Gearbox Oil (126/500/BIS) + Engine Oil (Running in/Viscosity)

[poxxxy]

Hi everyone,

So finally going to get round to assembling the engine and gearbox back to the car tomorrow... but I need to decide on a gearbox oil to use so I'm wondering what everyone is using... I know the standard is the Tutella ZC90 (SAE 80-90w/GL3) with no EP/Hypoid additives but its not something I can find on the shelves and it appears as GL3 is no longer active, its not really stocked by any Motorfactors. I could order some from Ricambio but with the 1.1 ltr filling quantity that means two lots!

After reading it appears that a good quality engine mineral oil of the correct viscosity of around 20-50w has the same viscosity ratings as the ZC90... I also read somewhere else that a straight 30w oil is near enough SAE 90w. I'm wondering what other people are using and what they recommend other than the ZC90 and non EP oils. I hear GL4 won't damage phosphor bronze and yellow metals like GL5 would but otherwise read elsewhere it still has EP additives and "NO" EP for 126 gearbox's is necessary... otherwise i'd have bought some from halfords earlier and still might if GL4 is actually ok. The cheapest option is definitely looking like a decent 20-50w mineral oil though at the minute.

So anyway today I went and picked up some cheap mineral oil to put in the engine. Some 15-40w "mineral" optilube that cost me £15.50 from a local motorfactors. I'm unsure what grade I really want to use in the engine at the moment. Perhaps a straight 30w would also be better for running in the engine after deglazing and replacing the piston rings?

I'm wondering what everyones using, and B&Q appear to have some carlube Daytona classic motor oil for reasonable money £10-11 for 5 litres... I'm going to do some checks to see if its actually not even part synthetic though before buying anymore.

Oh and back to that "mineral" optilube. The website appears to list it as "Mineral" but then when you goto the datasheet it states semi-synthetic... now are they passing of something as Mineral when its clearly not and trying to sell it as mineral? Doesn't state anywhere on the bottle that its anything but pure mineral. . http://optichemicals.com/downloads/ - Product OPTLK. So i'm not sure I really want to use that either!

Looks like the daytona has anti-wear additives in it afterall . http://www.carlube.co.uk/product-carlube/carlube-20w50-daytona-mineral

Someone must know something I can pickup easily . Perhaps halfords 20-50w classic multigrade might be suitable! http://www.halfords.com/motoring/engine-oils-fluids/engine-oil/halfords-classic-oil-20w50-5l#tab1

[andyzeetec]

This site has equivilents to ZC90, not sure how valid though...

http://www.durucan.com.tr/motec.pdf

or 126fan are selling Valvoline GL-4 80W90

http://www.126fan.sk/eshop/index.php?main_page=product_info&cPath=10_11&products_id=459

although it is a mild EP oil ??
http://www.valvolineeurope.com/english/products/transmission_oils/gear_oils/cid(6897)/valvoline_gl-4_80w-90

[Gadge]

For my engine I use castrol gtx 15w 40 semi synth and for the box I belive it was comma 80-90 gl5?

[poxxxy]

Hmmm worth checking if gl5 is ok... Quite detrimental to yellow metals it seems but perhaps they dont use phosphor and sulphur in production of the ep oils. I went for some 20-50w mineral oil in the end so will update everyone on how it performs. .

Maybe the EP oils of these days aren't unsuitable and may actually help.

Are the gears in the air cooled 126 much different compared to the bis?

[Gadge]

I belive there more or less the same. The stuff I used isn't an EP sort - I made sure of that as there was a bottle next to it with EP written on it. I've done about 1300 miles with it an they slip in and out quite nicely so no problems yet.

[poxxxy]

Fingers crossed! Sure all / any thing is probably suitable. I've not split the back of the box off but I couldn't see any yellow metals on the diff or under the top cover but phosphor bronze is definitely on the input shaft bushing... that doesn't come in contact with oil anyway.

Now where exactly is the fill plug as I just guessed the fill amount and would like to check the level if possible .

[Gadge]

The "official" place to check/fill is a little square plug just about where the starter sits however if you have the box out just take the top cover off and pour it straight in. It takes an annoying 1.1 litres so you need to buy 2 one litre bottles

[andyzeetec]

I bit the bullet and bought the proper stuff.. 

http://www.ricambio.co.uk/453-gearbox-oil-tutela-zc90-1ltr-80w-90-

[poxxxy]

Does that mean you have .9ltrs going? lol.

[andyzeetec]

Blimmey the oil came the following day from Ricambio. The other parts I bought from Axel a while ago.

[jeffgainford]

This site has equivilents to ZC90, not sure how valid though...

http://www.durucan.com.tr/motec.pdf

or 126fan are selling Valvoline GL-4 80W90

http://www.126fan.sk/eshop/index.php?main_page=product_info&cPath=10_11&products_id=459

although it is a mild EP oil ??
http://www.valvolineeurope.com/english/products/transmission_oils/gear_oils/cid(6897)/valvoline_gl-4_80w-90

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[danthemanic]

I've been using Lucas Gear Oil 80w-90 and it's been just fine.

https://www.amazon.co.uk/gp/product/B0007ZFTOA/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

[amam]

whatever you do don't fall into the trap of buying the "halfords classic" 20/50 or comma classic 20/50 or wilkinsons 20/50

you can tell because they come in a tin and the oil is green, its very nasty recycled oil, it burns very quickly and has lots of nasty additives such as seal swell and will not do your engine very good (especally with no oil filter)

[andyzeetec]

Didn’t want to risk damaging the phosphor bronze / yellow metals within the box, so bit the bullet and bought the Fiat recommended EP oil TUTELA ZC90(80W-90).. 

http://www.ricambio.co.uk/453-gearbox-oil-tutela-zc90-1ltr-80w-90-