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Discussion in 'Hangar Talk' started by Ted, Jul 17, 2020.
Unfortunately I won’t have the new bearings until next week.
Bearings arrived, floor torn apart. I'm debating whether I should Plastigauge the bearings, at least one of them, to confirm I don't have an undersized crank. I don't really see much point in doing them to confirm the exact tolerance, more that I need to make sure that I'm not 0.010" or 0.020" too big vs. what the bearings should be. Maybe I should be more concerned. The Cat experts on one of the Cat groups I'm on say not to bother. And, of course, @NealRomeoGolf will be pleased to know that the bearings come in genuine yellow Cat boxes.
The water damage, well that was interesting. Before our last trip we found a soft spot in the floor in front of the bathroom where a couple of the tiles started falling through. The tiled area of the floor has two layers of plywood - the main subfloor plywood that the whole RV has, and then a second layer of the same stuff (both about 1/2" thick) to help make sure the tiles don't crack. Add material to prevent warranty claims, of course. When we got the tile torn up and the first layer of plywood up, it was apparent that the second layer around the center of the RV was also rotted through. Pics:
We haven't torn that up yet, but we're looking through sections. We also were (and still are) attempting to pinpoint the source of the leak. When we had the RV at the stop to fix the windshields falling out and find the propane leak (which they successfully found) they said the slide seals looked fine. Well, we do keep the RV outdoors (which we shouldn't but it's our limitation at the moment until the new shop is built) and yesterday was raining. I looked around the slide seals during the rain and, sure enough, found a leak right in the area where we had all the rot. There are also a lot of hoses there so it's very likely a combined root cause of multiple leaks.
Additionally, the big front slide doesn't seem to be going out all the way in the back. I need to look into that and reasons why that could be. More research is required, see below:
That white part shouldn't be visible, that's the slide wall. I don't know if that would necessarily seal out the water, but I can feel cold air coming through, so that's also bad.
While tearing the fridge area apart, we found more fun. The fridge support floor was covered in mold/rot (not surprising). It had insulation on either side, which was also moldy, especially because the fridge is right above the propane heater. This is just a bad design all around. So we're going to fix things and do something unconventional.
The propane heater is getting removed and relocated to the dumpster. We'll also remove the propane fridge, which, while I like the propane function of it in theory, creates a lot of problems between needing vents (which let in cold air and moisture, and rain in some cases) depending on the angle. I'm going to plug up all these holes/vents and add insulation to them. We've found we really hate the propane heater. Not only does it seem to create an environment for mold, but when we've used it to heat the RV at night we have gotten terrible sleep. The unit cycles on and off every time and, while not extremely loud per se, is right where you're sleeping so you hear it. With the heat pumps (remember it has two of them) we can leave the fan to run continuously, and so the compressor kicking on and off isn't too big of a deal. Yes, the heat pumps require electric (either generator or plug-in) but we've found that we essentially always have hook-ups or are running the generator anyway, including while driving down the road. End result: the propane heater is an extra system that we don't use, creates problems, and takes up space that would be better served being used for other functions.
We've removed the propane/electric fridge and we're going to replace it with a residential electric fridge which will be larger and better suited to our needs. I was originally against this idea because I liked the simplicity of propane for boondocking. But we've found we just don't boondock, and if we do, we leave the generator running anyway. Getting to plug up extra vents that are causing problems is a good thing.
Oh, and then the bathroom. Well we never liked the shower, and we had to pull it because of the rotted wood area. So we found a slightly larger residential shower that will still fit and will be a lot nicer.
End result: We didn't want to do this work, but the finished product will be a much nicer and much needed update from the factory. We'll solve some health/safety issues and this will be "ours", ready to go for a long time to come.
Do they heat pumps put out enough heat for colder temps? I have zero idea, thats why I ask.
A good question for sure. We've camped with overnight temps in the 20s, and have remained comfortable so long as some long-haired idiot didn't leave a window open.
We do have a couple of space heaters we bring with us as well, and so I think that with the combination, it's fine. Keep in mind we're not likely to be going out RVing if the weather is truly frigid, so while the design requirements need to accommodate that to at least some level, from a practical standpoint it's not necessarily needed.
The negative of course is the heat pumps are roof-mount and thus are blowing hot air down. Wrong direction, but it still seems to work fine. There's enough air velocity and circulation to get the air where it needs to be.
Have you considered the 12V DC fridges? I know they are residential size, but I believe they are up to 10 cu ft now.
