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Oil filter question...

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GlennMGB Avatar
GlennMGB Glenn G
Fort Worth, Texas, USA   USA
1967 MG MGB GT "Rose"
Thousands of MGB owners have driven thousands of miles with the inverted filter, and their engine bearings are still working fine. There is always some oil left in the bearings when the engine is stopped. Anyone who has taken apart an engine can see this. The remaining oil is enough to protect the bearings for ten or twenty seconds until full flow is restored.

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MGB-GT V8 Olds Avatar
MGB-GT V8 Olds Howard Fitzcharles III
Smyrna, TN, USA   USA
1970 MG MGB GT V8 "The Green Dragon"
1970 MG MGB V8 Conversion "The Green Dragon"
Anti drain back valves do not prevent oil draining through the bearings back into the pan and hot oil does that so the inverted filter drains not back to the pump but through the filter into the bearigs and into the pan especially when the oil is at operating temperature. The anti drain back valve is on the out side of the filter and does not prevent oil from draining into the bearings and into the pan. This was the reason for the tube as it held oil in the filter but only to the top of the tube and on long filters that was a large space. A shorter filter is better providing it is not so short as to restrict flow into the end of the tube. I believe that clearance should not be any closer then 3/4 inch thus giving the pipe sufficient flow as the pipe is the only feed to the bearings.

Rod H. Avatar
Amity, Oregon, USA   USA
1964 MG MGB
1968 MG MGB GT
In reply to # 3514650 by MGB-GT V8 Olds Anti drain back valves do not prevent oil draining through the bearings back into the pan and hot oil does that so the inverted filter drains not back to the pump but through the filter into the bearigs and into the pan especially when the oil is at operating temperature. The anti drain back valve is on the out side of the filter and does not prevent oil from draining into the bearings and into the pan. This was the reason for the tube as it held oil in the filter but only to the top of the tube and on long filters that was a large space. A shorter filter is better providing it is not so short as to restrict flow into the end of the tube. I believe that clearance should not be any closer then 3/4 inch thus giving the pipe sufficient flow as the pipe is the only feed to the bearings.

On what do you base the 3/4"?



I can't understand why people are frightened of new ideas. I'm frightened of the old ones. John Cage

'63 MGB
'68 MGBGT
'80 VW Vanagon Kombi
'09 Mazda 3 with 5 speed manual

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MGB-GT V8 Olds Avatar
MGB-GT V8 Olds Howard Fitzcharles III
Smyrna, TN, USA   USA
1970 MG MGB GT V8 "The Green Dragon"
1970 MG MGB V8 Conversion "The Green Dragon"
Dick, that large empty space in an inverted filter is in between the pump and the bearings and is full of air after the hot engine has sat for a while. That tube only keeps an oil level in the filter up to the end of the tube and all the space above it will drain through the bearings into the pan. True that the "B" pump is good about pumping instantly but it has to fill the filter and exhaust all that air through the bearings before any oil pressure is applied to the bearings and thus the cylinder walls too. I worked in MG dealerships when BLM started that inverted filter and every car knocked when started after sitting. The ONLY reason they put the tube in up through the center of the filter was to keep at least some oil in the filter.

dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
I don't doubt your experiences. I do know that oil pressure will not show on the gauge until all the oil galleries are filled and enough resistance to oil flow is generated to establish pressure, since hydraulic pressure is equal throughout a vessel. Unless rod bearing shells are extremely worn, oil pressure in an MGB will register on the gauge within a second or two of the engine starting. This means that, necessarily, oil must be flowing to bearings and journals within that time frame. It may take longer for a car whose engine has not been started for extended periods of time, but an engine that's started regularly will surely show pressure on the gauge within mere moments of starting...

Dick

In reply to # 3514663 by MGB-GT V8 Olds Dick, that large empty space in an inverted filter is in between the pump and the bearings and is full of air after the hot engine has sat for a while. That tube only keeps an oil level in the filter up to the end of the tube and all the space above it will drain through the bearings into the pan. True that the "B" pump is good about pumping instantly but it has to fill the filter and exhaust all that air through the bearings before any oil pressure is applied to the bearings and thus the cylinder walls too. I worked in MG dealerships when BLM started that inverted filter and every car knocked when started after sitting. The ONLY reason they put the tube in up through the center of the filter was to keep at least some oil in the filter.



