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Tanuki

"Blue Box" oil-filters...

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I made the mistake recently of doing an oil-change on my TD5 and using an oil-filter canister that came in a blue box. It was all I could get in a hurry. In the past I've used Mahle, Mann&Hummel, or Allmakes without problems.

After the oil-change I had about 25PSI pressure with a hot engine at normal driving-speeds.

Aiee!! Scheiss! Sapristi! Zut Alors! Merde! or other international words to that effect.

Before the oil-change, running with 12,000-mile-old oil and the Allmakes filter that had been in there for a year I was getting nearer 50PSI. I drove home slowly and borrowed another car to visit a genuine Land-Rover dealership who sold me a "LR Genuine Parts" filter, which when fitted restored my oil-pressure back to what it should have been. Big sighs of relief and time for a bottle or two of Fursty Ferret.

Now I'm going to take my angel-grinder to both the old Allmakes filter and the new blue-box one to do a 'compare and contrast' on the insides.

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Just as well you had an oil pressure gauge.

Looking forward to photos of the autopsy.

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Autopsy Report part 1:

 

The filters came apart easily - I just angle-ground round the 'can' as close to the mounting-flange as possible, and the insides were then revealed in all their slimy glory.

First impressions: construction is similar though the internal filtration-module of the Allmakes one was slightly taller (75mm) than the blue-box one (70mm). They were both the same diameter. The depth of the pleating is essentially the same in both cases though the blue-box one appears to have slightly fewer pleats.

See photos. The old Allmakes one is the more-discoloured of the two, on the right of the photo in each case.

Tomorrow, after I've left them to stand and let some more of the oil drain off, I'm going to cut the paper part off and unfold it so I can measure it and then we'll be able to compare the effective filtration-areas between the two.

But first - it's Beer-hundred-hours here!

IMG_3658.JPG

IMG_3667.JPG

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1 hour ago, mmgemini said:

Who makes the oil filters in the first place. Not Land Rover

True, but I hope JLR have decent quality-control and require that whoever actually makes their filters has certain standards to meet as part of the contract.  Even if the manufacturer is in China, Eastern Europe, South America or similar.

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8 hours ago, mmgemini said:

Who makes the oil filters in the first place. Not Land Rover

They spec the parts though, and test them before accepting them. As TSD discovered doing an autopsy, even a genuine Bosch starter motor that fits a TDi does not have the same level of sealing as a genuine Land Rover starter motor made by Bosch. Likewise almost any part fitted by any manufacturer Vs the OEM replacement.

As for blue boxes, I reckon their stuff is specced by sending a blurry camera-phone photo of the part to China and taking the lowest bid on something that looks like it might just fit if you squint and stand a long way away.

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Don't quite get this. You are saying that the "upper class" filters increase the oil pressure by 25psi?  Normally oil pressure is an indication of how tight/good the big-end  and main bearings are, and of course that the oil pump is working.  I would expect a good filter to work well while allowing oil to pass as freely as possible, not double the pressure causing a reduction in flow and load on the pump.

If there is a difference in pressure across the filter, it will probably be due to the material itself i.e. how porous it is.  Not so easy to measure.

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3 hours ago, Alsace_rangie said:

Don't quite get this. You are saying that the "upper class" filters increase the oil pressure by 25psi?  Normally oil pressure is an indication of how tight/good the big-end  and main bearings are, and of course that the oil pump is working.  I would expect a good filter to work well while allowing oil to pass as freely as possible, not double the pressure causing a reduction in flow and load on the pump.

If there is a difference in pressure across the filter, it will probably be due to the material itself i.e. how porous it is.  Not so easy to measure.

No, he's saying that dire filters like Britpart's bock the flow and drop the pressure of a healthy engine by a potentially catastrophic amount.

The quality of the filter paper is important, but the reduced length and heavily reduced pleat count in the Britpart filter probably reduce the paper area by 50%, hence the poor flow.

