Manufacturers fit one as standard in the transmission if I'm not mistaken.

 

The arguement for and against these plugs is, quite frankly, irrelevent. Installing one will do no harm and you may actually catch something (see the other thread on that subject!) Not installing one will save you some money. End of story

Like you, I'm not about to buy one as the return to sump catch tank pipe goes where the plug used to be! Now, there's another subject for Pete to get his teeth into?
I have something of a perverse admiration for Pete's wind-up skills but that is all I admire about him even though I share a similar age bracket!
(Read my posts #48 and #57 if you missed them.)

JohnD

 

This thing about iron parts on a engine not wearing:

Why is it I've seen plenty of engines (not necessarily Subaru) with camshaft wear (steel), lifter/follower wear (steel), oil pump gear wear (steel), crankshaft wear (steel), cylinder bore wear (steel) and piston ring wear (steel).

If on inspection of a working engine (i.e one that to all intents appears to run ok) where I find worn steel components, I have to ask...if many of these parts are rubbing against a softer metal (especially crank and bores), why have they worn? Of course the easy answer is to blame the issue on lubrication and maintanence, but one would expect the engine to show some serious evidence of imminent and catastrophic failure, when its simply not the case. Most of the time it appears to be simply wear and tear.
Most recent one was a Daewoo with basically no camshaft lobes left. Rest of the engine was fine. New camshaft and lifters and away it went happy as Larry.

Given that, how much of a issue is oil filtration? My old motorbikes have no oil filters, nor magnets (as with my lawn mowers), some have a small sludge trap and a thimble-sized wire mesh on the pickup in the oil tank, but thats it. Usually upon draining, the oil contains very fine metallic debris from component wear. Yet these engine carry on running regardless.

Granted tolerances are slacker and component stresses and loads are probably lower from a degree of over-engineering which more modern engines lack. Still, it doesn't appear to harm them that much.

So with this given experience and insight I'm pretty sure I could bin the oil entire filter on a modern engine (including the Impreza), and given regular oil changes it'd probably last not much less than one fitted with a filter! I've seen torn oil filter media on cartridge type oil filters found on many modern cars, and it doesn't seem to have made the blindest bit of difference - stick in a new filter and send it on its way, comes back for a service 15K miles later, fine, another 15K fine, another 15K still fine!

The fact that Imprezas are fitted with spin-on filters...and nodoby ever opens them up, who is to say that the filter media inside hasn't torn or split allowing unfiltered oil to pass, or even the by-pass valve to fail or stick open? It'd be great if eveyone who changed their filter takes a can-opener to it and has a look. I bet a fair share probably have failed, and the driver is none the wiser! I doubt its a problem on a maintained engine anyway hence my thoughts that the presence of a filter TBH isn't as critical as people may think.







....Can a borrow a engine to try it out on?

 

I'm running my engine in at the moment after a full re-build including a re-bore ,piston and rings. I have a magnetic sump plug so i will be interested to see if there is any evidence of the bedding in stuck to the magnet come oil change time

 

That will depend upon how scrupulous the cleaning was after the re-bore. If it wasn't done thoroughly, you'll have iron filings from the cylinder boring all over it first time of looking. That is why most engine builders insist on a filter change at 600 - 1000 miles, to get that debris out.

David APi

 

does the debris stick to the sump plug???


sorry couldnt resist

 

Reminds me of a photo-build thread of a Seat Cupra where the onwer fitted uprated pistons and honed the bores with engine block still fitted in the car.

There is no way on earth he could have properly cleaned out the metal particles from honing the bores. Not sure how that affects the way the rings bed in or even the valve seats either (as the metal dust gets everywhere).

But the engine worked and developed good BHP, so that showed me! Even so, I wouldn't do it unless I was rebuilding a shed/banger on the cheap.

 

So if cleaned properly there should be no evidence of the rigs / liners bedding in together?

I'm sure my engine will have been built and cleaned to the highest possible standards.
Like yourselves the builder i used is highly respected and highly recommended.