We did, but don't think it makes a lot of sense. 10 cuft is smaller than the existing fridge (12) and one of the problems we have with the fridge we removed was the space. Good thought though.
Uploaded a quick video on what I found.
Looks like a lot of work!
Ted, I’ll provide a respectful challenge in one respect. The concern I have is you’ve only used it one season, and I think you may regret not being able to boondocks. A lot of very awesome places out west don’t have electric and don’t allow a lot of genset hours. You’re fine on the fridge because it can use battery inverted power at night, but heat might be a lack. You can also go to in floor propane heated radiant floor or some people use the indoor safe propane radiant heaters. I’d hate to completely lose the option to be warm and quiet while boondocked
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Certainly reasonable, and like you said we've only used it one season so we've got more learning to do. At the same time, there are real, tangible benefits to the upgrades we want to do, and being that I modify everything, I could always change something again later if I feel like it. I'm not deleting the entire propane system, so there will always be the option of adding something else in the future if I want.
We often turn the gas off when we go away. our refer will stay cold for about 2 days. Then it must be pumped down.
I changed out (almost) all the bearings in the 3126B today. One of the new rod bearings and one of the new main bearings from Cat had imperfections that I didn't like, so I'm going to exchange them at the dealer before finishing up the job. Really not a bad job to do, just takes time to do correctly.
It's worth noting that on the rod bearings, all of the upper halves (the part that does the work) had very noticeable wear. All the lower rod bearings had wear, and a couple had started flaking the coating off. The main bearings had very minor wear, other than the thrust bearing, for which the lower was pretty noticeably worn (more like the top of the rod bearings). The tops of the main bearings all looked new, which again, not surprising.
Also not surprising, the crank journals all looked perfect. No wear noted whatsoever. Good Cat!
I also got the pickup and discharge tube off of the old oil pump so I could return the core. While comparing it to the replacement oil pump, I thought it interesting to note that it's a completely different pumping element. The two gears on the old pump had quite a bit of play between them, and between that and the bearings having noticeable wear, it seems reasonable to me that I've found the cause of my oil pressure issues. The 3126s have a lot of reports on the internet of low oil pressure being common.
In thinking about it, my guess is that there's a bit of a chicken-egg situation regarding my bearing wear. I'd bet that the bearing wear was caused by the low oil pressure, which then probably resulted in lower oil pressure resulting in more bearing wear. And aside from perhaps a sub-optimal pump design, one thing that everyone agrees on is that these 3126s like clean oil. It wouldn't surprise me if the previous owners weren't adhering to the recommended oil change intervals and making it worse. In 8,000 miles of driving I've changed the oil 3 times (recommended interval is 5k miles, so I've done well below that) and plan to keep up the clean oil plan.
Overall from my inspection of the engine, all the things that really matter look great. The cylinders all have good cross-hatching on them, all the piston oil squirters are still there and look good, the crank and rods look perfect. So hopefully I put this back together and I'm good to go for a while longer.
Oh, but after doing a bit of digging, it also looks like a C9 would fit if I had a cause to replace the 3126B.
Best post of the thread.
One of the things I've been asked a lot is "How do you get the engine out of that thing?" to which I've responded "I have no idea, and it's terrifying." Freightliner provides the RV chassis to the manufacturers with the engine, transmission, axle, etc. all installed and the manufacturer then just puts the house on top of it.
After spending a bunch of hours under the RV looking at it, though, it's pretty apparent that the engine just drops down between the frame rails after unbolting the mounts and potentially the turbo. Of course that would require getting the RV up in the air on a lift so it's not an insignificant job, but it's better than having to remove the body of the RV. Interestingly, the C9 is significantly heavier than the 3126/C7, but it's not much larger (at least according to the interwebz dimensions I've found).
Conveniently, the RV has its own built-in jacking mechanism with the leveling jacks, so I actually can get it up in the air easily enough, and while the engine weighs over 1,000 lbs, that's not very much for any floor jack. It'd need a cradle of some sort to balance of course, but not a big deal.
Regardless, I'm putting new bearings in this thing and have done a good amount of work on it so I'm not interested in swapping right now. With only 92k miles on it, it's a low mile machine and I'm hoping it'll last me as long as we have it. What I might do is have it reflashed to the 350 HP spec from the current 330 HP one, that would be nice getting on the highway.
I spent a day watching a motorhome's engine being removed and replaced, it took less than 8 hours to do the swap.
The jacks they used were remote controlled from a the guy cell phone.
