interesting info on alusil motors
07-07-2005, 08:01 PM
#1
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interesting info on alusil motors
found this while perusing a bmw board. interesting that alusil liners can be had.
http://www.bmwseven.com/Alum_engine.pdf
http://www.bmwseven.com/Alum_engine.pdf
07-07-2005, 08:45 PM
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Good find!
It's interesting that it says "reduce to block height" for the 100mm 928 liners, but not for the 944 liners. They are the same part number. I thought 944s had a lower deck height which is why 951 pistons are 4mm too short to run in a 928 engine.
It's interesting that it says "reduce to block height" for the 100mm 928 liners, but not for the 944 liners. They are the same part number. I thought 944s had a lower deck height which is why 951 pistons are 4mm too short to run in a 928 engine.
07-07-2005, 08:46 PM
#3
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Very Very Interesting
Originally Posted by shaaark89
found this while perusing a bmw board. interesting that alusil liners can be had.
http://www.bmwseven.com/Alum_engine.pdf
http://www.bmwseven.com/Alum_engine.pdf
to say the least!
07-08-2005, 12:19 AM
#4
Alum Liners
Does anyone know if they take special request sizes other than the bores
they list on their site. If you had a stroker crank and a 108.5 mm bore would
that make a 7.0 ltr mtr ?
Joe.
they list on their site. If you had a stroker crank and a 108.5 mm bore would
that make a 7.0 ltr mtr ?
Joe.
07-08-2005, 03:41 AM
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Those liners have only about 2.5mm wall thickness and can not support themselves at all. This means there have to be several mm's of additional material in the block around them. If average 100mm bore 928 engine has cylinder tower outside diameter in about 116mm region it means there is very little extra left in 100mm. If 6.35mm wall thickness is needed for original block walls to hold maybe about 4.5mm is enough for sleeved block?
116mm (tower outside d) - 2 x 4.5mm (remaining support) - 2 x 2.5mm (liner walls) = 102mm max bore
They do have 110mm outside diameter raw casting available that can be machined to desired shape within it's limits. It can maybe support up to about 103mm bore diameter. With more block material to begin with sleeve will become limiting factor. Unless top flange is left of completely, then maybe 105-6mm. These are really meant for fixing stock sized block walls.
Even with original healthy 116mm block, going beyond 104mm requires totally new cylinder towers made with many times thicker walls that can support themselves. Some 928 blocks have more than 116mm. 108.5mm bore would require over 121mm outside diameter. Best candidate for large piston is 968 block and it could maybe take few mm more than 104mm. Too bad factory didn't do any 928 blocks with adjoining towers join together.
116mm (tower outside d) - 2 x 4.5mm (remaining support) - 2 x 2.5mm (liner walls) = 102mm max bore
They do have 110mm outside diameter raw casting available that can be machined to desired shape within it's limits. It can maybe support up to about 103mm bore diameter. With more block material to begin with sleeve will become limiting factor. Unless top flange is left of completely, then maybe 105-6mm. These are really meant for fixing stock sized block walls.
Even with original healthy 116mm block, going beyond 104mm requires totally new cylinder towers made with many times thicker walls that can support themselves. Some 928 blocks have more than 116mm. 108.5mm bore would require over 121mm outside diameter. Best candidate for large piston is 968 block and it could maybe take few mm more than 104mm. Too bad factory didn't do any 928 blocks with adjoining towers join together.
Thanks!
