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October 26, 2005
Oiling System Tests
My oiling issues first appeared with this new engine. The oil pressure would drop under sustained cornering (big bend at Limerock, the oval at Pocono, etc...). Added a 3 qt Accusump, but that didn't help much.
Oiling system is a wet sump, Melling 155HV
blueprinted pump (Canton), fed through -12's to a CM filter, through the cooler, and into the front of the block (Dart LittleM). All galleys were fed in parallel. I removed the engine, verified pickup clearance at about 3/8", and blocked off the front of the lifter galleys so the mains are fed first. Lifter galleys then get fed from the rear of the block through .1875 orifice plugs.
For my tests, I removed the intake manifold, and had my oil pump primer driven by my drill press head spinning at 590 rpm (1180 engine rpm effectively). There is a lab grade 5" pressure gauge at the oil inlet at the front of the block, and my Autometer gauge at the rear of the block (reads 4 psi low to the same source, but all numbers are corrected below).
Tests using 20W50 oil at 60 degrees air temp.
Test1 - Block off front lifter galleys, no plugs/orifices in rear Front gauge at 30 psi, and rear at 27 psi.
Test2 - Block off lifter galleys completely. Front gauge at 63 psi, rear also at 63.
Test3 - Feed lifters from rear with .1875" orifice plugs. 35 psi front, 27 psi rear
Test4 - Block off passenger lifter galley completely. Drivers has .1875 orifice. Pressure back at 60 psi.
Just realized the oil pump primer may be blocking the oil galley orifice, so I measured w/ the mic, and there is plenty of room in the groove. For kicks - I raised the primer slightly, and pressure jumped to 55 psi. Raised it again, and up to 60 psi. I think it's time to get the old dist, and turn that into a primer. Anyone know what kind of oil flow & pressure hydraulic roller lifters need? The "techs" at CompCams tell me not to restrict it, but can't tell me what sort of flow I need.
I then took an old distributor, bolted down the intake manifold, and ran the pressure tests - 63 up front and rear. I guess the generic $20 primer gave funny data. Anyways, I'll leave the orifices in place for now, and see if the lifters tick. I also considered making an engine run stand that I can rotate to 63 degrees to simulate 2g cornering (not that I come that close), and seeing if the oiling issue is drainback from the heads under hard cornering.
Tangent(tilt degrees) = Simulated G's
Tan(63.4)=2 G's
Posted by Z28tt at October 26, 2005 7:50 AM