[P@blo]

Interesting debate. I always thought the holy grail to internal combustion engine longevity was primarily the wear associated with a cold start-up not filtration. Maybe an engine pre-oiler is something worth looking into?

[Sirrotica]

Originally Posted by P@blo

Interesting debate. I always thought the holy grail to internal combustion engine longevity was primarily the wear associated with a dry start-up not filtration. Maybe an engine pre-oiler is something worth looking into?

That was covered in another thread recently. Castrol is the oil company that started the dry start up controversy and everyone thought the Babbitt bearings were where the wear was occurring. The dry startup wear was in the upper cylinder ring area, so pre oiling would have zero effect on dry startup.

The SAE has written about it, but in a nutshell here is what they found out:

An SAE paper written about start up wear attributes the start up wear to residual fuel on the rings and cylinders which will quickly start corrosion on the rings and cylinders, especially when the moisture content is at a high percentage in the atmosphere.

Priming the oil system is going to pre-oil the bearings and other internal wear items, however the startup wear is in the upper end of the cylinder, pre oiling the bottom end will do nothing to change it. There is start up wear, but it's not in the internally oiled wear parts, like everyone thinks it is. The source of the startup wear is most likely omitted because it doesn't fit the narrative of castrol. Certain oil and fuel additives can reduce startup wear due to the ability to retard corrosion in the upper cylinder, the fuel additive is 40% effective and the oil additive is 30% effective used by themselves. The problem is if both are used they tend to cancel out each other and become less effective.

Additives in the fuel and oil can help, but if used in both, they tend to cancel out the effectiveness of the other additive. The moisture content of the air and residual fuel has the effect to starting corrosion in the upper cylinder area, that is where the dry startup actually causes wear, not in the bottom end of the engine.

The discussion started about whether people prefill their oil filters during an oil change. The oil and the filter manufacturers as well as engine manufactures see no reason to prefill an oil filter when changing oil and filter. The residual oil left in the engine is plenty sufficient in the few seconds it takes a filter to fill using the oil pump. And the people on the forum did a survey that they feel sooooooo much better prefilling the filter. Even though in my own experience of 50 years of wrenching I have never filled an oil filter in my own, or customers cars. Literally thousands of oil changes with no ill effects.

No filter manufacturer recommends it and in the case of Caterpillar they actually recommend not prefilling oil filters. Because no one fills the filters from the outside, which is the contaminated side of the filter, they fill it through the center hole because it's easier, which is the clean portion of the filter. Any contaminants are pushed right into the engine bearings upon startup. That pretty much negates prefilling the filter to save the engine wear.

[P@blo]

Correction cold start-up; I edited my post. Not sure how this by-pass filter stuff keeps coming up.

[Sirrotica]

Cold start or dry start, same difference, the primary wear is in the upper cylinder area caused by corrosion by leftover fuel and atmospheric humidity, not the bearings in the bottom end, like many have been led to believe.

Only time you'd have a truly dry start is a new engine with no residual oil anywhere in the engine, and it was started with no oil system priming.

[dataway]

I have to dry start the wife sometimes.