Author Topic: Love this thead  (Read 5688 times)

Offline hairygit

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Re: Love this thead
« Reply #15 on: January 22, 2018, 11:59:26 AM »
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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Re: Love this thead
« Reply #16 on: January 22, 2018, 10:12:28 PM »
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.



Offline hairygit

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Re: Love this thead
« Reply #17 on: January 22, 2018, 10:44:30 PM »
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

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Offline taysidedragon

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Re: Love this thead
« Reply #18 on: January 23, 2018, 12:34:29 AM »
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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Re: Love this thead
« Reply #19 on: January 23, 2018, 09:38:08 AM »
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.

Offline Seabeowner

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Re: Love this thead
« Reply #20 on: January 23, 2018, 10:07:31 AM »
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.
Phil
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Offline Trigger

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Re: Love this thead
« Reply #21 on: January 23, 2018, 12:24:58 PM »
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

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The 750

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« Last Edit: January 23, 2018, 08:06:42 PM by Trigger »

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Re: Love this thead
« Reply #22 on: January 23, 2018, 03:43:38 PM »
Many different types of filter exit from the centre,  it seems more common that way generally.

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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.
« Last Edit: January 23, 2018, 03:45:17 PM by K2-K6 »

Offline Seabeowner

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Re: Love this thead
« Reply #23 on: January 23, 2018, 05:58:52 PM »
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.
« Last Edit: January 23, 2018, 06:13:43 PM by Seabeowner »
Phil
1971  CB500K0  Candy Jade Green or Candy Gold
1973  CB500K1  Candy Ruby Red
1975  CB550F1   Shiny Orange
1978  CB550K     Excel Black

Offline hairygit

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Re: Love this thead
« Reply #24 on: January 23, 2018, 07:18:06 PM »
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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Offline Trigger

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Re: Love this thead
« Reply #25 on: January 23, 2018, 07:54:45 PM »
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  ;)


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Re: Love this thead
« Reply #26 on: January 23, 2018, 10:01:27 PM »
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.

Offline Trigger

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Re: Love this thead
« Reply #27 on: January 24, 2018, 07:03:53 PM »
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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Re: Love this thead
« Reply #28 on: January 24, 2018, 08:31:57 PM »
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.
« Last Edit: January 24, 2018, 08:33:32 PM by K2-K6 »

Offline royhall

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Re: Love this thead
« Reply #29 on: January 25, 2018, 07:35:59 AM »
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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