Engine Oil

[The_Matrix_Master]

I expect this topic has been covered many times before but here goes

I am interested in what grade of oil members are using in their betas ~ mineral, semi synthetic or full synthetic.
For years I have allways used 10/40W mineral oil in my Beta Spyder and Montecarlo for no other reason that it was standard at the time the car was made.
10/40W basic mineral oil was allways substantially cheaper than the equivilent 10/40w semi synthetic oil coupled with that most semi synthetic oils state on the bottle suitable for cars built after 1990 so hence I have steered away from these.
However now I notice that the price of semi synthetic 10/40w is very close if not the same as that of basic mineral oils.
Since the semi synthetic is supposed to afford the advantages below
Has /is anyone running on semi synthetic and have they noticed any difference

Advantages of Semi Synthetic
Measurably better low- and high-temperature viscosity performance at service temperature extremes
Better chemical & shear stability
Decreased evaporative loss
Resistance to oxidation, thermal breakdown, and oil sludge problems
Extended drain intervals with the environmental benefit of less oil waste.
Improved fuel economy in certain engine configurations.
Better lubrication during extreme cold weather starts
Longer engine life
Superior protection against "ash" and other deposit formation in engine hot spots (in particular in turbochargers and superchargers) for less oil burnoff and reduced chances of damaging oil passageway clogging.
Increased horsepower and torque due to less initial drag on engine
Does not contain detergents

[lukasdeopalenica]

I use semisynthetic 15W50 (Motul Classic) and is just fine.

[cheeky monkey]

i've alternated between 10w 40 semi synth and Penrite 20w 50 mineral in recent years

[lukasdeopalenica]

May I use Shell Helix Ultra Racing 10W60 which actually is mineral hydro cracked oil not synthetic? What do you think about such a change? My engine was rebuilt, but when hot oil pressure is just not sufficient. Before I strip down it again I would like to try something simplest.

[WestonE]

OK

I have to stay calm with this reply. I am ex oil company from the Lubricant division so I have had to learn a lot about engine and gearbox oils and I run a 277 BHP Montecarlo. These engines have primitive oil pumps by modern standards and run large engineering clearances compared to modern vehicles even before wear takes place. This means oil drain back and time to running oil pressure are both issues. 20w 50 in any formulation is a poor choice because great care is needed to warm the engine under no load before use. This might work for racers but not for road use. The cold oil number should be as low as possible. So a 0W 50 would be great for road cars. However practically 10W 60 is a very good spec for our engines and what I recommend to avoid unnecessary damage from start up and warm up. It will also give solid oil pressure resisting heat and load demands.

By definition 10w 60 will be either Semi-Synthetic or Synthetic Chemistry with a lot of misleading marketing hiding chemistry that is not in reality fully synthetic. Some US Oil companies have been allowed to call semi-synthetic oils synthetic!!  However anti-wear agents like ZDDP being present maybe more important for road use as this gives protection at start up and in oil surge which Betas suffer from unless a baffled sump is installed. Be aware that ZDDP has been reduced in some oils in recent years to protect Catalyc convertors.

In my Montecarlo I have a baffled sump an oil cooler and an Accusump Pre-Oiler and surge protector. I use Miller Oils CFS 10W 60 in my Montecarlo and I have due to a new higher compression piston install (300BHP spec) inspected the engine components and I am happy with what I found.     

I hope this will help people on here to make a more informed choice.

Eric   

[mangocrazy]

Thanks Eric, very helpful. For initial running in of a fully rebuilt engine, what grade of oil would you recommend? Iseem to recall GC stating that you shouldn't use fully synthetic oil when running in a rebuilt engine as it inhibits proper bedding in of the mating surfaces. Would you agree with this?

I've always tended to the old-school method of warming the engine up fully before applying load, but realise that this isn't particularly practical in the real world. When I finally manage to get my Spider 2000 engine rebuilt with all its new components I'll definitely be using 10W60 synthetic as per your recommendation.

[lukasdeopalenica]

Thank you Eric for your clarification. I only run my beta in warm sunny days, so there are rather no cold starts in my case.
The mentioned shell racing is more mineral than synthetic, even the manufacturer claims it is fully synth., what is just a marketing bullshit. I was rather wondering if it has no additives like detergents which can be harmful for engine parts eg bearings etc, similarily to transmission oils containing EP additives that damage synchromesh.

[WestonE]

Graham

For a re-built engine with a re-bore or new rings and a hone a running in oil is the best idea and this is always a mineral oil that will allow the bores and rings to gently wear into each other. It is not in the engine long though before an oil and filter change to a normal running oil.
With new cams you would also coat them in anti wear lubricant just before start up so they can bed in running at 2000 rpm to form a hard surface for long term use. This is all well described in GC's books.

Detergents and dispersants in modern oils are not a threat to engine components and are very important as they stop black sludge forming and blocking fine oil drillings. The oil carries the carbon from combustion within itself so it leaves the engine at drain down oil changes. Oil left in place too long can drop the sludge out and form acid compounds that attack the internal metal work in the engine. Hence an engine left unused for a long period after running and no recent oil change can have acidic oil and benefit from a oil change to clean the engine then a change to normal running oil.

I hope that helps.

Eric     

[mangocrazy]

Hi Eric,

Many thanks for that. I've been doing some digging on Opie Oils site (I tend to buy most of my oil from them) and found this regarding a running in regime using Millers Oils CRO 10w-40 Competition Running In Mineral Engine Oil:

http://www.opieoils.co.uk/pdfs/millersoils/Millers-Oils-CRO-How-To.pdf

I'm guessing that this kind of regime would need either an engine test-bed facility or dedicated dyno time?

[WestonE]

Hi Graham

Yes that running in routine would be at a rolling road on a new engine. This is something I have done a couple of times now with new engines before real mapping starts on fresh oil and a new filter. I like Opie Oils as they also sell the excellent Mahle filters.

you can of course run in on the road if you are certain about jetting and this is described in Guy's books.

Eric

[mangocrazy]

Thanks, Eric. I suspect that when it happens, my engine will have to be run in on the road. But with Guy's recommendations on jetting, I can't see the mixture being very far out, if at all.