Oil valve solution to oil falling to crankcase

Thanks.

Here‘s my interpretation / understanding:

The separator is in the OIL TANK breather line… not the engine breather line.

The engine still breathes into the oil tank.

So, actually, the main oil separator is the oil tank itself, ie most oil stays in the tank, and gasses escape via the oil tank breather.

The oil separator is only there to catch any oil vapour, or drops, that might escape the oil tank and pollute the atmosphere. Although I have no idea if unburnt oil is any more polluting than burnt oil ?!

My own oil tank breather just vents to atmosphere and there is very seldom any oil or other liquid emitting from that. So I would have to suggest that the separator shown isn’t really being asked to do very much work under normal circumstances.

Basically, the separator is there for emissions purposes and not engine breathing purposes I believe.

The vacuum created by plumbing the separator into the intake is going to put the oil tank under a slight negative pressure. But I would suggest that will be totally overcome by the pressure and suction created by the pistons rising and falling.

I can’t see why a reed valve engine breather would work any better or worse this set up as any other personally.

Thats for anyone wanting to do so. A moot point for you Glen if your bike is dry, as there wouldn’t appear to be a problem that requires solving !

worntorn said:

The earlier 850s with plastic airbox might have the same breather/ separator system?

Click to expand...

Apparently not, or not all.

The Mk1A didn't, and some (most?) Mk2A had a breather tube feeding into the upper right-hand rear of the black plastic airbox at a different location to the Mk3 separator connection, however, the separator parts are listed in the Mk2/2A supplement for Mk2A.

My early MK2a has no separator and has the tank breather pipe entering the black box at the top right hand side. Adding the separator must have been a running change not a strict change from first MK2a.

Big_Jim59 said:

I have been pumping the oil out of the tank, when I park the bike (semi long term) using a cheap Harbor Freight hand pump. No more wet sumping. Problem solved.

Click to expand...

+1, but I use an oil extractor I bought at West Marine. FWIW I have a larger version that I use for oil changes on my dry sump bikes and cars too via the dipstick tube.

Fast Eddie said:

Thanks.

..... I can’t see why a reed valve engine breather would work any better or worse this set up,as any other personally. .....

Click to expand...

I was surprised just how much difference it made. In my experience, my bike was transformed by the XS650 reed valve in the breather line back to the oil tank. Leaks stopped, the bike sounded and felt more crisp. Bizarrely, even when hot, the oil return to the tank was less frothy. Of course, could be a placebo effect, but I was a bit sceptical before I installed it, it was cheap and didn't take much effort to fit, so not a lot 'invested' in making me believe it worked .

How can it work? I think what it does is, by significantly reducing any gas flow from the tank to the case, it means there is a reduction in pressure within the case. Not a vacuum, but less pressure than there would otherwise be. Perhaps, as well as reducing the pressure forcing oil and gasses out of the case, barrels and head through any weak spot, this also reduces the force required to move the pistons downwards (firing / induction cycle). Clearly, I'm guessing. But I did notice a difference. I think it's the best thing I've added to my bike (apart from oil).

bluto said:

+1, but I use an oil extractor I bought at West Marine. FWIW I have a larger version that I use for oil changes on my dry sump bikes and cars too via the dipstick tube.

Click to expand...

Oh I like that! The only issue I have with the hand pump solution is managing the inevitable drips. I have a second bucket where I keep the hoses and I have to be careful when wrapping the hoses and stowing them that I don't dribble all over the place.

Mart UK said:

I was surprised just how much difference it made. In my experience, my bike was transformed by the XS650 reed valve in the breather line back to the oil tank. Leaks stopped, the bike sounded and felt more crisp. Bizarrely, even when hot, the oil return to the tank was less frothy. Of course, could be a placebo effect, but I was a bit sceptical before I installed it, it was cheap and didn't take much effort to fit, so not a lot 'invested' in making me believe it worked .

How can it work? I think what it does is, by significantly reducing any gas flow from the tank to the case, it means there is a reduction in pressure within the case. Not a vacuum, but less pressure than there would otherwise be. Perhaps, as well as reducing the pressure forcing oil and gasses out of the case, barrels and head through any weak spot, this also reduces the force required to move the pistons downwards (firing / induction cycle). Clearly, I'm guessing. But I did notice a difference. I think it's the best thing I've added to my bike (apart from oil).

Click to expand...

I fully agree that they work, no question in my mind.

When you see the back and forth pumping taking place without one, vs the almost nothing taking place with one, it’s obviously a better situation.

Mart UK said:

I was surprised just how much difference it made. In my experience, my bike was transformed by the XS650 reed valve in the breather line back to the oil tank. Leaks stopped, the bike sounded and felt more crisp. Bizarrely, even when hot, the oil return to the tank was less frothy. Of course, could be a placebo effect, but I was a bit sceptical before I installed it, it was cheap and didn't take much effort to fit, so not a lot 'invested' in making me believe it worked .

