Block comparisions
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Block comparisions
Hi to all, is there any difference between a GTS block and a s4 or gt block??? I'm betting there is not. I thought the differences were the cams and the rods and the pistons. There maybe other small differences but I'm talking about inter-changeability. I believe I could put a GTS crank in a s4 block. Am I right or wrong? Thanks. 
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From: Ft. Lauderdale FLORIDA
I've pondered this before. My pondering has told me that the original series, 4.5 and 4.7 liter blocks are NOT boreable to 6.5 liters as per Devek fame....
The later 5.0 and 5.4 liter blocks are. You know, I've called both Californian 928 shops and asked why...and haven't gotten an answer~
WELL duh! The obvious conclusion is that the folks in Stuttgart put more meat in the cylinders that they cast for the later engines, so that they can be bored out more later.
Conclusions are one thing; Questions are another.
-Why won't the western Pacific shops say this~?
?
the N~
The later 5.0 and 5.4 liter blocks are. You know, I've called both Californian 928 shops and asked why...and haven't gotten an answer~
WELL duh! The obvious conclusion is that the folks in Stuttgart put more meat in the cylinders that they cast for the later engines, so that they can be bored out more later.
Conclusions are one thing; Questions are another.
-Why won't the western Pacific shops say this~?
?
the N~
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From: Ft. Lauderdale FLORIDA
I called them on a normal working day in Orlando. They are three hours behind me, which works out perfect since I usuallly stay up till 5-6 AM when I'm home. I fly freight 747's primarily at night, so the late hours work best for me.
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From: Anaheim California
the 95 mm and 97 mm bore USUALLY can be bored to 100 mm ...five liter size stroke it and it can make a 6 liter . The 100 mm bore USUALLY goes 104.5 which is the 968 piston size . A stroked 104 is about 6.5 liters . Some core shift occurs in the molding casting of the blocks which can make the cylinders thicker on one side or the other . The unaswered question is how thin can the cylinder walls be before they split ?? But yes , Porsche used a different mold for the 100 mm block .
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From: No Turbo, No SC
The unaswered question is how thin can the cylinder walls be before they split ??
Obviously, I am hoping it has never happened
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max the cylinder walls are approx. 7 mm thick. Depending on how much you bore it results in the remaining wall thickness, to state the obvious. When boring these blocks care needs to be taken so that the block doesn't get to hot. It may result in a out of true bore, also the thinner the walls the less area to seal the headgasket. Personally I would love to see a replacement liner made that had a nicasil type coating. Then we would have no problems what so ever.
I have contacted a company that makes these, but they are quite expensive. These guys also do the F1 motors so they don't really understand budgets of ordinary folk. In Australia I can get the nicasil coating done for $200 AUD per cylinder. Somebody would just have to get some barrels made and then we would be right. Maybe those sleeves could be made for about $100 AUD each so that would be $2400 AUD and that's about $1600 USD plus the cost of maching the block to fit the sleeves.
Perhaps ask Marc at Devek he has the most experience is this regard. There may not be a very big problem at all.
I have contacted a company that makes these, but they are quite expensive. These guys also do the F1 motors so they don't really understand budgets of ordinary folk. In Australia I can get the nicasil coating done for $200 AUD per cylinder. Somebody would just have to get some barrels made and then we would be right. Maybe those sleeves could be made for about $100 AUD each so that would be $2400 AUD and that's about $1600 USD plus the cost of maching the block to fit the sleeves.
Perhaps ask Marc at Devek he has the most experience is this regard. There may not be a very big problem at all.
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From: Anaheim California
When Mark Anderson first proposed boring to 104 mm nearly everyone told him it would not work the cylinders would split 6 liters was as big as you could make one ...........so naturally he bored one to 104.5 starting with a 100 mm 5 liter block . Thus far there has not been any splitting/failure of the cylinder walls or problems with headgasket sealing with any of the engines which we have been involved . We recently had one bored and nicasiled to run aftermarket pistons which greatly expands the choice and size of pistons available but that engine needs hours of abuse before we know it will work .