mk e wrote:
It didn't end in consensus.
They (totalseal) say the gapless top makes more hp and pulls more vacuum which implies more pressure/hp but in talking to them I mostly they only talked about possible oil control issues due to the vacuum on street engine that run low throttle a lot of the time...but Will run it an was happy althogh I think he s doing a rebuild now that started with oil control issues?????
My engine's problem was bore finish... actually twice now. Northstars are difficult to hone, apparently. Centrifugally cast grey iron liners that are subsequently cast in place in the block must be harder than most. I've found a company in North Jersey that is a production remanufacturer handling Northstars. They have a brand new Rottler, diamon stones, profilometers, etc. so they should be able to get it right for me. I'm close to having everything ready to haul the block up for them to work on.
When I assembled my engine, I installed the gapless rings with the main ring gap and rail gap 180 out. They were not still in that orientation when I removed them as I recently disassembled my engine. Having seen that, one has to wonder if the gapless rails rotate until the gaps of both parts align. If they move relative to each other in the first place, there's nothing stopping them from moving that far. The big question is: Once the gaps *DO* align, do the rails continue to rotate so as to make the ring gapless again? I'd *LOVE* to see data on that.
That may also be one reason OEMs don't use them... potentially inconsistent performance over the life of the engine. Getting power from modern DI/Turbo/VVT engines is EASY. Staying emissions legal is what's hard. Even if gapless rings can increase oil change intervals, OEMs are already pushing those intervals so far that the timing can actually result in detriment to the engine. They can do that because modern engine technology is SO GOOD that they have engine longevity out the wazoo despite slightly detrimental emissions-related policies.
Gapless rings are also significantly more expensive to make and require more touch labor to install. The OEMs haven't reached the point at which they're ready to pay the extra for the gain.