JIMT is right, the #4 (left) as a bent conecting rods so the piston is lower
by 1/4in (it should be equal to #1):
http://www.benplace.com/bjp/100_0158.jpg

On this picture you can see where the rod touch the cylinder (2 places), you
can even see the curve in the rod.

Now, my problem is that i cause that bending!!!!!! this engine was working
(not well) before it enter my shop, the head(#4 location)and piston have no
damage at all!!!! but the cylinder wall, crank (#4) and rod show sign of
wear and are dried up as opposed to the 3 others cylinders, after intensive
research, here is my conclusion:

The #4 piston rings where almost seized due to a faulty head gasket, coolant
was leaking in the cylinder drying this one and slowly seizing the rings,
the result is an bad lubrification in that cylinder causing this one to
overheat and distord the rod, when i started back the engine with a rebuilt
head and full top end compression the rod didn't hold!!!!!!!!!!!!!!!!

What that does tell you, that the rebuilt of a head(S) is a risk for the
rest of the engine, i always tell people that a top end rebuilt is a risk!!!
the low end may not last for ever.....

Gentlemen's
http://www.benplace.com/bjp.htm