Opinions needed on the grade of oil and pressure

[Brit01]

As most of you know I have my Alfa 33 1.7 8v with flat hydraulic tappets. Recently rebuilt.

I opted to now use Castrol TWS 10w60.
I was informed "20W50 was the old spec even Castrol even listed RS 10W60 in their Classic section as a modern alternative to their older spec "XL 20W50"
20w50 was commonly used in these old flat four alfas but is only available in mineral.

When the engine is hot these are the readings I get:

idling @ 900 : 15 psi
@3000 rpm : around 50 psi
@4200 rpm : around 55 psi
@5000 rpm: 60-65 psi

Alfas maximum pressure limit is 88 psi at 6200 rpm.

I don't believe I need to go down a grade to 50 viscosity oil do I? Or maybe I could try to see the readings. Shame Castrol here don't do a 50 synthetic. 40 or 60!
I understand the flow is more important than pressure but how do we measure flow?

I don't have excessive oil pressure here.

Should I stick with the TWS Castrol? I am not causing excessive wear on the engine due to the thick oil?

Regards

Chris

[WhizzMan]

The oil is not thick. It's 10W, very thin. It just doesn't thin out as much as 20W50 does at 90-100 degrees, that's all. By the way, 42-thousand RPM? I'd love to hear that engine.

[Brit01]

Hi whizzman,

Lol yes 42000 rpm. That must have been my son intervening with the keyboard!

10w for cold starts works out great in winter here yes.

So 60wt oil shouldn't be a problem in my flat four?

I'm getting a lot of grief from people because I dare to use a 60wt oil! (According to these so called 'experts' these engines were not designed for these modern oils!!).
'No it's only for racing - not for a normal car. It will cause excessive wear and overheat and it doesn't have any detergents!' (just some of the comments)

Sorry but 10w/60 TWS was designed for high performance BMW engines, some with flat tappets, which are used for daily driving. Please correct me if I'm wrong.


Regards

Chris

[WhizzMan]

Unless you can find the ZDDP additive for your oil, chances that you'll find oil that will be better than this but with more ZDDP in it are virtually none. the 60W is not a problem, but a gain. It has better shear strength and viscosity than the W40 or W50 oils.

The "flat tappet" myth doesn't seem to hold for Alfa engines. In the 16V twinspark and 24V V6 engines, the exact same tappets are used and for several of those, 10W60 is factory mandated here in Europe. You found that BMW uses 10W60 in their engines and also use the same type of hydraulic tappets.

If you're worried, get the additive. For run in of new cams or tappets, get oil with enough ZDDP in it. For engines that aren't specced to run with 10W40 semi synth (the boxer was in the latest years), please consult the manufacturer. For this engine, really I don't see any reason why not to use 10W60 apart from cost.

[Brit01]

As you mention it 3 bottles of ZDDP MAXX are in the post from USA as we speak.
Purchased them last week.

The oils with more zddp are not imported into Uruguay unfortunately like Castrol Edge syntec (at least not at the grade I need it).
10w50 is the factory recommendation for my 1988 model. The Castrol syntec only comes in 5w30 and 5w40. 40 would just thin out too much in my opinion.


Thanks for the assurance of running 10w60 oil.
I keep reading cons of using thicker oil but I don't see any excess oil pressure or temperatures with my engine.

[Urbancamo]

One thing to remember when using ZDDP additives. Too much of these additives mixed with your oil can attack camshaft and cause excess wearing. So common sense is a must when using these additives.

I use ZDDP Plus with my grinded and nitrided camshaft. 30 ml of ZDDPlus in 4 litres of oil will bring zinc and phosporus levels in 1000+ ppm region wich is pretty much enough for any ordinary old engine. I use API SN graded oils wich in typical have 600 ppm of these additives.

So one tiny little bottle is enough for three or four oil changes!

[Brit01]

Thanks Urbancamo. Yes I heard that too much is bad (like anything really).

I was planning just to add a little from the bottle to get the level to around 1300 ppm to be on the safe side.
TWS can have between 900-1000 ppm of zinc which is a little on the low side IMO for flat tappets.

The bottles of MAXX come in 60ml measures so maybe half a bottle. So it should raise the level about 300+ for a 4 litre sump.

I have to say the staff from ZddPlus.com were very helpful as I was having discussions with them about adding zddp to the castrol oil. I had 3 of their tech guys in the discussion.

[Brit01]

200 km round trip on the highway and the oil was at 90 degrees at 120km/hr.

Drops to about 85 when slowing down through the towns.

The sensor is in the main oil channel on the block so it could be picking up some heat from the block but nothing excessive here.
Good temp to burn off any fuel or water.


So 10w60 oil too thick/will generate too much heat comments from many people is not the case here. Correct me if I'm wrong.

I'll be getting an oil dipstick sensor soon which is the best option for accurate readings.