Waterproofing the 231

/wwwthreads_images/icons/tongue.gif My guess is that the lip seal(which has all the edges TOWARD THE OIL) is letting the transfer case get a snootfull of water when the aluminum case is dipped in cold water and instantly transfers the heat away from the the case itself, and from the air inside the case, causing a momentary vacuum inside the case. In order to prevent this, you will need to pressurize the case slightly by using a Pep Boys or Auto Grinch grade 12volt air compressor to pump up the cases before you dip in. All it takes is SOME pressure, not a lot. The alternative might be to install a SET of seals, and turn the outer one around to get the lip AGAINST the incomong water. One other note: when you dip a hot Jeep, you need to know that the aluminum cases will shrink like crazy, clamping the hot bearings tighter than the normal case-to-bearing fits usually are, and premature bearing failure will result UNLESS you stop in the area just across the stream and have a coke while the case re-heats from the internals. That's why INDY crews HATE a long pause for wreck clean-up after they have once got everything all warmed up. Ever wonder why the thermal blankets come out on a long restart to wrap up the gearboxes?/wwwthreads_images/icons/crazy.gif Aluminum is nice, and it helps cool the boxes, but you have to remember that Aluminum is the fourth best conductor of heat that there is(Sport-Cars-Go-American.....Silver-Copper-Gold-Aluminum), and it will cool off like mad when dipped, or exposed to cold air, while the internals are insulated by the case walls and the oil./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

You could use a second inlet to the case (MAYBE THE FILLER PLUG?)and that way the long hose on the existing vent would act as a restriction to build up just a tad of pressure in the case. That would be the ideal way to go. If the case pressure was still too low, just use a smaller hose from the vent. Be sure that the vent hose is long and goes way up on the firewall.

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

Eliminate the cooling altogether. Make a small shell and tube heat exchanger (small tube of fluid to be heated inside larger tube of hotter fluid). Run a small electric pump to push t-case fluid to the heater and set to on/off by the 4wd indicator switch. Run hot coolant from the engine (like the heater core hoses) to the large annular space (big pipe), flow tranny fluid in the middle tube (see ascii diagram). Now, the t-case fluid will not drop as much in temp when you hit the water. For better performance, coil the inner pipe for more heat exchange area.

to radiator =======~~~~~~~~~~~~~~~~~~~~~~
| (hot coolant) |
from t-case to t-case
| (hot coolant) |
~~~~~~~~~~~~~~~~~~~~~~~========= from engine

Just a thought.

Non compis mentis./wwwthreads_images/icons/crazy.gif

/wwwthreads_images/icons/tongue.gif Actually, Joe the problem is that the oil and the internals STAY hot, while the outer case touches the cold water in the river and COOLS OFF....rapidly, more rapidly than the internals could possibly cool, and THAT is what makes it suck water and squish the bearings. It's true that if you kept everything at or near river water temperature that the problem would go away, but that's kind of hard to do. It isn't the overall heat that is the problem, it's the differential between the internals and what the case can cool down to in a very short time. Formula I and Indy car guys just HATE this. Run car....get everything good and hot....rain comes in and a cool breeze...race is stopped....cases radiate heat like crazy and shrink....race resumes...bearings go by-by./wwwthreads_images/icons/frown.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

/wwwthreads_images/icons/tongue.gif It most assuredly is. Although I believe it is sand-cast and somewhat thicker than the die-cast 231 cases. It would probably take a little more to shrink it because there is simply more weight of Aluminum. Just remember that once across the river, stop and let the internals and the oil reheat the case. Is coke THAT expensive that you can't pause for one? The Jeeps in front and behind will have the same requirement unless they are naive or have cast iron cases. Heck, if you drove through water as deep as the t-case, you SHOULD stop and congratulate yourself. What you can do is install an oil temperature gauge in the case which reads oil temp. Then use a cylinder head temp gauge off a Porche which measures case metal outside temp. As soon as the temps get as close together as they do when running the dry, you can zoom off again in search of the next water hole!/wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

/wwwthreads_images/icons/wink.gif Oh Absolutejeep,.....there is SO MUCH for you to discover.....some of it can cost big bucks/wwwthreads_images/icons/frown.gif some of it is right here in this BBS for free./wwwthreads_images/icons/smile.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

Okay, I understand that bit CJDAVE. The air in the case loses heat faster to the river-cooled case than the hot t-case fluid can heat it, creating a loss of volume for the air and in comes the water. How much cooling does the t-case have to do? Can you insulate the case to slow the transfer of heat to the river water?

Non compis mentis./wwwthreads_images/icons/crazy.gif

/wwwthreads_images/icons/wink.gif Now you've got it Joe. The area that the water is acting on in a deep dip is extensive, and the aluminum really reacts fast. You would probably need to have a differential of at least 60 degrees F for it to have a significant shrink effect. Insulating the case would be one way to reduce the shrink effect; having a cooling system that kept the case below say 100 degrees F would be another way to do it, although patently impractical under most conditions. I don't have the figures right here for the shrinkage, but Aluminum shrinks 5/32" per foot as it goes from molten(about 770F) to room temperature, so it does move plenty. Interestingly enough, as our Jeeper extended his vent hose, he added restriction from friction loss and causes the pressure differential in the transfer case to increase and pull in more water. So the rule is: if you lengthen the vent, add diameter. It is quite remarkable how quickly the air volumn does change just from sloshing some water on the case. Here is your pop quiz for the day, Joe: Farmer Clem has a new Diesel tractor with a Roosa-Master fuel injection pump on the side of the engine(it could even be a Bosch,it doesn't matter) Little Lem gets home from school and sees his Dad out pulling the heck out of a disk with the new tractor. When Dad finishes, little Lem wants to be a big help so he washes the new tractor, engine and all, with the hose(cold water). The next day it would not pull squat, like it had a fuel restriction problem. What happened?/wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

/wwwthreads_images/icons/smile.gif the vacuum is caused by rapid cooling of the case, and the vent hose is too small and too long to equalize it quick enough. Yep, you're right about the seal, and as you can see in my earliest post, I suggested a "set" of seals, one each way, or one combination seal. They make all kinds of seals. /wwwthreads_images/icons/smile.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

Okay, let's put a canister, say twice the size of a Coke can three inches up the vent line from the t-case then continue the vent line up at a greater diameter. Equalization fast, minimal restriction.

Non compis mentis./wwwthreads_images/icons/crazy.gif

/wwwthreads_images/icons/wink.gif Now you're beginning to think like an engineer, Joe./wwwthreads_images/icons/smile.gif Often, pressure-tight vessels will have what they call a conservator attached, which is just a big bladder tank that allows expansion and contraction, yet prevents outside air from contaminating the vessel. Yep, a simple "surge tank" in the line would be a big help in quickly equalizing the pressure. You can see that just enlarging the entire vent system from case to end of hose would make a lot of difference; along with installing a tricky, double-ended seal arrangement to prevent water intrusion. You know, I just can't remember what the seals on the WWII GI truck cases looked like, but they were made to go under water with remote vents and all the rest, including a totally waterproof ignition./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.