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MG MGB Technical - Of Oil Filter Studies, etc....

I recently answered an inquiry about the fabled internet Oil Filter Study that a fellow enthusiast found mentioned in the Archives. I wrote him the following. Hopefully it will be useful info to any of you, and will help to update Archive content a bit.

"The original Oil Filter Study site has moved several times over the years, and the most current link to that content I have found is here: http://www.frankhunt.com/FRANK/corvette/articles/oilfilterstudy/oilfilterstudy.html It has been passed around by email and its content copied and posted elsewhere many times as well. As I recall, the gent who put this together got some sort of "hounding" from persons (perhaps allied with the oil filter companies) such that he had to take it down. How it got back up, I don't know, it doesn't matter for us. However, if you have the ability to save the webpages, then do so as it may well go away altogher someday.

"Also, you should note that the info is a bit dated now, perhaps why it's once again available.

"There are a few other oil/filter related sites out there such as these which may also be of interest to you as look around the web."

http://home.moravian.edu/students/m/stmtm02/filtersurvey.htm

http://www.ntpog.org/reviews/filters/filters.shtml

And then, this chestnut:

http://www.bobistheoilguy.com/ (No, not me, but a better informed Bob!)



Bob Muenchausen

Cool info, Bob. Thanks for the heads up.
Luigi

I have recently opened several new filters and there are some differences between brands. All but the AC motorcycle filter have anti-drainback valves. All have a bypass valve. Some bypass valves require more pressure to open than others. I started with a Fram PH 8A and cross referenced their number to other brands with the exception of the Nissan and AC filters. Some have paper or fabric end covers and the others have steel caps. Oil feed inlet holes have different sizes, some have 8, 6 and one has 5 holes. The filtering media in the Fram was 50" long, the Purolator was 100".
Others were somewhere between. My ovservations are not scientific and I didn't bother to weigh the filters.

I have plastic bagged all the filters for later study and reference. Some filters have better internal sealing than others. If a filter goes into bypass due to a clogged or faulty filter element the engine oil pressure should drop by the amount of pressure required to open the bypass valve. If the oil pressure drop across the filter exceeds the bypass pressure the bypass opens and will feed unfiltered oil to the engine. Cold thick oil may cause the filter to bypass the oil.

My plans are to open all used filters I remove, not so much to check dirt but to see if anything unusual happens inside the filter.

Photos of filters I have opened are in my Yahoo pthoto albums, it's open to the public but you may have to become a Yahoo member, it's free. I hopev this link works.

http://pg.photos.yahoo.com/ph/flash1929/album?.dir=a084&.src=ph&store=&prodid=&.done=http%3a//photos.yahoo.com/ph//my_photos

Clifton
Clifton Gordon

I think most of this filter stuff is overdone. I haven't heard of anyone taking down their engine and finding lots of grooves in the bearings from contaminated oil scratching the bearings unless they blew something and kept driving. The sump oil capacity flows through multiple times in a minute. With a good air cleaner there is very little dirt in the air, and very little of that dirt gets past the rings and into the crankcase. The oil is designed to keep carbon particles in suspension. If you have bad rings, the filter can take some of that carbon blow by out of the detergent suspension.

A by pass partial flow filter that picks up the stuff every 3rd pass is going to protect your engine over the long run. It is a good idea with an upside down filter to have a good check valve to protect against a dry start. But even without the check valve the oil is there in 5 or 6 seconds. The existing oil film is more than adequate to provide a boundary layer of protection under those no load momentary start up events.

If it is teeny weeny stuff thats getting past your filter it probably won't do much damage anyway.

I have yet to see a study that shows an engine lasts longer with a better filter than a worse filter.

When my parents bought a new '55 Chevy, the detergent oils that held it all in suspension were just begining to be popular. An oil filter for the engine was an extra cost option. These engines ran ran 80 to 100k miles with no filter, poorer oil, dirtier gasoline, and poorer ring seal.

Stick an old sock in the filter canister, it's probably good enough. Don't change your filter often. The more gunk in the filter, the better it collects the dirt.

Barry

Barry Parkinson

I currently use a Mann W917 (can also be obtained from a Volvo dealer by asking for the standard Volevo filter) exclusively in my '73 because of the drain back issue of the upside down filter. For those of us with oil coolers the time taken to pressurize the system can be disconcerting as we listen to the clatter of obviously dry bearings.

It is well know that the most wear in an engine occurs during startup. Minimizing the time period to pressurize the system has an effect on wear. A Mann W917 is the only filter I have found that gives pressure virtually instantly on startup.

The proof is in the pudding. My car is a daily driver. I rebuilt my engine in 1980 and the rebuild is 25 years old with 120 K miles on the rebuild. My oil pressure runs 70-75 on the highway and about 20-25 at idle when fully warmed up.

