Thread: Oils

I would be concerned with the start up wear with an oil that thin. LR recommend 15w-40 on the 3.5lt. I have run HPR 30 before when up north, but have been running HPR 15 (15w-60) recently and get similar oil pressures to you, as well as running a bit smoother on initial start.

Flat tappets must have zinc,, the rest is personal preference,, ( Penrite HP10 )

There’s zinc in the 5w-50. Penrith recommenced their 10w-60 racing oil
FYI. But I’m going south so temp not a big concern at moment. However these very modern high spec oils - with zinc in both Penrite and Nulon seem pretty good

Originally Posted by Konradical

I would be concerned with the start up wear with an oil that thin.

Nope, that's not how viscosity ranges work.

A 5w-50 is a bucket load thicker at any start up temp in Australia than it is at operating temp, by the order of several multiples.

It'll just be thinner than a15w-50 at start up, and so will have less load on the oil pump drive and get to the top end a tad quicker.

Conventional lubricants are Newtonian in nature, that means that their viscosity is less as their temperature is raised, they don't magically get thicker at operating temp.
Only some silicone fluids can do that.

If the engine is 'built' and not 'reconditioned', then follow the builders recommendation for viscosity. They will have made a decision on what the appropriate clearances are and what the minimum clearances are.

If the engine is 'reconditioned' i.e. factory spec, factory tolerances, then use an oil that meets or exceeds the factory recommendation.

In this day and age it is not hard to use a full synthetic 15w50 oil which will more than adequately cover any operating condition you may expect to place your vehicle in, as well as provide extended drain intervals.

If you have never before pursued oil sampling, then absolutely now is the time to commence.

do it every 5000km for the next 40,000km and do not get caught up in the "oh this is bad" scenario. Look for the obvious contaminant issues like silica, copper and sulphur / carbon.
There are some less-than scrupulous oil analysis agencies out there who do not really understand what they are printing out.

Modern surface treatments for lifters, cams, valve tips and stems are more than adequately protective in instances where a less-than-satisfactory operating condition exists.
That's not to say bulletproof, what it means is the components will withstand harsh environments and operating conditions a little better.

You can absolutely use a cheap oil, so long as you change it regularly with a new filter (5000km) or you can use an expensive oil and change it out at 40,000km extended drain intervals, so long as you are doing filters at least every 10K and topping it up appropriately and regularly - IF you are doing regular sampling and analysis.

In doubt? talk to a lubricants expert. Most will tell you that oil brands use marketing fear and pseudosience to promote the advantage of their "superior additive"

99.9999% of it is 100% Bullsh**

The economics of oil changes can only be ascertained through correct sampling intervals and oil analysis. You're either going to find out you're changing it too frequently, in which case you can save a few $ by extending drain intervals, or you're not changing it soon enough, in which case you have to spend $ more frequently.

Everyone's got their own brand preference, so just stick with one you trust and get the sampling done. i.e. start right now with what is already in your sump.

reserve a sample of the clean stuff you use to change, and send that off with the next lot of dirty oil, so there is a 100% direct comparison between the clean unused sample and the dirty oil.
If you continue this practice, it will save you longterm $, but it will take you more than a year to realize / amortize the cost benefits of doing it.

You're familiar with my old 107, so have a look at this:
m117.968-post.jpg

at 228,000km.
note the dye stamps still visible on the balancing pads of the rods. 32 years ago.

Originally Posted by rick130

Nope, that's not how viscosity ranges work.

A 5w-50 is a bucket load thicker at any start up temp in Australia than it is at operating temp, by the order of several multiples.

It'll just be thinner than a15w-50 at start up, and so will have less load on the oil pump drive and get to the top end a tad quicker.

Conventional lubricants are Newtonian in nature, that means that their viscosity is less as their temperature is raised, they don't magically get thicker at operating temp.
Only some silicone fluids can do that.

Ok, could you explain it to me.

From what I know and have been taught, the first figure is the "winter weight" or cold viscosity, from memory the flow at 0 degrees and the second figure is the flow of that oil at 100 degrees.

The change in molecular structure at the higher temp, gives the higher viscosity, but retains flow characteristics.

Unlike a single weight oil which would have an increase in flow as the temp increased.

To me this explains why as when oil gets older it loses its ability to reach the required viscosity and you lose a bit of oil pressure.

Now based on that knowledge, my comment was directed at using that weight of oil in a Rover V8, that I have presumed was standard. Factory recommend a 15W-something and a 5W would be too thin for the tolerances of that motor over a period of time. This being a motor designed in the 50's, built in the 80/90's and most likely done over 200k KMs.

Many years ago I experimented with trying a thinner oil in my LS1 ute over the winter period. From memory it's a 15W required and I tried maybe a 10W (all penrite, it's all I ever use), could have been lower and I ended up having to change it out before 1k due to excessive noise on start up and the pressure light flashing on hard acceleration. All went away with the recommended oil.

Now I am happy to be corrected, I am open to learn something new or have what I do know pushed back into the correct direction, so please don't think I am trying to rebut.

Look forward to the lesson.

Originally Posted by Konradical

Ok, could you explain it to me.

From what I know and have been taught, the first figure is the "winter weight" or cold viscosity, from memory the flow at 0 degrees and the second figure is the flow of that oil at 100 degrees.

The change in molecular structure at the higher temp, gives the higher viscosity, but retains flow characteristics.

Unlike a single weight oil which would have an increase in flow as the temp increased.

To me this explains why as when oil gets older it loses its ability to reach the required viscosity and you lose a bit of oil pressure.

Now based on that knowledge, my comment was directed at using that weight of oil in a Rover V8, that I have presumed was standard. Factory recommend a 15W-something and a 5W would be too thin for the tolerances of that motor over a period of time. This being a motor designed in the 50's, built in the 80/90's and most likely done over 200k KMs.

Many years ago I experimented with trying a thinner oil in my LS1 ute over the winter period. From memory it's a 15W required and I tried maybe a 10W (all penrite, it's all I ever use), could have been lower and I ended up having to change it out before 1k due to excessive noise on start up and the pressure light flashing on hard acceleration. All went away with the recommended oil.

Now I am happy to be corrected, I am open to learn something new or have what I do know pushed back into the correct direction, so please don't think I am trying to rebut.

Look forward to the lesson.

No worries, but I'm lazy, I've written a ****load on this in the past and what the numbers relate to and how they work and will dig it up.
You are on the right track regarding the xW number relating to flow, but the temps they relate to are well below 0*, eg 15W IIRC relate to a flow pressure at -20*, 5W are below -25* or -30*, etc.
Sometimes their actual kinematic (measure) viscosity above 0* will be identical, or even reversed depending on the oil.

[edit] This is an article I wrote for Loaded4x4 http://www.loaded4x4.com.au/issue-003/#95

Meccles , are you talking KRE Engines here?

The supercar engines definitely do wear and KRE admit it openly.

Not one supercar team would use the same engine for a second season.

Freshened is not the word , KRE totally rebuild them.

KRE build race engines of the highest international standards and since KRE became the name in Australian motorsport engine reliability has increased exponentailly.

I'm a speedway fan and since the rise of KRE , engine failures are a rarity. I would use whattever oils they recommend , but so many teams are sponsored by so many different oils its really the specification that needs to be adhered to not the brand