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

MGB-GT V8 Olds Avatar
MGB-GT V8 Olds Howard Fitzcharles III
Smyrna, TN, USA   USA
1970 MG MGB GT V8 "The Green Dragon"
1970 MG MGB V8 Conversion "The Green Dragon"
Glenn, I agree that there is a small puddle of oil in the bottom half of the rods, mains and cam bearings but that is not sufficient oil for bearings under a load of starting. It is well documented that the majority of wear on any engine is in the first few seconds of running and the knocking of the inverted filter engines should tell you there are far shorter "thousands" of miles driven on inverted filter engines. If you want to do a simple test as we did in one dealership do this.
Heat up some engine oil and heat up a clean bare sheet of metal and coat that metal with the engine oil and stand the sheet up against a wall and leave it there and check on it to see every so often to how long it takes it to rust. ( an indication there is no oil at all on it ) We rebuilt our own engines in the dealership (MG, Triumph, A-H, Lotus and Jaguar)
We often had to let an engine sit for a week or two before we could put it in the car and some mechanics were in a hurry and didn't spin the engine until they seen oil pressure before starting and the result was a damaged cylinder walls and bearings. If you don't think that knocking noise is not doing any damage then keep a tall inverted filter.

dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
I rebuild many engines in my shop (MG, Triumph, A-H, Jaguar {haven't had the pleasure of doing a Lotus engine yet...} ), along with domestic engines of pretty much every configuration. If your shop experienced engine failures on rebuilt engines that hadn't been started for a week or two, then you were obviously not properly applying various appropriate assembly lubes during the process. I use five different lubricants during engine assembly.

I build one or two engines a month, many for members of this august Forum, and many of my engines are not fired for the first time for months or longer. I tell folks to try to spin the engine over with the spark plugs out to see if they can generate oil pressure on the starter motor. But if no oil pressure shows up after a few tries, I tell them to just screw the spark plugs in and light it up. Oil pressure always appears within a couple of seconds, and the assembly lube protects the components in the meantime.

Never had a problem...

Dick




In reply to # 3514682 by MGB-GT V8 Olds We rebuilt our own engines in the dealership (MG, Triumph, A-H, Lotus and Jaguar)

We often had to let an engine sit for a week or two before we could put it in the car and some mechanics were in a hurry and didn't spin the engine until they seen oil pressure before starting and the result was a damaged cylinder walls and bearings. If you don't think that knocking noise is not doing any damage then keep a tall inverted filter.



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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Rod H. Avatar
Amity, Oregon, USA   USA
1964 MG MGB
1968 MG MGB GT
Dick, your engines have proper clearances so with a little lubrication in there they don't knock for the second or two with no pressure. smiling smiley



I can't understand why people are frightened of new ideas. I'm frightened of the old ones. John Cage

'63 MGB
'68 MGBGT
'80 VW Vanagon Kombi
'09 Mazda 3 with 5 speed manual

GlennMGB Avatar
GlennMGB Glenn G
Fort Worth, Texas, USA   USA
1967 MG MGB GT "Rose"
Quote: It is well documented that the majority of wear on any engine is in the first few seconds of running

Where is this documentation? I've seen this along with a lot of other well-intended nonsense on internet forums, but never in a scientific study.

Quote: If you want to do a simple test

If you want to do a relevant test, open up an engine that has sat in the corner of a garage for five years. The crankshaft journals will be shiny, protected by the layer of oil held between the journals and the bearings by capillary action.

Quote: If you don't think that knocking noise is not doing any damage then keep a tall inverted filter.

I agree that less time to full pressure is a good thing, not because I've seen documentation or damage, but because it makes sense. That's why I use a short filter, either an AC PF13 or a Mann 917. I have also added notches to the top of the oil standpipe in case a filter is too short. Usually time to full pressure is under five seconds, and there is no knocking. If the filter is left to drain for a few days, the time can be as much as ten seconds. After an oil change, the time can be more than ten seconds. This is the only time I hear knocking before the pressure comes up.

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the omega man Avatar
the omega man phil wilkins
staffordshire, Stafford, UK   GBR
I've been using this type of filter, with no drain back valve, for a long time now. Start up pressure is instant, running pressure is 70 lbs. Hot. No knocking or rattling on start up.


