Cracked Porsche 968 block - help replace.....
Discussion
I notice you're in Wiltshire, so I'd recommend speaking with Jon Mitchell as I've no doubt he can advise the best way forwards http://www.jmgporsche.co.uk/
2.7 944 8v, 3.0 944S2 16v and 968 blocks are slightly different but can be interchanged but there are a few details you need to pay attention to during the build to ensure everything has the right clearances etc.
968 blocks are obviously superior in several respects as the last evolution of the 104mm bore blocks, but some of the differences such as the piston squirters are still controversial 20 years after they were used in this series of engine..
Hope this helps
Jon Mitchell
968 blocks are obviously superior in several respects as the last evolution of the 104mm bore blocks, but some of the differences such as the piston squirters are still controversial 20 years after they were used in this series of engine..
Hope this helps
Jon Mitchell
It was just another evolution.
Improved windage ports between cylinders in the lower crankcase over the 2.7
Shallower waterjacket to improve coolant flow to the area of the bore actually seeing combustion.
964/993 style piston squirters directed at lower piston face for oil cooling of the pistons.
None of them cost them more money, other than probably 27p per piston squirter x 4 at their cost price, but reduced the chance of warranty claims with a car with improved performance over the previous car using a similar block (S2).
Also due to sand casting of the blocks, every time they made a block they had to make a new sand form for the block, so only minor modifications had to be made to the form/plug used to make the sand castings for the next series of blocks.
Over the years there are many changes to blocks, 1982, 1983, 1985, 1986,1987, 1988, 1989, 1992. On each of these dates the 944 blocks evolved across the range. For example in 1987 both the turbo castings and the non turbo castings changed... In 1988 they had 3 new blocks being cast, each with different casting numbers, in 1989 they still had 3 blocks in current production, but a completely different set of 3 than they did in 1988.. By the time they got around to 1992, they were casting only one block, the 968 16v blocks.
Another example is 1985 and 1986, during 1985 they were already tooling up for the 1985.5 model change which used a different block, a 1985.5 944 turbo block is different to a 1986 block (the 85.5 turbo block is thicker walled), which shows in just six months they chose to use a completely different sand casting form/plug, showing how little of a cost implication there was, especially as the only reason for doing it was to save a tiny amount of weight and a little in material costs.
Improved windage ports between cylinders in the lower crankcase over the 2.7
Shallower waterjacket to improve coolant flow to the area of the bore actually seeing combustion.
964/993 style piston squirters directed at lower piston face for oil cooling of the pistons.
None of them cost them more money, other than probably 27p per piston squirter x 4 at their cost price, but reduced the chance of warranty claims with a car with improved performance over the previous car using a similar block (S2).
Also due to sand casting of the blocks, every time they made a block they had to make a new sand form for the block, so only minor modifications had to be made to the form/plug used to make the sand castings for the next series of blocks.
Over the years there are many changes to blocks, 1982, 1983, 1985, 1986,1987, 1988, 1989, 1992. On each of these dates the 944 blocks evolved across the range. For example in 1987 both the turbo castings and the non turbo castings changed... In 1988 they had 3 new blocks being cast, each with different casting numbers, in 1989 they still had 3 blocks in current production, but a completely different set of 3 than they did in 1988.. By the time they got around to 1992, they were casting only one block, the 968 16v blocks.
Another example is 1985 and 1986, during 1985 they were already tooling up for the 1985.5 model change which used a different block, a 1985.5 944 turbo block is different to a 1986 block (the 85.5 turbo block is thicker walled), which shows in just six months they chose to use a completely different sand casting form/plug, showing how little of a cost implication there was, especially as the only reason for doing it was to save a tiny amount of weight and a little in material costs.
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