How thin the oil?

Postby 1up3down » Sun May 27, 2012 7:09 pm
So Steve,

What do you suppose is the reason why the chief engineers at Norton, Triumph, BSA tested and stated was the necessary and correct weight oil for their air cooled twins, both street and all out race bikes?

They really knew as you do that hot thing oil is really better but just wanted to keep it a secret forever?

ATF was available way back when they built AMC gearboxes, why do you suppose they did NOT recommend it?


And why would you assume that you know more than those engineers did?

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What makes ya think I assume anything, even the ancient and accepted wisdom's, so hobby is poking and proding in case there's any exceptions to the rules. Golden era designers had to work with what was available and what the bean counters allowed them. But this is today so in special cases I wonder what might be gained vs what might be lost. I am scratching at every straw for a power planting show downs.

1up3down said:

ATF was available way back when they built AMC gearboxes, why do you suppose they did NOT recommend it?

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Probably because AMC knew what they were doing. Sleeve gear bushings are wear items and replaceable whereas gear teeth should really be preserved with extreme pressure lubrication.

Unless you are going to run heat transfer oil or transformer oil in your engine, for all intents and purposes there is little difference between the various engine oil weights in their ability to remove heat. It is a matter of mass flow per unit time.

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Ok ugh, I'm aware of that factoid, as best counter point I can't ignore, but it also mostly nullifies your counter point, as implies not that much difference in heated lube layers surfing around either. Maybe down to 30 'wt' ? I'm not trying to win any controversy here just picking brains not to seize right up w/o being too conservative. Only extra heat transfer benefit I would expect would be out of the thin spinning spaces not to over all engine temps. I ave a few seasonal temperature range and usage vs oil viscosity range charts to consult. But if oil gauge don't tell the whole story how can we tell what limits oil grade before too late?

Rod ends are the weak link. Will have to find out Peel's rod clearance to plug into the new data points above but also look in regularly till some shell wear signs then renew and bump oil up thicker. The clearances increase with temperature is the biggest oil grade issue in air cooled clunkers. Btw technically the W stands for winter grade not weight but whose nick picking : ) If I use oil weight term its just same slang even hi end vendors use.

1up3down said:

So Steve,

What do you suppose is the reason why the chief engineers at Norton, Triumph, BSA tested and stated was the necessary and correct weight oil for their air cooled twins, both street and all out race bikes?

They really knew as you do that hot thing oil is really better but just wanted to keep it a secret forever?

ATF was available way back when they built AMC gearboxes, why do you suppose they did NOT recommend it?


And why would you assume that you know more than those engineers did?

Just naturally smarter I reckon?

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There has been a lot of R&D flowing under the bridge the past 30-40 years... so I reckon a modern oil will out perform the best of the golden era.

With Race engines on the dyno, the hotter the oil - the more power they produced.. just that at 130+°C we started to worry about flash point and engine damage.
With rally cars it was pretty normal to run ATF or even Neo-Oil (ridiculously expensive) but gave faster gear changes and less wear.
Not sure if this would be relevant to our Nortons though....

Unless some nutter is willing to try it out so we can all benefit from his quests, revalations and mistakes.

Is it time to play the "Slick 50 card" yet.....?

Slick 50 and similar additives are a godsend on race cars with occasional oil starvation problems... I use that X1-R stuff in ALL of my engines (except the mower) I have a good supplier/sponsor in the retail lubrication trade.

Finally... Consider that Norton got the Commando frames outsourced to Italy to save a few shillings... so naturally the cheapest oils that would do the job would have been used OEM.

Go for it Hobot and share your findings....

Sorry for the long Post! ;-)

Mike

hobot said:

but whose nick picking : )

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I am. It is "nit picking".

ludwig said:

If those engineers knew so well , why did their products fell apart short time after leaving the showroom , and went their companies belly up long ago ?

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Falling apart after leaving the show room? Ok

Companies going belly up. Well this assertion comes up now and then. I think it takes more than one to tango and there is a well documented history of the British motorcycle industry and its collapse. I seem to recall a management influence somewhere.

I doubt there were any big economies between using one type of oil over another on intial fill of a gear box. They could have used and recommended watch oil for the engine and gear box but the power gains on a 45 hp motorcycle would have been minimal and durability would have been a manufacturers nightmare. Power gains could have been achieved in a more efficient manner.

I say through intuition and logic it is safe to say they got it reasonably well for the bikes intended use.

LOL! Yoose guys are great mental teasers and testers for me, leaves me chuckling this Hot am as well spelling nit picking properly.

