oil filter bolt, "ball valve"?

hi ,all
i am converting my xj600 to a spin on oil filter, i have most of the bits to do so, including a sandwich plate with take off's for oil pressure and temperature gauges.
my question is ,what is the purpose of the little ball and spring, inside the original oil filter bolt that holds the cover on . its item 4 on the drawing.
i assume its some kind of pressure relief valve, but the engine has that at the oil pump, and the spin on filter wont have it?
Yamaha XJ600 (3KM3, 1990) 999 A 1990 YLFILTER supplied next day (UK only) by Fowlers Parts

 

Is it a oil bypass valve l wonder if the filter gets blocked?

 

Yes

 

Yes, for people who don't change their filters and scream the nuts off the bike while cold...

 

good ,then , not needed for us regular maintenance guy's .

 

Not needed because spin-on filters have check-valves in them.

 

Well now - check valves or relief valves? A check valve I would term a non return - specifically to prevent drain down of the filter when the engines off. a relief valve is what the OP has.

 

Relief valve. Brain fart on my part. This Sunday has been a very busy working day, instead of a relaxing rest-day.

 

Did I tell the story of the MGtb (1930s) engine I rebuilt recently? The felt oil filter had been replaced by brazing a plate in the split casing, allong with a nipple to take a spin on oil filter. It was used like this for years. The only problem was that the flow was backwards, and the check valve prevented any flow. So the bypass valve provided the flow path....

 

now then' which spin on filters have the valves in? are you refering to the ones Chacal sells.
i was planning on using a bog standard filter, like the one on my goldwing , now i'm confused

 

Alll spin on oil filters have a bypass valve built in. Every single one, regardless of manufacturer.
The old "standard" motorcycle oil filter is just the filtering element, which is why the bypass valve is in the bolt for the filter cover.

The old standard has made somewhat of a comeback since they are less expensive to produce (not that they cost less to buy), and have a lower impact on landfills.

 

i looked up the bypass pressure on spin-on filters that fit the threads and dimensions the adapter needed.
i knew i'd never remember the number but it was a filter for a Subaru Justy
it crosses to a lot of other cars but i can remember that strange little car

 

It's funny how a relatively normal car was such an oddball because it didn't really fit into Subaru's traditional line, other than the 4-WD.

 

Should have called it "Rusty"...

 

thank you very much, k-moe, i had confirmed earlier exactly what you said, that all spin-on's have the valve inside, my engineer brother confirmed it.
its something i never realised before, and iv'e changed dozens of them, in the past.
so , alls well,

 

Well I don't think they all do, sure enough most do, but a google of the part number usually gives away their secrets.

 

All do. There is no way a company would want to risk a class-action lawsuit over ruining an engine because of the lack of an internal part that costs pennies to make and install.

 

Not quite - the one above was for a 70's design - maybe you've heard of it, a few million cars sold. Hint is in my id...

 

Are the pressure triggered reliefvalves all the same in regard to the pressure to open this valve?
Had to change a filter once in France (Honda V65) and they were very meticulate to sell the proper filter because of this valve (pressure).
Even asked about the viscocity of the oil used.

 

Was, or is? There were some motorcycles into the early 80’s that didn’t have oil filters at all (Moto Guzzi in particular). The filter for the engine in my old pickup didn’t have a bypass valve unto the late 60’s, and the basic engine was developed in the late 1940’s.

 

Was and still is - not sure of the significance really.

 

The engine pressure control valve (relief valve) is set at 50 to 70 psi, the filter bypass is set really low don't quote me but 5 psi or thereabouts - its to bypass the filter if blocked. When building race mini engines I allways block this up - better low oil pressure than bits in the bearings.

 

i just get one for a Subaru Justy and don't worry about every other filter on the planet

 

Fair enough. I'd have thought that one would have been added by the '80s at least.