How can it work? I think what it does is, by significantly reducing any gas flow from the tank to the case, it means there is a reduction in pressure within the case. Not a vacuum, but less pressure than there would otherwise be. Perhaps, as well as reducing the pressure forcing oil and gasses out of the case, barrels and head through any weak spot, this also reduces the force required to move the pistons downwards (firing / induction cycle). Clearly, I'm guessing. But I did notice a difference. I think it's the best thing I've added to my bike (apart from oil).

Click to expand...

I added one of these reed breathers to the 920 after reading somewhere that the breather had stopped a head gasket leak.
Seemed a stretch but , as you say cheap and easy.
Of course it made no difference at all to the head gasket leak.
The engine was oil tight other than the head gasket, so no change there.
Performance on Dyno hill stayed the same as well.
After the third retorque the head gasket leak eventually became a head gasket weep.
Maybe that's as good as it gets with a 10 to one 920 and copper gasket.
Even Steve Maney expects a bit of leakage here on his big bore engines.

I could see where an engine that had oil weeping from the crankcase joint or timing cover could benefit from the reed valve.
I expect one needs to go for the sump mounted Comnoz valve to obtain the sump pump effect.
I don't think the breather tube mounted XS will do this, at least I haven't noticed that effect with the 920.



Glen

Big_Jim59 said:

Oh I like that! The only issue I have with the hand pump solution is managing the inevitable drips. I have a second bucket where I keep the hoses and I have to be careful when wrapping the hoses and stowing them that I don't dribble all over the place.

Click to expand...

The extractor tubes can make a mess too when you remove them so I've learned to clip them up high and give them plenty of time to drain into the extractor. FWIW the tubes on the bigger 7 quart version reach the bottom of the oil pan on nearly every car I've used it on.

A simple test is to disconnect the reed valve, loosen the oil cap and let it just sit on the oil tank - it will bounce up and down without a reed valve (alternating psi) but with a reed valve connected it will just sit there and not bounce (no .psi). Yes copper head gaskets will weep or leak when good and hot after time no matter how carefull you are and no matter how flat the surfaces are milled. The only way I have found to keep them oil tight is with pliobond on each surface and .005" copper wire around the pushrod tunnels and oil return. With the right gasket material (or paper with lots of glue) yamabond for the cases and oversize viton O rings for the tranny (available from McMaster Carr) - your Norton can be oil tight.

The oil mist scrubber, or separator I fabricated for my Atlas. Any oil tank could be so modified by welding in a similar tower modified as shown in this link:


Works a treat! No more oil mess on my rear wheel.

Slick

worntorn said:

I added one of these reed breathers to the 920 after reading somewhere that the breather had stopped a head gasket leak.
Seemed a stretch but , as you say cheap and easy.
Of course it made no difference at all to the head gasket leak.
The engine was oil tight other than the head gasket, so no change there.
Performance on Dyno hill stayed the same as well.
After the third retorque the head gasket leak eventually became a head gasket weep.
Maybe that's as good as it gets with a 10 to one 920 and copper gasket.
Even Steve Maney expects a bit of leakage here on his big bore engines.

I could see where an engine that had oil weeping from the crankcase joint or timing cover could benefit from the reed valve.
I expect one needs to go for the sump mounted Comnoz valve to obtain the sump pump effect.
I don't think the breather tube mounted XS will do this, at least I haven't noticed that effect with the 920.



Glen

Click to expand...

When we talk about leaking head gaskets, I reckon it’s good to think of the head gasket as 3 (almost) separate gaskets:

1. Head gasket
2. Pushrod tube gasket
3. Oil return hole gasket

When we talk about oil leaking from the head gasket, a clean burning engine shouldn’t have oil in the combustion chamber, so if it leaks, we‘d more likely see sooty deposits as evidence as no oil should actually leak from the head gasket itself (1).

So an actual oil leak is far more than likely to really be coming from either 2. or 3.

Both 2. and 3. are under the influence of crankcase pressure, so are potential beneficiaries of a reed valve breather mod.

And both 2. and 3. is what JS recommends using the copper wire to seal.

My 920 has proven to be oil tight ish on all 3 so far (touch wood) with only a slight misting after a thoroughly good spanking (ie on the track with prolonged use of WOT and high rpm).

On mine I did use the JS method and it does appear to work. But it was incredibly faffy dealing with that copper wire! I think that next time I’ll stick it to the head gasket itself, that can be done in the well lit comfort of the kitchen table, nice and flat, which should make it easier to do a decent job.

The whole area is subject to high pressure from compression, I suspect that is why the reed valve installation didn't help.
There is oil present and if even a tiny amount of that compressed charge gets thru in the oily areas, there will be oil escaping. A small negative crankcase pressure loses the battle with 170 psi of compression thumping away.
I used copper spray on the gasket. Next time around I'll try the fine wire method.

