GRiSO ghetto
Would you like to react to this message? Create an account in a few clicks or log in to continue.


12425 - Established June, 2013 - all GRiSO, all the time...
 
HomeRegisterLog in
 

 Where does the oil go?

Go down 
AuthorMessage
Pete Roper
GRiSO Capo
GRiSO Capo
Pete Roper

Posts : 7398
Join date : 2013-05-30
Age : 63

Where does the oil go? Empty
PostSubject: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 7:26 pm

Was asked to do a photo essay on the way oil moves through the spacer on the 8V for people over on ADV. some of you might find it interesting too.

I can't seem to get the whole post with pics to copy from there and can't be arsed to do the whole thing again so here's a link to the page. It's about half way down.

[You must be registered and logged in to see this link.]
Back to top Go down
beetle
GRiSO Capo
GRiSO Capo
beetle

Posts : 7747
Join date : 2013-10-01

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 7:34 pm


Allow me to help. Check your email.




Back to top Go down
https://www.griso.org
Pete Roper
GRiSO Capo
GRiSO Capo
Pete Roper

Posts : 7398
Join date : 2013-05-30
Age : 63

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 7:47 pm

OK. Dunce's hat on. Thanks Mark!


OK, so returning to 'Stuff you may or may not want to know about your lubrication system' let's have a look at the Lubrication circuit.

First up though let's just clear something up. THERE IS NO SUCH THING AS 'SUCK'. OK, having got that out of the way we'll move on and I will use the term freely while explaining what is going on in the lubrication circuit but in fact all that is happening when the pump is working is creating a low pressure area and crankcase pressure is forcing the oil into the pump but using the term 'Suck' is easier.

Allright, having got that out of the way let's look at the sump spacer.

In this first picture you can see the orifice into which the pick up strainer is inserted and bolted to the spacer flange.

[You must be registered and logged in to see this image.]

Oil is 'Sucked' up through this by the pump and gets there through this orifice in the top of the spacer.

[You must be registered and logged in to see this image.]

The reason why this gallery is larger than the others is simple. As noted above the only thing pushing the oil into the pump is the comparatively feeble crankcase pressure. Once it has passed through the pump it is actually being mechanically forced so it will flow easily through a more restrictive gallery.

Once the oil has passed through the pump it descends again, under pressure, through the middle of the three holes at the front of the spacer.

[You must be registered and logged in to see this image.]

From here It passes along a gallery that contains the oil pressure relief valve which lives under the big, hexagonal, domed nut visible here.

[You must be registered and logged in to see this image.]

The lubrication system is basically a series of tubes, (The bearings.) with leaky plugs in, (The shaft journals that run in them.). The purpose of the oil pressure relief valve is to ensure that the oil pressure does not get too high as this is both wasteful of energy and can be dangerous to the integrity of the bearings. When the oil is cold and thick this can be particularly problematic so the relief valve has a set 'Crack Pressure' when it will open and dump excess oil and pressure back into the sump via a hole in the casting. It's a simple spring loaded plunger that is unseated and lifts, exposing the gallery, when the pressure gets too high. It's virtually foolproof.

Once the now pressure regulated oil is past the OPRV it passes on to the oil filter. It enters the outer part of the filter from this gallery.

[You must be registered and logged in to see this image.]

And then exits through the threaded hole the filter has that screws onto the central boss.

[You must be registered and logged in to see this image.]

Now from there there are a couple of ways that things can happen but since we are talking STELVIO we are talking 8V motor which is substantially different to the 2VPC motor that preceeded it. This is because on those motors there was only ONE oil pump and the oil temperature was governed by a thermostat that lived under this plug in the spacer.

[You must be registered and logged in to see this image.]

From there the oil was either sent through the cooler via the exit and return ports in the front of the spacer

[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

if the oil was hot enough or simply directed to the delivery side.

On the 8V there is no thermostat and the oil cooler is on a different circuit. Those ports are simply blocked off and all the lubricating oil is delivered to the bearings, (And under piston sprays, they too are fed off the high pressure lubrication circuit.) either directly up into a gallery in the block from the third orifice.

[You must be registered and logged in to see this image.]

Or, at the rear of the motor, through the brass coloured pipe that runs from front to rear on the spacer.

[You must be registered and logged in to see this image.]

Allof the galleries in the spacer have to be drilled and then their outer, non functional ends, plugged with welch plugs. As you can see the spacer is festooned with them. It's quite a complex piece of manufacturing.