At this point the RV is ready to have the oil pan put back on, then I can start the engine. However the oil pan needs a bung welded in for the oil temp sensor that I'm adding (something I think is important on an engine like this working as hard as it is) so I need to run by a friend's house to get that done before I put the pan back on. Picked up the new gasket today from the Cat dealer. They'd told me before to just use a gasket maker, but I decided after thinking about how difficult it was to get the pan off due to the position of a coolant pipe that trying to use a gasket maker and having any hope of it sealing would likely not work very well.
I spent a lot of time cleaning out the pan, which had a good sum of bearing material in it. That's disappointing for the low mileage of this engine, but being that this is a high horsepower variant of this engine, probably not unexpected. The transmission wants to lug the engine with its programming, and I'm sure that the previous drivers didn't force it to hold lower gears longer which probably hurt things further. I figure I'll cut open the filter before trashing it. But regardless, I also am pretty confident I've found my bearing issues.
Today my friend welded the bung on the RV pan. I've decided to paint it Cat yellow before putting it on, so given the weather the next few days, I'm going to plan to go ahead and do that at some point.
We started putting the bedroom back together and we're really happy with how things look. I'm trying to figure out how to adjust the bedroom slide, which it seems they didn't intend for very good adjustability (like any) and it's going to require some shimming. I need to adjust the slide about 3/4-1" aft as it's sitting all the way forward. I also need to adjust it so it tilts more inward, as when fully closed the top is about 1" out, which isn't good for anything. I'll get it done but it's going to take some effort on my part. Whatever slide type they used (I can't figure out the brand) seems to only have adjustment for the in/out travel tension.
I also am thinking I might need a new motor, which might be part of why it doesn't seal properly coming inwards. It goes in and out just fine with no slipping, but upon reaching the end of travel the gears somewhere start clunking. I need to look into this closer to see where the fault is, but that may be part of my problem.
The front slide I know needs adjustment as well, as I can tell it's not opening all the way. I want to get those done before getting too far with replacing the rotted floor in the front just so that I know everything is sealed up as much as it can be. Of course, soon the RV will be living inside the shop anyway, but I want to get all of this right.
That thing seems like a lot of work. Have you considered getting something lower-maintenance, like a Cessna 414?
The heat pumps are probably good down to 15F, maybe a bit lower. I have three HVAC systems at my house. The two that run the main level are dual fuel, propane furnaces with electric heat pumps. I've found that inefficient ductwork on the one system limits its usefulness to an outside temperature of about 20F. The other is effective down to 15F. In theory, they would both work at 0F, but only if my ductwork were 100% efficient so the air coming from the vents would match the outlet temperature at the heat exchanger.
I was warned ahead of time that old RVs do require a lot of work, lots of little adjustments. Tons of systems and you're driving the thing down the road so that means they're subjected to additional vibrations and harshness, etc.
But man is it nice to be able to do all of the work myself, not have to mess around with maintenance manuals and logbooks, FAA... there are actually fewer regulations than for my house since I don't have to get a permit to make changes.
I've been researching the heat aspects some more on the RV forums. It seems that the first nut I need to crack is making sure that the thing is properly sealed up. There are a LOT of areas where this thing is not sealed correctly, from the factory. We're addressing a number of those areas. Stop the air leaks and your required BTUs of heat go down.
I think one thing we're realizing is that we probably aren't going to do much RVing in the winter, like 99% of other RVers. If that's the case, that convinces me further that we're fine by deleting the propane heater.
One other interesting thing I've figured - it looks as though the residential fridge we bought will hit the old CRT TV cabinet that's still there. I hate that cabinet, so it gives me a good excuse to shrink it to get the fridge in through the door.
You're on the right path by refining your mission specs. You're not going to come up to North Dakota and live in your RV all winter while you work in the oil patch. When it gets down to -40 and the wind is howling at 40 knots, those guys put on skirting, add insulation, buy bigger propane tanks, and run extra heaters to keep warm. If you're cold, you can just drive south.
Sealing air leaks is a good call. The heater has to make up for all heat lost through the insulation and air leaks. Plug the air leaks, and it only has to make up for heat lost through the insulation, which is much less. Same story as the race car guys who spend $50,000 on an engine while their friends strip out carpet to get the same power-to-weight increase. Chase the easy things first and see if you even need to bother with the hard ones.
It's amazing how many air leaks come with this thing from the factory...
That's a CO safety feature!
I've wondered about potential condensation problems inside something that's too tight.
It's easy to run a dehumidifier, which adds heat (another good thing in the winter). So far we've found ourselves running a humidifier because it's too dry when we have to use a heater, not unlike a house. So far, I'm not seeing any issues.
