classic motor oil

[lisbon_road]

I know this subject has been done to death, but I'm not sure what I should get.

 

The Vauxhall Viva could do with an oil change.  I believe that as it has flat tappets, it would benefit from an oil with ZDDP in it, but it seems quite difficult to get hold of now and not cheap as an additive.  Possibly been frowned upon being sent in the post.  Classic motors oils are available and some seem to have ZDDP in them.  They're all 20W50 and it seems a shame to put that in, as a 20 oil when cold will be very thick when I'd prefer to put say 5/40 in it.

 

I suppose that it was built to run on 20/50 so should survive ok.

 

Any thoughts?

[PiperCub]

It'd have used 20/50 when it was new. So would have thought that'd be more suitable than 5/40??

 

Penrite (I think) used to do a 15/50 IIRC in their 'Classic' range, might be worth a scan of their website. Or try Millers or Morris oils, they cater for the older/classic markets extensively.

[Shep Shepherd]

I've been using Halfords 'Cla$$ic' 20W50 in The Volvo for the last three oil changes. It runs beautifully and burns/leaks next to no oil, which wasn't the case when I ran it on 15W40.

[DodgeRover]

Valvoline mineral 20/50 race oil, high ZDDP levels, lovely oil

Buy when on special it's normal £25ish delivered for 4 or 5 litres.

 

When we had our Viva I put 10/40 (because it was cheap and in stock) in and it used loads, maybe a pint in 100 miles! Swapped to 20/50 and it never used a drop. I just wouldn't have thought it would make that much difference but it did

[lisbon_road]

I think I will end up doing as suggested as there isn't much choice.  Look at this graph though.  The viscosity of 20/50 is mental when cold, it just goes off the graph, meaning %^&* all lubrication when the engine is cold.  I think that there should be a market for a synthetic classic oil, so that old cars get the benefit of a wide range of viscosities and the additives they need.  That's my invention.

 

Possibly I could bend some synthetic in it to keep the viscosity down when cold?  That might be a bad idea!

[Parky]

In 1991 I had a 1256 Chevette with a similar engine and used to run that on Comma Motorway 20/50. Which you can still get. It was good enough for 1991, it’s probably still good enough today.

 

Comma do a couple of ranges of 20/50. Have a look on Amazon

 

Elf have also introduced a new range of classic car oil called HTX - http://www.elf.com/en/consumers/car-oil/vintage-car-oil.html which might be worth a look?

[Bren]

Valvoline do a 20/50 with the zinc additive but it is not cheap.

[trigger]

The cheapest oil I've seen for 20w/50 lately is the Comma X-Flow stuff at £11.90 for 4.5litres, I'm not sure why it's so cheap mind you.

 

https://www.amazon.co.uk/gp/product/B00OIPZ21A/ref=ox_sc_act_title_2?smid=A3P5ROKL5A1OLE&psc=1

[oldcars]

The cheapest oil I've seen for 20w/50 lately is the Comma X-Flow stuff at £11.90 for 4.5litres, I'm not sure why it's so cheap mind you.

 

https://www.amazon.co.uk/gp/product/B00OIPZ21A/ref=ox_sc_act_title_2?smid=A3P5ROKL5A1OLE&psc=1

That's what i use in the Reliant. Local place sells it.

[captain_70s]

20w50 in all my old stuff.

 

I bough this and had it posted to my door. Most convenient!

[DodgeRover]

I shouldn't worry about comparing cold viscosity, the engine tolerances were designed with those specs in mind.

[cort1977]

I shouldn't worry about comparing cold viscosity, the engine tolerances were designed with those specs in mind.

Exactly, manufacturer's spec all the way, as the engine gets older and clearances increase then thicker is the way to go surely. 

[steveo3002]

if thats what was on the shelf back then , they must have made the clearances etc to suit , id at least try it and see how it sounds 

 

modern thinner stuff might be too thin and cause just as much hassle 

[Guest Hooli]

Thinner oil is designed for smaller clearances, the film it produces can breakdown easier if the tolerances in the engine are too large.

[lesapandre]

When I refilled the gearbox on my Landcruiser I sourced a non EP gearbox oil from Morris Lubricants. They were about the only people who did non EP - the Landcruiser has bronze parts in the gearbox which are attacked by the EP and leads to premature failure...ie not at 500,000 miles...I can't advise on your specific case but found Morris very helpful and well priced.

 

https://www.morrislubricants.co.uk

[jonathan_dyane]

Wilkinsons do 20w50 own brand; I'd use that and change it often.

[jonathan_dyane]

https://www.wilko.com/en-uk/wilko-classic-car-oil-20w50-5l/p/0342792?nst=0&gclid=EAIaIQobChMI5emg4p6B3AIV8QDTCh0ZzQt5EAQYASABEgKKh_D_BwE&gclsrc=aw.ds

[Guest Conan]

Living in a hot climate, 40 and 50 weight oil is an abundance. I used to run my W124 on 5w-50 and there's actually some oil that has 0w-50 rating and they aren't special (read: expensive) oil either. I'd have expected some would find it's way over there at least? Apparently Mobil 1 does do 5w-50, but the availability might be a bit lacking in cold climate? But I still wouldn't know how good they'll be for classic engine.

