Author Topic: OMG an oil thread!!  (Read 421 times)

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Offline scottly

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OMG an oil thread!!
« on: December 31, 2025, 09:15:44 AM »
I'm also a fan of Shell Rotella. It's non-detergent
 
Rotella IS a detergent oil! In fact, diesel specific oil has more detergent than standard oil, due to the dirty burning fuel. ;)
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Offline Godffery

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Re: OMG an oil thread!!
« Reply #1 on: December 31, 2025, 12:32:11 PM »
I'm also a fan of Shell Rotella. It's non-detergent
 
Rotella IS a detergent oil! In fact, diesel specific oil has more detergent than standard oil, due to the dirty burning fuel. ;)
Oh...? Well now, that's news to me then.  :-[
« Last Edit: January 01, 2026, 07:58:24 AM by Godffery »

Offline HondaMan

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Re: OMG an oil thread!!
« Reply #2 on: December 31, 2025, 07:06:59 PM »
Rotela's diesel-rated oils are not detergent-y. It causes havoc in diesel engines if it foams.
When I worked in the oilfield this was a huge deal: guys got fired for ever getting it mixed up, and those big trucks used 4-6 gallons of oil per change. The V-24, 4800 CID frac engines used 32 gallons of it.
See SOHC4shop.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
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Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

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Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

Offline scottly

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Re: OMG an oil thread!!
« Reply #3 on: December 31, 2025, 07:49:11 PM »
Rotella diesel oil has a high level of detergent. When a diesel engine is run with standard oil for any length of time, the rings get so gummed up with carbon that the engine develops "Enough blow-by to float a Cat-Hat over the breather". :o The reason people started using it in our old bikes and cars is because it still had the zinc in it, when they phased it out of oil for new cars.
« Last Edit: December 31, 2025, 09:06:16 PM by scottly »
Don't fix it if it ain't broke!
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Offline PeWe

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Re: OMG an oil thread!!
« Reply #4 on: January 01, 2026, 05:51:06 AM »
I'm also a fan of Shell Rotella. It's non-detergent
 
Rotella IS a detergent oil! In fact, diesel specific oil has more detergent than standard oil, due to the dirty burning fuel. ;)
+17 ;D ;D
Finally oil talk!! ;D

I have read about diesel oils with their zinc content AND the detergents that clean the zinc off.

Modern oils have less zinc due to the catalytic converters.

I wonder how modern bikes use the good Spectro and Redline oils when they have cat's that must be short lived when zinc content is 1940-2125ppm.
I guess the vehicle inspections do not test motorcycles as cars .

That amount of zinc is good for our old bikes. Plus good viscosity, not too thin.

I have ordered zinc in small bottles for my oils with low zinc content.
https://ebay.us/m/oMpKDH

Not too much either.
« Last Edit: January 04, 2026, 12:22:01 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline BenelliSEI

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Re: OMG an oil thread!!
« Reply #5 on: January 01, 2026, 06:35:24 AM »
I'm also a fan of Shell Rotella. It's non-detergent
 
Rotella IS a detergent oil! In fact, diesel specific oil has more detergent than standard oil, due to the dirty burning fuel. ;)

Thanks for the info. Didn’t know that! I like to use around the farm as it is priced right. I also use it for “first starts”.

Offline britman

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Re: OMG an oil thread!!
« Reply #6 on: January 01, 2026, 12:12:40 PM »
Nothing wrong with a good oil thread......Always brings to mind the old saying about opinions and a certain body orifice.......

Offline lash

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Re: OMG an oil thread!!
« Reply #7 on: January 01, 2026, 02:38:23 PM »
Never gets old!
Analog mind in a digital world..

Offline Tracksnblades1

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Re: OMG an oil thread!!
« Reply #8 on: January 02, 2026, 08:16:23 PM »
Rotella diesel oil has a high level of detergent. When a diesel engine is run with standard oil for any length of time, the rings get so gummed up with carbon that the engine develops "Enough blow-by to float a Cat-Hat over the breather". :o The reason people started using it in our old bikes and cars is because it still had the zinc in it, when they phased it out of oil for new cars.

👍

+1 High Detergent oil.

