fiberglass sidecar, originally from a “Jawa” and high gear ratio. the other one I have is more original, with a heavy metal sidecar and original ratio so it is much slower )-: )
I may switch to synthetic or half-synthetic.
I rebuilt the engine lately, and would hate to do it again.
The work, time and money to rebuild gets me to agree that Its better to spend the extra money for the better oil..
Thanks guys!
Noam.
email (option): noam10@gmail.com
And here's my bit..Due to the high detergent content of synthetics, which leads to a lot of particles of carbon etc. in suspension, the general recommendation seems to be that a proper cartridge oil filter should be fitted when using these oils.
It doesn't apply too much to our old bikes with seperate engine, gearbox and transmission resevoirs but due to the inclusion of 'friction modifiers' in these oils (which are there to reduce friction) they are a completely unsuitable for wet clutches such as the Triumph clutch and will obviously cause additional problems if they get anywhere near an M20 clutch. Remember that if your M20 drops its oil into the crankcase it can leak into the primary and get to the clutch.
Finally, I have been told that for the same reason (friction modifiers/reducers) these oils should be avoided when running in older type engines as they actually inhibit the process of wearing in mating parts.
This would be less important in new engines which have close tolerances and much higher surface finishes from the outset than older types.
I have never used synthetics at all so cannot quote from actual experience... However, if you can get 50,000 miles from an M20 or similar engine on 'conventional oils' (and you can easily exceed that) then there may be a good argument for leaving synthetics to the engines that really benefit from them like turbo diesels and Suzuki Hyabusas..especially when the increased cost is factored in...Ian
email (option): ian@wright52.plus.com
It's interesting to do the sums on this.
The AA used to do 50,000 miles on their outfits before they were returned to BSA for a top end overhaul..so I will assume a top end overhaul could be required at that mileage.
Using BSAs recommended oil change interval of 2000 miles and the 5 pint oil capacity of the M20 oiltank that works out to 25 oil changes...or 125 pints of oil.
That equates to 15.62 gallons. Currently you can buy 5 litres (approx. 8 1/2 pints) of straight 40 for about £15.
So 125 pints divided by 8 1/2 = 14.7 or approx. 15 tins at £15 per tin. That comes to £225.
Horror quoted a price of £30 for 4 litres of synthetic..125 pints is approx. 71 litres so at the price quoted that works out to £532 approx.
A difference of roughly £307.
If you are one of the very few people that might actually cover 50,000 miles it could be considerably cheaper to stick with the monograde and do the top end overhaul, specially if you plan ahead and buy the piston, valves, guides etc. now!!.(£120 should cover it)....and there is also the fact that even with synthetic oil you are still going to have to do that overhaul at some point..Ian
email (option): ian@wright52.plus.com
Good point Ian.
Actually, I can get 4 liters of a good mineral straight 40, API-SF/CD for about 10.8 UKP,
Which even have a MIL-L-2104D standard.
(The green goo foaming oils are cheaper, but you might as well put in a shampoo…)
So, If one can expect to get some 50000 Miles / 80000 Km on it, it would take be about 75 years to get there,
In my current pace…
email (option): noam10@gmail.com
I have invested a lot of money in the bikes I have and as we all know, engine rebuilds etc get very expensive. so I'm not going to quibble over a few hundred pounds in 50,000 miles if I could actually do that on every bike. I doubt I do much over 1000 miles a year on any one bike, some only a few hundred. That means I don't have to change the oil every year. Talking about sludge build up in engines, if you're getting that, your oil is rubbish..! The idea of a good oil is to remove the crap when you change your oil keeping the engine clean. Yes I've heard that engine don't run in well on synthetic oils, well that to me proves the point. mineral oils let the engine wear and synthetics don't. I got fed up with seeing the oil from my bikes glistening with speckles of metal in the sunlight. TRM is a 20/60w and designed for roller or plain bearing cranks so ideal for classic bikes that are used hard. I agree it is probably over spec than some of these bikes or riders need, but as I said, I've invested a lot of money in my bikes.
email (option): horror@blueyonder.co.uk
Weeeellll . . . , it's not quite that simple. Even when you don't do lots of miles on any particular machine, oil oxydizes (and therefore is no longer doing its job of lubricating) a year after you open the container and, therefore, needs to be changed every year, even if you've only put a few miles on the engine during that year. In fact, some say that very infrequent running is worse than constant running because acids build up in a cold engine but they turn into vapor which is exhausted, once the engine gets up to running temperature.
Separately, "run in" and "wear" are not the same thing. The point was driven home for me when I bought a new 2011 car a few months ago. The dealer, knowing that I do my own work, "reminded" me that the first oil change needs to be at 1,000 miles, subsequent ones every 10,000 miles. I was nothing short of amazed when I found lots of "glistening . . . speckles of metal" in the oil I drained at 1,000 miles. I am sure I will not be finding any at all at the next oil change, even though the car will have done ten times the amount of mileage by then. It's just the nature of run-in. Perhaps more to your point, this car specs ONLY for full synthetic oil but the speckles were there, nonetheless.
email (option): jonny.rudge@verizon.net
"Weeeellll . . . , it's not quite that simple. Even when you don't do lots of miles on any particular machine, oil oxydizes (and therefore is no longer doing its job of lubricating) a year after you open the container and, therefore, needs to be changed every year, even if you've only put a few miles on the engine during that year."
