Sleeved 951 motors
05-01-2007, 03:31 PM
#46
Burning Brakes
Join Date: Jan 2007
Location: Austin TX
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BMW uses something similar to Alusil in their aluminum V8's, and there is a corrosion issue relating to the fuel that is used here in the US. Apparently it has more sulfur than similar european fuels? Ill make a jump and say that if the metalurgy of Porsche's design and BMW's design are similar, then the Porsche would also have suffered these issues due to poor American fuel quality. I'm biased, all the engines I have really messed with are iron block or sleeved aluminum block, and they've really worked. They weren't 944 motors though.
05-01-2007, 08:00 PM
#47
Originally Posted by pjburges
BMW uses something similar to Alusil in their aluminum V8's, and there is a corrosion issue relating to the fuel that is used here in the US. Apparently it has more sulfur than similar european fuels? Ill make a jump and say that if the metalurgy of Porsche's design and BMW's design are similar, then the Porsche would also have suffered these issues due to poor American fuel quality. I'm biased, all the engines I have really messed with are iron block or sleeved aluminum block, and they've really worked. They weren't 944 motors though.
05-01-2007, 09:50 PM
#48
Rennlist Member
that's funny you mention that about the V12 BMW's. My 750il just got totalled Tuesday. 234,014 miles. Motor has never been apart. Ever. I'm now going to find someone who wants to part it out for me and split the profits of the sales. Sucks.
My 3 liter is Nikasil as well as David Raines (Powerhaus) motor and he has over 90,000 miles on his. Drives it to the track etc. I believe both, done correctly, should last. About sums it up with what others are saying. Built it right and it'll last.
My 3 liter is Nikasil as well as David Raines (Powerhaus) motor and he has over 90,000 miles on his. Drives it to the track etc. I believe both, done correctly, should last. About sums it up with what others are saying. Built it right and it'll last.
05-01-2007, 11:17 PM
#50
Drifting
The biggest reason that I go to sleeves is ring selection. With the factory Mahle pistons you are suck with the Goetz rings. The difference is cylinder sealing between the OE stuff and the aftermarket rings I have been using is night and day. This in a N/A motor is huge. I regularly get 225rwhp on a Superflow chassis dyno with 968's that run F class in PCA.
I have used JE and CP pistons with dry sleeves in both N/A and turbocharged engines without a failure to date. All but one car are race cars. All have slight initial piston slap that is gone in less than a minute. Turbo engines benefit from better cylinder sealing in many ways as well including not getting any oil into the intake. Another big gain is cylinder stability. How round do you think an Alusil cylinder is at 6k rpm with 1.3bar added to it?
I have used JE and CP pistons with dry sleeves in both N/A and turbocharged engines without a failure to date. All but one car are race cars. All have slight initial piston slap that is gone in less than a minute. Turbo engines benefit from better cylinder sealing in many ways as well including not getting any oil into the intake. Another big gain is cylinder stability. How round do you think an Alusil cylinder is at 6k rpm with 1.3bar added to it?