And New Rotella T4 has more detergent than Old Rotella…
Run detergent oil in an engine with a full pressurized oil and filter system.
Non-detergent oil was used in old non oil filtered or by-pass oil filtered engines..
So the impurities would be trapped in the sludge and not recirculated…Since most were splash lubed babbit bearings you could manually clean the sludge out when you took a shim out of the bearings to quiet the knocks up every 3-5k miles or sooner if you ran the crap out of them..
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Offline PeWe

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Re: OMG an oil thread!!
« Reply #9 on: January 03, 2026, 01:28:33 AM »
I searched for zinc content in motor oils.  "Flat tappet + zinc" and similar search.
Mostly www.bobistheoilguy.com  (forum)

Later oils have less. I was surprised about the highest levels. I thought it should be more zinc in the 1970-80's.

There are also people discussing too high zinc content.
I saw one article where a guy claimed that too much zinc will cover the bore honed surface causing oil burn.

Very high content for cam break in.

Our modified engines with race valve springs shimmed for high pressure PLUS an agressive cam profile.
This must need more zinc than a stock engine, right?

Spectro Heavy Duty Mineral is a proven good oil for a known bike on this forum. Stock CB750 without taking oil after more than 250.000 km. Zinc around 1940ppm.

Content as Redline has with 2125ppm might be needed with race cam, springs and race riding style.



*** API vs years and Zinc content ***

SQ Current
Introduced in March 2025, designed to provide protection against both fresh and aged oil low-speed pre-ignition (LSPI), improved timing chain wear protection, improved high temperature deposit protection for pistons and turbochargers, sludge and varnish control.
API SQ with Resource Conserving matches ILSAC GF-7A by combining API SQ performance with improved fuel economy, enhanced emission control system protection, enhanced low temperature pumpability and protection of engines operating on ethanol-containing fuels up to E85.


### The date is when the associated classification ended. ###
SP 2025
SN 2020
SM 2011
SL 2004
SJ 2001
SH 1996
SG 1993
SF 1988
SE 1979
SD 1971
SC 1967
SB 1951
SA 1930

Motor oils of the following API service classifications had the following amounts of Zinc in them

SM MAX 800
SL/SJ 1000-1400
SH 1000-1400
SG 1000-1400
SF 1000-1400
SE 1000-1200
SD 1000-1200
SC 1000-1200
SB 1000
SA 0

EDIT:
I have an SM rated motorcycle oil specified to have 400-800ppm of zinc.
Add zinc a must.
« Last Edit: January 04, 2026, 12:23:16 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline grcamna2

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Re: OMG an oil thread!!
« Reply #10 on: January 03, 2026, 05:33:58 AM »
I was looking at some specs on Shell Rotella T4 15/40wt. and one of them is 1200ppm of zinc.
75' CB400F/'bunch o' parts'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline PeWe

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Re: OMG an oil thread!!
« Reply #11 on: January 03, 2026, 06:13:29 AM »
I forgot to mention that the API classes I wrote are for  petrol engines.

Diesel engine oils have a different letter.

API categories explained: API categories for diesel engine oils follow a simple two-letter format, like CF-4 or CI-4. Here's what each part signifies:

First Letter (C): This denotes the oil's suitability for diesel engines (indicated by "C").
Second Letter: This represents the oil's performance level, with higher letters indicating better performance for modern engines.


https://me.caltexlubricants.com/en_me/home/learning/from-chevron/heavy-duty-diesel-vehicles-and-equipment/understanding-diesel-engine-oil-api-specifications-explained.html

More interesting details here:
https://penriteoil.com.au/knowledge-centre/Specifications/194/api-service-classifications/363


*** Wet clutch: JASO MA vs MA2 ***
My CB750 K6 970cc (+100whp, double torque numbers than stock)  on the edge of clutch slip will get MA2. (V-Twin oil). 
This despite of later K7/F2 clutch, glass beaded metal discs and hard Barnett springs, middle number -66-

JASO MA2 oil provides increased friction performance – essentially, more grip. That means the clutch lever will feel less progressive, almost like an on/off lever, which some dirt bike riders like. For some riders, an MA2 fluid might be a little too “grabby.”

More details here:
https://blog.amsoil.com/whats-the-difference-between-jaso-ma-and-jaso-ma2-oil/


Would be better to have a later bike's stock clutch that can be bolt-on with a minimum of modifications.

I wonder which clutch a 120whp setup need?
70-72mm bore + 69-70 mm stroke + better flowing head with bigger ID of inlet spigots.
« Last Edit: January 03, 2026, 08:29:28 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Tracksnblades1

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Re: OMG an oil thread!!
« Reply #12 on: January 03, 2026, 10:35:00 PM »
I was looking at some specs on Shell Rotella T4 15/40wt. and one of them is 1200ppm of zinc.

Yes. Shell states a maximum of 1200ppm Phosphorus. Generally testing between 1100-1200ppm for T4 with the triple protection additive package..

