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-   -   99-00 head + 11:1 c/r = Interference Engine??? (https://www.miataturbo.net/engine-performance-56/99-00-head-11-1-c-r-%3D-interference-engine-106110/)

NASSEX Nov 29, 2021 09:50 PM

99-00 head + 11:1 c/r = Interference Engine???
 
main question: Will this build into an interference engine?
Build specs summary:
99-00 cylinder head + Stock valves + stock MLS head gasket + stock 99-00 camshafts.I'm not sure yet whether I'm going to go with super tech 11:1 compression pistons yet or have the head milled to achieve something close to 11:1.

But assuming that I go with either the 11:1 ST pistons or something lower (and have the head milled to compensate)

Also I want to get a Flyinmiata adjustable cam gear for the intake cam. Maybe the exhaust also even though I know that doesn't do much unless it's turbocharged.

More details although probably less useful to you guys:
Ultimately the goal is to get somewhere close to 11:1 c/r.
The only reason why I would attempt to shave the head instead of buying pistons is due to my own understanding that higher compression pistons will likely weigh more. The same concept applies to oversized pistons. The wider they are, the more metal there is hense they should weigh more.
Because I plan to put some attention to cutting down on the rotating assembly mass. For improving response and high RPM.

curly Nov 29, 2021 10:21 PM

Probably. But Miata timing belts don’t typically snap if they’ve been replaced in the last few years, and you have solid lifters. Don’t shift like a moron and you won’t have any issues.

Arca_ex Nov 30, 2021 02:50 AM

Not sure why you're all that concerned with it being interference or not when you're going through the trouble of building the engine. Don't money shift and change the timing belt a little more often and there's not much to worry about.

On the other hand, why are you so determined to run a high compression setup with a turbo? You'll be restricted to race gas or e85 pretty much all the time for what amounts to a little bit of off boost drivability and spool when you could just get a better turbo.


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