Hi, I posted this in the technical area yesterday, figured it'd be better here... Does anyone know the original dimension for the 308 engine block deck height? There is no special for it in the factory service manual. Of course, the mechanically minimum deck height can be determined by adding stroke, rod length, wrist pin to piston crown and quench dimensions, but the machinist is curious how much deck height the blocks have originally. It could have been decked somewhere in the past. Liner protrusion will be set following the deck cleanup. Thanks!
Deck height is a common term in the engine machining business ... decks get "skimmed" up to the point where you can't skim them any more because you mess up other things. But in a en engine with liners, this term my not be relevant as your liner sets the height of the cyl heads and skimming is not a valid concept unless you shorten the liners as well...
The liners of a 2v engine protrude .002. The non-domed/flat area of stock pistons sit .054 below the top of the liner. The quench of these motors was quite horrid from the factory, but that was not anything they knew about back then. The shelf stock high compression and stock compression pistons Superformance stocks, which I believe are made by JE, are actually quite good in that the flat portion sits about even, + or - .003 of the deck above or below. This helps the quench quite a bit. That all said, discussing quench in a 2v hemispherical chamber is sort of moot as any round domed piston design is not optimal anyway. These things are what they are so there is no need to reinvent the wheel when digging into them other than handling the basics to get it running right.
