wtf does closed/open deck omc block mean???

[baja200merk]

wat does closed and open block mean wats the diff?? whats better

[H2OPERF]

Its a term used for how the cylinders are supported in the block. On an open deck the cylinders are not supported at the head end and you can see around the ends of the cylinders where the water flows to cool it all the way down to the top of the port bosses.Merc v6 and omc crossflow blocks would also be considered open decks. On a closed deck the out side (water jacket) ends of the cylinders are not exposed and are closed in by the block casting giving better support for the end of the cylinder,basically the Same as a common car motor block.The closed deck blocks have less cylinder distortion due to heat with the extra support and are also less suseptable to corrosion at the ends of the cylindrs in the water jacket.kinda hard to explain on paper but hope you got the idea. Dave

[Raceman]

"what does closed and open block mean wats the diff??"

Closed means the way it should be. Open block means that T Rex's been runnin' it.

[baja200merk]

thanks guys