 

One thing is for sure, modern lubricants technology is much improved from the 70's.

 

(Fun fact: Over here Alfa Romeo owners actually recommends 10w-60 for Twin Spark else they lose a litre every 1,000km.)

[Bren]

I had a senator that i filled with 15/40 oil. I switched to duckhams qxr which was 10/40 - engine was smoother but I car developed a smoky exhaust and needed frequent topping up. So I went back to the heavier stuff.

[mercrocker]

You can get classic green Ducky 20/50 now....

 

Zippidoodaa is in there too...

 

https://www.duckhams.com/wp-content/uploads/2017/11/PDS-20W-50.pdf

[lisbon_road]

OK I agree with the general notion that if the car was running on 20W50 for decades of its life, it'll be ok now.  Fine and I will get some.

 

So if you're curious, read the following but don't lets get hung up on this.

 

Any engine spends most of its life running at 90-100 degrees c under load, so the viscosity at that temperature has to be right to maintain oil pressure.  20W50 has a viscosity of about 20-25 cst at that temperature. 

 

When it is cold, say 10 degrees c, 20W50 has a viscosity of about 1200 cst.  But the 5W50 Conan refers to would have a viscosity of about 300 cst at about 10 degrees c.  Which would be why 20W50 isn't going to flow round the engine well when it is cold, and the '5' would be better though still very thick when cold. 

 

I guess when cold the clearance might be larger, but not so much larger that they need these high viscosities. 

 

I think Conan is right that oils have come on a long way. 

[DSdriver]

I was sad to see that the Duckhams headquarters building in West Wickham has been demolished. I used it's details as part of my art A level.

[mat_the_cat]

Comma XT2000 is a 15W40 oil with a reasonably high ZDDP content. How much of a difference will it make? Dunno, but it's nice to feel good about an oil change!

[Guest Hooli]

You can get classic green Ducky 20/50 now....

 

Zippidoodaa is in there too...

 

https://www.duckhams.com/wp-content/uploads/2017/11/PDS-20W-50.pdf

That's good news. I'd used halfrauds classic for years because it's green.

[DodgeRover]

I'll just reiterate what I said earlier, the engine was designed with those cold viscosities in mind, viscosity will not have changed although stability and film strength etc in modern oils will have improved massively.

If you are an experienced engineer who knows more than the design team for the vehicle then use something other than what was recommended otherwise don't get blinded by science.

If you are really that worried about it then using a 0w50 or 0w60 oil designed for extremes of temperature variations will give low viscosity when cold, It might sound like a bag of nails when cold though.

 

Edit, one thing you could do if you feel oil technology was a limiting factor at the time is to check the oil recommendations for later versions of that engine / the metric version used in the Chevette - just make sure that the internal design and tolerances were not changed as well.

[sierraman]

Engines are built to such fine tolerances these days, I'd love to see how long an VW TSI or equivalent would last on a diet of 20w50.

[PiperCub]

One thing is for sure, modern lubricants technology is much improved from the 70's.

 

(Fun fact: Over here Alfa Romeo owners actually recommends 10w-60 for Twin Spark else they lose a litre every 1,000km.)

 

That sums it up really, the 20/50 you get today is a world away from that which was around in the 70's, oil technology has moved on hugely (thankfully!).

 

As for AR - I think they still recommend (or used to anyway) Selenia 10/60 for T/S cars over here too. 

[Guest Hooli]

Engines are built to such fine tolerances these days, I'd love to see how long an VW TSI or equivalent would last on a diet of 20w50.

 

You don't even need to go that new. The reason CVHs all turned into rattley old lumps was people putting 20w50 in rather than 15w40. It's too thick to get into the lifters & they collapse due to low internal pressure hence the rattles.

[Junkman]

What are we talking about here?

 

A car that was designed at a time when oils weren't even close to anything sold nowadays.

Heck, people chucked straight 30 weight into those back in the day and they worked fine.

 

I think it's high time to debunk the Urban Myths surrounding motor oils once and for all.

 

Use some decent quality oil and add the appropriate amount of ZDDP Additive.

Do not overdose, since too much ZDDP is worse than too little.

 

I'm using this one:

 

https://uk.eastcoastadditives.com/products/east-coast-zddp

[davidfowler2000]

I shouldn't worry about comparing cold viscosity, the engine tolerances were designed with those specs in mind.

 

Yes. This. It's the same with all cars but from what I see is that in more modern stuff they give you a list of different grades of oil depending what environment you are in. For example my Volvo 740 runs 10w/40 semi synthetic in the UK. If you live in Arizona or are frequently towing a house then the book says you can use 15w/40. On the other hand if you live in northern Finland then it might be an idea to use 5w/40. My Golf says on the oil cap to use 5w/30 fully synthetic but reading through technical data will reveal it will actually handle 0w/30 which I tend to use as I can get an extra 10mpg out a cold engine.

 

Where was I going with this? Oh aye - Thicker oils might be like tar in winter but the engine will be built to take account of that. Besides an older, worn engine will actually prefer the cuishioning of some of the thick stuff when it's cold with tolerances like the grand canyon.