Also beware CO2. If you get it so tight you're not exchanging any air with the outside, your own breathing becomes a problem. Does your heater have fresh air induction? (Commercial setups do but I have no idea about RVs. Home units usually do not because houses usually exchange enough air with people going in & out and general leaks.)
I thought Ted inhaled Avgas and exhaled Jet-a?
I started doing the reverse so as to reduce the lead content in my body. Needed to lose some weight.
If you are using a condensate dehumidifier, the ones I know of are really refrigerators. Cold on one side to condense the water from the air, warm on the other side because they are heat pumps. Net heat gain is small because the heat pump isn't 100% efficient. Just being picky here.
I think his wife would be pleased IF his effluent smelled of Jet-A.
That's what I've used in the past. I've also found the net heat gain in an area is enough to be noticeable when I've run them in the basement of homes.
Ted, just being picky here. I've used them, and noticed the warm air our the back too. It's like the condenser of your home refrigerator, which is warm, too. Like your refrigerator, the inside of the dehumidifier is noticeably cooler so the water can condense.
You will get the enthalpy of evaporation back, too- that's part of what drives cumulus/cumulonimbus development. I've used them to help dry things in basement. I would get about 4 L of water a day, 4000 g. The heat of enthalpy for water is about 2200 J/g. 2200 *4000 -> 8,800,000 J. At 86400 seconds per day, that comes to about 100 watts of heat, similar to a bright light bulb, if I did my math correctly. So you'll get 100 watts of heat and whatever heat is thrown off from the refrigeration unit.
You chemists, doing all that fancy math like that.
Because efficiency <1 of the compressor (and it seems like most dehumidifiers use pretty inefficient compressors), you'll always be adding some level of heat to the area around. It's not a ton, but I've noticed it to be enough to increase the temperature of the basement by a few degrees in the summer.
True, like a refrigerator isn't 100% efficient and so tends to warm the area. I tend to only use mine when something gets wet and any heat gain is lost evaporating the leftover dampness
Wow it's been one heck of a Journey so far with that RV! Like any older vehicle there's bound to be surprises but once you get all the kinks ironed out it, it should treat you well. It's nice to see all the sides of RV ownership not just the glamor shot with it parked overlooking some National Landmark.
Sometimes it's no older than 5! We did a week at the Portal in Moab a few years ago, everything parked there were high end units. But you can go just down the road a mile and there's parks that allow anything in there. For the most part if you can't afford a newer RV you'll probably be avoiding the resorts with stringent rules on RV age as they usually charge as much or more than a motel (Portal is $79/night), the rules and cost do keep out the riffraff. In Moab I'm normally slummin' it up at SandFlats but with my folks, sisters and their husbands we opted for the quiet "nice" place. In the West with the vast BLM and USDA NFS lands you'll always find a place to camp (last year being the exception).
There's been a huge gain in popularity for classic RVs (the trailers in particular) in last few years and a vintage Airstream in top shape can sell for far more than one of the new low end units coming out of an Indiana Factory. I just happen to book a weekend at the same time a Classic RV Forum gathering was happening in Delores CO at a park called "The Views" we hauled a rented beater travel trailer off of Outdoorsy.com down there behind my pickup and were openly welcomed. Some of the classics we saw there were really nice units especially the Avions and Airstreams even some of the lesser brands like Shasta can be made into very nice units. So I'm not totally on board with just having an age requirement.
Wow! I thought it was illegal to even let your dog ride in a travel trailer.
Like airplanes they're a lot of work. Yes, big journey thus far. But the glamor shots (and the experiences getting there) are priceless and worth all the effort.
Got the 3126B back together, and oil pressure better than ever. A set of bearings (well, two sets - rod and mains) plus an oil pump, and now even with 10W-30 it does much better. I'm a happy camper.
Next: To get back to the RV interior putting back together...
Video of my findings, enjoy!
The old CAT parts all started with a number and then a letter, like your old pump did: 7E. That new pump starting at 496 means it is a fairly new part number. In 2006 they were still in the 3's. I think they started going into the 5's about 5ish years ago.
So I was right, it is a new design! Cool to know that it’s that new of an update. I wonder if there were any interim pumps and this is the latest and greatest.
Interesting note is that it’s a gear-rotor pump instead of a straight gear pump like the old one was. Supposedly in the 90s most manufacturers made the switch.
You were right about that pump being compatible for C7s, btw. Scroll down to the Compatible Models section: https://parts.cat.com/en/altorfer/496-4800