Honda-SOHC
Other Stuff => Tricks & Tips => Topic started by: Trigger on January 20, 2018, 07:51:38 AM
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http://forums.sohc4.net/index.php/topic,170170.0.html
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I guess they don't bother cleaning the parts after a rebore. The bearings in that engine must be toast. ;D
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I guess they don't bother cleaning the parts after a rebore. The bearings in that engine must be toast. ;D
The debris on the magnet are from the end of the new rings and the rings scrapping into the crosshatch on the bores ;)
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Point taken Trig, just looks like a hell of a lot of metal in that oil. Maybe that's the magnet trick doing its job well. A lot of that shit may be stuck to the inside of my cases as there was nothing like that amount at first oil change.
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Am I the only one that thinks this is a totally pointless exercise.
Why would you put something within the engine that could potentially brake up or work lose and find its way around the engine?
Doesn't the filter catch the bulk of the debris?
If the magnets worked why can I see so much crap in the oil still?
Shouldn't you change the oil to remove contaminants anyway?
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Sod the technicalities of magnets and stuff, you can see how Mr T was voted in from some of those gentlemen's theories.....
Wierd the software here would not let me refer to that god like man by name. It overwrote *** #@%$ free zone *** etc. (Let me do it there though) STEVE?
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Is it usual after a rebore to have that amount of crap in the oil? I have never seen that much before by quite some way. That would worry me.
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Sod the technicalities of magnets and stuff, you can see how Mr T was voted in from some of those gentlemen's theories.....
Wierd the software here would not let me refer to that god like man by name. It overwrote *** *** This is a #@%$-free zone *** free zone *** etc. (Let me do it there though) STEVE?
I put that in during the election campaign (all 18 months of it)
The US site gets bogged down in politics. You are the first to mention it... 8)
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Would I take the piss ;D To be honest, it just shows how much the filter does not trap. The thread is just a alternative to a magnet sump bolt. If the filter is that good, then why do I find loads of crap in most sump pans ;) When you next do a oil change, drop a powerful magnet in the oil afterwards, you maybe surprized.
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I'm not going to worry about a little bit of crap in the oil if its soft it won't damage anything.
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The 750 schematic shows the filter housing flooded first and then exit via the filter bolt centre to the pressure galleries.
I can see the logic of having magnet in sump somewhere as it would "if effective" let less ferrous go through the pump first. But as already said, the filter should be able to stop further circulation just based of its micron rating.
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If these bikes are well maintained they do 100,000 miles plus without problems. So why is it 50 years on we now need magnets on the filters. What a load of bull, that's just a fix looking for a problem that doesn't exist . As I said earlier, I have never seen anywhere near that much crap in the oil when it's changed. That guy's engine is eating itself, bet he's talking about rebuilds by spring.
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Agree it looks back to front and slightly illogical but the honda illustration definitely shows oil supply from filter bolt into distribution galleries for crank etc.
Isn't the filter pushed against the engine case with a spring to leave the first holes (nearest to bolt head) exposed? The route through those holes into the bolt cavity is the overpressure (blocked filter) route I thought. Haven't got one in front of me, so please correct if wrong.
Most filters like this flow inwards as they generally have a cage in the core to prevent collapse. If you blow out through the filter structure it can't be supported to prevent it dismantling itself. You do see that type but they've normally got a metal "can" with holes in it to allow that pressure direction to be contained.
The filter housing pressure is more or less the same which ever way it's pumped as the whole oil system from pump out to bearings is equal, maybe a very small pressure drop across the filter material, but that's all.
Canister car type filters are usually the same, in through the peripheral holes and out through the centre bolt.
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If the filter becomes clogged, the pressure in the housing builds up, pressing down on the relief/bypass valve in the hollow bolt, allowing unfiltered oil to flow round the engine. The theory being, unfiltered oil is better than NO oil.
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Yes, if the filter gets more restrictive through particals, then pressure rises on the outside of element to a point which will breach the pressure set by the blead valve in the bolt.
This has got to be below the oil pump pressure relief valve threshold or it would just go out that way first.
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Which is why it's NEVER a good idea to use an aftermarket bolt in the oil filter housing, as you can never be sure if the valve will open as it should in a crisis, whereas with a genuine Honda one, you can be quite certain it will do what it is designed for.
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Try thinking of the valve inside the bolt as an inlet valve in the intake port, the holes in the bolt being route from carbs.
If you pumped oil under pressure down an engine intake it'd open the valve by pushing on the back face and pull the valve spring with it, so opening the port and letting flow go through that route.