Conker, your feedback is the most thought provoking pleasing so far. I've got some Lucas oil treatment on hand I dose tractor and mower and PU with but not yet a Norton, hm. Will look into the Slick 50 and related products but growing up we knew a STP sticker or two was worth a few extra ponies and mph in our minds : ) There are a couple of heat and clearance tolerance things not available long ago, cryogentic tempering and dry friction coatings, both of which past and present Peel had-has. Newest mileage & pollution device to hit the news is an exhaust to oil heat exchanger that heats the oil to 300'F to lower friction loses and plumbed to avoid the oil cooling off in the sump/oil pan. Much as if flys against the feelings of experts hot oil, short of its flash point, is better for everything in engines, that do not depend on oil for over all cooling. Its been calculated that oil is worth about 6% of Norton engine cooling as just not designed to use oil to cool.

Ludwig i think you nailed the state of affairs that made thick oil the better option, ie: keeping some inside mostly. As to your view on ATF, I think you are behind the times and ain't pressed your Commando to learn my drive train lesions. Its not the cog teeth wear, which in Nortons I have never heard a case of them wearing out, but Peel has torn teeth off snicking 3rd instead of 2nd to chase back up to a Ducci Monster I'd waited and waited behind a slow car - so they could see what they couldn't catch until a long open I allowed it, they instantly freaked at sight of a vintage clunker to pull a wheelie limited sprint w/o a fair neck and neck start. Our cogs are up to the wear and tear likely even w/o lube, but their alignment is at grave risk d/t no lube able to get into the sleeve bushes when not in 4th or sitting still. When these bushes don't get cooling lube flow they turn surfaces into ceramic grit, get sloppy then wobble main shaft and clutch and cog teeth alignment and shifter dog contact, which risks teeth loss and primary belt toss. I'm sticking with what rally car and drag racers do, like Mike conkers.

I'm hankering to wipe off sneers again and put Norton name in the news running a vintage like Commando against liter+ size digi brained limited balloon tire squirmy ringing rigid elites every where but bee line land speed contests. Ms Peel better have more power and torque to mass ratio than these to stand a snowballs chance in hell, in the opens already know Peel's got em licked in any leaning power planting. No such thing as wobble or weave in Peel, believe it or not, I know. That's why I'm so brazen I ain't speculating on handling leaned on power the rest of ya, sport bikes included can't even relate too. Just need mo power to go in quicker and leave faster. So for special events - how thin can I get away with?
Response to throttle means a whole hell of a lot in this type shoot out.

Btw Peel will run one quart low from factory capacity which is more efficient to get to temp and worth most a hp in mass and more than a hp with the tank gone too. It would be a kicker if Peel has too little oil for the cooling area.
I am learning all your cautions of too thin oil are correct for long service in real life, but even there 20-50 may be over kill in the new age with nit picking expert constructed new engines.

Here's some more thin oil mental bench racing to contemplate.
http://racingarticles.com/article_racing-72.html

9. OIL - As much as I don't want to believe it, there is hidden power in motor oil. When going from SAE 20w-50, to synthetic 30, and then to synthetic 20, 2-5 average points in power were found. Thin oil makes more power than thick; synthetic oil makes more power than regular. The gains aren't huge but they do exist and they are clearly seen on the dyno runs.

Too much oil pressure reduces power. It takes more energy to turn the reciprocating assembly as it slings off excess amounts of oil. Too much pressure can prematurely wear the cam and distributor gears. If you have an engine that won't hold timing, pull the distributor and look at the gear. If the gear is worn, the cause may be excessive oil pressure or an improperly clearances distributor gear and shaft. A good rule of thumb is Terrill's 10lbs of pressure for every 100hp.

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More entertaining data points.
http://www.carcraft.com/techarticles/sy ... index.html

But claims and talk are cheap, so Car Craft had Westech Performance run some of the new Mobil 1 0W-30 in Ford's prototype 392 small-block stroker crate engine. The Mobil 1 was compared to the generic (and recommended for this engine) 20W-50 factory-fill conventional oil, as well as 10W-30 conventional oil. All tests began with the oil temperature stabilized at 210 degrees F. The engine ran from 3,300-6,200 rpm, and several runs were made for each oil to ensure repeatability.

