| here it is directly addressed to you: Q: Why it is that when all I did was remove the axial slop from the VTC mechanism, it stopped rattling? A: You have to sum ALL of your variables, you did not only remove "axial slop," in disassembling the sprockets you have also: 1a) drained the oil (sounds redundant but read on). The oil cavity in the sprockets is a closed system in that oil does not drain from them when the engine is off. 1b) by allowing air into the cavity, you are displacing a volume of uncompressible oil with a compressible gas. In my opinion this air takes some time to bleed out of the sprockets and while it is in there, it serves to dampen the effect of residual oil pressure by compressing and contracting. This is the exact same scenario that happens when someone replaces their front VTC springs and the sprockets quiet down for awhile. Not only were the springs changed, but air was also introduced into the system. 2) if you did not mark and reassemble the pistons onto the camshaft helices and then into the main sprockets in the exact same original locations, then you have changed the wear patterns affecting friction. Eventually all the parts will seat themselves together, reducing friction, but this will take some amount of running time. 3) you have admittedly installed them completely void of any lubrication whatsoever, this most certainly has affected friction. Q: Why is it that although I used the original internal spring, which has 180K miles on it, that the the modified VTCs do not rattle? A: Please see above, until the air is out of the system, you cannot do a direct comparison. It doesn't matter how many miles are on the springs, they do not wear out, they are not stressed high enough to ever wear out under normal operating conditions. They are however, marginal with respect to their load capacity in being able to do the job they are supposed to, even with stock valve springs. Add stronger valve springs and its shortcomings will be revealed... as soon as the air has been bled from the system. Because, you must remove the sprockets to replace the valve springs this will put anyone back up to my answer 1b, everytime, and this is why it takes awhile before the sprockets begin to make noise. Give it some time, you will find the noise will come back and my guess is that it will happen before you reach 5K miles. I don't know of any practical way that you could install the sprockets and bleed all of the air out of them to be able to say that you have addressed and negated this undeniable variable.
|
