Tombo wrote:
Allrighty then.
I have 4 magnets on my filter......... and cutting it open with an exhaust cutter (so no swarf) there was about 1/8 of metal silt there, more than the magnetic plug could hold.
Yes, of course the magnets will hold some of the crap. But if they weren't there, it would not be going through the engine in any event. It would have been caught by the filter.
Tombo wrote:
On the subject of particle proximity to the magnet, look at it this way, i had a 1500L fish pond, the filter was at a guess 1L volume, this does not mean the filter only saw 0.00066% of the water, the pump flowed 3000L per hour. So the whole pond went through the filter every half hour which means it will end up catching most of the stuff there.
100% of the flow through your fish tank pond filter goes through the filter. On that example you have given it would take a little over 1000 hours to pass nearly all the water through the filter.
This is not the case in any car engine and with the magnet / filter theory although there is a good deal of flow through the filter, all that does enter the engine components in fact, hardly any will 'see' the magnets as only a tiny fraction will pass anywhere near the infulence of the magnets. With the filter ALL the oil has to flow through it, where as with the magnets a very small amount pass near them. A portion of the oil could never see the filter as it may never be picked up by the oil pump and even if it were, it could go via the by-pass valve.
Further, as VulcanBB18 has pointed out, there is a lot of non-ferous material that the magnets would have no effect on what so ever.
I have never bothered with magnets as would around 99%+ Mini Owners. To do 1000 kM in a Mini, the crankshaft turns over about
1 500 000 (1.5 million) times. That's only to do 1000 kM. In that distance the oil in the sump turns over about
700 000 (seven hundred thousand) times. So all those particals that get past the filter see the internal engine components in
excess of 500 000 (half a million) times in only 1000 kM.
I don't see too many engines that have been ground away because magnets were not fitted. In fact I've never seen any that have been ground away.
An engine that I rebuilt back in about 1989, fitted to a customers Moke has never had magnets fitted. That engine (when I caught up with the owner at Wagga at Easter last year) had done over 300 000kM, with only routine maitenance done to it since it was fitted some 20+ years ago. Not a bad innings for an A Series Engine. As it still goes well, does burn some oil, but not yet needing topping up between changes. But it still has very good oil pressure and no noise from the bearings.
No magnets here.
Do the maths. How many times has that crank etc seen particals that have gotten past the filter?
As I have said above, if it makes your wife love you even more, then go for it
<EDIT> Yes Gaf, I saw your pun - that's pun, not bum!