Nothing seems to bring out the oil leaks better than a hot 4-500 mile day in the mountains.

You think you have it oil tight after doing some 50 mile local rides, then find out otherwise!



Glen

Here's something I don't understand about head gaskets even after I learned that the copper ones from AN are not pre-annealed. I've always used copper head gaskets on Triumph and BSA, and I've never had one leak and I've never re-torqued their heads. I've also re-used them after annealing and no leaks.

On Norton, I've given up on copper head gaskets. The last one I installed was new and properly annealed - leaked. Re-torqued - leaked. Switched to composite - no leak but of course re-torquing required.

Any idea why?

Mart UK said:

I was surprised just how much difference it made. In my experience, my bike was transformed by the XS650 reed valve in the breather line back to the oil tank. Leaks stopped, the bike sounded and felt more crisp. Bizarrely, even when hot, the oil return to the tank was less frothy. Of course, could be a placebo effect, but I was a bit sceptical before I installed it, it was cheap and didn't take much effort to fit, so not a lot 'invested' in making me believe it worked .

How can it work? I think what it does is, by significantly reducing any gas flow from the tank to the case, it means there is a reduction in pressure within the case. Not a vacuum, but less pressure than there would otherwise be. Perhaps, as well as reducing the pressure forcing oil and gasses out of the case, barrels and head through any weak spot, this also reduces the force required to move the pistons downwards (firing / induction cycle). Clearly, I'm guessing. But I did notice a difference. I think it's the best thing I've added to my bike (apart from oil).

Click to expand...

I also have the XS650 breather fitted onto the OE crankcase breather body which i can't believe how well it works...last summer i carried out a test & purchased a timing case inspection plug, i drilled it and fitted a nipple so could be connected to a vacuum gauge
I cannot believe the amount of negative pressure being created by the PCV... and when the fantastic fork here say that with one fitted engine oil leaks are history...well significantly reduced, on my evidence i have to agree

marshg246 said:

Here's something I don't understand about head gaskets even after I learned that the copper ones from AN are not pre-annealed. I've always used copper head gaskets on Triumph and BSA, and I've never had one leak and I've never re-torqued their heads. I've also re-used them after annealing and no leaks.

On Norton, I've given up on copper head gaskets. The last one I installed was new and properly annealed - leaked. Re-torqued - leaked. Switched to composite - no leak but of course re-torquing required.

Any idea why?

Click to expand...

I tried to answer that above, IMHO it’s because much of the time with Nortons it’s not really the head gasket per se that’s leaking, its the pushrod tube or oil return hole gasket that’s leaking.

Triumph‘s don’t have this issue, the head gasket only has to seal the head gasket !

olympus said:

I also have the XS650 breather fitted onto the OE crankcase breather body which i can't believe how well it works...last summer i carried out a test & purchased a timing case inspection plug, i drilled it and fitted a nipple so could be connected to a vacuum gauge
I cannot believe the amount of negative pressure being created by the PCV... and when the fantastic fork here say that with one fitted engine oil leaks are history...well significantly reduced, on my evidence i have to agree

Click to expand...

What was the value of the negative pressure you measured?

Slick

Fast Eddie said:

I tried to answer that above, IMHO it’s because much of the time with Nortons it’s not really the head gasket per se that’s leaking, its the pushrod tube or oil return hole gasket that’s leaking.

Triumph‘s don’t have this issue, the head gasket only has to seal the head gasket !

Click to expand...

There is also the issue of hairline cracks within pushrod tunnels where the head stud drilling has weakened the tunnel wall. Was watching a restore video on an 850 and the experienced Norton mechanic was quite surprised when his inexperienced son discouvered both tunnels had cracks, only visible when shining light into tunnel while looking down the stud hole. Locktite into the stud bore solved the leaks.

EDIT:

Here is the video. Jump to 10:30 mark for the stud work point:

These days in Australia, historic racing rules require a permanent fitting on oil lines. However when my bike is at home in the shed, I put a bolt up the outlet pipe from my oil tank, to stop wet sumping. I would dearly love some way of controlling the situation, which would not present a risk of a major blow-up due to no oil pressure. Wiring a cut out to the ignition switch, simply creates more points where there can be an electrical failure.
The one thing I always check before starting the motor, is the oil line is on and tight. The last time I raced I did that, but I did not check the fuel line which is right up under the tank. Too many things to check, can be bad.
A friend has the same problem with a Manx. He uses a tap which has a switch on the back of it. But there seems to be wires going in all directions. I think it cuts out the magneto, but there are more places where things can go wrong.

texasSlick said:

What was the value of the negative pressure you measured?

Slick

Click to expand...

Gauge was bouncing around a bit as it wasn't damped... but i seem to remember around 3-5 in HG