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I can see what you are saying Snagger , it would suggest that the oil pressure gauge feed is on  the out-flow side of the filter ? as the pressure before the restriction would be greater . Is the spring on the left filter some sort of blockage bypass relief valve?

cheers

Steve b

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You always put the pressure gauge on the output of the filter so you monitor the pressure fed to the bearings, and so that you would be aware of a blocked filter by a drop in pressure.

If it were on the inlet it would register high pressure if the filter was blocked.

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OK, I've sliced off the pleated parts and unfolded them so I can measure the lengths - but for the life of me I can't find my measuring-tape.

The spring-bit shown in the photos lives in the bottom of the canister - where it pushes the filter-element up against the rubber sealing-washer, which itself also forms the anti-drain valve when pressed against the mounting flange of the filter-case. Both filters use the same approach.

Looking at the construction of the bits in the centre of the filter-element, there is a difference between the two: the Allmakes one has a large-diameter hole up the central tube, with a spring-loaded assembly visible; the blue-box one has the same diameter of main central tube, but with a smaller-bore device in the centre (blocked-filter bypass?) - the hole in this through which the oil must flow is only about 8mm diameter - could this be the cause of the pressure-drop?

Photos to come later today, when I've found my measuring tape!

Does anyone know the design flow-rate of oil (Litres per minute) in a TD5? With that, and the viscosity of the oil known, the pressure-drop across the small-hole-device could readily be calculated from Bernoulli's equations.

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The autopsy continues: all this section refers to the 'blue box' filter; the Allmakes details are to follow.

I cut off the paper by running a Stanley-knife around each end, pulling the end-cap off to release the paper, then slitting it along one plleat and un-concertina-ing: the effective length stretched-out is 65 inches.

Then I looked at the rest of the filter.  The pleated paper concertina is supported by a spirally-fabricated perforated metal tube up its centre; that's to be expected.

Into the middle of the perforated metal tube is a tubular protrusion which connects to the centre outlet of the filter flange.filter1.thumb.jpg.02b610753719bcf17e164e851189fe06.jpg

The only way for filtered oil to pass from the void between the perforated tube and the filter-outlet is by way of the hole in the centre of the protrusion.filter2.jpg.thumb.JPG.e3f125f754c8d4a13e7979227702f682.JPG

This hole is *tiny* - I couldn't put a 6mm rod through it; what you see sticking out of it in the third photo is a 7/32" twist-drill.filter3.jpg.thumb.JPG.ef722b1f04728d13cc7367711a6b0f9b.JPG

To make this hole's oil-flow prospects even worse, on its inner side is an anti-drain valve - a 'top hat' shaped rubber thing pressed against the inside of the hole by a spring.

So, we have the entire engine's oil-flow having to go through a hole that's less than 1/4 inch diameter, with a further restriction once the oil's made it through the hole!  

I think that's where the pressure-drop is coming from.

Edited by Tanuki

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OK, the final teardown - this time of the old Allmakes filter.

Stripping the pleated paper filter-element itself out and measuring it gave 64 inches un-concertina'd length. That's within the margin-of-error compared to the blue-box one [but remember that the 'core' of the Allmakes one was 5mm taller...]

 

Without the ability to measure the permeability of the paper used in the two filters, I can't say one way or another whether the pressure-loss difference between the two is related to the area of filter-material. But I suspect it isn't.

Ripping off the spiral core-support tube (same construction as the blue-box filter) revealed a similar _style_ of centre outlet-fitting, but implemented differently. This one had a *much* larger hole in the middle for the oil to flow through - 14mm diameter!

filter5.thumb.JPG.991e5f84a4023ab224831d044bcd37ec.JPG

 

Since area of a circle = pi times the diameter of the circle, if we give the blue-box one's centre hole the benefit of the doubt and call it 6mm we get:

        6 x 3.142 = 18.852 square millimetres of cross-sectional area for the oil to flow

Whereas the Allmakes one's 14mm centre hole gives

        14 x 3.142 = 43.988 square millimetres of flow-area.

