Engine oil advice

[Westie777]

Oil advice required:-

This is the spec of my Westfield kit car engine:-
1760cc X Flow engine built to custom stage four spec
Accralite forged pistons
ARP bolts throughout
dry sump
motorsport spec oil pump.
Cylinder Head fully gas flowed with modified ports with matched set of valve springs including big valve head and hardened valve seats
Cutting and throating of valve seat areas to accommodate bigger valves
Full engine balance Crankshaft reground and polished
All new mains and big end bearings
Decked pistons and block
Steel main caps and block line bored
High performance fast rally camshaft fitted

Its now done 1300 miles since rebuild. Any recommendations on oil spec and synthetic or mineral?

[E-bmw]

Just because you have different bits inside it doesn't necessarily mean it needs different oil to standard.

If you had it built by someone ask them, if not go for manufacturers standard.

Syth/semi-synth/mineral based issues are generally around seal types if this helps.

[Westie777]

The guy who rebuilt the engine at Specialised Engines Ltd in Essex says 20w50 all day long. Other oils are too thin for these engines.

Thanks guys

[clubsport]

I have always used Valvoline "Racing" 20/50 in a tuned Xflow.

10/40 semi synth if you don't mind a few leaks!

[Sardonicus]

Then you want Valvoline VR1 20/50 it also contains the appropriate levels of Zinc ZDDP for your flat tappet camshaft they also do a semi syn version in a 10/60 viscosity

[e30m3Mark]

Westie777 said:

The guy who rebuilt the engine at Specialised Engines Ltd in Essex says 20w50 all day long. Other oils are too thin for these engines.

Thanks guys

I'm with him. I've always found modern oils are way too thin for my old BMW M10 engines and RS2000 Pinto's. I opt for a good quality mineral oil every time.

[seveb]

e30m3Mark said:

Westie777 said:

The guy who rebuilt the engine at Specialised Engines Ltd in Essex says 20w50 all day long. Other oils are too thin for these engines.

Thanks guys

I'm with him. I've always found modern oils are way too thin for my old BMW M10 engines and RS2000 Pinto's. I opt for a good quality mineral oil every time.

What does that mean ? Too thin ? If the spec is 20w50 then the 20 and 50 specify the viscosity at two temperatures. So a modern 20w50 should be the same as an older mineral 20w50. A so called synthetic oil should be even better at staying in grade so will stay nearer the 50 point than a mineral oil at higher temperature.

Maybe it's the detergents which dissolve the gum that got everywhere over the years ?

[e30m3Mark]

seveb said:

e30m3Mark said:

Westie777 said:

The guy who rebuilt the engine at Specialised Engines Ltd in Essex says 20w50 all day long. Other oils are too thin for these engines.

Thanks guys

I'm with him. I've always found modern oils are way too thin for my old BMW M10 engines and RS2000 Pinto's. I opt for a good quality mineral oil every time.

What does that mean ? Too thin ? If the spec is 20w50 then the 20 and 50 specify the viscosity at two temperatures. So a modern 20w50 should be the same as an older mineral 20w50. A so called synthetic oil should be even better at staying in grade so will stay nearer the 50 point than a mineral oil at higher temperature.

Maybe it's the detergents which dissolve the gum that got everywhere over the years ?

In some cases quite possibly but even in newly rebuilt engines I had leaks where some properties of modern synthetics just didn't work for older engines and their often greater tolerances.

[gordmac]

Modern oils will have low viscosities for fuel consumption reasons, I wouldn't use them in an old engine design. Miller's oils are very helpful, I would ask them. I used Miller's cfs 10/60 in my Vauxhall slant 4 engines a decade or so ago.

[markymarkthree]

Sardonicus said:

Then you want Valvoline VR1 20/50 it also contains the appropriate levels of Zinc ZDDP for your flat tappet camshaft they also do a semi syn version in a 10/60 viscosity

Would you (or anyone else) also recommend Valvoline VR1 20/50 for Pinto & Essex engines as an upgrade ?
At present I use Halfords Classic 20/50 in both cars but don't mind spending a few more bob on a better oil.

[e30m3Mark]

I used Halfords Classic for a couple of years without any issue. When I couldn't get it though, I swapped to Millers and would stick with it now.

https://www.millersoils-shop.co.uk/cro-10w40-engin...

ETA - Possibly cheaper via Opie?