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Caption translates to: "By cutting this part, it is possible to create a relief to prevent warpage without changing the size of the apex seal assembly."
The apex seal on the 13B engine was changed to a two-piece, and there were rumors of heat problems. Even a stock 2-piece engine can be used without any problems if it has a stock engine and a stock turbine with a boost-up specification (approximately 330ps). However, in the case of circuit use such as turbine replacement vehicles, the problem is "warping" of the seal due to heat. Compared to a 3-piece structure consisting of 3 parts, a 2-piece structure changes the coefficient of thermal expansion. There is also a method of processing normal 2 pieces into 3 pieces, but there is also a problem of accuracy when cutting. The normal 2-piece apex seal is made to very high precision. There are almost no individual errors. Therefore, by cutting a part of the area within the inner apex seal spring, it is possible to provide a "relief" without changing the size of the apex seal assembly.
Apex seals dont usually break in the middle from detonation, so I wouldnt be worried about this weakening the seal in a turbo car.
Heat from friction is an issue with high rpm NA motors as well, but the solution is carbon/aluminum or ceramic seals.
This will make putting in the apex seal springs the Mazda way more difficult, but one can load the springs in the seal and push it all in the slot as a unit.
okay, so i get that they are saying the 3-piece seals are better when racing (or otherwise inflicting higher thermal loads for extended periods), and i think i even get why they're saying that. however, the part that i do not get is how cutting this relief works to mitigate it.
I am thinking that the working edge gets a lot hotter, so it tries to expand and bow the center of the seal out. if the middle is relieved, there is less temperature difference between the two long surfaces so less warping.
At least, that is me hammering a theory to fit the why.
I am thinking that the working edge gets a lot hotter, so it tries to expand and bow the center of the seal out. if the middle is relieved, there is less temperature difference between the two long surfaces so less warping.
At least, that is me hammering a theory to fit the why.
I am thinking that the working edge gets a lot hotter, so it tries to expand and bow the center of the seal out. if the middle is relieved, there is less temperature difference between the two long surfaces so less warping.
At least, that is me hammering a theory to fit the why.
so ... something along the lines of the center of the seal sort of caves inward (toward the spring) due to several factors, with heat saturation being one of them, but cutting the relief forces the heat elsewhere in the seal? is that close to what you're saying or am i way off?
so ... something along the lines of the center of the seal sort of caves inward (toward the spring) due to several factors, with heat saturation being one of them, but cutting the relief forces the heat elsewhere in the seal? is that close to what you're saying or am i way off?
other way, tip gets hotter than the bit deep in the groove, grows out (longways expansion, like welding one side if a beam) and wears more on housing and over spark and exhaust ports over time. The thinner the section the less strain and temp difference edge to edge. Explains why a certain style of aftermarket 3 piece seal works.
02-26-23, 10:26 AM
