Castrol Classic 20w-50 Engine oil

Hello Ashman,\

Questions about using STP in your engine oil!

1) Does it thicken oil to the point you have higher oil pressure at very hot oil temperatures (I don't know if you have a pressure gauge)
2) What ratio of STP to oil do you use and how did you decide on the ratio?

My first job was at a gas station where some customers asked for STP with their top up oil. Oil came out of a can whose top one pierced and
we marvelled when customers could pay with a credit card using the handheld technology that wiped back and forth to get an impression of the card

Dennis

olympus said:

Had a response from Castrol

Good morning Malcolm,

Roller bearings should use a monograde oil, as the shear effect of the bearings can cause a multi-grade engine oil to lose its viscosity. However this would occur over a number of miles so if your bikes are not in regular use then you may not have found any ill effects of using 20w/50

Depending on the bike, our XL30 monograde may be the more suitable alternative.

If you can advise on what bikes you’re using, we can investigate to find the manufacturers recommendations.

Best regards,




Brendan Goodjohn

Business Development Executive

Castrol Classic oils

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So i assume this degradation of the oil by roller bearings applies to every mineral based engine oil

DennisMo said:

Hello Ashman,\

Questions about using STP in your engine oil!

1) Does it thicken oil to the point you have higher oil pressure at very hot oil temperatures (I don't know if you have a pressure gauge)
2) What ratio of STP to oil do you use and how did you decide on the ratio?

My first job was at a gas station where some customers asked for STP with their top up oil. Oil came out of a can whose top one pierced and
we marvelled when customers could pay with a credit card using the handheld technology that wiped back and forth to get an impression of the card

Dennis

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In my vast experience, all oil loses oil pressure when warm and even more hot. I set my Norton blow off valve pressure to 60 and a little more , so it settles down to about 45 PSI when warm at about 2500 rpms it would be lower at idle when hot. My Toyota Supra does the same and the different weights of oil show different reading. When I first started with Nortons in 1973 and in my first race bikes I used to run straight 40 and 50 wts, But I did warm up the bikes while moving or for the first few laps before I gave her the beans wide open. I use 20-50 "zinc oils" now. Modern oils are great on their own. I don't use STP in motor oil.

After studying Jim Comstock's oil research, I went with Mobil1 V-Twin 20w-50 and BG MOA additive. My 1973 850 that has never been opened has 11,000 miles on it and runs noticeably quieter. I like using Mobil1 V-Twin mainly because it is available almost everywhere for 10-11 dollars a qt. It's harder to find the BG MOA additive where I live but it can be ordered via Ebay or Amazon. Comstock gave this combo very high marks.

MexicoMike said:

I think there is far too much overthinking involved. I have a good friend who - around 15 years ago - rode from central Mexico down to Tierra del Fuego, then up to the North Slope of Alaska and then back to central Mexico. When he needed oil he bought "whatever the local grocery store had on the shelf." The Commando is still running just fine.

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I agree! In the late 60s and early 70s I lived near a refinery. Gas stations had re-refined 30W oil for about $0.10/quart. That's all I used in my Triumph until I moved away.

IMHO, for Commandos is hot areas, 40W would do just fine and in cooler areas/times 30W. I use Castrol GTX 20W50 Conventional because it is readily available in the US at a decent price.

L.A.B. said:

No, Castrol USA still calls it mineral oil.

Motorcycle Mineral Oils for Smooth Performance | Castrol® USA

Motorcycle mineral oils provide enhanced cooling and protection for older engines. Find the right Motorcycle mineral oils for your bike today!

www.castrol.com

USA.

Difference between synthetic oil and mineral oil | TotalEnergies

There are two main types of engine oils: mineral oils and synthetic oils. Let’s explore their features and differences!

services.us.totalenergies.com

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British company with a US division being very un-American.

You believe what you like - there's no mineral oil in a auto parts store in the US, but there is plenty in a US grocery store and you bike will not like running on it just like your baby will not fair well if you put motor oil on his butt!

Mineral oil in the States.

olympus said:

Had a response from Castrol

Good morning Malcolm,

Roller bearings should use a monograde oil, as the shear effect of the bearings can cause a multi-grade engine oil to lose its viscosity. However this would occur over a number of miles so if your bikes are not in regular use then you may not have found any ill effects of using 20w/50

Depending on the bike, our XL30 monograde may be the more suitable alternative.

If you can advise on what bikes you’re using, we can investigate to find the manufacturers recommendations.

Best regards,




Brendan Goodjohn

Business Development Executive

Castrol Classic oils

Click to expand...

I asked the same question and posted the reply here nearly two years ago. The reply got “rubbished” by a member because his spelling and grammar was wrong. I deleted it as I ended up getting misquoted and the reply from Castrol appeared to have been from me.

marshg246 said:

You believe what you like - there's no mineral oil in a auto parts store in the US

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Yes there is because it is mineral oil.

British company with a US division being very un-American.

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No, I don't believe that.

"Mineral engine oil is a type of lubricant derived from the refining of crude petroleum."

They obviously don't sell Belray mineral at the local shop as it says mineral on the container or do they put it in the pharmaceutical section.

"What is mineral engine oil?​

Mineral engine oil comes directly from crude oil. It has a simpler chemical structure compared to synthetic base oils. It can be a good choice for older types of vehicles and moderate riding conditions."

"Mineral engine oil, also known as conventional engine oil, is a traditional type of engine oil. It is refined directly from crude oil through a selective refining process to remove impurities and undesirable hydrocarbons."​

The thing to remember is that all of the oils on the first page of Comnoz’ test are good.

