Engine oil

[Coolbreeze]

I hate to open this oily can of worms, but I have concluded there may be an underappreciated reason to use high zinc, high viscosity oil. I start the year using 20-50 Valvoline VR1 on my '56 KHK. As it needs more oil and the year gets warmer, I add straight 50 weight VR1. Others have suggested that a lighter weight oil will get to the bearings and wearing surfaces more quickly on startup, but I have elected to use the high grade, thicker oil.
Last weekend, I saw a particular advantage to using the 50 W VR1. I rode to a wedding in a town ~45 miles away at interstate speeds. When I arrived, I discovered the oil tank was empty, the cap was askew, and the right side of the KHK was coated in sticky engine oil! After the ceremony, we filled the tank with 20-50 VR1 (straight 50 weight was not available), and I rode it ~45 miles back home. The engine seemed to run fine with no additional noise.
I have yet to change the oil and to filter the drained oil in search of metal particles, but I may have dodged the bullet on this matter. If the bike survives, it will be in large part because the sticky oil with zinc stayed on the bearings long enough to keep them protected even though oil was no longer being pumped to them. I am tempted to scope the cylinders to see if there is any scuffing.
It may be that this oil saved the bike from ruin. Now, we need to protect the bike from an owner that fails to fasten an oil cap properly! 56 KHK by woods with pump in background.JPG

[Lyle Manheimer]

Oil can be a ticky subject. With that being said, I dislike having a different oil for every old machine I own. Ten or fifteen years ago I started using VR-1 20-50 in my 1964 FL with no problems. Then had my 1965 BMW R50/2 rebuilt and thought why not. I had talked to Vech about it and he recomended VR1 10-40 but said since all of my riding was done in summer 20-50 was fine. I run it in my BMW, 64 Pan, 78 Lowrider and my stock 49 Ford flathead with filter, never a problem. The exception being an old brain washed Harley Tech telling me " That's car oil you can't run that in a motorcycle you have to run a special formulated Harley oil in that Pan because it has a special additive package for air cooled engines."

[chuckthebeatertruck]

the fact it’s an all roller bearing motor saved it.

[otis71]

Does anyone know if a heavier 50 or 60 weight non detergent oil is available for bikes not running oil filters?

[bernhardt]

Here's my .02 on oil. Brad Penn makes a 50wt non detergent oil. I used it a couple times as a break-in oil, but it creates too much muck in the oil tank and elsewhere. I use harley detergent 50wt on everything. I was convinced by a friend who has over 100k miles on his '37 knuck, and he doesn't run a filter. In the fall, when the riding season ends, I go for a ride and then right away drain the hot oil. I drain the gas too. When you start up in the spring, it won't have sumped, if that's a problem. You will have fresh oil, and no spoiled gas.

[chuckthebeatertruck]

You don't need to run different oil because you do or do not have an oil filter.

Detergent oil appeared before filters were common -- not because of filters as is often touted. Second; you'd be surprised how many older vehicles went on bypass very quickly in the filter system. As a result, a lot of cars (and motorbikes) with filters didn't actually filter all the time. And, pretty much every on-road vehicle produced in north america after 1952ish was shipped with detergent oil in the sump regardless of filter presence.

The truth is that non-detergent oil, as bernhardt points out, dirties a motor very, very fast. The particles that "drop out of solution" are mostly carbon - usually from rich running and oil burning. It becomes pure carbon sludge that gets harder and almost like a plastic film with heat. When you split the cases you will spend days cleaning and scrubbing all that crap out. I've literally had to drill crank pins to clean it out. That same motor if run on detergent oil will be clean as a whistle. Neither will show more wear than the other provided everything else is the same and both are maintained well.

A good air filter is the best defense against particles in your oil.

[chuckthebeatertruck]

When I wrote earlier that the motor survived because it is a roller motor -- I left out some really important stuff. I attached photos with captions from a 59XLH I ran without oil to illustrate.

The fun part about SV motors is that we don't have to worry about oiling the top end nor top end oil draining down to oil pistons. Instead, when Harley moved from the U series to the K series - -they seriously upped the oil volume to cool pistons and allow for high compression out of a flatty. 7:1 in a flatty running 5500 rpm produces some serious heat!

So, HD upped the pump volume from circa 4 oz a minute at circa 3000rpm with the U series to just over 32 oz a minute at circa 3000 rpm for the K model (and later sportster). That's a massive increase in oiling and the K is just a bit bigger one-half the displacement of an ULH (45 inches for a K; 55 for a KH or KHK vs 74 or 80 inches for a U). That massive increase in oil is a big part of the reason a K motor can go a lot further between top end services than earlier flatheads produced by Harley.

In either case, the bottom end of the motor often survives when run out of oil. Read that again -- whether 4 oz or 32 oz, the BEARINGS do fine. This is because roller and ball bearings prefer to be lubed by oil mist, not an oil film. The rollers will handle it; but your bearing cages may not. This primarily affects the Big End Female Rod in k/kh/khk/sporty.

And I speak from experience here. If you run a sporty or K out of oil; there is generally 3-6 ounces still in the bottom end. About 2-2.5 ounces will stay in the cases and is flung around. That same volume of oil is good for about 50-75 miles of running before seizure starts to be a possibility. My personal record is just over 50 miles with no oil at all making it to the bottom end. Pictures of the motor internals on disassembly attached.

