ZR-1 Net Registry Forums - View Single Post - How much boring inside the cylinder liners?

VetteVet · 02-11-2013

Daniel,

Outboards use aluminum blocks with steel sleeves for the production stuff. The high performance/racing stuff is all aluminum/nikasil.

I would imagine that the heat cycles with the dissimilar metals would contribute to head gasket fatigue/failure. Obviously not rapid, as proven by the cast iron sleeve motors that are out there, but the dissimilar thermal expansion coefficients have to take some kind of toll in head gasket durability. Doesn't Cometic have a gasket available for our motors? If so, that's what I would consider if I did a big-bore motor.

The bottom line is that as BMEP increases(resulting in higher thermal and mechanical loading), the dissimilar metals become more of an issue.

Jep

02-11-2013	#7
VetteVet Join Date: Jan 2009 Location: Mandeville, LA Posts: 340	Re: How much boring inside the cylinder liners? Daniel, Outboards use aluminum blocks with steel sleeves for the production stuff. The high performance/racing stuff is all aluminum/nikasil. I would imagine that the heat cycles with the dissimilar metals would contribute to head gasket fatigue/failure. Obviously not rapid, as proven by the cast iron sleeve motors that are out there, but the dissimilar thermal expansion coefficients have to take some kind of toll in head gasket durability. Doesn't Cometic have a gasket available for our motors? If so, that's what I would consider if I did a big-bore motor. The bottom line is that as BMEP increases(resulting in higher thermal and mechanical loading), the dissimilar metals become more of an issue. Jep