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  1. I would replace the broken metal section--cut it out, replace with one wider and thicker.and high strength steel, not scrap iron. An easy job for a GOOD metal fabricator . Cut the old one out with ?? plasma torch. Re-weld with MIG. PWHT with oxy-acet torch with rosebud tip. What the picture tells me is this was a progressive 'fatigue' failure starting from a brittle spot in the weld affected zone. Getting a good weld etc might require removing the part from the coach for access.
  2. Perhaps I can shed some much needed clarity on exhaust treatment of diesels. Stage 1) was using exhaust gas recirculation (EGR) to reduce oxides of nitrogen (NOx). The recirculated mostly nitrogen lowered the peak combustion temperature, dramatically decreasing NOX. It required engine and lube oil manufacturers to change things --a LOT for lube oil formulation scientists. Soot loading of the lube oil more than doubled, and the lube oil had to have MUCH better soot dispersion capability, and oil filters had to have much more soot holding capacity to prevent 'bore polishing' and resultant high lube oil consumption-- so much for Stage 1. Remember, all along the engine folks were beating on refiners to make better diesel with much lower sulfur. They also improved fuel injector technology, piston crown shape and cooling, and other 'metal modifications' to improve fuel economy , durability at high soot loadings etc. There WAS a steep learning curve. Stage 2 was to further control exhaust soot---particularly the very fine particles (less than 2.5 microns in diameter). Particulate filters were in addition to much improved very high pressure 'common rail' electronically activiated fuel injectors with better optimized spray patterns--which improved fuel economy and reduced particulates This is DPF. The fundamental issue is how to filter well (to minimize small particles) without plugging up. A host of chemical and mechanical issues were/are at odds. The most common is now ceramic filters that a periodically 'burned clean' by injecting more fuel and air in the hot exhaust to burn off the soot. Now remember, the 'turbo' should extract a lot of energy (heat) from the exhaust to power the compressor side to improve engine power and efficiency. Then you have to add a lot of heat to burn off the particulate filter ever so often. There are different methods used by different engines to determine when to do a burn-off.. Then the EPA mandated ultra-low sulfur diesel in all road trucks (and now off-road and railway, and ships too!). That caused lubricity related problems with certain injector pumps and fuel design scientists had to make and use 'lubricity additives. The ULSD is, by far, the lowest sulfur in any fuel gasoline, diesel, kerosene, lpg. Making it required refiners to spend $ Billions in research and new high pressure hydrotreaters, new catalysts, more hydrogen manufacture---all of which substantially increased the cost of making ULSD as compared to the old stuff. At first, there was not enough ULSD to go around and prices soared (law of supply and demand) . While ULSD prices have lowered SOME, they are still way above the real COST of making it. Other things being kept equal, the true 'cost' to make ULSD should not be more than about $0.10 per gallon than regular unleaded gasoline. ULSD also substantially lowered particulate formation, so soot filters are not as problematic as they were. Now comes Stage 3 where we are today. NOX levels were still too high according to the EPA. There are two (2) ways to lower NOx emissions---1 is to reduce the combustion temperatures--with the brief peak period making the lions share of the NOx. EGR does that , but also robs power from a given engine displacement (recirculated exhaust has much less oxygen than fresh air so it acts as a diluent--you are basically compressing Nitrogen and circulating it, taking horsepower to pump it around. The other easy to reduce NOx is to convert it back to Nitrogen and water vapor, which is what Diesel ExhaustFluid (DEF) facilitates. This requires a catalyst (reactor), injection , control, and monitoring systems, etc., but does not rob horsepower, and actually allows MORE power and better fuel efficiency---efficiency goes up and combustion temperature goes up, which makes more NOx , but you easily handle that with the DEF and catalyst. VIOLA for a measly $10,000 or more, you get better fuel economy, much lower NOx emissions, and much lower tiny particulates (and much lower sulfur oxides SOx emissions) all of which have dramatically improved air quality in about 2% of the US territory and 5% of the population. Modern, up to date diesel engines running on ULSD ARE much cleaner running, give improved fuel economy, and-----only cost a 150 $Billion to invent and a whole lot of additional fuel costs (money transferred from 'the people' to refinery stockholders.), the majority of whom are the 1% folks. The additional capital investments this required have long been recovered and paid for.
  3. As a recent purchaser of an extremely well maintaines and outfitted 30' Safari Sahara, 300hp Cat, Allison 6sp., I agree with most of the comments herein. We just finished a 600mile 'initiation trip' with 7 days at a nice RV park in Buena Vista, Louisiana--a few miles north of Morgan City. We had moderate to severe gusting crosswinds (20-40 mph across the road) and mixed rain. Returning the wipers were on 5 of the 6 hours. We had NOT loaded the front and most of the payload weight was in the rear. We drove 55-60 MPH and let the fast traffic go. The buffeting from large trucks and crosswinds was bad. It required close attention to stay inlane. With steady cross wind it was no issue at all. We towed a 2000 Saturn SL-1 and you could not tell it was back there. Other than the wind buffeting, the rig handled almost perfectly. I will renew sway bar bushings now to reduce rolling motion on poor roads a bit. (There are many very poor condition road sections on IH-10 between Lafayette and Houston, with dramatic uneveness and severe undulations 'all of a sudden' in curves and transitions. We WILL front load and perhaps even relocate the 'house' batteries (400# for 4 golf cart size) as far forward as we can. Since I AM a very good engineer, I can design and construct whatever cradle I need. Brett Wolfe made that suggestion when I spent several extremely educational hours with him (and his wife Dianne) picking up the Cat spare parts. I predict moving the House batteries and heavy payload stuff forward will greatly reduce buffeting from trucks and gusting cross winds. The Sahara is extremely well built and rides well. There is no wasted space and we had LOTS of room to live in. I looked real hard at front gas engine rigs. I would stay away from the Ford Triton V-10 if it has more than 30-40K miles and was not very well pampered. I know several folks who had the engine self destruct unexpectedly from broken connecting rods, cracked pistons, blown head gasket/hydrolock on starting etc.Their fuel economy (or lack thereof) is due to the ECU which only engages the closed loop combustion control (oxygen sensor, much better economy) when manifold vacuum is 12" or higher (going downhill) as anything greater than about 45 MPH drops the manifold vacuum to 10" or less. They did not have 'knock sensors' to manage knocking on low octane fuel (you can't hear it over the engine noise) and that knocking grows to preignition and rapid piston demolition on more than short pulls. If one is driving in low to moderate altitude rolling hills, higher octane fuel is needed to prevent possible engine damage. Later versions of this engine may have knock sensors and a better ECU. If they don't, choose wisely. The GM big block 454 V-8 is indestructible--except valve springs failing after 60K or so if operated at certain RPM. That was corrected in mid 90's I think. It is not a huge cost (less than $1000?) to replace all of them preemptively--it can be easily done through the hatch, engine stays in. The difference in fuel costs-- gas vs diesel-- is not enough to justify the much higher price for the diesel pushers. The turbo-charged diesels ARE clean burning and maintain rated horsepower up to 10,000' or so, while non-turbocharged gasoline engines loose 40% of their sea-level power at that altitude. If you are 'going high' , either accept crawling up grades in Ist gear or go turbo-charged diesel.
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