[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

Anyway, now you've seen how it all works I hope it's easier to see why, when that wretched gasket splits and gets squeezed out the gap it leaves on the 'Suction' side of the pump will allow air to rush in which it is far more willing to do than oil. When that happens delivery is compromised and the situation gets worse the hotter she engine gets and the thinner the oil becomes. Eventually not enough gets delivered to fill the reservoirs for the cam chain tensioner plungers and they can't work so you get rattles. By then things are pretty dire and the cam bearings which are fed from the same circuit, (The oil for the cam boxes travels up two of the cylinder studs.) are probably only getting very marginal lubrication. Luckily the cams only run at half crank speed but even so........

Quite simply, if you have any doubts? Replace the spacer gasket with one of the good ones. It may save you a whole heap of heartache!

Here endeth the lesson.

Any questions?
Back to top Go down
Lazlokovacs
Don Abbondio
Don Abbondio
Lazlokovacs

Posts : 75
Join date : 2015-08-21

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 8:56 pm

this is a great write up thanks

I'm gonna have the bike in the shop end of next week and will be changing the oil so will check the gasket and replace.

Just one thing in the write up gave me concern, you mention the cam chains rattling as being a possible symptom,

my chains have always made quite a noise at idle, even when cold, (one could say a rattle) which goes away as soon as power is supplied, is that normal? or could it be a symptom of impending doom?

I was under the impression that the 8v in its natural state is a noisy beast at idle
Back to top Go down
Pete Roper
GRiSO Capo
GRiSO Capo
Pete Roper

Posts : 7398
Join date : 2013-05-30
Age : 63

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 9:10 pm

The 8V motor is, by contemporary standards, noisy. Having said that they shouldn't make any real rattling noses, just a sort of disorganised thrashing! The later the motors, the quieter they got. Why? No idea! Perhaps they got better at putting them together. Perhaps they just tightened up the tolerances?

As it stands my *New* motor has always been hideously noisy. It was one of the first roller tappet motors built. The flat tappet, rollerised too late, motor my bike originally had was one of the first 8V's built. It was awful! People would pull up next to me at traffic lights and tell me I needed to take it to a mechanic! Very Happy

They're noisy but without hearing it I can't really offer an opinion.
Back to top Go down
waterbottle
GRiSO Capo
GRiSO Capo
waterbottle

Posts : 1780
Join date : 2015-02-03
Age : 59

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 9:53 pm

If you think they're noisey Pete, try missing a gear shift at 9k rpm . Yes i know i shouldn't do that , but no matter what i through at it , I just can't break it Laughing
Back to top Go down
Lazlokovacs
Don Abbondio
Don Abbondio
Lazlokovacs

Posts : 75
Join date : 2015-08-21

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Sun May 17, 2020 11:55 pm

Pete Roper wrote:

They're noisy but without hearing it I can't really offer an opinion.


quite! I'll report back as soon as I drop the sump

might do it today if i can get into the workshop

thanks

Back to top Go down
OldMojo
Carlotto
Carlotto
OldMojo

Posts : 47
Join date : 2018-04-11

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Mon May 18, 2020 2:11 am

Pete, I seem to recall that you said past a certain year they went with a different spacer and gasket combo that didn't suffer this issue?
Back to top Go down
Guzzi Cat
GRiSO Capo
GRiSO Capo
Guzzi Cat

Posts : 330
Join date : 2014-09-03

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Mon May 18, 2020 3:25 am

Isn’t the Verniers the most versatile of precision tools  jocolor I doubt that a digital one could have pointed out the 8V oil orifice’s so accurately  Very Happy
Back to top Go down
Pete Roper
GRiSO Capo
GRiSO Capo
Pete Roper

Posts : 7398
Join date : 2013-05-30
Age : 63

Where does the oil go? Empty
PostSubject: Re: Where does the oil go?   Where does the oil go? Icon_minitime1Mon May 18, 2020 5:37 am

OldMojo wrote:
Pete, I seem to recall that you said past a certain year they went with a different spacer and gasket combo that didn't suffer this issue?

To be honest I'm not absolutely certain one way or the other, it's not the sort of detail I can easily remember. As I stated above I thought they'd never changed it but I might be wrong.
Back to top Go down
 
Where does the oil go?
Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
GRiSO ghetto :: The Ghetto :: GRiSOLOGY-
Jump to: