Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec not your normal 3.0 post

a friend of mine was misunderstanding the 3.0 swap and came up with the question... what happens to a 2.5 with the 3.0 heads? does it raise/lower compression? what effect do the larger valves have? IS THIS EVEN POSSIBLE?i would do the math but i don't have the bore of the 2.5 or the volume of the combustion chamber on the 3.0 so figuing out the compression ratio is out of the question unless i can get this data. Anyone got an idea of what might happen here? And how would the 3.0 heads oval ports work with the 2.5 intake manifolds? I don't think im beating a dead horse with this question, Just trying to find out some possiblities

Assuming all that the cylinder liner is still covered by the head, I would expect that you would just have the disadvantage of having part of the force from the explosion directed down on the edge of the block as well as the overheating effect this would have on the edge of the block at the top. This overheating could cause the metal to be 'burnt' away much as a burnt valve does and would result in a damaged cylinder. It seems that wouldn't be a good option when you can get a 2.5l head and machine it larger for lower compression if you so desired. You could easily lower the 2.5L compression to 9:1 without any risk of damage with some careful machining. This would be exactly what I did with my 2.5L heads before I mounted them onto the 3L block. This would be ideal for the turbo guys if they really wanted to lower compression cheaply.

warmonger