Follower scar oil tests (2018)

comnoz · Dec 10, 2019

concours said:
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I understand that logic.
Yet, if sub filter media size (<25 micron) stuff accumulates in the crank, then dislodges in the form of bigger chunks....

You might be right.

I know a few years back when I switched from years of using VR1 in my 68 Mercedes to RP the exhaust would occasionally lay down a smoke screen for a block or two and then clear up.

It did that several times during the first few weeks and then it cleared up and has not done it since. I figured the RP must have loosened up something.

concours · Dec 10, 2019

comnoz · Dec 10, 2019

concours said:
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I have to wonder if that may be stuff from the oil tank more than the crankshaft. ??
I have taken cranks apart that had been using synthetic oil and seen a normal looking build-up.

concours · Dec 10, 2019

Anything is possible. I had thoroughly cleaned the tank a couple years before. Prior to that, anyones guess.
That said, even sludge in the tank, settles out of “filtered oil”, barring some lug dumping in dirty oil.

jseng1 · Dec 10, 2019

motorson said:
I'm the guy who sent in the Amsoil for testing. I was very disappointed that my precious 15w-50 Amsoil Racing Oil did not get top honors....

Amsoil was one of the 1st synthetics and I used it many years with good results (mixed with vavoline racing oil for economics). These were good oils for their time but now they've been surpassed. Likewise - someday the best oils listed in this forum will be surpassed.

Steves · Dec 10, 2019

concours said:
Anything is possible. I had thoroughly cleaned the tank a couple years before. Prior to that, anyones guess.
That said, even sludge in the tank, settles out of “filtered oil”, barring some lug dumping in dirty oil.

I got to say I thoroughly clean my oil tank every oil change. Your oil looks emulsified, water in the bottom of your oil tank? It’s difficult to tell from the photos of course.

kommando · Dec 10, 2019

I note the overlay playing has disappeared first by the oil hole positioned where you want maximum bearing material, ie the combustion gives the rod down onto the journal and the oil film thickness is at its thinnest Test of the damage is from dirt and debris in the oil. I fit plain shells on the top, hole gets blocked but you get bearing material where you want it.

comnoz · Dec 10, 2019

kommando said:
I note the overlay playing has disappeared first by the oil hole positioned where you want maximum bearing material, ie the combustion gives the rod down onto the journal and the oil film thickness is at its thinnest Test of the damage is from dirt and debris in the oil. I fit plain shells on the top, hole gets blocked but you get bearing material where you want it.

Actually the highest pressure is on the lower shell. The highest pressure seen on the rod shell is as the piston passes TDC on the exhaust stroke at high rpm. Combustion pressure is lower than inertia force unless you are suffering from detonation.
Wear seen on the upper shell is normally from detonation or lugging an engine.
Lugging causes wear because the cylinder pressure is high yet the rpm is too low to create a thick oil wedge. So only when lugging would the oil film be thinnest on the top shell.

concours · Dec 10, 2019

Steves said:
I got to say I thoroughly clean my oil tank every oil change. Your oil looks emulsified, water in the bottom of your oil tank? It’s difficult to tell from the photos of course.

Nope. The oil was not emulsified. That is the lighting. That's Amsoil Dominator 60 weight racing oil, changed every 2500 miles. And the bike is RIDDEN, not parade putted...

gortnipper · Dec 10, 2019

Fast Eddie said:
At first I thought your maths was suspect, after all £240 / 5...?

But then I concluded you are probably referring to it being 5 US gallons, which is just under 4.2 imperial gallons.

If the Royal Purple drum is indeed US gallons, you’re closer to the mark than I was at price per imperial gallon.

I have one of those in my garage. US gallons, mate. Sorry.

worntorn · Dec 10, 2019

Imperial gallons only exist in our minds these days. They are great for calculating feel-good fuel economy numbers and that's about it.
I recently found a very old Imperial Gallon can of paint at the back of the paint shelf.
The thing is huge.
Cheap too, the faded price tag reads $7.98.
Gotta be 40 years old and still liquid!

Glen

comnoz · Dec 10, 2019

concours said:
Nope. The oil was not emulsified. That is the lighting. That's Amsoil Dominator 60 weight racing oil, changed every 2500 miles. And the bike is RIDDEN, not parade putted...

Yeah, there is no question your damage is from trash going through the bearing.

Nortoniggy · Dec 11, 2019

Just to play devil's advocate slightly. I have read that transmission oil can do well in scar type tests but I don't think anyone would want to use it as engine oil.

Jim, have you ever tried transmission oil in your test? It might be interesting.

Ian

kommando · Dec 11, 2019

comnoz said:
Actually the highest pressure is on the lower shell.

The shell bearing manufacturers disagree.

