Is timing in reference to the rotor flank crossing the edge of the port, or when the side seal crosses? It seems that the side clearance of the rotor could provide a little bit of a flow passage, but maybe not enough to matter.



Thanks,

JW

For side ports the edge of the rotor. For peripheral ports the apex seal.



Lynn E. Hanover

Thanks for the reply Lynn. Before leaving the subject, how much can the corner seal be allowed to run over the edge of a side port? My guess is 1/3 of the diameter would be ok but half a diameter would make me nervous. If it is a corner seal with rubber insert, it seems like none of it should go over the edge. What is the standard practice out there?



Thanks

So long as the corner seal does not fall into the port opening, it matters not. The question should be:



Can I drop the leading end of the side seal into the port?



And that answer is no you cannot. If you move the open line that far, leave out the rubber plugs, or better yet use the early solid corner seals.



So the leading end must stay on the iron, and the closing line must be modified to bring the trailing end back onto the iron from inside to outside, to avoid rounding the corner off of the seal end, or, breaking the seal. At the bottom of the port make a bit of a notch so that should the engine be turned over backwards, you will not snap the end off the seal. Look at:



https://www.nopistons.com/forums/hap...re-t75286.html



Lynn E. Hanover