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If you can lay your hands on an old oil filter bolt it is much easier to understand. As you know the bottom set of holes (closest to the crankcases) are clear of the filter, BUT they are normally blocked by the pressure relief valve, unless the filter gets clogged and excess pressure builds up in the filter housing and forces the valve open against spring pressure holding the valve shut, forcing it open, allowing oil to flow unfiltered to the engine. If you have an old bolt, you will see it is cross drilled just above the end of the thread with a thin pin inserted across the opposite walls of the bolt. Using a thin punch or similar, tap the pin out, grab the exposed end with pliers and slowly pull it out, mind your eyes/face, the spring retained by the pin is under considerable pressure and may fly out with some force. Then the valve should drop out, and you should be able to see how it works better than anyone could explain. Also, next time you need to do an oil / filter change, warm the engine as normal, then remove the filter/housing BEFORE draining the oil. Then, making absolutely certain the ignition is switched OFF (remove the keys to be 100% sure) kick the engine over a couple of times, and you will see oil flowing from the smaller hole at the front of the crankcases, which would when assembled surround the filter, go through the filter, and return to the engine via the large threaded hole the bolt goes in, and on to the crank etc
Sent from my X6pro using Tapatalk
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I haven't started any of my 500 engines for over 30 years, so no chance of looking. I do have a few spare crankcases lying around, next time I see one I'll drop some fluid down the oil pump outlet and see where it comes out.
I remember the oil filter bolt quite well, certainly remember the way the valve was held in but never had the need to remove the valve. I seemed to recall the spring is the first thing fitted, then the washer, then the filter not the other way round as you explain it. It was why most people lost the washer when changing the filter as you couldn't see it under the filter and the pressure used to stick it to the filter sealing rubber and got thrown away with the filter, that would make the valve being fitted just under the head of the bolt not near the crankcase. If my recollection is correct of course.
I think you're confusing the pressure relief valve with the big spring that fits over the bolt. Different thing altogether. :o
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I've got it the same way as Oddjob, with the bolt in the filter casing, you first put the coil spring onto the bolt, then the washer, then the filter.
The spring when all assembled pushes the filter against the engine leaving the holes nearest the bolt head clear for bypass.
The filter is not needed to be located any more positively as the oil pressure is virtually equal acting on it from outside to inside (only a slight drop from filter restriction) in other words the whole filter housing is at the same pressure once oil pump is running.
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CB500 shop manual shows oil flow fairly clearly. Oil enters outside filter and exits via central bolt.
Looking at the centre bolt there are 4 holes that must be exposed above the filter when it is in situ. These are the 4 furthest from the crankcase. There are 4 more holes that must sit just inside the centre of the filter and these are blocked by the valve and spring up the CENTRE of the bolt, so that if excess pressure is built these 4 holes are exposed inside the filter and hence oil flows from the top 4 to the lower 4. The oil has now bypassed the filter, and can then enter the 6 further holes towards the threaded end as normal where it enters the galleries. Crisis averted...maybe. Sorry it's long winded.
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A few pics of 750 and 500. The oil leaves the pump and enters the oil filter housing on the outside. The oil enters the four holes at the top of the oil filter bolt, as the pressure builds up the oil pushes the spring down and exits at the next set of four holes.
The 500
[attachimg=1]
[attachimg=2]
The 750
[attachimg=3]
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Many different types of filter exit from the centre, it seems more common that way generally.
[attachimg=1]
As above most car cartridges are that way. Think it's partly because of more surface area outside and so longer interval before blocking becomes a problem. Also, pressure on the outside of a tube is easier to resist than the opposite with the same material's spec, so with both considerations you can reduce the filter size and still maintain the flow required.
Both fuel and air filters usually have outflow from centre generally if arranged in a loop configuration.
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A few pics of 750 and 500. The oil leaves the pump and enters the oil filter housing on the outside. The oil enters the four holes at the top of the oil filter bolt.
Surely if the oil enters the oil filter housing on the outside it simply flows through the filer. (unless it's blocked). It doesn't need the 4 holes at the top except when the pressure across the filter exceeds the spring setting.
Pressure alone will not open the bypass valve, only pressure drop across the filter.
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That's the whole point, if the filter is severely restricted or blocked, the exposed holes allow oil in the force the bypass valve open and flow down the bolt to the engine. If the holes weren't there, and the filter was blocked, how would oil get to the engine??
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Nope, the oil is under pressure from the oil pump (where the first pressure valve is) to the outside of the filter and if there is too much pressure then the oil under pressure enters the holes in red and exits through the next set of holes by compressing the valve and spring ;)
[attachimg=1]
[attachimg=2]
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There's always a pressure drop as you go through the system else the oil wouldn't flow.
The leak down via crank bearings and cam supply etc is what allows space for the oil pump to push volume, it's only pressured because the bearing design allows for a controlled leak down as the engine's designer wanted, which in turn (combined with pump capacity) gives the desired replenishment rate to each bearing location and type.
