Technical 14W50 oil for tuned 650

[gordinir8]

One thing to keep in mind. Modern "fancy" oils typically dont have the zinc protection of a oil designed for a "classic" car specifically. What do i mean about this over the years, modern oils have gone away from zinc as the high pressure wear additive, and unfortunately modern oils still do not give the protection that flat tappet cams neat (our cars included).

Now you might ask why zinc was eliminated?. Simply "catalytic converters", as cats have become popular in all cars starting in the 80, with their performance and longevity improving over the years, they have become super sensitive to specific chemical exposures. Zinc being one of them, zinc in the oil can "poison" a catalytic converter and destroy them. Thus oil manufactures have cut down or completely remove zinc as one of the major wear additives in modern oils; that is unless you buy an oil specific for classic/high zinc use. Unfortunately like i mentioned above, the replacement wear additives have yet to meet the wear performance that zinc provided, with that said modern engines are designed with different geometry/contact faces especially on the high pressure contact points on the camshaft/lifters that modern low/no zinc oils perform properly.

Just run a regular quality 20/50 oil (the 2nd number is the most important as that's the at temp operating viscosity spec), and just add a zinc additive to the oil and you should be good to go.

Our cars have flat tappet cams, and they need high zinc oils to survive. I really wish there was a way to run roller lifters in our cars



As far as oil pressure goes. Ive installed a pressure and temp sender in my car and have been observing temp/pressure with castrol gtx 20/50 oil. on start up, the car gets darn near instant 65+psi of pressure (seems to be what the factory pressure relief is). and with oil temps in the 100c on a hot summer day, running pressure is around 50psi, with idle pressure being at around 15-20psi at full operating temp. So high temp viscosity is important.

Now, at the store this year, i found castrol synthetic 5w-50.. I might give that a try next year along with adding a zinc additive. And see what pressures are like. Because there might be the odd chance i have to start and move the car on a super cold day, the lower "cold" viscosity rating might be useful. I will see.

I am really confused with oils since i can't find exactly what i am looking for here in Greece, Castrol 20w50 is available but not sure what is the difference between those two and if it is semi or just mineral with zinc or not. Cant even find specs on Castrol page. There is also a castrol classic 20w50 which is special for older cars but unfortunately can't find it here either.

 

[Bounding Bambino]

I am really confused with oils since i can't find exactly what i am looking for here in Greece, Castrol 20w50 is available but not sure what is the difference between those two and if it is semi or just mineral with zinc or not. Cant even find specs on Castrol page. There is also a castrol classic 20w50 which is special for older cars but unfortunately can't find it here either.

So. I believe Castrol changed their labeling recently, i had the same issue here. So my general consensus is. Both are conventional oils, (non synthetic). and both are the same.

Either one, i would use with no worries. And add a zinc additive for good measure.