In terms of peak numbers, we found that the engine gained nearly 7 hp with the thinner conventional oil, and was up nearly 10 hp with the synthetic. No peak torque gains were observed by changing from 20W-50 to 10W-30 conventional; however, the synthetic was up 15 lb-ft of torque at the peak. Looking at average numbers helps explain where the gains occurred--both the thinner conventional and synthetic oils broadened the torque and power bands overall, but the thin Mobil 1 showed the greatest improvement under 4,700 rpm, indicating that the thinner oil provides less initial drag for the engine to overcome.

However, thinner oil also translates to lower oil pressure: The 0W-30 oil developed 10 psi less than the baseline 20W-50. Only 46 psi was on tap at 6,200 rpm--kind of shaky as most gearheads like to see at least 10 psi per 1,000 rpm. Still, the engine ran OK, and the bearings looked fine on teardown, seemingly verifying synthetic manufacturers' claims that their products' greater shear strength more than makes up for lower viscosity. Is 10 hp and 15 lb-ft worth paying two to four times more for a quart of oil? Or the potential for extended engine life? You be the judge.

Read more: http://www.carcraft.com/techarticles/sy ... z1wBLiLQbg

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And last but not least which additive product that claims significant temperature reduces would say Steven McQueen use?

There has been a lot of R&D flowing under the bridge the past 30-40 years... so I reckon a modern oil will out perform the best of the golden era.

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You have to be careful and understand these old motors came from a leaded gas and non catalytic era. Zinc additive was part of the makeup of the oil. Now with Catalytic mufflers clogging up and EPA restrictions the oil formulas changed and reflect that. You need to find oil that will run with our old solid lifter days gone by super sport bikes.
My two cents,
CNN

Do note that the ZADP only forms its wimpy thin one use protection layer if the oil can get up near water boiling range. This should occur in the spinning surfaces even if total oil temp don't, but still need a good oil heating before shut down cool down.

Improvements of 7 to 10 hp gain for a 392 cubic inch engine corresponds to a 0.8 to 1.1 hp gain for our Commandos; probably less since the 392 is 100% plain bearing whereas the Norton is 50% plain bearing. I am guessing probably another 0.5 to 1.0 hp gain for using a lower viscocity gear box oil.

As for lower viscosity oil to gain more power and running less oil for quicker warm up, there are more robust and reliable ways to gain more power.

Seen enough pitted gear teeth to know better about gearbox lubrication on a Norton. I would not recommend ATF but it will certainly be an interesting experiment. ATF would probably be plenty adequate for land speed records where you might be struggling for that extra hp or two.

If the sleeve bushings are the new boogeyman of the universe then there are probably better ways to get lubrication to the sleeve bearing. I would recommend using Castrol fully synthetic gear oil 75W90; this is the oil recommended for the TTIndustries gear boxes.

Considering the hobot is putting a blower on the bike it will be interesting to see what happens. The gains in HP with thinner oils is a fart in a windstorm once you go with a blower where heat and extreme pressures are your new enemy. First thing to go will be the gear box. Just saying

Good valid points about vintage fuels and oils....

Just want to make it clear that on the rally cars we used ATF in the gearboxes of, they ran sycromeshed gears, we drilled the sycros to allow more oil in/out of the syncro surfaces and this combined with ATF sharpened up the gear changes.
On dog engagement gearboxes we used Everything from 75w gear oil, ATF and on cars (Toyota Celica ST165 Works rally cars) with active/reactive centre diffs NEO-oil.

Mike

Dances thanx for the ballpark figures and rationale for them. It matches my guessimate. Not much to count on. My main ponder was heat removal out thin shear zones with more flow, but the bantering / searching implies 40 w and thicker oils apparently lower friction better to cool whole engine significantly, though too thick oil ring don't scrap off so can consumes more oil than thinner. Peels blower heat definitely is on my mine and blown applications all seem to use normal to a bit extra thick oil. So I'll try some hi end synthetic in straight 40 or 50 and maybe 30 for a dyno run series : )

Dance's fart in a tornado analogy is realistic assessment I can't argue against, may need thicker oil to damper the response to hook up.

I'm not first to put ATF in AMC gear boxes, double checked a decade ago, so we just differ in which parts we use up most, you the gear faces me the bush shear spaces. Next time inside really take a good look at where the sleeve bushes live in relation to oil level and spin them to investigate the hydrodynamics of expelling fluid way better than letting it in.

Concur's brings up my only concept of partial solution - drill holes and a tangent so some inward pumping action that may over come the centrifugal force out, a good thing in the crank shaft journals but not tranny. If you have better insights to follow up on your lube fed suggestion I'm open minded stumped. Of course there are hi end thin tranny lubes too.