there IS actually a water channel between the two middle bores.
.. its effectively a steam ventilation channel... to prevent a buildup of boiling/steam.Both gen II and gen III blocks have it
Now.
. I have cracked a lot of blocks.. and it may surprise you all to know that Ive cracked both the gen II and gen III block in exactly the above fashion, picture perfect.Whats more.
. Ive cracked it on both cyl 2 and cyl 3! Its not restricted to one thinner wall.And on top of what, Ive had a block sleeved in both
#2 and #3 to remove casting defects etc with high quality iron sleeves.. .and I have cracked THEM too.This has been a major issue for me over the past few years.
. so Ive done a lot of research into why it happens. My current knowledge suggests that it is steam related... because the ventilation holes between 2 & 3 arent effective enough when cylinder wall temps rise too far. You will notice that on all 3sgte blocks, the vents between 2 and 3 are actually different to that of between 1/2 and 3/4. This was revised and improved on later model 5SFE blocks.. but Im yet to put one to the test.My current motor has been free of cracking.
. the solution? 1.3 bar radiator cap... to try and raise the boiling threshold.. and RICH tuning to keep cylinder wall temps down. On top of that, the stock manifold has gone.. removing the tendency to favour #2 and #3.. making them run leaner and hotterI can go into more detail about any of that if you wish