PEWE: good info.. Rotella lost its API certification when the maximum phosphorus content for catalytic converters went to 800ppm phosphorus maximum..

Also your info is the same I have heard for a long time.. the following is copied from google but it’s the same that our family lubricant engineer says..

**Too much ZDDP (Zinc Dialkyldithiophosphate) in engine oil creates a balance issue: while ideal levels (around 1200-1400 ppm) protect flat-tappet cams, excessive amounts (over 1500 ppm) can become corrosive, increase ash/deposits, interfere with detergents, harm catalytic converters, and paradoxically increase wear by causing spalling or pitting, making the "ideal" range crucial for classic engines needing high zinc but not modern ones with emission controls. **

Additionally there have been published articles of the different types of zddp used in low RPM diesel engines vs high rpm gasoline engines utilizing aggressive flat tappet camshaft profiles and heavy spring pressures.. remember most modern and older diesel have roller lifters.. Think old 855 Cummins and some old Cats even had roller lifters push rod activated
Fuel injectors too..
« Last Edit: January 03, 2026, 10:45:41 PM by Tracksnblades1 »
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Offline PeWe

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Re: OMG an oil thread!!
« Reply #13 on: January 04, 2026, 01:34:45 AM »
More about zinc, phosphorus levels.
Flat tappet cam car engines have no wet clutch to keep out of slip.

So much of the recommendations about later car oils with other antifriction additives instead of high zinc levels can not be a choice for our old bikes.

Here a later article:
https://www.enginelabs.com/tech-stories/do-classic-cars-actually-need-high-zinc-oil-lake-speed-finds-out/

This oil guru on youtube is impossible to miss ;D

It seems to be possible to use lower zinc level for a period since zinc has covered the grinding metal parts?
« Last Edit: January 04, 2026, 01:40:06 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Tracksnblades1

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Re: OMG an oil thread!!
« Reply #14 on: January 04, 2026, 07:59:46 AM »
More about zinc, phosphorus levels.
Flat tappet cam car engines have no wet clutch to keep out of slip.

So much of the recommendations about later car oils with other antifriction additives instead of high zinc levels can not be a choice for our old bikes.

Here a later article:
https://www.enginelabs.com/tech-stories/do-classic-cars-actually-need-high-zinc-oil-lake-speed-finds-out/

This oil guru on youtube is impossible to miss ;D

It seems to be possible to use lower zinc level for a period since zinc has covered the grinding metal parts?

Yeh, that’s is a neat video.. It tests different oils,  “single” rings, and cylinder preparation wear in the absence of combustion by products and other real effects. Better than nothing but falls short of real time testing with the Big Bangs included..

** borrowed from others documents in the ASTM papers** cherry picked to reduce size G77 & G206 lab machines***

**Limited Real-World Simulation: The primary limitation is that these tests cannot replicate all conditions that exist in a fired engine simultaneously. Key factors missing or simplified include:
Combustion Products: The chemical effects of combustion gases, soot particles, and corrosive byproducts on the oil film and surfaces are not present.
Complex Dynamics: Full engine dynamics, such as piston secondary motion (tilting/slap), complex oil flow in the entire system, and varying component temperatures and pressures, are difficult to simulate perfectly on a bench rig.
Wear Distribution: While some advanced simulators can replicate the high wear at the top ring reversal point (TRRP) where the oil film is thinnest, the overall wear distribution throughout the cylinder bore can differ from a real engine.**

I like watching Lake Jr’s videos, very informative.  But keep in mind he’s a well sponsored and paid voice…? 🤔

And Rotella’s additive package and others are engineered and real world tested to complement each other.. Rotella’s calcium isn’t going to bleach the ZDDP off the lobes and lifters..

« Last Edit: January 04, 2026, 08:07:35 AM by Tracksnblades1 »
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Offline PeWe

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Re: OMG an oil thread!!
« Reply #15 on: January 04, 2026, 11:49:20 AM »


Yeh, that’s is a neat video.. It tests different oils,  “single” rings, and cylinder preparation wear in the absence of combustion by products and other real effects. Better than nothing but falls short of real time testing with the Big Bangs included..

  high wear at the top ring reversal point (TRRP) where the oil film is thinnest, the overall wear distribution throughout the cylinder bore can differ from a real engine.
.......

You seem to know a lot about oils and engines. How to make them run as good as it gets.

- How much zinc do you think is good for a modified CB750 type of engine?