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That's correct, Johan.
Actually,
as far as I know it is 6 month for mineral oils before it oxidizes and need a change, weather you drove or not,
(Yes, worse if not)
and you can "stretch" synthetic oils change for up to one year.
email (option): noam10@gmail.com
'The proof of the pudding is in the eating' as they say..I did 79,000 miles on my B33 before I enlarged the engine to 600cc.
That mileage was made up of the daily hack to work, club runs, general running about and touring, winter and summer.
I ran the engine on either Morris's straight 40 or Duckhams 20/50 throughout that time dependant on which was available at a good price (mainly the SAE 40.) Oil changes were carried out at the recommended 2000 mile intervals.
I re ringed the engine at about 45,000 miles.
Over the entire mileage the engines bottom half was never stripped.
Obviously there was wear present in the bore and piston, but they were still within useable limits and after fitting new rings for a second time I fitted the barrel and piston to another engine.
Across all the BSA singles I have owned in the last 35 years I have never run a big end or main bearing, never had to replace cams, followers, rocker arm or spindles due to wear or had any identifiable oil related problem.
Further more all the road tuned or competition engines I have built have been run on conventional oils with the same result.
Whilst I agree that for certain engines synthetic oils may be advantageous and I am prepared to take on improvements when they come along and are beneficial, I think in the case of the BSA single range at least synthetics are not required to improve reliability and don't warrant the extra cost.
With these discussions it often boils down to which oil manufacturers information you decide, on balance, is the right information to follow and that is a personal decision...in fact most people prefer a particular MINERAL oil over the others..never mind synthetics.
I have always covered high mileages on my bikes as I don't run a car (never driven one actually) and currently have no plans to change the oils I use..
Why would I?
But if synthetic produces the desired result for anyone else it has to be the right choice for them.
email (option): ian@wright52.plus.com
John, I understand the difference between "running in" and wear. When an engine is first run after a rebuild, there is alway metal in the oil as it beds in. But if an engine runs in slower with synthetic oil, it shows it's good at it's job, which is the point of this discussion. I usually run an engine for 50 miles and change the oil, then 500, then 1000. This is when there is metal in the oil and I want it out as quick as possible. Maybe I'm over cautious these days but it's the things that have happen to me with engines that make me this way. I would rather buy another gallon of oil that do damage to a newly built engine.
Maybe I've just been unlucky, but I have changed so many cams etc on twins that it can only be down to the oil. I always used 20/50, Castrol GTX and Duckhams, then Valvoline. Although I have never had a big end go (eeeek that's tempting fait ) but as I said before on another post on this subject, I completely ruined a Commando engine in 2000 mile from a rebuild. There is no other reason than the oil which was Valvoline and a local enigineer confirmed that's what he thought. I went to Antig's who build speedway bikes, JAP engines, and other big singles, and asked them what oil they use. Obviously there were the caster oils which don't mix with other oils and aren't now the best, but do smell nice The oil they use is Rockoil TRM, after reading more about the oil it does seem right for me.
I do agree with you Ian, for a BSA single ridden normally it is probably over spec than required but certainly wont do it any harm if it was used. In fact if what everyone has said is correct, synthetic oils can be left in engines longer than mineral oils, clean engines better so no sludge build up, and resist wear better than mineral oils. All this for a few quid more a gallon. What's not to like
email (option): horror@blueyonder.co.uk
I agree with your sentiments Horror...and wouldn't question your experiences with different bikes and oils.(though poor or borderline oil supply might be a factor as well as the oil itself..early BSA twins suffered cam failures for exactly that reason)
In relation to my own bikes it's a bit like saying are we 93,000,000 miles from the sun or 93,000,001...the extra mile makes no practical difference.
The majority of viewers on this forum are unlikely to do 70,000 miles or more...as Noam said it would take him 75 years. So in practical terms there is no difference...UNLESS the use of synthetic oil prevents problems with a particular engine in the short term or an engine is being subjected to more extreme uses, such as racing, where due to the much higher loads benefits may be gained.
I certainly have found no need to improve the oils used in my BSAs as they haven't had any failures that indicate a problem, but that doesn't mean a Commando wouldn't benefit..they are completely different engines after all.
The limit of my opinion here relates to BSA engines where I feel any gains would be marginal or theoretical, as the engines are reliable and durable on mineral oils over higher mileages than most people do these days. That leads me to conclude a more than doubling of the price of the oil used won't really return any practical benefits in that application...Ian
email (option): ian@wright52.plus.com