Although I am beginning to see a need for a valve job, my car only burns about one quart of oil between changes. It has been using that quart of oil between changes for as long as I can remember.

I firmly believe that the longevity is due to three factors:

1) The engine was well sealed when rebuilt by attention to gasket surfaces and gasket glue. The crankcase ventilation system has always been funtional with an air filter on the inlet and crankcase gases going into the inlet manifold via a PCV.

2) Castrol GTX 20-50 has been used exclusively.

3) Mann W917 filter have been used exclusively to minimize startup wear.

Richard Smith 1

The fram "tough guard" TG43 (for Chrysler products)has an upgraded drain back valve that works well in my experience. And according to some filter studys has a good filter matrix. You can buy those filters anywhere. There is at least one investigator that claims the Mann filter matrix isn't that good.
Many of filters are made by the same company that just puts a different name on the can. The company manufacturing a brand of filter may and does change from time to time.
Barry
Barry Parkinson

I felt it was interesting the first time I read it, and I think it still has some value, if only in demonstrating a process by which an enthusiast can do some meaningful comparisons. To me, the info is probably out of date (for many reasons you have cited) and I think it is also too close to a generality when different cars can yeild differing results.

I just posted these for folks to peruse and catch up with. Certainly, not all of what we find on the internet is continually meaningful or even worth much to begin with, but these at least attempt to do an honest days work for the rest of us who aren't engineers and aren't well versed what's important to know and to look into and what isn't.
Bob Muenchausen

I had drain back problems with a Fram Tough Guard filter on a Nissan pickup. I sent it to Fram and they agreed that tests showed a drain back failure, I never received a follow up from them. They did send me 3 new filters, I didn't use them.

On two or three recent BBS threads filters caused low oil pressure on MGB's. In both cases the owners changed to a Fram and oil pressure was restored. I think Champion made the filters that failed. I opened two filters made by Champion, one was a WalMart Super Tech ST8A, the other was a STP S8A. Both have anti-drain back valves and bypass valves. The bypass vlves are in the base of the filter. They have the common rubber/nitrile or whatever type anti drain back valve. The inner part of the rubber valve is the bypass valve. On the base of the filter there are 8 holes around the outer rim for oil feed. Around the center part of the base are 6 six holes for bypass in event the filter is clogged or the oil is too thick to go through the filter. There is oil coming in to the base of the filter and the pressure opens the outer flap, the inner flap on the same ring is pushed open to bypass the oil. It appears to me the two flaps on the common ring are working against each other. All other filters I looked at have separate bypass valves. The
Champion filters have fabric end caps, all others I looked at other than Fram have steel end caps.

The Fram I opened is very cheap looking, I'm not saying they don't work. The end caps are made of cardboard, there was poor sealing around the bypass valve at the top. It had only half as much filter media as the crossover Purolator. The anti-drain flap feels flimsy. I see more Fram's on MGB's than any other brand.

Advance Auto sells a house brand filter named Totalgrip. On the box is the following, "This product is not manufactured by Honeywell International Inc, owner of the registered trademark Fram." It looks like a Purolator inside.

What does al this mean? Maybe nothing. Barry mentioned early cars had no filter and the early options were usuall bypass type filters. VW beetles didn't have an oil filter, they had a screen for a filter. Some of them needed early valve jobs but they had a very reliable bottom end.

My MGB is one of the early 74's that came from the factory with a hangdown filter, no anti drainback valve, it isn't needed. The filter also fits a midget and is small. It always gives instant pressure on engine start up and pressure is around 70 psi with a hot engine.

Clifton


Clifton Gordon

Clifton
I was thinking about the old (50's and early 60's) that didn't have a filter or had a bypass filter. They also were supposed to change oil every 1,000 miles rather than the 3-5 k or more, reccomended today.

The toilet paper by pass filter was popular with many during that time period. It seemed to filter out the carbon and make the oil look better.

If you think about it, what can get in the oil? fine pieces of worn bearings or rings are heavy and drop to the bottom and probably are never removed until the pan is removed at some point. Carbon is held in suspension with the detergent oils, with or without a filter. Certainly if you run in dusty conditions, fine grit can enter the engine and some blow by the rings and enter the oil sump.

If you start getting a cam or lifter breaking up, or a broken ring, that may be caught by a filter.

Probably, most of the time, there isn't that much for a filter to filter out. The first start up after a rebuild is the one most likely to produce foreign materials.

Barry
Barry Parkinson

I kinda started this when I asked Bob the off-line question about oil filters, while trying to decide which one to put on my car.

I know some of the stuff on the internet is old, but if you're like me, and you're new to doing a lot of work on your own car, anything you read helps. I'm building my car knowledge from the ground up - reading about anti-drain-back and bypass valves may be mundane to some, but it helps me to understand how my car works.