Shimmed race springs make some rocker pressure against cam.
More valve lash might help oil to lube the cam too.

CycleX spring comment from their webpage
Stock valve spring installed height (1.455ish) spring pressures with these Kibblewhite ENV-008 springs are:
65lbs (no shims)
80lbs (.060 copper shims)
180lbs @ 375 lift (no shims)
200lbs @ 375 lift (.060 copper shims)


- When too much?

I guess 1800-2000ppm will be fine.

Ca: 2500ppm or more is easy to get when adding zinc additive. My K6 is on the high side right now ;D
« Last Edit: January 04, 2026, 12:30:54 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Tracksnblades1

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Re: OMG an oil thread!!
« Reply #16 on: January 04, 2026, 06:50:51 PM »


Yeh, that’s is a neat video.. It tests different oils,  “single” rings, and cylinder preparation wear in the absence of combustion by products and other real effects. Better than nothing but falls short of real time testing with the Big Bangs included..

  high wear at the top ring reversal point (TRRP) where the oil film is thinnest, the overall wear distribution throughout the cylinder bore can differ from a real engine.
.......

You seem to know a lot about oils and engines. How to make them run as good as it gets.

- How much zinc do you think is good for a modified CB750 type of engine?

Shimmed race springs make some rocker pressure against cam.
More valve lash might help oil to lube the cam too.

CycleX spring comment from their webpage
Stock valve spring installed height (1.455ish) spring pressures with these Kibblewhite ENV-008 springs are:
65lbs (no shims)
80lbs (.060 copper shims)
180lbs @ 375 lift (no shims)
200lbs @ 375 lift (.060 copper shims)


- When too much?

I guess 1800-2000ppm will be fine.

Ca: 2500ppm or more is easy to get when adding zinc additive. My K6 is on the high side right now ;D

Your every bit my equal PEWE.. Hell I been telling everyone since 87, Im just struggling to be average in this over achieving and complicated world.. But on a serious note about your guess.. I’m sure your Spectrol engineers had their game face on when they selected the additive package and ZDDP type for their HD oil offering.. Just thinking out loud, I’m guessing a super high detergent diesel oil like Rotella (with an anti foam additive that foams less than a non-additive non-detergent oil does) detergent’s will bleach the diesel type ZDDP off before a car/motorcycle oil will. Because it’s detergent and additives package has to deal with the combustion by products of a diesel and no wet clutch or belts..

I think you’ll choose as well as I can, Kemosabe..🎯
If your oil’s engineers selected it, I wouldn’t worry about it..
It had to pass a lot of scrutiny and cost control to make it in the bottle..
Hope you have a prosperous 2026..
Keep posting the good stuff..😇🎯
« Last Edit: January 04, 2026, 07:13:48 PM by Tracksnblades1 »
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Offline Tracksnblades1

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Re: OMG an oil thread!!
« Reply #17 on: January 04, 2026, 07:32:34 PM »
PEWE..

Check out the link in your spare time..It may get you started better than I can..
I don’t know how accurate the info is, but it should get you enough terminology you can research
it adequately through ASTM publishings..?

https://bobistheoilguy.com/forums/threads/primary-vs-secondary-zddp.295359/
« Last Edit: January 04, 2026, 07:34:33 PM by Tracksnblades1 »
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Offline PeWe

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Re: OMG an oil thread!!
« Reply #18 on: January 05, 2026, 02:45:50 AM »
Interesting link ;D
It covers ZDDP versions for all kind of oils, not only motor oils.


I copied the part below of a comment that also mentions the viscosity as a vital part. 
(The context is drag racing engines where they use thin oils to get more power

Moly on the other hand can be bad for the wet clutch. I have read somewhere that there are different types.  Not all bad for clutch.)


"If your priority is wear (especially cam & tappet wear) then your priority should be to use a heavy oil containing not a lot of shearable VII; something like a 'tight' 20W50 for example.

I used to get paid to sell additives and yes there's a lot you can do to counter wear with Zinc & Moly.
However, any formulator worth his salt will tell you that, in terms of anti-wear, there's no substitute for non-shearable high viscosity & the presence of some genuinely heavy base oil in the blend.

By all means slap in a goodly amount of Zn & Mo on top but go heavy! BTW, it won't matter what type of ZDDP you use at these kinds of temps as both will be well above their respective activation temperatures."
##
......

I have found interesting info on Porsche forums. The older models are aircooled and even the later (1980's) are specified to use 20W-50 as CB750.

https://rennlist.com/forums/928-forum/709018-oil-and-zinc-additive.html

Post #6 has nice info.