I know which one I prefer.

 

Finally, here's a photo of the centres of the two filters side by side... draw your own conclusions.

filter6.thumb.JPG.add9d803fd566b32f5caa1da92ce34f2.JPG

Happiness is a Big Hole!

 

 

 

filter4.jpg

Edited by Tanuki
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Food for thought....

You could brake-clean the paper, then use a piece over a bottle top with a hole in, and measure how much water goes through in a given time....

But maybe you have better things to do!

Good write up though, as I say very much food for thought.

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I may do some filter-experiments like you say.... just gotta find a suitable bottle to use as a funnel.

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That's shocking! But even worse than those numbers suggest as you've used the equation for circumference, not area. Area is Pi r2

I make:

~28 for blue box 

~154 for Allmakes 

Flow area five times smaller is bound to hurt. That's gotta be a new low even for Britpart. 

Thanks for the write up, that's most interesting. 

Edited by lo-fi
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I used to work in the Agricultural/Plant industry, and took an interest in oils and filtration.......................

The times customers would come in and given the choice between a Genuine Parts and a "will fit" diesel filter, would insist on the cheap one because a Genuine one was three times the price AND blocked up too quickly ................................

We also did a lot of warranty work as a result of filter failure. It is ALWAYS better to buy a GOOD filter for any application.

Buy only Genuine manufacturer, or Mahle, Mann, or Purflux. and K&N air filters if you want one.

Cr****and, W*x, F**m should be avoided.

Faulty bypass valves, and poor filter mediums are the main problems. 

Tanuki was lucky. as there was an obvious symptom and fault. Poor filtration is normally insidious and gradual and in the long run will cost you a great deal

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This is curious, as it does not cost any more to punch a large hole as a small one. i could understand less paper, for instance, but can see no reason for a smaller hole, except perhaps making use of tools already set up for some other application. perhaps it is to do with the way the byepass valve is produced.

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3 hours ago, rusty_wingnut said:

I am about to throw all my Britpart filters in the scrap! Thanks for the post

Sell 'em at Sodbury, someone'll give you 50p for them!

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On 5/25/2018 at 1:25 PM, Sheffield said:

This is curious, as it does not cost any more to punch a large hole as a small one. i could understand less paper, for instance, but can see no reason for a smaller hole, except perhaps making use of tools already set up for some other application. perhaps it is to do with the way the byepass valve is produced.

Maybe they're mass producing that part and fitting it to filters regardless if the engine is 600cc or 5000cc? More smaller engine cars on the road so more volume and the smaller they are probably the cheaper to make. Plus in theory it's probably OK with a nice tight oil pump making the manufacturer quoted 'suck'?

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As to the "why" I guess it's a classic case of "because they can get away with it".

Historically, "Brands" emerged as a way of reassuring consumers that they were purchasing stuff with an underlying quality/value ethos. Sell carp with your brand on it and over time your brand gets devalued, so you can no longer expect to get a premium price for stuff with your brand on it.

"Blue Box" stuff, well, if it goes-in-and-out or round-and-round or has-stuff-flowing-through-it - I'll confidently de-recommend it!

[Another example: a while back Duracell batteries - when they were owned by Mallory - were truly the dog's danglies. Three decades later the brand has been sold on through various companies and now they're leaky as a five-dollar-whore and have ruined several of my Maglite torches].

Edited by Tanuki

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11 hours ago, Tanuki said:

...
Historically, "Brands" emerged as a way of reassuring consumers that they were purchasing stuff with an underlying quality/value ethos. Sell carp with your brand on it and over time your brand gets devalued, so you can no longer expect to get a premium price for stuff with your brand on it.

...

"Wolf" is another classic example, back in the day they produced good quality industrial power tools, now the brand is plastered all over cheap & cheerful DIY stuff.

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2 hours ago, rtbarton said:

"Wolf" is another classic example, back in the day they produced good quality industrial power tools, now the brand is plastered all over cheap & cheerful DIY stuff.

Bosch too.

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