I really appreciate all the experts like Les and Bob and Clifton and Paul and Dave and others reading all these posts and helping us newbies get to the point where we can help others. I'm 52, and I plan to own an MGB until I can't drive anymore, which I hope is a very long time from now. Maybe when I'm 72 I'll know enough to be explaining oil filters to some youngster like me!

John
John English

Barry,

Note that my primary purpose in using the Mann filter is the reliability of the anti-drainback valve and the effect that has on wear at startup. Also, every Mann or Volvo filter I have purchased has said "Made in Germany" on it. So, while there may well be different filter plants in Germany, at least I can say that the Mann filters are consistent in quality and the anti-drainback valve has worked properly in every one I have had - something I cannot say about Frams, Purolators, etc.

My recommendation on the Mann is based on long-term consistency, quality and reliability. Others may well find other filters that have these properties.

I do not have time to try out different filters and simply use the Mann because it has served me very well over the years. One settles on something when it works. I assure you that the first time I get a Mann that has a faulty anti-drainback valve, I will go hunting for other filters.

I cannot comment about the matrix but I agree with your post about how much actually gets filtered.

When I was unable to obtain a Mann in the past, I have used an OEM Leyland filter and the anti-drainback valve worked fine in it as well.

I am on about startup simply because that IS the most critical lubrication issue in an engine. Think about it. The way an engine bearing works is that it relies upon the oil physically separating the journal from the bearing. The viscosity of the oil prevents the journal from coming into contact with the bearing.

A long time ago in mechanical engineering school, a professor was lecturing this very point on lubrication. It prompted an immediate question from me - "Then please explain why journal bearings do indeed wear out." His response - "The wear occurs in the period when the lubrication film is not present and the journal CAN come in contact with the bearing, i.e startup before oil pressure is established."

Richard Smith 1

Richard
If there is no oil film remaining and there is metal to metal contact - of course.

You can take an engine down weeks after it's last run and there will be oil in the bearing. It only has to lube for a few seconds under light load until the oil starts flowing. I have seen bearings where the oil has broken down. There is a bearing smear. Sometimes there is a transfer of bearing material to the journal.

I've never seen that from a cold start.

You've been listening to too many Slick 50 adverts. The best unproven promotion in automotive history. It sounds logical and good but there are no objective studies to prove same.

Barry
Barry Parkinson

My uncle (to whom I owe my interest in cars) built sprint cars in his automotive machine shop. By the time I was working there as a teenager, he was building indy engines.

He used to drive a 63 ford falcon ranchero with a V8 in it. That car had nearly 200,000 miles on it without a rebuild (pretty good for a 60's engine).

I once asked him what he did to get that milage from the engine. He said, change the oil filter once a year. I asked about oil changes and he said about every 4 years or so. He felt the quart of oil added when the filter was changed each year took care of "refreshing" the oil.

I don't necessarily follow his advice, but then, he owned a machine shop and could rebuild an engine at little cost.

Bruce Cunha

The start up wear period is first 20 mins when engine parts are expanding at different rates until operating temps are reached. Apart from oil film anti wear additives (moly,zinc,esters) are also still on surface at start up to provide boundary lubrication until oil starts flowing.

Bruce,

As mineral oil ages it becomes more polar and may be a reason for long oil changes working in certain circumstances.
Synthetic ester based oils have this advantage to start with but are not the cheapest oils.

Paul
Paul

Barry,

I really do not pay attention to anything Slick 50 has to say - they take otherwise good engineering information and twist it to make their product sound great.

As for your comment regarding disassembly and finding oil on the bearings, of course there is oil there. But there is insufficient oil pressure and the oil film disappears quickly when the journal starts turning in the bearing with no pressure. If the pressure is not quickly provided there WILL be journal to bearing contact. The bearing smear you talk about occurs in extreme situations only.

For God's sake, Barry, put your thinking cap on - you can HEAR the clatter start after a few seconds of no pressure. This clatter is not valves or pistons or anything else but the journals hitting the bearing shells. If you hear this clatter then you are wiping bearings - maybe not enough to cause bearing smear but enough in small doses over the life of the engine to decrease the longevity of the bearings.

I am not speaking from a Slick 50 perspective but from a mechanical engineering perspective with my info on this coming from an accredited and well known engineering university from which I have a mechanical engineering degree. And, yes, I do get a bit touchy when my comments are compared to a Slick 50 ad...
Richard Smith




Richard
I don't disagree that getting oil to the bearing asap upon startup is a good idea. I just don't believe that start up and the few seconds under virtually no load is going to materially add to the wear of your bearings.

If you've got loose bearings to the point they rap on start up, you've probably already got lots of wear. I've had some high mileage cars in the past that rapped at every start up and just kept running and running.

