Oils ain't Oils

[WilliamInOz]

Hi all,
whats peoples views of detergent and non detergent oils. I assume that these old engines were running detergent or mineral engines.
I thought if i ran an engine with a newer engine oil till warmish then drain the oil that might get some of the crud thats thrown to the sides of the engine.

Cheers Will

[Patrick M Livingstone]

I (now) use single grade non-detergent oils in my engines. I used to use modern multi-grade detergent oils in my engines and always ended up with black sh*t everywhere.

[Andrew Mackey]

Non detergent oil is a lubricating oil without additives that remove varnish and gum from internal engine surfaces.

Detergent oil is a lubricating oil that has specific additives that do the following: 1) It loosens and disolves gums and varnishes from the engine interior surfaces. 2) It takes this material and suspends it in the oil solution, where it can be removed by the oil filter, or by draining the engine oil. 3) For a time, it neutralizes acids introduced into the oil, when the engine starts and runs (ever hear of acid rain).

When the hit & miss era was in full swing, Detergent oil did not exist. It did not come into use until the 1940s. If you have an engine that was run on nondetergent oil, you must NOT use detergent oil until the engine has been disassembled and thoroughly cleaned of all varnish, gum, and debris within the crankcase and ALL oiling passages (have the block boiled out, and all passages blasted clean). If the engine is not cleaned, you risk major damage from materials broken loose by the detergent oil getting into bearings and other surfaces. If your engine recommends nondetergent, stick with it!

DO NOT use detergent oil as a premix fuel for 2 cycle (stroke) engines! The detergents in the oil will have 3 effects on a 2 cycle engine. 1) It will loosen any gum and varnish on the interior of the engine block. This in turn will get into the bearings and the cylinder wall, causing erosion, scuffing and premature wear. 2) Detergent oil leaves a corrosive hard residue when burned. This will cause damage to the engine cylinder wall and rings, and probably will cause excess wear to the piston as well. 3) For those engines that use aluminum or zinc alloy pistons, the detergent has agents within that attack these metals directly, causing the pistons to become damaged within the combustion chamber.

NOTE: The 'new' energy saving oils are actually doing damage to your engines! The Federal government mandated that the oil companies decrease the amount of zinc and molebdynim metals from gas engine oil. These elements were essential high pressure lubrication additives. With the mandated decreases, camshafts, tappetts, and other critical steel on steel wear points are experiancing accellerated wear. The mandates have not affected the diesel oils yet, and the major auto manufacturers have noted the problem. Most engine rebuilders are either using diesel oil or are adding a high pressure additives
as is GM. Some small engine manufacturers have also run into critical wear issues as well, notably B&S and Kawasaki, with Kohler and Onan not far behind.

Look to the archives here on the Stak for nore info on this issue.

Andrew

[cobbadog]

Very well said Andrew,
In simplifying it all, detergent oils loosen all impurities in your engine, especially under the rings. If your engine is old and running well and you use a detergent oil you may well find that you need to rebuild your engine quicker than you thought because the carbon that was sealing up any minor gaps is gone and your engine starts blowing smoke.

[WilliamInOz]

So when an engine manual (R&T model N) it says at the bottom SAE 30 would that be the same back then to now?
it also says something about 100 and 90 grade oils?

Cheers, Will