So which makes more sense?

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55
Location
NY
Here's an interesting thought: the whole "oil never wears out" - (even though it does)- Lets just say your oil lasts 7500 miles. Oil filters- some on this site has even said it lasts over 15000-20000 miles, its just that you dont know if your in by pass due to it clogging. Others have said to change oil, but filter only every other time. So this all doesnt add up. Why cant you just change filters, and not oil? Theoretically, the filter and top off should add enough back into the oil- other than the fact that whatever the filter couldnt capture is still lurking around in the oil...
 
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1,261
Location
KY
Because after so many miles the additives deplete and the oil gets full of combustion by-products and needs to be changed, A filter change and top up wouldnt be enough to refresh everything. Some people with hard too reach filters prefer to change them every other time and that is perfectly fine with 5k dino changes.
 
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39,805
Location
Pottstown, PA
You need bypass filtration to get away with a perpetual sump. On a 5 quart sump it takes you until 15k for a "mature sump". At that point the sump exists in a 3000 mile band of as new as it can get and as old as it can get. It will be clean if you use something like a MG or Frantz. [I dont know] To keep the oil acceptable with just swapping out the full flow filter ..you would quickly run up a tab in filters that would make it uneconomical.
 
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3,478
Location
Millbrae, CA
oil does wear out shear, oxidation etc BUT more distruction and wear, sludge problems occur because the add Package wears out first or sooner. filtering will help to prolong it but oil will "wear out" bruce
 
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1,577
Location
Surrey, BC
I have cleverly solved this problem by having a car that uses a lot of oil. [Wink] Mine eats a quart of oil every 3 weeks. With a ~4 quart sump, I'm basically doing an oil change every 3 months without touching the drain plug. I'm toying with the idea of just changing the filter every 6 months or so and not dumping the oil at all, but I'm not quite confident enough to try it yet. Maybe there is some nastiness in there that only a proper drain can get out. But in theory, I suspect I could get away with changing only the filter for a fairly long time.
 
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2,724
Location
Herndon, Virginia
Interesting concept.. I'd never be able to link to the thread, but back during the first weeks I was reading in this den of iniquity, I remember someone advanced the theory that older oil (starting a couple or three thousand into the OCI) is better than the oil when first out of the bottle, owing, if memory serves, to activation of anti-wear agents with time-in-crankcase. Someone correct me, but I think his UOA supported the idea of using a really good filter, and draining 2 quarts every 5 or 6 or 7K and replacing with new, leaving two quarts (or whatever was left) of the original. Others piped up with (to me) an unfathomably complex formula showing the percentages and how often it actually WAS changed using the method. Anyone remember that? Vil, if you're adding a quart every three weeks, you ARE changing your oil a lot, probably not every three months, but at least you're replenishing the additives as if. On the other hand, maybe the by-products build up. Again, I defer to those that KNOW! [LOL!] What could it hurt? Is it blowing out visible smoke, or just...."using" it? Ya must have SOME catalytic coverter! [Eek!]
 

Pook

Thread starter
Messages
55
Location
NY
Here's what im trying to figure out- Is it worthwhile to do a bypass filter: Rising motor oil costs is one reason. The more it rises, the closer I look at bypass- instead of changing oil 3x a year- could I now change it 1x a year. BTW, I also have a racor LFS filter around. Its acutally made for commerical OTR trucks for their motor oil filtering (so you can see what is going on!) it comes with an indicator light to tell you when its in bypass mode too...
 
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2,724
Location
Herndon, Virginia
Yea, there is that. Plus, warranty wouldn't allow it. With a 100K warranty, you wouldn't start benefiting until the damage from crummy filtration was already done. What's it matter, by the time a healthy engine hits three or four hundred thousand miles, the rest of the car is (expensively) falling apart around your ears anyway? I established that for myself with my last car.
 
