Quote:
Originally Posted by Dcmgt
Does everyone here with DS seal up the engine to maximize vacuum, ie; plug up vents like on the oil breather cap, etc? I believe you're typically supposed to have a small dia vent line from the crankcase running to the DS tank, but otherwise seal it up. My factory race engine has the old Shelby American dry sump setup, however, which I doubt has anywhere near the suction power of modern setups, so have been vacillating on how necessary it is to make sure the crankcase is sealed......with very low vacuum it may be better to vent? |
No, I never ran a sealed motor that saw double duty in a track/street application, but do run all the race-only motors sealed. The main reason we ran the race stuff sealed was for the power advantage of the low tension/friction ring packages and gas-ported pistons. The gas ported stuff runs very thin, low friction rings that only seals on the combustion stroke. On the other three strokes the ring pack is doing very little and relys on DS vacuum to control
oil consumption. We also run rods with EDM holes to
oil the wristpins, special crank seals for vacuum, one-way pop-off valve, and silicone every gasket surface... among other things. On an all-out motor for a racing application there is a definite benefit, but I do not run that set up on the street... I vent.