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ozieagle Avatar
ozieagle Gold Member Herb Adler
Geelong Victoria, Australia   AUS
1958 Wolseley 1500 "Wooly"
1966 MG MGB "Bl**dy B"
I use the MOSS style hanging spin on filter conversion.

Herb



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Fairfield, CA, USA   USA
I noticed that Wally's no longer carries the base Purolators. Whole bunch of Frams. Some Mopars and Motorcraft and Delco, which is good.

Delco lists a PF13, which is short and about the same as the Fram PH-43, I think it is.... Since these are the ones for my 318 CID 97 Dakota, I have measured them (wish I remembered the measurements) and declined to install them on the B. Wix has a filter that is enough deeper then the PF13 that I do use it...can't recall the number, but it is something-68. NAPA filters use the same number. Bosch has a bunch that work well. And Ive used Delco PF 61, same as for a 93 saab, on the several times...it it a tall filter and for an upside down installation.

I like OEM-branded filters like Delco because they meet GM's stds and failure in service is a major expense for GM.

I normally shop ahead and like Amazon and if buying a bunch, RockAuto. I hate to pay $10 for an oil filter when I can get the same thing for less than 5.



1973 Pale Primrose Roadster. A nice 10-footer!
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Rod H. Avatar
Amity, Oregon, USA   USA
1964 MG MGB
1968 MG MGB GT
Mac, our local Walmart brought in Supertec filters again when they dropped Purolator Classics. I bought a half dozen Classics for my Van and the MGs when they were on closeout.



I can't understand why people are frightened of new ideas. I'm frightened of the old ones. John Cage

'63 MGB
'68 MGBGT
'80 VW Vanagon Kombi
'09 Mazda 3 with 5 speed manual

RichardTS Avatar
RichardTS Richard Smith
Covington, Louisiana, USA   USA
1973 MG MGB "The MG"
Get a Mann W917 and that problem disappears forever...

In reply to # 3514622 by MGB-GT V8 Olds Even though the inverted filter is easier to change, it is destructive to the engine. Have you not heard the knocks in the engine when starting? Many BLM decisions were not in your best interest. The area above the tube is empty of oil when it sits and that oil drains back into the pan. So each time you restart, the oil pump has to refill that empty space BEFORE any oil pressure is able to push oil to your bearings. Thus "Knock, Knock, Knock" on your bearings until that empty space is full. Not only no oil pressure to the bearings but no oil tossed on the cylinder walls either and if you think there is oil left there from when it ran last time you are wrong. The guy that said a short filter can be too close to the end of the tube is correct and if too close it will restrict oil flow all the time. An ideal size for the inverted filter is one that has about 3/4 inch clearance from the end of the tube to any obstacle in the filter, thus less engine running with no oil to the bearings or pistons and rings until that empty space is full. A better option is to go back to the bottom feed filter system and tell BLM where to stuff their top feed filter system.

MGB-GT V8 Olds Avatar
MGB-GT V8 Olds Howard Fitzcharles III
Smyrna, TN, USA   USA
1970 MG MGB GT V8 "The Green Dragon"
1970 MG MGB V8 Conversion "The Green Dragon"
All of the new inverted filter cars we received from the docks, knocked when started after only running during PDI. All inverted filter cars must exhaust all of the air in the top of an inverted filter before you have solid hydraulic pressure. That is a simple fact. We did take steps on our rebuilds by using assembly lubes (cam lube and a favorite on the rest of the engine was a 50/50 mix of STP and engine oil ) By experiments we found that STP stays on the metal where motor oil ran off and out of bearings. Even though STP was designed to be a viscosity index booster, it just happens to have the ability to stay on metal. Even an engine with correct oil clearances in the rods, mains and cam will have that oil run out with a warmed engine with warmed oil. But today synthetic oil is used a lot and I found that STP has a chemical reaction with synthetic oil and even by just painting the bearing surfaces not putting the STP in the oil. Guess what cam lube does it too. (at least Kent cam lube does) I can not get any oil company to do a chemical analysis on the results. If you don't believe me take a small jar of Synthetic oil and put just a small amount of cam lube or STP in it and shake it up and tell us what color it turned.

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