450/500T Startup

[Bryanj]

Personal opinion is mineral, i dont believe synthetics of any kind are needed when oil change interval is 1500 mile.

Yes sythetics are good on a comercial taking 30 ltrs and changed at 250,000km

[K2-K6]

After building my engine I filled it with oil and ran it with the starter motor on the bench with the cam covers off and plugs out. It took a while on the very first run to fill the centrifugal filter and oil galleries. All runs after that produced a good supply of oil which arrived at the inlet cam within seconds with oil at the exhast cam a few seconds later. I wish I could compare those bench runs to an engine with an old sloppy pump fitted. I think the pump is at least the partial culprit here. A pressure gauge would be an ideal defense.

I feel that people head the wrong way in interpretation of oil pump wear. It's often given that the oil should be thicker to perhaps stay "stuck" to the camshaft instead of draining away when turned off hot. Just a cursory look at oil when it's 90 degrees C will show that's not of any significance. 
Also oil viscosity is not protection  !! It's just system resistance.  When upping viscosity, the oil pump has to work under more duress but has no "extra" protection to prevent it wearing in this scenario. 
My understanding is that this engine would run 30 viscosity when used in temperature above 59 degree F ambient,  and 20 viscosity below that.
Has anyone got original specification for this ?
My understanding is that it would be ideal with a 0W 30 specification of modern oils to match in the best way Honda planning and intended flow rate when they made it.

It was designed with  20 and 30 viscosity tolerances hot when the R & D was carried out,  that flow rate is important in the overall design for many reasons,  most of which are never discussed within this topic.

Just quoting this post for 0W30. Just to be clear, should I be looking at fully synthetic or semi synthetic.

I'd not differentiate between the two distinctions in practical terms as the more you look at the "synthetic" word the more you can see how distorted it is in describing oil.
It seems pedantic of me, but in technical terms you can substitute "synthetic" with "ultra refined base oil" as that is what interests us most in the properties that are desirable.  "Semi" titled oils just have less of this part of the blend than fully synthetic, and so have a cost advantage.  None of them are what general opinion would view as synthetic if studied in depth as they are all petrochemical based, it really has turned into a marketing leverage term to justify prices. 

Fuchs make good oils,  but I don't understand the spec of the one listed, so difficult for me to judge.

https://www.amazon.co.uk/Castrol-15668E-EDGE-5W-30-Engine/dp/B011KRAGH8/ref=asc_df_B011KRAGH8/?tag=googshopuk-21&linkCode=df0&hvadid=310739960565&hvpos=&hvnetw=g&hvrand=15017347107296324641&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9045909&hvtargid=pla-563324061562&th=1

Would be an initial choice.

Or this one
https://www.eurocarparts.com/p/triple-qx-synplus-5w-30-gm-not-low-saps-5ltr-521776041?gclid=EAIaIQobChMI5vDf9ZDW7gIVumDmCh3RGQyKEAQYAiABEgJ6S_D_BwE

Both of them rated at 5W 30 with getting to a true 0W costing in the order of £2.50 ltr above this. These are LL (long life) focused oils that are specifically oriented toward maximum durability of oil film in highest load sites even at advanced mileage.

[K2-K6]

The economic view, short term at least, is relatively straightforward.  If the original oil change interval was set to 1500 miles, then moving to 3000 miles effectively makes this more expensive oil at parity with a mineral choice.

But it's not just that (enticing as that is) which is interesting. It's the potential wear reduction from oil performance that's of most interest in these (well any engine really) engines which can be more clear.  Changing oil at relatively short intervals gives less view of what the wear rate is in practice.  It achieves the the feeling of looking after the engine without actually proving it,  just an assumption mainly. Running longer duration and then checking the oil for accumulated worn metals  allows a more focussed view of what is happening in there.
My experience of using these types of oil clearly show that far less material wear is present, and virtually nil for engines with notable and recognizable component failures.  The oil's ability to sustain performance easily outstrips conventional / mineral types. 

[ST1100]

The oil's ability to sustain performance easily outstrips conventional / mineral types.

What about the impact on gasket- & seal materials?
I understood that modern oils contain ester... (good for keeping the engine clean, but I'm not sure what this does to vintage seals)

[K2-K6]

I don't believe these oils listed have ester as a component, hence the comments earlier about what "synthetic" means. It may be different outside UK market. 

Certainly they are labelled as ester based oils here for those containing it, and usually cost something toward double those we are speaking of.  It's quite a mixed up marketing focus of current products,  all obviously claiming they're superior in some way to other products.  Certainly they are not in any sense a "miracle" product,  but experience with them shows some very useful attributes, particularly when considered for engines like this one when there's anecdotal history of component lifing problems.

[K2-K6]

Personal opinion is mineral, i dont believe synthetics of any kind are needed when oil change interval is 1500 mile.

Yes sythetics are good on a comercial taking 30 ltrs and changed at 250,000km

Certainly I understand the position indicated here, also feel that the HGV economic model is effectively an advocate here. But with a smaller scale.

The prospect of losing camshaft and followers with the very restricted supply,  plus cost and the work to rebuild swings that I believe into the same realm, especially when the engine has just been rebuilt with those components sourced currently.  I'd view it as any margin you can usefully gain in reliability is worth a significant amount.