Moving along with my rebuild of a '99 2.5L (rebuilding to stock condition, except 0.020" over pistons, at 240K miles due to an unidentified knock). The data sheet that came with the Silv-O-Lite 3243HC pistons that the machine shop got me said to use FSM ring gaps for the 2nd and 3rd rings, but to add 40% to the top ring gap. FSM says 0.009" minimum top ring gap; adding 40% gives 0.0126". That seemed tight so I called UEM / Silv-O-Lite. They gave a totally different answer and recommended 0.025" - 0.027". I then talked to the machine shop and they said I would be fine at 0.020"; if I wanted additional safety margin I could use 0.022". They based this on the rule of thumb of (0.004" of gap / inch of bore) x (3.897") = 0.0156" and multiplying by 1.4 to get 0.0218" and provide the additional clearance Silv-O-Lite wanted.
I'm mentioning this as a heads up for anyone rebuilding a '99 2.5L (or other years with the same top ring gap FSM spec) with Silv-O-Lite hypereutectic pistons.
I am curious if anyone else has run into this issue of 'dueling ring gap specs' with Silv-O-Lite hypereutectic pistons.. It seems like a good way to ruin a new motor if the gap is too tight?
I'm mentioning this as a heads up for anyone rebuilding a '99 2.5L (or other years with the same top ring gap FSM spec) with Silv-O-Lite hypereutectic pistons.
I am curious if anyone else has run into this issue of 'dueling ring gap specs' with Silv-O-Lite hypereutectic pistons.. It seems like a good way to ruin a new motor if the gap is too tight?