My 67 gt is using a late model block and crank with nearly 140,000 miles when I rebuilt it. About 5,000 miles since rebuild. I put new standard size bearings in it and with 15-40 delo it holds 60+ psi hot at anything above about 2300 rpm. I have never heard any bearing rap, even with the filter completely empty.

The first time I put it together I used the wrong oil pump gasket and ran it for about 30 seconds at 2500 rpm,trying vainly to get oil pressure. I had to pull the engine down after about 2000 miles because - it turned out - the machinist had incorrectly installed the rear cam bearing which starved the head lubrication and wiped out the rocker bushings and tube.

While it was down I checked and replaced the bottom end bearings. They showed a little smearing from that egregious start up. Even then they never rapped at start up. The Oil pressure is better with undamaged bearing inserts.

With some oil film there preventing metal to metal contact, I see no reason to believe there is meaningful excess wear in those few seconds after start up. Obviously the lubrication dynamics are not the same as a pressurized film. It is nevertheless adequate lubrication for those few seconds after startup.

A bottom end can take a lot of abuse and just keep on a ticking as Cameron Swazy(sp) used to say.

Henry Ford hit over 100 mph in about 1904 in a car that had an open sump and grease in the bearings. Lubrication oil/grease was not as good then as now. The lack of oil pressure didn't stop the record run.

In my opinion, boundary lubrication is more effective at start up than the established engineering theory/common belief. With the film strength of modern oils, I don't believe there is that much excess wear at start up.

Every little old lady (or MG aficionado) who only drives their car a few miles at a time, should be having early bottom end failure. You don't see it happening.

An established and acceptable engineering approach in addition to theory, is the pragmatic approach.

Having said all this, I like to see my oil pressure gauge bounce up, immediately upon start up. I feel better.

Barry




Barry Parkinson

Barry,

My experience with my engine (since I rebuilt it some 25 years ago) has been that a period of 5-10 seconds will get the clatter in the last part of that period. I don't get the clatter if that period is under about 5 seconds. And I have had filters that took 10-15 seconds (seems like forever) for the pressure to build. These filters are the ones I am talking about. When I use a Mann filter, I usually have full oil pressure somewhere around 1-2 seconds (virtually instantly) and that cannot be a bad thing.

MG's have always been a little hard on big end bearings (don't quite know why - the bottom end is built like a tank). In one of my shop manuals or the competition manual (can't remember which) the recommendation is to change the big end bearings at only 45 - 50 K miles!

You are probably correct about the film strength in modern oils being high enough for this to not be a problem. I am simply a believer in doing absolutely everything I can to minimize engine wear.
Richard Smith

Richard

The new oils are a big change. At start up, heat breakdown is not a problem, but for overall bearing life high speed lubrication failure (heat) is the issue. I can recall in the mid 1960's winding an Alfa 1300 up to 6,000 plus rpm chasing a friend up a long grade, (just after I had changed the oil) feeling a momentary loss of power and seeing the oil pressure guage drop. The rear main had momentarily siezed.

The B's sold in the US typically did not have overdrive in contrast to the European sales. In the 60's in the US with the 5 main bearing engine, an oil cooler was needed to avoid catastrophic bottom end failure. Apparently there was reduced life but not catastrophic failure in Europe.

In contrast, with the better oils in the mid 70's, the oil cooler was deleted and the sump capacity was reduced by 1/2 quart.

The late model engine I'm using had a record of frequent and regular oil changes until the second owner bought it at about 114,000 miles - There was a record of one service in the last 15,000 miles.

The car was a Las Vegas Nevada car. The bearing inserts showed wear, but were not in a failure mode.

What stopped the car was up to 1/4" valve recession from unleaded gas. Some of the rings were stuck, but there was -0- cylinder ridge. The pistons slid right out the top with no problem. The maintenance record showed no work on the basic engine. Lots of tune ups over the years, carb and exhaust work etc. It did not appear the engine had ever had the head or pan off.

From my experience the bottom end is fine with modern lubrication.

Barry
Barry Parkinson

Barry,

Are you running an oil cooler? My '73 has one and that may well be the difference in our situations.

There is another factor regarding whether the oil cooler is/was needed or not. In Europe the average summer temperature is noticeably lower than the average summer temperature in the southern and southwestern U.S.

You mentioned a zero ridge at the top of the cylinder. When I rebuilt mine in 1980, I also had no ridge. That's probably because an OEM engine uses iron rings with similar hardness to the bores. This results in less bore wear than chrome rings (harder than the bore). I have been a proponent of iron rings for those of us not seeking the ultimate in performance but seeking engine longevity. When I rebuilt mine so long ago, I used Hepolite (OEM) iron rings. Unfortunately I have heard that the Hepolite rings are beginning to get very difficult to find and also expensive.

Richard Smith

This thread was discussed between 13/07/2005 and 18/07/2005

MG MGB Technical index

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