Clevite

Typically, a used bearing should exhibit signs of use over 2/3 to 3/4 of its ID surface in the most heavily loaded half (lower main and upper rod halves).

https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/cl77-1-205r.pdf

And money talks, sputter bearings are a very high performance bearing but typically 3 or 4 times the price of a normal shell bearing, so to keep the costs down they are only fitted in the high load positions ie rod upper and main lower halves.

Fitting instructions Sputter bearings are normally only installed on the pressure-loaded side of conrod bearings and main bearings (blue bearing shell). The less loaded anti-thrustside is equipped with conventional two or three-component bearings (yellow bearing shell). If the bearing shells are mixed up during installation, damage to the bearings occurs even after a short running time – as we know from experience.

https://www.techtips.ie/Pierburg/sputter-bearings--design-and--fitting-instructions.pdf

Hortons Norton · Dec 11, 2019

jbruney said:
Most likely not, but as with the rest of us he is in shock that his lovely old machines(children) have not been receiving the 'very best foods' to maintain their health..... I've always had visions of Castrol GTX 20w50 being depicted in the stained glass windows in churches myself. It was afterall the recommended oil when my Norton was a baby.

That was my oil of choice back in the day also, my truck and bikes and also the wife's car. Auto shop teacher said the best oil is clean oil, synthetic oil was just starting to show up and he said the real benefit was that you could leave it in there much longer. If I am not mistaken he said you could leave it in there for something like 20,000 miles?? I have since switched to the Castrol Edge for the truck and wife's car and Amsoil V-twin for the bikes. Will be looking for the Bel Ray this next Spring.

comnoz · Dec 11, 2019

kommando said:
The shell bearing manufacturers disagree.

Clevite

Typically, a used bearing should exhibit signs of use over 2/3 to 3/4 of its ID surface in the most heavily loaded half (lower main and upper rod halves).

https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/cl77-1-205r.pdf

And money talks, sputter bearings are a very high performance bearing but typically 3 or 4 times the price of a normal shell bearing, so to keep the costs down they are only fitted in the high load positions ie rod upper and main lower halves.

Fitting instructions Sputter bearings are normally only installed on the pressure-loaded side of conrod bearings and main bearings (blue bearing shell). The less loaded anti-thrustside is equipped with conventional two or three-component bearings (yellow bearing shell). If the bearing shells are mixed up during installation, damage to the bearings occurs even after a short running time – as we know from experience.

https://www.techtips.ie/Pierburg/sputter-bearings--design-and--fitting-instructions.pdf

Most wear occures on the top shell because most engines spend more time at lower and middle engine speeds, but peak load will be from reversing the piston at high speed. [particularly on a long stroke engine with high piston speeds]

This does not apply to diesel engines where sputter bearings are used. [or lower speed supercharged engines]

comnoz · Dec 11, 2019

Nortoniggy said:
Just to play devil's advocate slightly. I have read that transmission oil can do well in scar type tests but I don't think anyone would want to use it as engine oil.

Jim, have you ever tried transmission oil in your test? It might be interesting.

Ian

I tried both conventional and synthetic ATF. The synthetic was better than the conventional but neither one held more than a small fraction of the load that motor oil did. With low ZDDP it worked about like Aeroshell.

A "classic" scar tester would likely give much different results.

Kvinnhering · Dec 11, 2019

comnoz said:
I tried both conventional and synthetic ATF. The synthetic was better than the conventional but neither one held more than a small fraction of the load that motor oil did. With low ZDDP it worked about like Aeroshell.

A "classic" scar tester would likely give much different results.

We know that you prefer synthetic AFT in the ACM gearbox. If the ATF oil has weaker oil film than Bel Ray engine oil. Will BelRay engine oil be a better alternative in the gearbox?

jseng1 · Dec 11, 2019

You also see more wear on the top side of the piston pin boss - because of down ward pressure on the pin. The small end of the stock alum rods start to show cracks radiating downward - especially evident in 1000cc motors - again from downward pressure. But I remember Ron Wood telling me the highest stress happens at the end of the straight when shutting off the throttle at peak RPM - when the piston is trying to exit through the head into the stratosphere.

comnoz · Dec 11, 2019

Kvinnhering said:
We know that you prefer synthetic AFT in the ACM gearbox. If the ATF oil has weaker oil film than Bel Ray engine oil. Will BelRay engine oil be a better alternative in the gearbox?

They have different chemistry to deal with a load, so I can't say for sure.

Part of the load handling ability of motor oil is the ability to lay down a hard film on the metal from the ZDDP. That happens at high temps in an engine [and in my tester] but I'm not so sure it would do the same in a transmission.

Transmission lubes generally rely on other additives for extreme pressure. Sulfur being one of the older additives.