So the Castrol oil on the list is good.

The only downside is that being a none synthetic, and a multi grade, it will break down sooner.

So, provided it’s changed out more frequently (no problem given its low price) all should be good.

And I seem to recall Sir Comnoz saying pretty much that !

DennisMo said:

Hello Ashman,\

Questions about using STP in your engine oil!

1) Does it thicken oil to the point you have higher oil pressure at very hot oil temperatures (I don't know if you have a pressure gauge)
2) What ratio of STP to oil do you use and how did you decide on the ratio?

My first job was at a gas station where some customers asked for STP with their top up oil. Oil came out of a can whose top one pierced and
we marvelled when customers could pay with a credit card using the handheld technology that wiped back and forth to get an impression of the card

Dennis

Click to expand...

Dennis I use to run a straight 50 grade Pennzoil in my Norton for many years as we live and ride in very hot summers, the original recommended GTX oil was not up to the task and my Norton ran very hot with it till I started using the Pennzoil but after a few years my importer was taken to court by Pennzoil Australia but after a few years he won the case as the Australian Pennzoil was produced by Caltex here and wasn't the same as the US Pennzoil so I started to mix the STP in my oil Penrite oil.
Now my Norton runs a small round 3ltr alloy oil tank 2ltr motor oil and 1ltr of air space so I mix 500ML of STP to 2ltr of Penrite classic oil, its the recommend amount on the STP bottle, if you run 4ltr of motor oil they say use 1 bottle of STP, so I mix 1/2 bottle to my Norton oil, I been doing this since 1982, ai also use the same mix when assembling a new motor on the bearing and conrod bearing.
I have had very long life out of my motor, I also run a Lochead oilcooler since 1978 for our hot summers all year round, the oil still gets up to running temp, I don't run with a oil pressure gauge although I have one for it just never fitted it, with running my Norton for 49 years it run very good with what I been doing since the early days.

Ashley

Are there any owners in the UK running a monograde w30 or w40??

robs ss said:

Well. I've been using Royal Purple HPS 20W50 since Jim's recommendation and am very happy with it.
If "someone" wants to criticise it - bugger 'em! No nerves here.

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Seems to available on eBay.co.uk so may give it a try when I exhaust my stock of XL

olympus said:

Are there any owners in the UK running a monograde w30 or w40??

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Yes, I use Silkolene Chatsworth 40. I used it for years without problems and was then persuaded to switch to Valvoline 20/50. This eventually resulted in me having to replace a worn out camshaft and followers. So I will be sticking with my ancient 40 grade dino' oil.

So on a hot day in traffic you are essentially back to 20wt?

I don’t mean to ad infinitum on an oil thread BUT …
I live at the seashore where boating is prominent and popular.
Synthetic oils have ( or at least HAD - past tense ) a bad reputation for use in marine motors that are only used occasionally as it is so slippery it may drain away from surfaces while sitting leading to dry starts .
I tested this myself some years ago in a very amateur way . I took a piece of precision ground steel rod and Scotchbrited the surface , cut it into two equal length halves and dipped one in synthetic oil and the other in old school monograde and hung them for two weeks. You could easily hold the synthetic sample between two fingers while the old school sample was still slippery.
Perhaps things have changed since then but if you do not regularly start your motorcycle you may want to think about this before using synthetic.

Richard Tool said:

I don’t mean to ad infinitum on an oil thread BUT …
I live at the seashore where boating is prominent and popular.
Synthetic oils have ( or at least HAD - past tense ) a bad reputation for use in marine motors that are only used occasionally as it is so slippery it may drain away from surfaces while sitting leading to dry starts .
I tested this myself some years ago in a very amateur way . I took a piece of precision ground steel rod and Scotchbrited the surface , cut it into two equal length halves and dipped one in synthetic oil and the other in old school monograde and hung them for two weeks. You could easily hold the synthetic sample between two fingers while the old school sample was still slippery.
Perhaps things have changed since then but if you do not regularly start your motorcycle you may want to think about this before using synthetic.

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I’ve been using synthetic oil in an old bike for at least 30 years, summer only and have never seen the effect you describe.

I rather suspect the opposite of your claim is true.

Triton Thrasher said:

I’ve been using synthetic oil in an old bike for at least 30 years, summer only and have never seen the effect you describe.

I rather suspect the opposite of your claim is true.

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Several marina owners and their experienced mechanics would
disagree - perhaps things were different in your experience - I certainly have no reason to doubt you . One notable failure that was reported to me was camshaft failure. I am only passing on what others have told me and the results of my own test , however unscientific and amateur it may have been .

Richard Tool said:

Several marina owners and their experienced mechanics would
disagree - perhaps things were different in your experience - I certainly have no reason to doubt you . One notable failure that was reported to me was camshaft failure. I am only passing on what others have told me and the results of my own test , however unscientific and amateur it may have been .

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I have read, in the past, similar poor results, such as insufficient rust prevention properties. To the extent Amsoil had an ad campaign touting that they were in fact SUPERIOR, in attempt to debunk the rumors.
An engine sequestered in a wet bilge, is SO LIKELY to suffer damage, from drain down or corrosion.
JMWO

STP sticks like glue and if the motor for some reason sits for long periods of time the shiny bits will be protected, I remember back in the 70s a local garage had an old Holden motor on a test stand and they ran the motor without a sump just lubing the motor with STP every Saturday they have that motor running, snake oil I don't think so, my Norton has proved that with high miles, so I keep using it mixed with my oil.