So, what does this have to do with the statement by the OP about oil weight?

The concept of oil weight saving a motor under these circumstances denies the reality of what is happening in the motor. Oil weight matters if you can control the ultimate temperature the oil will equalize at with the motor. With a total loss system; we drip in just enough oil to keep the temperature under control. But without any type of oil addition or circulation; the temperature in the bottom end spikes. That instantly pushes the bottom end well past 275 degrees and starts to vaporize the oil. The oil vapor helps keep the bearings going; but does nothing for the ring friction. So the motor starts getting hotter and hotter. The oil left will reach equilibrium with these extreme temperatures as there is no way for it to shed heat. This means the oil left will go way, way higher than when in an oil tank -- often by at least 100 degrees (ie 180 in the tank; 280 in the cases).

Under these circumstances, both a mono and a multiweight oil will be nowhere near their viscosity rating. Both will be thinner than water and neither will "protect" as they are starting to flash at those temperatures regardless of viscosity.

If you only rode say 3 or 5 miles with no oil then yes, a "thick" clingy oil will "last" a bit longer. But after 10 miles . . .let alone 40 to 50 miles; nope the viscosity of what's left in the cases won't matter a hoot.

Again, I am not speaking from theory. I've had this happen on a motor substantially similar to the KHK -- and the pictures are attached.

[chuckthebeatertruck]

Oh, and you won't know if your bike is "saved" by a bore scope. It likely won't show anything more than normal streaking.

You'll know your bike is saved if you can get through a tank of gas (200 miles) with no increase in smoking, no increase in oil consumption, and no new rhythmic tapping from the bottom end. When the cages break and the pin starts getting eaten; those particles embed in the piston skirts and cause the smoking. Clear black spots of death in the skirts. The rhythmic tapping sounds just like a loose valve; but it never goes away with rpm. Either situation suggests you "got home" but you didn't escape. You have to take the WHOLE thing apart, right down to splitting the wheels and removing the crank pin to clean it out and fix it all if this is the situation. Bits of junk will be everywhere and waiting to bite you otherwise.

Generally, you'll feel you are golden for the first 50 miles . . .then you notice the bike feels a bit off . . . then the smoking when revving it up starts . . .then it start smoking on engine braking . . . then you hear the tapping start.

[T. Cotten]

My father told me, Folks,...

Never put detergent oil in a sludgy motor.

That's probably why they make non-detergents.

....Cotten

[DEEBS47Chief1991]

Non detergent oil lets gravity make the dirt "fall" and eventually collect in the sump to be cleaned out periodically.

Detergent oil suspends dirt and is then passed through a filter were it is held. Remove it and install a clean one. This is clearly the superior system.

I always run Harley air cooled EVO oil 50W in my Indian with good results. I have a hidden filter in the oil tank to remove particles. Originally it had no filter so it ran non detergent back in 47. Had to clean out the sump periodically and flush the oil tank.

Never run non detergent oil in a system that has an oil filter.

motoroel-sae50-002-9578.jpg

[DEEBS47Chief1991]

Non detergent oil.jpg

[T. Cotten]

Non detergent oil lets gravity make the dirt "fall" and eventually collect in the sump to be cleaned out periodically.

Good trick; Split the cases (on a K!), DEEBS?

Detergent oil suspends dirt and is then passed through a filter were it is held. Remove it and install a clean one. This is clearly the superior system.

Never run non detergent oil in a system that has an oil filter.

In a perfect world of fresh rebuilds,.. no doubt, DEEBS!

But what if, just by luck, you've found a "barn-find", and you know its a veteran?

You agree in theory with my father, just not in scope and practice.

....Cotten
PS: Your warning against non-detergents with a filter is exciting;
Will they plug up and explode, or are they just defeated by the settling-out elsewhere?

Thanks in advance,

[DEEBS47Chief1991]

"Good trick; Split the cases (on a K!), DEEBS?"

Unfortunately, yes. I had a 69 BSA lightning with a sludge trap (inside the crank pin of all places) that was just about full with a tiny orifice left to pass lubricant. If I continued to operate the engine like that it would have eventually self destructed. And yes, I agree with your father that if you used detergent oil (or Rislone) in that motor, the sludge could have released and clogged up the lubrication system and that would have been a serious issue.

"PS: Your warning against non-detergents with a filter is exciting;
Will they plug up and explode, or are they just defeated by the settling-out elsewhere?"

Sure, exciting. It's not a good idea to use non-detergent oil in a system that has a filter element to pick up suspended particles. Also, detergent oil is common, in stock on any shelf, and relatively cheap.

Why would anyone run non-detergent oil in a filter element system? To avoid sludge breaking away and ruining the motor? If your motor is that dirty, you should get it up on the bench and manually clean it out because it needs serious maintenance (like my BSA).


PS: I love oil threads. We just don't get to chat like this very often and I miss it.

ezgif-6746f7067a6ea5.jpg DSCN1864.JPG Sludge trap.jpg Sludge trap 2.jpg

[DEEBS47Chief1991]

Oh wait, this was about zinc....

[otis71]

So back to non detergent oil. I’ve been running Harley detergent oil for lack of a lot of availability of anything else but was under the impression that without a filter using non detergent oil the sludge accumulates in the oil tank and flushing the oil tank (and sump if equipped with a drain) with every oil change keeps things in check and the sludge doesn’t recirculate as much.