The oil will simply take the path of least resistance. If the oil bolt blead valve is set above the resistance offered by a filter in good condition, then the oil's easiest route is through the filter material. If that becomes more restrictive to the point it exceeds the blead valve resistance then the easiest path is that through the emergency bolt holes.
The above has to be lower than the oil pump's own relief valve though as you'd get a non supply through that route being opened.
It's the same as any pressure relief valve though, in that you can design it pointed in either direction. This one is just used as an exit from the filter housing as it exceeds the spec it's designed to if the normal operation is impeded by the filter material being blocked.
It's right to say that it is going to a low pressure area though as the bearings are inheritently leaky so if supply slows down, the pressure will drop accordingly. That's why the oil light would come on if you reduced supply volume.
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Can we all agree that the magnets will work ;D ;D ;D
A magnetic oil filter bolt would work much better than a magnetic sump bolt, me thinks ;)
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Oddjob, as you say it's something that's so reliable you never really have cause to do anything with it other than when you replace the filter during service.
Trigger, I'd say sump was preferable just so anything you catch hasn't had to go through the oil pump, both sides of it and also expose the leak back valve, plus possibly the pressure relief valve to bits that may degrade their operation.
You're going to get most of it during run in of new bores as you've pointed out "sump marzipan" (well that's what it feels like) which is going to diminish fairly quickly when rings etc have completed lapping.
Less interaction on the 400/500/550 though.
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OddJob has an engine with 263,000 miles on it without problems. Just how would magnets enhance that. We have managed nearly 50 years with nothing other than a magnetic sump plug to help things, and loads of engines go over 100,000 miles without issues. Surely that's why we change the oil so often, so with magnets we can go 5000 miles between oil changes then. I think not. I'm not really sure what problem this fix is fixing. ;)
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The magnets is helping collect crap while running in after a re bore ;) As K2-K6 has said, the worst amount of metal in the oil is from the meshing of new gear box cogs. All these new parts have sharp edges which need smoothing and as a result the engine could suffer damage from these new parts.
I have been in so many workshop where the mechanic will remove the oil filter housing to change the filter and not clean the housing before replacing the filter. And as Oddjob stated, ignore the washer, stuck to the filter >:(
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royhall, agree that it's al very competently designed system and seems to serve the purpose well but oddjob's high mileage example just shows the potential and not necessarily the aggregate of what happens to all the examples. Plenty out there that get nowhere near that total without significant wear problems, for whichever reason.
And we don't know what level of wear is in that example to make it definitive.
Reality is that you're going to get something resulting from the initial wear of new components, question is how is that best delt with. I think it's something that's worth debate to see what the combined knowledge and experience on here throws up.
My feeling is that I'd rather not push it through the oil pump if that were possible. It looks like the filter will catch it but we don't know the micron size of the debris and if it has the potential to pass through the filter which appears to be around 10/15 microns.
Also likely that if we stood in Trigger's position then a more concerned view is apparent as most engines going out are rebuilt and fall into this category. I don't know the "warranty" position that's taken but any additional precautions can only enhance that type of work in delivering to clients.
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I would hazard a guess that running in can mark the difference between an engine getting to 250,000 miles which is roughly where my 500/4 got to with its sidecar, hard to say when the clocks have died twice and its been round the clock as many times, and yet I have bought cb 500 and 550s that show 35k on thr clock and wear on seat, footpegs etc makes this seem genuine and the engines are totally goosed, right through destruction. I would think the odds of many cb500 or 550 bikes going round the clock are fairly low, bikes tend as a rule to not cover massive milages. So basically I think trigger is right, controlling that swarf from running in is likely to be key to long engine life. My high miler bike has less engine wear than bikes on a quarter the mileage and in my ownership it arrived with oil like tar, already with 60k on the clock and a sidecar so constantly worked hard. Seems the only thing to explain the fact it got there is that it was run in hard.
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found these which covers the flow :D
(https://i.imgur.com/a0yW88V.jpg)
(https://i.imgur.com/4kA2kAp.jpg)
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Magnets in oil systems are common place in aero engines, especially the piston engines of the 40s and 50s and the early gas turbines. Their main purpose was early detection of imminent failures, but they also collected a lot of the fine crap that the filters could not catch, which has to be beneficial to any plain bearings in an engine. It is strange that people think that filters catch everything. If they were designed to do that you would need a massive oil pump to overcome the pressure drop resulting from trying to push oil through such a fine filter.
Modern aero engines still have “chip detectors”, as they were known, but they are now linked to software that can interpret was is on the detector. In some cases they are so sensitive they have to be switched of for the first few hours of running post build.
Raymond
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The one item that most of us rarely look at on an engine but is the only one with unfiltered oil is the oil pump. Hondas oil pumps do seem to be very robust and over speced with little wear showing even when mechanical disasters have happened. Way back when i did a lot of Ford and Vauxhaul engines i refused point blank to not fit a new pump but they were a lot cheaper.