Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   Engine Performance (https://www.miataturbo.net/engine-performance-56/)
-   -   Cracked piston? (https://www.miataturbo.net/engine-performance-56/cracked-piston-110616/)

DaveGage Aug 22, 2025 06:16 PM

Cracked piston?
 
A friend took apart a motor that was smoking pretty severely tonight. The #2 piston (factory 99 piston) was cracked across the center of it inline with the wrist pin. The rings appear to be in great shape, no signs of detonation, rod bearings look good and even the cylinder walls are fine. This happened on decel while on an offramp while exiting the expressway. Any thoughts on what might have caused this?

thebeerbaron Aug 22, 2025 07:44 PM

Way more information needed.

Is this a stock powertrain, or is there a turbo, aftermarket ECU, etc?

Was the engine smoking before it went kaboom?

Is the piston cracked all the way through? It’s odd that you say the rings look perfect. I can’t imagine how that’s true if the piston is now in two pieces.

What kind of maintenance history do you know about the car?


All times are GMT -4. The time now is 02:20 AM.


© 2026 MH Sub I, LLC dba Internet Brands