+ From post #37
 A long interesting post where the oil's film strenght is mentioned as a top priority.
(I have read this on other forums too. That's why I believe in V-Twin oils where the oil film has to work with a much longer stroke than a CB )
.....

Zinc is used as an extreme pressure, anti-wear additive. But, zinc “DOES NOT” build-up over time like some type of plating process. For those who have actually taken an engine apart that has been running high zinc oil, you know that you don’t find a build-up of zinc that looks like some sort of coating or sludge build-up. Zinc does NOT work that way. And zinc is not even a lubricant until heat and load are applied.
Zinc is only used when there is actual metal to metal contact in the engine. At that point zinc must react with the heat and load to create the sacrificial film that allows it to protect flat-tappet camshafts and other highly loaded engine parts.

Another thread:
Post #9 below
https://rennlist.com/forums/928-forum/1335715-bruce-and-sean-buchanan-buchanan-automotive-on-oil-tt-and-tbf.html

Post #16 below
https://rennlist.com/forums/944-turbo-and-turbo-s-forum/973124-oil-question-for-my-951-a-2.html

Post#5 below
https://rennlist.com/forums/968-forum/854352-968-engine-motor-oil.html


I have read another thread where the guy Buchanan/Jet951 had commented the viscocity importance and also found how quick it could degrade.
Castrol oil tested after not long use. Also how Porsche engines failed quickly due to low viscocity oils.

The Porsche engines are used as street cars plus track days.
Like a modified CB750 with occasional speeding rides. ;D

So, what have I learned now? ;D ,;D
- Viscosity  (not too low)
- Film strenght (V-Twin oils must have that)
- ZDDP that last. I'll follow the Spectro mineral example of 1900ppm level,  Redline ester synth only 100ppm more.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline PeWe

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Re: OMG an oil thread!!
« Reply #19 on: January 05, 2026, 03:06:36 AM »
One more!! ;D D

Post #8
https://rennlist.com/forums/944-turbo-and-turbo-s-forum/973124-oil-question-for-my-951-a-2.html

With a workshop oil pressure gauge connected on a last century Porsche & at 95 deg cel oil temp , every 5w-50 we have tested in the last 15+ years reads a lower oil pressure than a 20w-50 ( same brand )
........
A typical 5w-50 is really just a 5w-40 with more Vii's ( viscosity index improver's )
......
See post #24
More true observations and conclusions based on years (decades) of experience.
« Last Edit: January 05, 2026, 03:26:09 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Tracksnblades1

  • My Son was a collegiate competition Trap, Skeet, and sporting Clay
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Re: OMG an oil thread!!
« Reply #20 on: January 05, 2026, 06:01:38 PM »
PEWE:

Slow down. I’m struggling to keep up with just trying to be average..😜 You’ve piled the homework on me…🤕
I think we’re on the same page. you’ve picked out that high quality and proper viscosity base stocks don’t need a lot of help from additives..⭐️🎯

.I’ve been to several oil seminars and a few in house informational training sessions through the years.. I was very young at the first one. Not a lot has really changed. And as you pointed out, the high quality base stock is the key in the formulation. Poor base stocks are still poor regardless how good the selected additive packages help them..

 For instance the 5w-40, I was taught the ideal base stock would be a 25-30weight depending on where the oil would be sold and used. Then the appropriate additives would be added to make the chosen base stocks flow like a 5w oil when cold and likewise a viscosity modifier to make it act like a 40 weight when hot.. The worst example being the same 5w-40 formulated from a 5weight base stocks and then adding enough viscosity modifiers to make the 5weight act like a 40w when hot. And then sold to the end user for use at the equator….🤢

I’ll read up on the homework you’ve assigned..😁
But I’m thinking your already on the right page…

And to think Detroit Diesels (2 Strokes) knew the viscosity laws way back in the late 30’s..Still recommends Straight 40 weight High Detergent. Nothing else can protect them as good. They do allow straight 30 weight HD when temps permanently dip below freezing. Kinda like the same time frame Aviation engineers knew all about 4valves per cylinder, Nitrous Oxide, EGR (for detonation control only no epa then) superchargers, turbo chargers, water/methanol injection, fuels, octanes, oils, and on and on and on…. And we still argue about this SH*T instead of reading what been published, tried, and proven since the 30’s..

