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oil sight glass

rado360

lowrider
I found this picture of what someone did to secure the sight glass on a oilhead engine in a plane he was building.
 

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Maybe a little over kill, but cool nun the less.

It is maybe overkill on a motorcycle - where if it pops out all you do is fry the engine.

Up in the sky, it's a bird, it's a plane - such a failure might be a tad more serious, or even on the ground if it's your house the plane hits. :)
 
Up in the sky, it's a bird, it's a plane - such a failure might be a tad more serious, or even on the ground if it's your house the plane hits. :)
No kidding. Wouldn't do it on a motorcycle, but in an airplane... I imagine it takes a very long time to hit the ground... or at least it probably feels like a long time.

"If only I'd secured the sight glaaaaaaaaaaaaaaaaaaaassssssss..."

--chiba
 
I found this picture of what someone did to secure the sight glass on a oilhead engine in a plane he was building.

I thought about doing something similar years ago after reading posts of them popping out. Instead I just carry a small Nalgene jar with a spare sight glass and a few quick-disconnect O-rings.

It shouldn't really pop out, but at least I won't be waiting for one if it does.
 
Wouldn't do it on a motorcycle, but in an airplane... I imagine it takes a very long time to hit the ground... or at least it probably feels like a long time.

Only in Hollywood do planes go totally out of control when an engine quits...remember the 2nd Indiana Jones movie. :lol

When the engine quits, its a glider. How do you think we land?
 
I thought about doing something similar years ago after reading posts of them popping out. Instead I just carry a small Nalgene jar with a spare sight glass and a few quick-disconnect O-rings.

It shouldn't really pop out, but at least I won't be waiting for one if it does.

+1
 
Questions about sightglasses

So if the sightglass is in good condition, why would it pop out? All I can think of is high crankcase pressure.
How likely is that?

And if it does pop out, why wouldn't the new one pop out as well?

And, how long have you got before all the oil is gone and the motor gets wrecked?

Believe it or not, this sightglass thing bothers me more than FD failures or all the other 'issues' the boxers have.

:ca
 
And if it does pop out, why wouldn't the new one pop out as well?

Because its new.

I have no idea why any of them would pop out unless they are pushed out from the inside due to pressure or if they are so old and dried out to no longer create a good fit.

Beats the hell out of me why I never have any issues with my BMWs, but I do believe in being prepared.
 
So if the sightglass is in good condition, why would it pop out? All I can think of is high crankcase pressure.
How likely is that?

And if it does pop out, why wouldn't the new one pop out as well?

And, how long have you got before all the oil is gone and the motor gets wrecked?

Believe it or not, this sightglass thing bothers me more than FD failures or all the other 'issues' the boxers have.

:ca

Mine came out several years and 50,000 miles ago on my R-11-RS. It had approx 30,000 miles at the time. I don't know why. I went approx.1/4 mile (top of my street and back) before all of the oil was out. Left a nice trail on my street and left boot / pant leg. :doh Found the old sight glass and it looked ok, but did not reuse it. I ordered a new one and installed. Goes in very easily. No problems sence on either of my oilheads. I thinking of getting a spare now as I getting older and wiser. Older anyways. :gerg
 
It seems that a friction fit plastic and rubber object will degrade over time and numerous heat / cooling cycles. I don't have a hard time understanding this concept. I do have a hard time understanding why bmw can't understand this and redesign the item to prevent blowouts. Losing your oil can lead to a full failure of your engine as has already been documented on this forum.

I'm planning on replacing it as a matter of course on my bike in the next year. I figure a routine replacement on the basis of every 20k to 30k miles or every 5 years whichever applies will reduce the probability of it self detaching on the road. Damn DAMN stupid situation to have to do that but it's cheaper than an engine rebuild

That was something I never ever had to be concerned with on my old airheads. Using a dipstick to check the oil was pretty darn easy and functional. The glass is not an improvement IMO. Pretty is not always a step forward if it requires more maintenance or contributes to expensive equipment failures.
 
It seems that a friction fit plastic and rubber object will degrade over time and numerous heat / cooling cycles.

I could be wrong, but I believe the oil sight glass does have an internal metal frame...much like an oil seal.

Is it the whole thing that pops out or just the see-through lens?
 
That was something I never ever had to be concerned with on my old airheads. Using a dipstick to check the oil was pretty darn easy and functional. The glass is not an improvement IMO.

There is nothing like "simple and functional", but I guess the folks too lazy to uncrew a dipstick are to blame for so-called progress.
 
Rubber O-ring?

The spare oil sight glass that I have looks more like an oil seal with a glass window....so does the one in my oilheads.


Yep an oil seal that after numerous heat and cooling cycles degrades in fit tension allowing it to self remove from the engine, usually while running down the road. This leads to a rapid oil draining situation for the engine. Ain't that just a wonderful "feature"?
 
Only in Hollywood do planes go totally out of control when an engine quits...remember the 2nd Indiana Jones movie. :lol

When the engine quits, its a glider. How do you think we land?

And next time you see a military helicopter fall like a rock in a movie because the engine stalled, demand your money back.
 
Yep an oil seal that after numerous heat and cooling cycles degrades in fit tension allowing it to self remove from the engine, usually while running down the road. This leads to a rapid oil draining situation for the engine. Ain't that just a wonderful "feature"?

Let me toss out a useful tidbit. They almost never fail without warning signs. The sign is seepage - little smears of oil around the outside edge of the rubber ring. After the rubber has lost some elasticity oil seeps between the rubber and the recess in the aluminum case. After a while, not only is it not tight when the case gets warm and the hole expands - but it's well lubricated too.

So when you see that seepage it is time to replace the sight glass.

p.s. I've never looked, but somebody told me they used a snap ring on the R1200 motors. True?? Will somebody go look and report back please. Thanks
 
Yep an oil seal that after numerous heat and cooling cycles degrades in fit tension allowing it to self remove from the engine, usually while running down the road.

No different that the numerous oil seals within the engine employing the same construction, yet they don't pop out.

In fact, some of the old oil seals are a PITA to get out, they're so seized into place.
 
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