I hear that Power Wagons require Non Detergent
type motor oil. I understand that detergent
is a substance put into most modern motor
oil as a sludge preventor. My question:
why wouldn't you want to use detergent motor
oil in an old engine like a 230?
With a "full-flow" filter, such as a typical spin-on
filter, what many people don't know is that there
is a pressure-relief valve built into the filter.
This valve lets oil bypass the filter at times
of HIGH pressure at the inlet side of the filter,
rather than low. For example, when you first start
an engine on a cold morning and the oil is thicker,
the spin-on filter's bypass valve may open up
for a while to allow unfiltered oil to be circulated
directly to the bearings, because the thick oil
may not be able to pass easily or quickly enough
through the filter element. As with the 230's
setup, this helps get oil to the bearings faster
with a cold engine. Also, as the filter becomes
dirtier, the bypass valve in the spin-on filter
allows the unfiltered oil to skip the clogged
element and pass directly to the bearings. When
the filter is only partially dirty, the oil may
only be partially bypassed at higher engine speeds
or when the oil is colder. As the filter becomes
ged, almost all of it will eventually be bypassed. Hence, one should keep a very clean filter in the vehicle at all times...for either type of system.
I would say that with the 230's system, you may be circulating a larger percentage of unfiltered oil than you would with a spin-on setup, but I don't have figures to support that.
In any case, however, both systems still allow a significant amount of unfiltered oil to pass through your bearings.
There is one other consideration. A problem with non-detergent oil is that when chunks of sludge do come loose...and they will...bigger chunks are pumped through your oiling system, possibly scoring a bearing or other surface. With detergent oil, the sludge particles tend to remain very small and are held in suspension, so that they tend to pass through more or less benignly, to be trapped by the filter on the current (or subsequent) passes through the system.
My own approach would be to start with a clean engine, with no significant sludge deposits, and stick with detergent oil. If there is a significant amount of sludge buildup in your engine, you might want clean it out before switching, or perhaps just stay with the non-detergent oil until you do an overhaul.
Another interesting approach with a spin-on filter setup is to install dual filters to reduce flow resistance and keep the bypass valves from opening as often, ensuring a higher percentage of filtered oil to be circulated. This approach may have some merit for the 230 as well, since a freer-flowing filter setup would help keep the differential pressure higher across the bypass valve, allowing it to divert oil through the filter for a higher percentage of the time, especially as the filters begin to get a bit dirty.
One last comment: Even with a non-detergent oil,
sludge deposits can be kept to a minimum if you
use a proper thermostat in your engine to keep
its operating temperature up. This prevents droplets
of oil to mix with moisture in the crankcase and
condense on the cool walls of the crankcase and
other surfaces. If you keep your engine warm enough,
it keeps the condensation to a minimum. A secondary
benefit of this is to keep the oil at a high enough
temperature that the bypass valve keeps diverting
oil through the oil filter instead of bypassing
As to full-flow systems, I agree totally that the type of filter element itself is not the determinator of the basic system type. I believe I used the phrase "such as a typical spin-on oil filter system" to refer to an example of a typical full-flow system. After all the vast majority of systems designed to use spin-on filters are full-flow systems. That said, I suppose it might have been clearer to say "a full-flow system using a spin-on filter." I will be more careful about semantics in future postings.
The reason for mentioning a typical spin-on full-flow filter system
was to provide a simple and clear example of how even a full-flow system
bypasses unfiltered oil around the oil filter element and delivers that
unfiltered oil to the bearings under certain conditions. I was going to
mention that you can take apart a typical spin-on filter and examine its
built-in bypass valve. In some full-flow systems, the filter bypass valve
is integral in the filter mount or located elsewhere in the system, but
usually (especially with spin-on filters) it is built into the filter element
itself. With a full-flow system, unfiltered oil is, as I said, typically
delivered to the bearings when the oil is very cold, or when the filter
starts to get dirty. Also, there are some oiling systems, especially on
high-speed, high-performance engines, that will provide enough volume at
high engine speeds that the pressure differential across the filter bypass
valve/filter element will be enough to open !
the bypass valve, guaranteeing adequate oil flow and pressure under high-speed operation.
All of the oiling systems that I've seen on modern vehicles (and most of the older vehicles)...whether they are full-flow or not...have a filter element bypass provision. A true full-bypass system, such as the 230 does not deliver filtered oil to the bearings, whereas a "full-flow" system will deliver filtered oil to the bearings...MOST OF THE TIME. As mentioned, with a cold engine, a dirty filter element, or in some cases at high engine speed, unfiltered oil WILL be bypassed around the filter element and fed directly to the bearings. Without this provision, the bearings could starve for oil under those conditions.
The purpose of a dual spin-on filter (or any other kind of dual filter, thank you) on a full-flow system, is, as mentioned, to reduce the pressure differential across the bypass valve/filter element and to allow filtered oil to feed the bearings under conditions that would normally cause a bypass situation. Naturally, even with a dual filter, if the elements become plugged badly enough, the oil will still eventually be bypassed.