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39,805
Location
Pottstown, PA
The sump size and the filter interval dictate your sump maturity level. If it's a 4 quart sump and you change your filter and add 1 quart of oil ..then you're at equalibrium at 12k/12m (whichever basis you're using for changing it out). From there on out the sump sees a variance of condition of 3k from the day/mile you add a quart to the day/mile you remove a quart. It's as old or as new as it can be. It doesn't really work this way ..but the numbers should work out the same if you just assumed that one quart was in there for 15k ..one for 12k ..one for 9k ..one for 6k and one for 3k. In reality the stuff is composed of x% of 12k old oil and various increasing % of newer oils. But that composition doesn't change, measurably, when you reach that "steady state" that varies only 3k in difference. Pook ..which LFS system do you have?? Parker - rancor filtration products It's hard to quantifiy a bypass filter in $$ and $0.01. You're getting a finer service out of it. It's not necessarily something that can be viewed in straight pay back in avoided costs. It works well for fleet usage ..just due to the mega miles that they accumulate in a short period of time. You do reduce your annual expenses to about $6-$8. There should be no need for an annual oil change if you verify that "steady state" with a UOA. The sump will not change beyond that 3k range for the rest of time.
 
Messages
1,577
Location
Surrey, BC
quote:
Originally posted by toocrazy2yoo: Others piped up with (to me) an unfathomably complex formula showing the percentages and how often it actually WAS changed using the method. Anyone remember that? Vil, if you're adding a quart every three weeks, you ARE changing your oil a lot, probably not every three months, but at least you're replenishing the additives as if. On the other hand, maybe the by-products build up. Again, I defer to those that KNOW! [LOL!] What could it hurt? Is it blowing out visible smoke, or just...."using" it? Ya must have SOME catalytic coverter! [Eek!]
This is the (unfathomably complex?) formula I use. After 3 weeks, 75% of my original oil is left. Top it up. Another 3 weeks, 75% of the original (before topup) oil is left. And again and again. So after 3 months the original oil should be at 0.75 * 0.75 * 0.75 * 0.75 = 0.32. So only 32% of my oil is what I installed right after the last oil change. Take that out to 6 months, and I'm down to 10% original oil. Seems like the breakdown of the old oil shouldn't be a factor at that point. I suspect it's both burning *and* leaking. My cat is pretty close to failing the local pollution testing, but it's 12 years old so that's not unreasonable. There's a fair bit of blackness on my engine block too, though I haven't figured out where it's coming from. Even if I did, I probably get a choice between a $700 repair job or keep filling up with some $2 oil. Hmm. [Wink] Thicker oil doesn't seem to help either. It usually gets 5W30; I tried a quart of 10W40 and not much change. A couple weeks ago I crossed my fingers and topped up with 20W50 and it's still drinking at the same speed. [I dont know]
 
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2,724
Location
Herndon, Virginia
2.00 oil? Man, some of these guys are getting .49 oil, but can't remember what kind.. As far as the stratagy, it would take the old heads to tell you whether you EVER need to change out. Sounds like it's being continuously replenished.. As yes, unfathomably complex. I NEVER said I KNOW, I just guess a little, and let the few that KNOW fill in the blanks.. Good luck, Vilz! [Cheers!]
 

Pook

Thread starter
Messages
55
Location
NY
I have the LFS 92- Its not even listed on their site, but it closely resembles the size of the 90. I got it cheap off EBAY in the box, for my early versions of veggie oil conversion for my truck- at the time Greasel was recommending the LFS 35 as the "final filter"- (thats a different rant all together, as to why you would use a 28 micron as a final for any diesel injection pump... but greasel seemed to think it was ok) I bought it anyways, i figured it was a good unit to have, played around with it a bunch. Gary, why do you ask? I have a bunch of other racors that I use as well- a 500FG and a 900FG. I really should have gotten the 1000FG, as its filter element is vastly superior in size. (Double, if not a bit more). But the application space was rediculous- Try needing 2 feet of vertical space. I also use the a giant CAT 2 micron diesel fuel filter as well for the veggie filtration.
 
Messages
39,805
Location
Pottstown, PA
quote:
Gary, why do you ask? I have a bunch of other racors that I use as well- a 500FG and a 900FG.
 - Just curious. I've seen these offered in stuff like Jeg's and whatnot. Not as much surface area as the cylindrical filters ..but does offer alternative fittment possibilities.
 
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