SAE30

Phoenix of Hamble

Phoenix of Hamble

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My engine requires single grade SAE 30 oil, and could do with a little top up....

I noticed recently that the local DIY store sells 5 litre cans of SAE 30 as lawnmower oil at a very reasonable price...

Anyone think of a good reason why I shouldn't use this?
 
I use Comma's "Classic Oil" in my Volvo MD5B which is 25 years old. This is a single grade SAE30 oil and is reccomended for classic cars and lawnmowers. The old engines do not require nor indeed like these modern type oils. I get mine from a local motor factors and pay £12 per 5 litres.

Paul
 
Many of the older engine quote a straight single grade SAE30 oil mainly because that was what was available at the time. An example of that is the Bukh fitted in my boat. All the books and manuals that came with it say SAE30 while the gear box goes from SAE30 to SAE40 depending on operating temperature but when queried with Bukh they said no worries use a SAE15/40 multigrade MINERAL oil for both and recommended Shell Rimula-X. I questioned the info in the manuals and it was expalined that in the old days the oils (multi grades) were not as good as they are today (and were expensive).
Spoke with the techie folk at the gbox manufacturer and they confirmed the use of multigrade MINERAL oils - not synthetic oils.

Perhaps some of the old "Bolinder" class donk-donks need a single grade oil - I really could not say for certain - better you contact the engine manufacturer and ask them.
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“Artificial intelligence is no match for natural stupidity”
Skype id:cliffillupo
 
IMHO, you could use pretty much any SAE 30 grade oil, but I think I'd favour a 20W50 oil for basic engines such as the halfords stuff. The multigrade is a bit thinner when the engine's cold, so it'll circulate quicker to build up your oil pressure. It may also improve cold weather starting. As the engine warms up the multigrade doesn't thin out as much as the straight stuff, so you'll get better oil pressure when idling.

The important thing is not to use any synthetic or semi-synthetic oil.
 
As the "Bolinder" representative on this forum I can only echo what Cliff has said. In a recent conversation with my Ancient Volvo Specialist, in response to exactly the same query, I was recomended to use 15/40 VDS-2 spec (VDS-2 spec is the commonly-available-at-boat-stores stuff). The manual for my MD7 says use SAE30.

The same debate has been raging, unresolved, in the classic motorcycle world for years. Some folks swear by old "straight" oils, others by modern multigrades. Neither side can provide conclusive evidence that the others are wrong, ie by documented (or even anecdotal) evidence of high wear or catastrophic failure. In truth in the motorcycle world it's actually a bit more critical; multigrades do break down at high temps and most motorbikes are aircooled and run close to those high temps. For the same reason my VW Beetle manual used to recommend SAE30 oil. However our boat engines don't run at such high temps and modern multigrades are the thing.

And in reference to hand-starting, swinging a stone-cold diesel in winter can be made so difficult by thick monogrades that you can never get them turning fast enough to start up.

Note "straight" correctly refers to oil without any additives, not necessarily monogrades.

Regards, Mudhook
 
[ QUOTE ]
Why not use sythetic oil? Please explain.

[/ QUOTE ]It's something I've been told by several mechanics. Your question provoked a google and I found this, which seems to make sense:

The only real downside to synthetic oils is the cost. It is typically two or three times the cost of conventional oil for a good synthetic. Another little-known downside is that switching to a synthetic oil on an old engine can result in oil leaks. Why? Because the detergents in the synthetic oils will "clean-up" the varnish and sludge left by conventional oils. If your engine seals are worn, the synthetic will break down the oil varnish that may be maintaining the seal. So it's not that the synthetic oil caused a leak, it just that it revealed worn seals by cleaning the varnish off of them. Many people have switched to synthetic on 100,000+ mile engines with no leaks, so it just depends on how often you changed your oil and the overall conditon of your engine.
http://www.vx800.net/workshop/advice/engine_oil.htm

Another site suggested that over the years, an old engine is likely to have accumulated all sorts of abrasive and/or corrosive crud in nooks and crannies. The better cleaning effects of synthetic oil may not let these sleeping dogs lie, but send them round the engine biting your bearings. The filter should pick it up eventually, but the really tiny particles will still get through.

So it seems that it's not a case of whether the oil's up to lubricating your engine, more one of whether the engine's up to being lubricated by the oil.
 
[ QUOTE ]
Why not use sythetic oil? Please explain.

