A&Q about 350Z
Q:
I've been reading about using strong magnets on the oil filter to trap ferrous particles to keep them from circulating back in the engine. How much does this technique really affect the longevity of a motor? How much does this really trap? Does this get increasingly less important as more of the car is made out of aluminum, despite the widespread use of ferrous sleeves and whatnot?
A:
if the filter element isn't stopping the metal bits, you're in trouble anyway
don't buy cheap filters and you won't need such bandaids.
A:
I don't know of any reason that magnetic drain plugs and magnets on oil filters could hurt anything. No doubt there are metalic particles so small that they wash along with oil and are not removed by the very best strainer type filters. The greatest benefit must be enjoyed by the folks selling the magnets. Centrifigul filtering with mutiple magnets added...now that would remove every type of particle even non-magnetic. People considering spending money on these filtering extreems may do better spending toward getting some proffesional help. Overheating due to coolant loss will still be the most significant longevity factor.
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I use Wix filters already, and I have no plans of anybody getting my money over this issue. I plan to use the extremely strong magnets out of an old hard drive.
A:
Such devices are factory fitments to the hydraulic systems in heavy machinery.
In car engines (as you've pointed out) fewer parts are ferrous and the oil is changed more often.
The magnet traps are a great early warning device. When you find metal in them you then go looking for the cause of it.
If the same metal ends up in a filter, you never see it.
A:
having worked exlusively with mostly-aluminum motors, I've never understood the point of magnetic drain plugs, let alone all the other magnetic devices.
What, exactly, will it show you? When the crankshaft is disintigrating? When the conrods are rubbing on something? When the wrist pin is falling apart?
It definitely won't show you babbit material, let alone any other bearing material!
I make a habit of now and then cutting open a filter and inspecting it for metal bits for motors that I'm worried about. This will show bearing material, among all other metals. If you are seing pieces of the crank, cam(s), valves, conrod or any other ferrous metal on a drain plug magnet, your motor is already destroyed.
of course, if you have a mostly iron engine....well...you still can't see bearing material, so it still doesnt' do you much good.
on a hydraulic system, I'm sure this might be different. I couldn't comment on that
A:
I thought the sleeves and rings in my ECOTEC are still ferrous, despite the widespread use of aluminum in the motor. Is that correct?
A:
hehe, nothing damaged if you catch that early too. Just a quick bottle hone and maybe some new rings at the worse if you had a magnet!
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If only I had a magnet on this engine before it blew
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conrod?
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actually, I do take some of that back. All valve trains have ferrous to ferrous metal contact for the most part. If you had a cam lobe scoring badly, it would show you that. But thats it.
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yah, fractured con rod that let go. Punched a bunch of holes in the cases
Engine failures sometimes give you warning signs. Sometimes they don't.
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i've heard it first hand. with a friend, racing. got the bang then that terrible "rattling" sound of the conrod bits flying around in the crank case. then we found a 3" hole in the block where the best part of the no. 2 cylinder's conrod made a break for freedom.
A:
Going a little OT, but Iv pulled what looked like lead shot out of a sump.
It was actualy little round balls of piston material. The centre of the piston had melted out, and molten metal had formed balls as it fell into the sump, before cooling. Exactly the same process used to make lead shot.
A:
the piston melted?
there was something seriously wrong with that engine...