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Q: Cliff & Joy McCalister wrote:I own a 1970 FJ55. I am planning on re-arching my springs and adding new busings all around. All the magazines seem to push poly type busings but the spring guy I talked to recomended rubber bushings because the others crack in the cold weather. I live in Colorado. What is your opinion. A: I don't usually see winter temperatures much below -30F in my area. But I have spent a couple of winters in spots where we saw it as low as -50F every once in a while. I've got a couple of friends who travel the trails with me, and live a bit further north. They deal with -60F on a temporay, but reoccurring and regular basis every winter. So far I have not experience any problems with ploy bushing due to cracking in cold weather. I have not heard it mentioned by the folks slight north of me either. The biggest arguement I am aware of against the polyurathane bushings is that they are usually much harder than the rubber ones. This will produce a firmer rid, and a slightly tighter/quicker steering, but it will reduce articulation by a small amount. The original factory type rubber bushings are more expensive as far as I have been able to find. Personally I use the poly units, and have had no complaints. Q: Steve Laird Wrote: I have a 95' LC with a Borla exhaust. Man-a-fre has come out with their own headers. How do you feel about the depenability factor of putting on headers? I know their first prototype was held back due to the dash light coming on. Man-a-fre claimed the O2 sensor was getting too much heat. They have since "jet coated" these and state the problems are gone. Could you explain why the O2 sensor comes into play and the pros and cons of headers. As you can tell, I am unsure of doing this done as I have heard of warping, bolts needing re-tightening, noise, and higher engine temps. A: A well built tubular header does not have to have any dependability considerations. That said, most of them available for the various Cruisers do have such shortcomings. Part of this stems from the stout and fool proof nature of the rig itself. Any dependability problems really stand out. To take it from the top, in the earlier rigs, a tubular exhaust header will increase performance, over the fairly restrictive factory manifold. In your model however, the exxhuast design is much improved, and not nearly the handicap that it is in the older Cruisers. The factory unit(s) will last for the life of the engine, and warping/cracking will not be a concern. If you install an aftermarket header of tubular steel construction, you will probably notice more engine noise (due to the thin wall construction, and lower mass of the header).Yyou will see a slightly higher underhood temperatures due to the increased radiation from the new header. There is a higher possibility of warpage (again due to the lighter construction), and cracking (from flex and vibration) and rust through as well. On most headers, sealing at the head is more problematic than with the heavier factory manifolds. Bolts loosening doesn't seem to more of a problem with headers. It is something that has to be watched for anytime the exhaust manifold is removed and replaced. The less restrictive headers (even if only marginally so) will result in lower engine temps, as they allow the hot gases to exit quicker, and allow them to cool quicker. The can result in a need to richen the mixture slightly, as they can allow more complete combustion of the fuel air mixture. With the complex computer control of the late model engines, this is most likely allowed for automatically. As to the O2 sensor question, I am not really sure. I would have to spend more time with the 80 series rigs than I do, and take a look at the headers themselves. A couple of things come to mind. It might be due to the cooler gasses that are delivered to the catalyst, not combusting as effectively when they get there. It may be due to lower temp gases reaching the sensor. Threre is no reason to think that it isn't due to it getting too much heat as they report. The catalyst has a specific heat range that it is designed to work within, and variance is going to affect it's effeciency. When all is said and done, from a long term maintenance point of view, combined with the increased performance consideration, as well as the cost of the purchase and installation, I personally would spend my money elsewhere for more gain. If we were discussing this installation on an older f or 2F engine, that would be a different situation, but the late model engines are much more refined, and the gains will be much less significant. I probably won't make many friends at Man-A-fre with this position ;( Send your questions to Mark at cruiser@rockcrawler.com |
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