Thread: The Air Filter Poll

The Franz filters are excellent but pricey and When I get the dosh I would like to fit the double set up on the disco and then invest in Mobil 1.

I had the bloke out to quote fitting them onto a couple of tractors but it was going to be way too expensive for the tractors at the golf course but then working out what im spending on 6 or 7 services a year and 7 1/2 litres of oil and filters on each it could be worth it.

I asked him about 4 or 5 times on the phone just to give me a price but he insisted on coming out and I only wanted to know roughly how much so I could add it to the budget but I ended up feeling like I wasted his time when I didnt just buy them straight up.

They seem to be a great investment seems you can take it from car to car when you sell it.

Originally Posted by Gavo

1. Pre cleaners are only really effective if stationary or at very slow speed (earth moving equipment).
They rely on the air being drawn past some blades and spinning the air around depositing particles in a collector.This is very unlikely to happen or be effective at 100km/h.
2. I would fit an indicator in the intake before the filter and only change it when the indicator changes colour. Don't even think about changing it until it goes off.
3. I used to have a MIL MAC 4M dunny roll filter in my 2a and on my disco 200tdi. I think the are the best thing you can get the extent engine life. You can afford to use better quality oil as well as you are not dumping it every service interval. When you have to change you dunny roll filters you only loose 1 to 2 litres of oil. Makes you feel green and warm inside to know your not hurting the environment.
Franz home page. http://www.frantzfilters.com.au/

Mil Mac 55 Riseley St Ardross 6153 (look up the on line white pages)

I don't think I've ever travelled at 100klm/h when driving off-road, usually top speed gets up around 40klm/h sometimes 60klm/h, if your travelling in a group it gets a bit hairy driving fast through a dust cloud, when I was working on the gas line job and travelling behind I used to have to empty the Donaldson Cyclonic pre-Cleaner every 20 K's or so, traveling at about 30klms/h, so they certainly worked there, Regards Frank.

Originally Posted by isuzurover

- it is actually bad for your engine to change the air filter too frequently

Really??..........is that for all brands of air filters???

So dust isnt atracted to the oil in the filter, and I wouldnt be able to see particals gathering in the bottom of the white clean icecream container that I use to clean my inner filter.

Ben the reason behind rovers big statment that aircleaners were being changed too often in the service bulletins was because of $ nothing more, I would love to know the reasoning behind the so called over servicing of aircleaners.

You blokes that use paper filters do more damage blowing them out with compressed air and you are only meant to tap the filter on a hard surface to clean them.

Your oil filter only will sort particals down to 30 microns on a good day if your using a good quality filter unless your using something like the franz filter system so id imagine you would be doing more damage to your engine with particals flowing around your engine in your oil than what is going in and out the combustion chamber.

There are technical specs that can be interpreted many different ways as with any test, Im happy with my filter and I would recomend it to other people but it's really up to the individual but the paper filter is only designed for normal duty and should have a pre filter or something fitted if using it in dusty enviroments as they dont cope.

This is not a dusty environment, so the 93 D1 V8 has always run the standard paper type - 290,000ks approx and not rebuilt.

I change it when it looks foul, (every few years) but I give it a shake out every three months or so... and I find little bugs in there, but not much dust.

GQ

Originally Posted by Gavo

1. Pre cleaners are only really effective if stationary or at very slow speed (earth moving equipment).
They rely on the air being drawn past some blades and spinning the air around depositing particles in a collector.This is very unlikely to happen or be effective at 100km/h.

Sorry but the truth is the axact opposite - cyclonic pre-cleaners work WORST at idle and best at high airflow (i.e. when the engine is revving hard). These devices work on using particle inertia to make the particles impact on a wall (etc) when the inertia of the particles become too high for them to bend with the flow field. Most (properly designed) cyclonic precleaners have a flow-field inside the device which is largely unaffected by the speed you are travelling - only the flow rate of air through the device.

2. I would fit an indicator in the intake before the filter and only change it when the indicator changes colour. Don't even think about changing it until it goes off.

This is spot on though!

3. I used to have a MIL MAC 4M dunny roll filter in my 2a and on my disco 200tdi. I think the are the best thing you can get the extent engine life. You can afford to use better quality oil as well as you are not dumping it every service interval. When you have to change you dunny roll filters you only loose 1 to 2 litres of oil. Makes you feel green and warm inside to know your not hurting the environment.

