hi all, just wondered if magnetic sump plugs are worth the moneys. or do the leak etc?

 

got one in mine with no problems

 

what one have you got in urs mate?

 

I got one in, has a tiny leak i think as i can't see where else it's coming from, but i mean tiny.

 

think it was from motorsport developments, they used to advertise on here. Been on for a few years now

 

I have one and have no leaks. Shouldn't leak if you use a new copper washer.

 

It's probably not on mine, just can't see where it's coming from and the drip is on the plug.

 

The engine is alloy. The bearings are alloy. What does it collect?

 

I have 1 on mine and everytime i do an oil change arround 3k miles i always have to clean the sump plug, i can see very fine bits stuck on it. Its not as much atm as it was after the rebuild. I think for the sake of £15 i would have it.

 

I looked into it a few years back on my classic but for the sake of £30+ or whatever they wanted i decided not to get one

 

I think you mean the "block" not the engine mate. The vast majority of items that wear are steel.

 

Ive got one coming to be fitted. Im due to do an oil change and thought I'd get one at the same time. Are they worth it?....I can see the science behind them but if they make a difference in the real world, I dont know.

That said, the plugs on the diff and gearbox are magnetic from the factory so Subaru must of seen the benefit/need to have that. Why Subaru didnt make the sump plugs magnetic too....god knows.

Was it worth £25? Probably not but hey, too late now.

I got a Zero/Sports one from Scoobyparts, Ive got a lot of time for Scoobyparts, they are a good company and have bought from them many times before.

 

Nearly all gearboxes will have a magnetic plug or a magnet somewhere inside them this is because the gears are made of metal. These gears do wear with normal use but as Alcazar has said the engine block is alloy as are the bearings so no need.
If your magnetic sump plug is picking up bits of metal then I'd be worried there is something wrong with the engine.

 

The bores arent alloy mate, nor are the piston rings, valves, followers, cams, oil pumps, cam bearings, in fact, NOTHING in an engine that actually wears out is made of alloy. God knows where that rumour came from on ScoobyNet, its the only forum I have ever heard it on!

 

Theres a lot of that around!!

I fitted on simply cos it looks better than the standard one, and my standard one was rounded so much it was nearly round.

 

My point being that the primary wear item on an engine is the big end shells which are steel coated in an alloy of white metals which is not magnetic and is much softer than the crank so will wear quicker. As said if your magnetic oil sump plug is collecting stuff then id be worried something was wrong.

 

The primary wear item is far from the big end shells, as they are under very little frictional load due to being hygroscopic, thus they are likely the least wearing item. In fact, if we could actually remove all the microscopic metal particles from the oil, which is what the magnets are for, the shells would wear out significantly less than they already do. Engine wear is primarily caused by oil contamination, its as simple as that.

Sadly, we cant remove carbon with magnets, thus making bad remappers the primary cause of advanced engine wear in the world. LOL

 

Hygroscopic means they attract moisture! Not sure what you mean by that.
The big end bearings are under a massive amount of load during each firing sequence hence why if the timing isn't correct it will eventually destroy the big ends.
These particles you refer to i agree do cause wear in the engine but i know of many cars that have done 250,000+ miles and still running strong without the need for magnetic oil sump plugs, the oil filter itself if replaced regulary should be all that is needed to prevent wear of an engine especially on modern engines.

 

Sorry, what I meant was its a fluid film bearing, not a roller bearing and thus is not subjected to the same frictional wear as many other bearing types.

The load the big end receives is actually critical to its operation as the journal moves through its high, fixed and hydrodynamic zones which is why detonation, as you rightly say, causes mass destruction of teh bearing material and then, as it breaks up, the bearing journal itself.

Its not the load itself that causes the damage, its the detonation pressure wave that causes sudden dissruption of the oil wedge that this type of bearing is designed to run upon. These bearings, under normal use, have 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.

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 a lot longer with one in, for the very simle 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 flyin around your engine at high speed and pressure, acting like fine lapping paste.

Anyway, I only pulled you on your odd suggestion that the engine was alloy and thus the wearing parts were not magnetic, not to get into a minor technical argument about bearing technologies.


Interestingluy, that is not quite true... as the filter clogs, its filtration ability improves, and is designed to do so, thus changing it far too often can potentially shorten the engines lifespan a little.

 

Fair enough I'm not one for getting into arguments on forums lol.
Fair point about the filters though although too much clogging is another matter lol.

 

I have had one I'm my car for 2 yrs now and change the oil every 3000 miles. No metal filings on the plug , but a black paste like stu describes and engine is running fine.
I was skeptical at 1st after hearing a few stories about the magnets coming off when the engine is hot and going through the engine , but bought one all the same. Worthwhile IMHO as irrespective of how often you change your oil/ filter you will always get some engine wear.

 

That only happens with the cheap alloy ones as, believe it or not, they just press them in and of course the expansion coefficient between alloy and neodymium is different, so the fit becomes looser as the plug heats up!

The proper ones are all steel, so the magnet will never leave the steel sump plug even if its bonding process failed.

 

Whats the best one on the market?

Thinking of getting one for mine and one for my cousins Legacy EJ22 engined Crew Cab.


Steve

 

on a different subject lol does anyone know what size the magnetic filler and drain plugs are on the gearbox and rear diff? ino theres no filler plug on the gearbox lol ? anyone? thanks mike

 

got oe on mine fitted it 2 days ago after a oil change and no leaks etc :-)