Seems like we’re all quilty of trying to reinvent the wheel when there’s several good ones already..😇
And these guys and gals do this everyday, week after week, month after month, and year after year for 30+ years,
 and we all know what’s best….😏
Age Quod Agis

Offline Tracksnblades1

  • My Son was a collegiate competition Trap, Skeet, and sporting Clay
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Re: OMG an oil thread!!
« Reply #21 on: January 05, 2026, 06:07:08 PM »
Ell PEWE, last I’ve read on air cooled Porsches, they was into the 60weight stuff…
Nearing top fuel stuff…?
Age Quod Agis

Offline Kelly E

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Re: OMG an oil thread!!
« Reply #22 on: January 05, 2026, 07:17:00 PM »
PEWE:

Slow down. I’m struggling to keep up with just trying to be average..😜 You’ve piled the homework on me…🤕
I think we’re on the same page. you’ve picked out that high quality and proper viscosity base stocks don’t need a lot of help from additives..⭐️🎯

.I’ve been to several oil seminars and a few in house informational training sessions through the years.. I was very young at the first one. Not a lot has really changed. And as you pointed out, the high quality base stock is the key in the formulation. Poor base stocks are still poor regardless how good the selected additive packages help them..

 For instance the 5w-40, I was taught the ideal base stock would be a 25-30weight depending on where the oil would be sold and used. Then the appropriate additives would be added to make the chosen base stocks flow like a 5w oil when cold and likewise a viscosity modifier to make it act like a 40 weight when hot.. The worst example being the same 5w-40 formulated from a 5weight base stocks and then adding enough viscosity modifiers to make the 5weight act like a 40w when hot. And then sold to the end user for use at the equator….🤢

I’ll read up on the homework you’ve assigned..😁
But I’m thinking your already on the right page…

And to think Detroit Diesels (2 Strokes) knew the viscosity laws way back in the late 30’s..Still recommends Straight 40 weight High Detergent. Nothing else can protect them as good. They do allow straight 30 weight HD when temps permanently dip below freezing. Kinda like the same time frame Aviation engineers knew all about 4valves per cylinder, Nitrous Oxide, EGR (for detonation control only no epa then) superchargers, turbo chargers, water/methanol injection, fuels, octanes, oils, and on and on and on…. And we still argue about this SH*T instead of reading what been published, tried, and proven since the 30’s..

Seems like we’re all quilty of trying to reinvent the wheel when there’s several good ones already..😇
And these guys and gals do this everyday, week after week, month after month, and year after year for 30+ years,
 and we all know what’s best….😏

I used to drive a Detroit Diesel super turbocharged(a turbo bolted to the top of the supercharger) 8V 92 in a 79' Freightliner conventional. That truck was badass. I had to do the oil changes on it. Get the hand truck and wheel out 9 gallons of Chevron Delo 400 15w/40 oil. It was the most fun truck I drove ever. 8)
Never Give Up - Never Surrender

The Rust Bros. Garage Collection
1974 Honda CB 550 K0                                            1971 MGB/GT
1975 Honda CB 400F Super Sport                          1972 MGB/GT
1977 Kawasaki KZ 1000 LTD                                   1985 GMC S15
1978 Kawasaki KL 250
1980 Suzuki GS 1100E
1983 Honda CB 1100F
1984 Honda VF 700S Sabre
1984 Honda VF 1000F Interceptor
1990 Moto Guzzi 1000 Le Mans
1994 Kawasaki Concours ZG 1000A9
2005 Harley Davidson Fat Boy

Offline scottly

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Re: OMG an oil thread!!
« Reply #23 on: January 05, 2026, 07:32:57 PM »
You were a truck driver Kelly?
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline Kelly E

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Re: OMG an oil thread!!
« Reply #24 on: January 05, 2026, 07:53:13 PM »
You were a truck driver Kelly?

Yep, one of several careers I had. Truck driver, mechanic, cabinet maker, remodel carpenter, electromechanical assembly, cook and Mr Mom. I probably missed a couple.
« Last Edit: January 05, 2026, 07:55:14 PM by Kelly E »
Never Give Up - Never Surrender

The Rust Bros. Garage Collection
1974 Honda CB 550 K0                                            1971 MGB/GT
1975 Honda CB 400F Super Sport                          1972 MGB/GT
1977 Kawasaki KZ 1000 LTD                                   1985 GMC S15
1978 Kawasaki KL 250
1980 Suzuki GS 1100E
1983 Honda CB 1100F
1984 Honda VF 700S Sabre
1984 Honda VF 1000F Interceptor
1990 Moto Guzzi 1000 Le Mans
1994 Kawasaki Concours ZG 1000A9
2005 Harley Davidson Fat Boy