 

he certainly is, he is the one im going to use when the time comes

 

My car has never run smoother. It's quiet when cold with no piston slap noise i can hear and so far has used no oil what so ever. Although im not revving higher than 4k it was revved higher during the running in map being installed without problem.

sorry so go off topic folks.

 

Rings to liners / cylinders is more of a polishing situation. Both are nominally round and the process is to make them both the same shape [ radius ], So there is no real debris created, rather more like the finest of fine particles and the filter will grab them every time. Yes, in that situation they will get attached to a magnetic sump plug, but normally a good quality filter is all that is necessary.

David

 

Magnets have advanced since I was in the industry 15 years ago. However I can say that fitting a good sintered Neodymium Iron Boron magnet such as N45 grade will do do harm and WILL pick up ferrous particles. Whilst maybe the filter will catch most of the ferrous debris some very fine particles will find their way through and typically end up embedded in the white metal Bearings - being softer than iron! I have no allegiance to any supplier of these and I'm not running one myself, but as others have said, they will do no harm.

 

They will do no harm ..... true ...... until one of the following happens:-

1. The magnet becomes detached and attached to god knows where in the engine.

2. The clump of very fine particles gets washed off the magnet, now being a larger lump of magnetised metal of course.

It's a personal choice, I'm a Yorkshireman and I don't buy things I don't need.

 

Yup, Middlesbrough is just a small town in North Yorkshire.

 

no its not,its a **** hole in county durham

 

I think if the magnet were to become detached it would more than likely attach itself the the bottom of the sump pan and cause no damage.
Secondly, if you had "a clump" of metal particles stuck to the magnet the engine would be knackered anyway. Plus i doubt the oil would be able to simply wash it off the magnet, if it did i expect they would also fall to the bottom of the sump pan and stick if they had become magnetized.

 

dont confuse pissy's posts with facts, he is always right,we know this

 

Goes to show what you know, which is very little.

 

Pete, stop trolling. As an experienced engineer, you'll no doubt know that the 'clump' of particles won't be washed off the magnet and, if it somehow was then, it would no longer be a clump of particles as it would not be magnetised and would disperse and be captured by the filter. As for the magnet becoming attached to something rotating, no it would be attracted directly to the nearest ferrous metal, i.e. the sump. You should be doing much better

Indeed

 

I forgot all about this topic!

Yes... and its far safer there than running round your engine for 1000 miles. Also bear in mind that modern cars do not have this low mileage oil change. My missus new Nissan has its first oil change at 12months / 12000 miles!

A filter wont grab those particles at all, the filtration medium can only collect quite large particulate. think about it, how would it work otherwise?

Absolutely correct. its the fine particles that work like a lapping paste, slowly grinding away at everything.

 

But only if those parts are not cylinder bores, piston rings, oil pump rotors, camshaft bearings, camshaft lobes, camshaft drive chains, camshaft drive wheels, cam followers, valve shafts, valve springs, valve collars, turbocharger shafts etc etc? Why is that?

Reference the soft metal bearings, I am sure the engineers amongst you know that these dont actually wear at all in normal operation, having virtually no wear whatsoever on a running engine. I would estimate that around 70% of crank bearing wear is caused during cranking and around 25% by foreign matter in the lubricant... its this foreign matter that we try to cut down with the use of magnets.

Nobody has suggested an engine wont last for a very long time without a magnetic drain plug in, but its a simple fact that they will likely last longer with one in, for the very simple reason that a paper filtration medium can only filter down to around 35 microns, and the magnet will attract particles far less than that. With a good strong magnet in use, its normal to see a thin smearing of black paste around the magnet at oil change time. Those are largely the particles that a paper medium cannot filter, and they are the particles traveling around your engine at high speed and pressure, acting like a fine lapping paste.

Ref the magnet coming off - how is that going to happen with a steel drain plug? Have you ever seen an OE use an alloy sump plug? Anything built out of alloy for this purpose is built to a cost, so you can probably guess how good the magnet quality is, given that is the most expensive part of the whole assembly!

 

Steady on TT, we all know PS loves to wind us up and largely gets ignored for that reason, until someone rises to the bait. But there is no need to start getting offensive about it.

 

Agreed, tone in down mate.