And, this dual-element approach still has merit on full-bypass systems,
such as the 230, since with two filter elements, here's what happens: At
46 psi at the filter OUTLET (not the inlet...I got that part right this
time), the bypass valve opens. However, if the filter is dirty, the reduced
flow through the filter element can only push the bypass valve open a small
amount and still maintain 46 psi (very low flow). With a clean filter,
a less restricted flow through the filter element will be able to push
the relief valve further open and still maintain the 46 psi (higher flow
rate). With two filters in parallel, there is even less restriction of
flow through the elements, and it will be able to hold the bypass valve
even further open at 46 psi (still higher rate of flow). This means that
the oil will cycle through the filters more often and stay cleaner. Naturally,
this assumes that the oil pump was built with adequate "over capacity"
as most of them are. There are numerous d!
ual-element adapters on the market for all kinds of engines and oiling systems, both full-bypass as well as full-flow systems. But, would I use one on a 230? Well, I think that just keeping a clean filter element in the engine will do a pretty good job of keeping the filter flow rate up on most stock engines, including the 230.
One more thing...could you re-check what I had written about the condensation issue? I think you'd agree with what I was saying. I was warning against running an engine without a thermostat, in which case you tend to have a very cool water jacket/block upon which the hot crankcase vapors and oil droplets condense. Without a thermostat, these surfaces will REMAIN cool and NOT reach normal operating temperature, even while the reciprocating parts warm up, hence these depositis will continue to build up layer after layer until big chunks begin to fall off. If you have a proper thermostat, which allows the engine block to reach a normal operating temperature along with the rest of the engine, this will prevent the vast majority of these condensation deposits from taking place, making it easier for any thin deposit to be removed, either by oil splashing action or by detergents or solvents present in oil. Even non-detergent oils have a certain amount of natural solvent action.
I've seen engines that were run without thermostats for years, which had 1/4- to 1/2-inch thick deposits of dense, black sludge coating the inside of the block and other interior surfaces. With a full-bypass system, as chunks of this stuff break off they are going to be pumped through the bearings, and might even clog the inlet screen. So, always use a proper thermostat. You don't see as much of this problem lately, as thermostats tend to last longer than they used to (better seal material, I suspect).
Most of us have heard about engines that run hotter with a thermostat than without. This is a relatively rare situation (which should invite numerous anecdotal cases, I suppose). It is also, perhaps, the subject of another discussion.
So, thanks again for bringing my flow direction oversight to my attention, and I will try to state things a bit more succinctly in future postings.
And again, my personal preference is to start with a clean engine and
use a detergent oil.
Also, a follow-up question: does anyone know where I can get a
definition of the SAE and API motor oil standards? What's the difference,
for example, between API SJ and SH?
Contact them for specifics on oil ratings, but the later the letter in the alphabet the more stringent the requirments for the oil - later is better so
J is better than H. If you cleaned the engine well, change the oil now (500 miles) and then again in 500, then progressively increase the interval.
Remember - oil is cheap - engine repair is not.
Non detergent oils have no place in road vehicles. By all means use a 10-30 or 10-40 motor oil but only if you are reasonably sure the your engine is clean of gross residue (sludge). The result of previous poor maintenance (extended drain intervals), the use of non-detergent or poor detergent oil may have left large quantities of sludge deposits all over your engine. Any attempt to remove this sludge with additives, diesel fuel, ATF, or any commercial cleaning additive will result in everything washing to the sump of the oil pan. That is where the oil pickup is located. Enough sludge in the pan will plug the screen of the oil pickup resulting in oil starvation.
Living example; 1980 Ford 351 cid V8 with about 100,000 miles. The original owner changed oil as recommended by the manufacture, every 6000 miles. (Poor interpertation on owner part) He used a leading brand of 10-30 oil. (advertised by a famous “golf pro). Later he sold vehicle to an equantance who preferred a different (superor) brand of oil. After an oil change, and less than 2000 miles on a cross country trip, the engine seized. We dismantled the engine after it was towed home. Oil pickup was solidly plugged with sludge as was every nook and crany where oil can be found. We believe if we had continued using the oil recommended by famous golf pro the engine would NOT have seized (so soon), although its condition was terminal.
Moral of story is start with good detergent oil in new, rebuilt, or clean engines, change every 3000 miles, and stay away from oil advertised by famous golf pro’s. I’ve got more examples but this was a classic. The only non-detergent oil in my garage goes in my air compressor.
A good grade of oil has many properties and does many things, i.e.; exibits low pour characteristic, low carbon residue, good oiliness, high film strength, high resistance to oxidation, anti corrosion, anti foam, high dispersion, high detergent, and hold dirty particles in suspension.
The majority of the oils available to us have these features...some better than others. Racing oils are for racing and have better oiliness and film strength characteristics, but less detergent additives. Use common sense here.
P.S. I have traded in the case of ND oil based on the data I got from the original posting. Thanks for your response!