[/ QUOTE ]Unless the engine has been run on synthetic oil from new (or since a full rebuild including cleaning of all the oilways and galleries) then it is not a good idea to change to synthetic due to the high detergent action of the synthetic oils loosening deposits within the engine. In addition there is some talk of seals not being compatible with synthetic oils and expanding or tightening resulting in serious leaks. Combine this with the removal of sealing laquer and one has a recipe for major problems.

Combine the additional costs of the oil and there is no benefit to be gained as engines in boats generally have an oil change once a season whether the engine has done the hours or not.

All in all it is one hell of a price to pay to be "stylish"
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“Artificial intelligence is no match for natural stupidity”
Skype id:cliffillupo
 
My engine (BMW D12) also recommends straight SAE 30. For the last 10 years I have used an ordinary 10-40 multigrade mineral oil with no ill effects - in fact, I can actually hand crank the bloody thing in the winter now! This year I used a semi-synthetic. Don't know what that has done to it, but it still goes!
 
Interesting stuff....

I was informed that the problem with multi grade was not with the engine, but with the gearbox which receives its oil from the engine, and will slip if modern multi grade oils are used.....

I've bought 5ltrs of the mineral SAE30 grade oil from doi it all for £11.99..

its says suitable for all 4 stroke applications on the can.....so still not 100% confident...
 
Interesting debate and one which I had also considered, I have two points to add;
1) A good source of a range of single grade oils are chandlers on canals ( in fact they are a good source of many things and cheaper than those in large marina's-- diesel 20% cheaper for instance)
2) A respected engineer who looked at my troublesome Bukh gearbox swore that it had been badly affected by using a modern oil with detergents in it. I am not convinced he was right but I now use SAE 30 in the gearbox and a 10/40 mineral in the engine ( Bukh)

Regards
 
[ QUOTE ]

2) A respected engineer who looked at my troublesome Bukh gearbox swore that it had been badly affected by using a modern oil with detergents in it. I am not convinced he was right but I now use SAE 30 in the gearbox and a 10/40 mineral in the engine ( Bukh)

Regards

[/ QUOTE ]

... and he was almost certainly right! Most gearboxes including Bukh have cone clutch mechanisms which are designed to work in a specific type of oil. Synthetics are simply the wrong lubricant for them (unless specified), and being much more 'slippery' will cause serious problems and can even write off the gearbox altogether. I came across a Parsons box to which someone had added Molyslip to try to reduce gear whine. The clutch was completely wrecked in less than a seasons use, and the box would not take load without slipping, and neutral had completely disappeared - straight from forward to reverse!

Made manoevering at close quarters most entertaining - for lookers on!

I have heard it said that using synthetics in an older engine will flush it out so thoroughly that it can 'loosen up' worn parts, causing early problems and failures - but have never actually seen it for myself.
 
I'm not sure about this thing of old engines not liking modern oils. My 1958 MGA has been fed on Castrol GTX since I partially rebuilt it in 1983 and seems fine. Until recently I used 20W50 but can only find 15W40 now. It's handbook says use Castrol XL which was 30.
 
Synthetics hae two problems in older engines and gearboxes:

They get very thin when they warm up and you will see a considerable drop in oil pressure when the engine is hot,and will find leaks where you never had leaks before.

The older type oil seals are not compatible with the modern oil. A lot of car manufacturers had this problem when these oils first came out.
 
Ahem,
speak up from the back!
Powertrain Development Engineer say buy the COMMA 30SAE at cheapest price. It is the old fashioned stuff, and I run my Honda 2.3BF on it as well.
No real modern additives except a minimum amount of detergent.
 
Interesting - as the actual problem with the gearbox was probably to do with the clutch cones - in neutral the prop shaft continued to turn slowly as if the clutch was dragging as a little pressure (my hand) would stop it. Anyway the outcome was that the engineer had a 2nd hand gearbox which he fitted and "guaranteed". I still have the old one ---- any takers?
 
I can believe that gearboxes with cone clutches would not like some modern oils. You get the same problem with motorbikes, the majority of which use the engine oil to lubricate the clutch (believe it or not). "Fancy" oils with friction modifiers and so on lead to clutch slip and subsequently wrecking the plates/friction linings. It's not the "synthetic" bit that matters so much as the additives, as there are a number of bike-compatible synthetics.

My Yanmar 3GM uses Halfords diesel multigrade, or a branded oil if cheaper (I understand pricing policies even less than lubricant chemistry!).
 
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