Oil filter issue? 41 Dodge

[GTfastbacker]

please can someone explain the bypass oil filter to me?

 

I received new oil filters from the USA. However, the filter that was installed is about 1:2" higher than the new filters. To check whether the oil flow was still guaranteed, I emptied the filter again.

 

As I understand it, the oil comes from outside, runs through the filter material and returns cleanly in the riser pipe? But I can find only a tiny 0.1“ hole 1“ below upper end in the riser pipe?

 

Am I making a mistake in my thinking?

 

Thanks

Joe

 

Edited January 14 by GTfastbacker

[soth122003]

I think your confusion comes from the misunderstanding that this type of oil filter is not a full flow oil filtration system. Oil is not continuously going through the filter. It only goes through the filter when the oil pressure is greater than the resistance of the spring in the oil bypass valve. The shop manual is great on how to do things, but sucks on explaining the theory behind how it works. 

 

Originally these cars did not have an oil filter. It was a dealer option. The oil change interval was 2500-3000 miles (city). In dirt or gravel environments (rural) it was more often, probably 1000-1500 miles. These cars had a crankcase ventilation system that took air in at the oil filler cap and vented it through the downdraft tube at the back of the engine. This was to keep water and water vapor out of the oil. However it did not address the dirt and particulate in the oil. Hence the oil changes at shorter than todays interval with the sealed crankcase. 

 

On a warm engine the bypass oil filter only worked when the oil pressure was at higher at higher engine RPMs and the bypass valve was open. At low Rpms your oil pressure goes down and the bypass valve would close and the oil did not travel through the filter. This ties into the crankcase vent system which did not work at low speeds as it needed higher speeds to create a vacuum by having air rush past the down draft tube to create said vacuum. At 30-45 psi it is not a problem to force oil through that small hole. I think at the bottom of the riser pipe are couple more holes as well. As long as the holes are between the top and bottom of the oil filter the oil is forced to go through the filter. Since it is not a full flow system it does not need a lot of holes to return oil to the crankcase. That's also why when the manual calls for 5 quarts of oil, it's more like 5 1/2 with the oil filter because the oil in the filter does not drain back into the crank with the engine off even if the filter sits higher than the crankcase.

 

On todays cars the oil always flows through the oil filter. Since it is a sealed system, dirt and debris can't be sucked in the crankcase. The longer interval for changes is for burnt oil and engine wear particulate to be changed out with new oil and a filter. 

 

That's my story and I'm sticking to it. Hope this helps.

 

Joe Lee

 

 

[OldPly]

Will this help you understand 

[motoMark]

 

Interesting. So does this mean that the oil filter housing sees up to 40 - 45 psi until the bypass valve opens? It looks like my filter housing lid gasket is leaking and wasn't sure how much pressure is in there. 

[Sniper]

It is my understanding that the oil does not go to the filter until the bypass valve opens. Which is why it is called a bypass oil filter.

[Ivan_B]

Going back to the original issue: did you order the same oil filter you had in there before? There were a few different options, available, using different filters (I believe). My engine is using Wix 51076, and I have an orange FRAM canister

[DJK]

I have a filter assembly that takes a Wix 51201 (Purolator P40), I also have another filter assembly that requires a Wix 51080(Fram C134PL). Both filters are significantly different.