fording depth

[kreiten]

what is the fording depth of a stock 200 series LC? how far up are the diff breathers, trans etc.. anyone extend them up further? thanks in advance for any info -Ken

 

[Billfish]

think its 700mm - that 27&1/2 inches in old money.


There are 3 breathers you should consider lifting to at least match the height of the front diff breather up under the hood. They are: 1.Rear Diff breather which is ridiculously low just above the diff, 2. Transfer case breather and 3. the gearbox breather. Some people also raise the fuel tank breather but if your planning on getting that wet your plain doing it wrong in a 200 and should also consider a snorkel.

 

[kreiten]

thanks for the info!!!

 

[kreiten]

when your building a 70k offroad rig why not spend the extra dollar and run the diff breathers all the way up, just wondering

 

[gaijin]

when your building a 70k offroad rig why not spend the extra dollar and run the diff breathers all the way up, just wondering

Because water can not get into the diff through the breather even if is completely submerged - no need to extend it.

 

[kreiten]

Because water can not get into the diff through the breather even if is completely submerged - no need to extend it.

that's what I like to hear!!! Is it because the pressure in the diff etc?

 

[Tucan viajero]

If you look at the pictures of the grey 200 series here, you'll see a very close approximation of the maximum fording depth, as its automatic tansmission failed shortly after this trip as a result of water getting into it. The white one, on the other hand, had no problems whatsoever.

The grey one is completely stock, while the white one has a 2"/0.75" OME lift on 285/70R17 tires.

 

[Billfish]

Because water can not get into the diff through the breather even if is completely submerged - no need to extend it.

Dead wrong. The breather valves on LCs are the same old design as has been used for years. People extend the breather tubes to raise the height of the one way breather valves on their ends BECAUSE they cannot be relied upon to stop water sucking back in. A hot diff when submerged in cool water immediately creates a pressure vacuum as the air inside rapidly cools.

Gaijiun, just wondering what it is you know about the LC non return valves on the breather lines that would give you confidence to make your claim.

Its no coincidence that the maximum reccomended wading depth of 700mm for the LC200 just so happens to coincide with the top of the lowest beather valve of the rear diff The air intake is significantly higher.

 

[gaijin]

Dead wrong. The breather valves on LCs are the same old design as has been used for years. People extend the breather tubes to raise the height of the one way breather valves on their ends BECAUSE they cannot be relied upon to stop water sucking back in. A hot diff when submerged in cool water immediately creates a pressure vacuum as the air inside rapidly cools.

Gaijiun, just wondering what it is you know about the LC non return valves on the breather lines that would give you confidence to make your claim.

Its no coincidence that the maximum reccomended wading depth of 700mm for the LC200 just so happens to coincide with the top of the lowest beather valve of the rear diff The air intake is significantly higher.

A hot diff has a very high specific heat - i.e. it retains heat for a long time. There is no way a hot diff, upon submersion in cool water, would "immediately" cool enough to create enough of a vacuum to allow the ingress of water. Further, we can assume that while the diff is submerged the vehicle is still in motion - continuing to generate heat in the diff.

I suppose if one were to park a car with a hot diff so that the diff breather tube was submerged, and turned the car off, then after some amount of time the air volume in the diff may cool enough (i.e. decrease in volume sufficiently) to possibly allow some water in; but that scenario is unlikely IMHO.

 

[4x4tripping]

I did extend my breathers for my buildup...

 

[crazy1323]

While it is true that iron has a very high specific heat capacity, water's is higher. Water also has an excellent coefficient of heat transfer. Now consider that the volume of water is much greater than the volume of iron when fording. The temperature of the water will technically increase because the temperature must equalize (energy cannot be created or destroyed, only transferred), but the increase would be unmeasurable given a fair volume of water (enough to worry about fording depth).

Think of putting a cast iron skillet under water. It cools very quickly.

Given the ideal gas law PV=nRT, as temperature decreases in a closed system pressure will decrease as well. While not a complete vacuum, it would be less than atmospheric pressure. This would created a vacuum pretty quickly. a coffee siphon works the same way.

That aside, one issue people have not mentioned is water in the bearings. As you go through the water, the water will try to drive itself into the hubs and axles. It can force water into bearings. It wouldn't be a bad idea to repack bearings after an extended water crossing. As the depth increases, the pressure forcing water into the bearings increases exponentially.

A hot diff has a very high specific heat - i.e. it retains heat for a long time. There is no way a hot diff, upon submersion in cool water, would "immediately" cool enough to create enough of a vacuum to allow the ingress of water. Further, we can assume that while the diff is submerged the vehicle is still in motion - continuing to generate heat in the diff. I suppose if one were to park a car with a hot diff so that the diff breather tube was submerged, and turned the car off, then after some amount of time the air volume in the diff may cool enough (i.e. decrease in volume sufficiently) to possibly allow some water in; but that scenario is unlikely IMHO.

 

[Tripledave]

I love this! LC owners are smart, you know about science and stuff. Never thought I would have thermodynamic/physics flashbacks on MUD!

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