As is this - but bypass centrifuges like that fitted to the TD5 work just as well (and can be bought neww for retrofitting to older engines). It is best to use synthetic oil if you want to extend service intervals as long as possible.

Originally Posted by Merv

Really??..........is that for all brands of air filters???

It is true for ALL air filters (and many other types of filters - basically every filter which doesn't work by sieveing). The dust you collect on your filter has a minimum void space of 70%, and a relatively small pore size. The air must flow through this "cake" before it even gets to the filter media, so once the filter has collected some dust, subsequent particles are then collected by the dust, rather than the filter fibres.

A new filter increases exponentially in efficiency for the first part of its dust accumulation, with initially NO increase in presssure drop across the filter, then a linear increase, once a cake starts to form (the initial stage is known as depth filtration and the later surface filtration in filter terminology).

Originally Posted by mcrover

So dust isnt atracted to the oil in the filter, and I wouldnt be able to see particals gathering in the bottom of the white clean icecream container that I use to clean my inner filter.

There is NO attractive force between dust and filter oil - unless the oil is charged, which is unlikely given the extremely low electrical conductivity of oil. Oil actually decreases the efficiency of a filter (for initial particle capture) as it decreases void space with impervious droplets of oil. What oil does is stops "particle bounce" occurring - making sure that particles do not hit and then rebound away, or are no reentrained.

Ben the reason behind rovers big statment that aircleaners were being changed too often in the service bulletins was because of $ nothing more, I would love to know the reasoning behind the so called over servicing of aircleaners.

See above - all filters will get "better" as they accomulate dust - unless they develop holes or tears, which is unlikely.

Your oil filter only will sort particals down to 30 microns on a good day if your using a good quality filter unless your using something like the franz filter system so id imagine you would be doing more damage to your engine with particals flowing around your engine in your oil than what is going in and out the combustion chamber.

Depends on the filter - some FULL FLOW synthetic media goes down to a 50% removal efficiency at 5 microns. The TD5 Bypass centrifuge can still remove 0.02 micron soot particles!!!

Much of the dust that goes in the engine air intake ends up in the oil - ever seen an oil analysis report? 100% of the silica content that shows up in the report is from dust.

Seems to be plenty of opinions on the K&N Filters, mostly negative.

I've used Uni Filters for many years on most of my 4WDrives and wouldn't use anything else (anything else as in a paper element), just ordered one for my D1. I also found the Uni Filters fitted/sealed better around the air box than some of the originals (Toyota, Nissan, Mazda).

Apart from that, on series Landies with the 2 1/4 motor I used the original oil bathe filter. The only problem I ever had was once or twice at high revs, doing some tricky beach driving a bit of oil got sucked into the motor (that was my guess with the amount of smoke that chuffed out the exhaust for a bit).

EDIT: As for oil filters, what do you think is the most negative thing the oil could contain and what size are the particles?

Best regards
DarrenR

Originally Posted by DarrenR

Seems to be plenty of opinions on the K&N Filters, mostly negative.

I've used Uni Filters for many years on most of my 4WDrives and wouldn't use anything else (anything else as in a paper element), just ordered one for my D1. I also found the Uni Filters fitted/sealed better around the air box than some of the originals (Toyota, Nissan, Mazda).

Apart from that, on series Landies with the 2 1/4 motor I used the original oil bathe filter. The only problem I ever had was once or twice at high revs, doing some tricky beach driving a bit of oil got sucked into the motor (that was my guess with the amount of smoke that chuffed out the exhaust for a bit).

EDIT: As for oil filters, what do you think is the most negative thing the oil could contain and what size are the particles?

Best regards
DarrenR

Have you seen this? http://home.stny.rr.com/jbplock/ISO5011/SPICER.htm
The UNI filter isn't much better than the K&N when both are tested against the ISO standard.

I have never tested it, but I suspect the Landie oil-bath filter would be no better than a cyclonic pre cleaner ON ITS OWN (i.e. no filter) - since it works on the same principle (with the addition of some very coarse steel wool and oil to stop particle bounce).

I don't really understand your question about the oil? Almost all particle size distributions are log-normal - but in oil you get a bi-modal distribution (2 log normal distributions) - the coarser particles being dust (silica) and the finer being soot. Coarser particles have the potential to do more damage, but small particles are there in much higher concentrations.