This is one on my christmas present list:
Gamma Technologies - Engine simulation
I think it is also very pricey software/software package.
Maybe I will try Dynomation. It is only one I can afford. I have old Dynomation version, so I can get cheap upgrade.
Motion Software, Inc. Automotive Engine And Vehicle Simulation Software
Lotus Engine Simulation also looks very interesting. Freeware version simulates only one cylinder, but that is not big deal if it is free.