Thinking about 104mm bores
#48
Rennlist Member
I always thought I would paint them rainbow colours so the net effect in there would be a lighter, white spectrum mix resulting in faster piston speed and lighter load. I would recommend against running two tolerance groups in every other cylinder. In order to stay balanced, you may want to saw each piston in half and weld them together
#49
Former Vendor
Here's an idea, Mike:
Rob Edwards has a pretty "hurt" GTS crank that isn't ever going to be normal again. It has one journal worn to about .080 undersize.
Since you are going to need to "create" a custom rod for this engine, anyway....
Give Rob a few bucks for this crank and have it machined down to a chevy rod size. Pick up a "little bit" of "economy" stroke, for this project.
This would be really unique and interesting!
Rob Edwards has a pretty "hurt" GTS crank that isn't ever going to be normal again. It has one journal worn to about .080 undersize.
Since you are going to need to "create" a custom rod for this engine, anyway....
Give Rob a few bucks for this crank and have it machined down to a chevy rod size. Pick up a "little bit" of "economy" stroke, for this project.
This would be really unique and interesting!
#50
Former Vendor
BTW
Used pistons should always be custom fit to bores, anyway. I've seen used "group 2" pistons that measure the same as used "group 0" pistons.
.01mm or .02mm is not very big....I'm not sure many people can bore and hone an Alusil block this close anyway!
Used pistons should always be custom fit to bores, anyway. I've seen used "group 2" pistons that measure the same as used "group 0" pistons.
.01mm or .02mm is not very big....I'm not sure many people can bore and hone an Alusil block this close anyway!
#52
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#53
I have -85 S3 and cylinder tubes are min 115,5mm measured at top, don't seem to be very thick walled block.
I got very cheap 4,5L block and 4,7L crank, could I wet sleeve it with MID steel tubes and stroke the crank with Carrillo Nascar 6" rods which have 48mm big end bearings? I need custom pistons with 22mm pin and rods centered at top but it's much easier to get pistons for steel bores than alusil and maybe also easier to get some company to wet sleeve the block than get a good bore to alusil at my country. Rods are very light and have bore for oiling to the piston pin ( DLC coated).
I got very cheap 4,5L block and 4,7L crank, could I wet sleeve it with MID steel tubes and stroke the crank with Carrillo Nascar 6" rods which have 48mm big end bearings? I need custom pistons with 22mm pin and rods centered at top but it's much easier to get pistons for steel bores than alusil and maybe also easier to get some company to wet sleeve the block than get a good bore to alusil at my country. Rods are very light and have bore for oiling to the piston pin ( DLC coated).
#54
Nordschleife Master
Thread Starter
I have -85 S3 and cylinder tubes are min 115,5mm measured at top, don't seem to be very thick walled block.
I got very cheap 4,5L block and 4,7L crank, could I wet sleeve it with MID steel tubes and stroke the crank with Carrillo Nascar 6" rods which have 48mm big end bearings? I need custom pistons with 22mm pin and rods centered at top but it's much easier to get pistons for steel bores than alusil and maybe also easier to get some company to wet sleeve the block than get a good bore to alusil at my country. Rods are very light and have bore for oiling to the piston pin ( DLC coated).
I got very cheap 4,5L block and 4,7L crank, could I wet sleeve it with MID steel tubes and stroke the crank with Carrillo Nascar 6" rods which have 48mm big end bearings? I need custom pistons with 22mm pin and rods centered at top but it's much easier to get pistons for steel bores than alusil and maybe also easier to get some company to wet sleeve the block than get a good bore to alusil at my country. Rods are very light and have bore for oiling to the piston pin ( DLC coated).
If you have the budget to try some things, then toss them in the trash if it doesn't work out and start over, I say give it a shot and see what happens. Otherwise I would keep to a narrow path of what others have done in the past and is known to work.
What country are you in?
What are your goals for this motor?
#55
"What are your goals for this motor?"
More cm3, about 250g lighter rods, steel cylinders = almost "limitless" choices of pistons.
I would prefer supercharger but impossible to register on street.
I have learned today that only one company bores and hones alusil in Finland about 210$ per hole.
Many companys make wet and dry sleeves, 928 block can't bee very different to work. I'm thinking to fill bottoms of water space with epoxy.
More cm3, about 250g lighter rods, steel cylinders = almost "limitless" choices of pistons.
I would prefer supercharger but impossible to register on street.
I have learned today that only one company bores and hones alusil in Finland about 210$ per hole.
Many companys make wet and dry sleeves, 928 block can't bee very different to work. I'm thinking to fill bottoms of water space with epoxy.
#56
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Many companys make wet and dry sleeves, 928 block can't bee very different to work. I'm thinking to fill bottoms of water space with epoxy.
I tried eboxy to make deck support on top of water jacket. No use what so ever in strenghtening towers. We are looking into having support rings made locally from jointless steel pipe. Some dry liners have caused cracks into remaining cylinder tower destroying block. Thus idea to try to prevent this by adding another support around Alusil.
Check http://www.9xxfin.com for local Porsche discussions.
#58
Nordschleife Master
Thread Starter
#59
Almost Deleted
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Rennlist Member
i'm in the process of researching a 'fun' 16v project.
Has anyone used the OEM 104mm 944s/968 pistons [as opposed to the J&E-forged variants]? I was checking Pelican and they list for $370 for a set of 4.
Has anyone used the OEM 104mm 944s/968 pistons [as opposed to the J&E-forged variants]? I was checking Pelican and they list for $370 for a set of 4.
#60
Nordschleife Master
Thread Starter
I've bought (4) 968 pistons for my project motor, still looking for another 4.